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CLASSIFICATION, VEGETATION-ENVIRONMENT RELATIONSHIPS,
AND DISTRIBUTION OF PLANT COMMUNITIES ON
SOUTHEAST FARALLON ISLAND, CALIFORNIA
A Thesis submitted to the faculty of San Francisco State University
In partial fulfillment of the requirements for
the Degree
Master of Arts
In
Geography: Resource Management and Environmental Planning
by
Jamie Lee Hawk
San Francisco, California
May 2015
A 63G
2-01$
Copyright by
Jamie Lee Hawk
2015
CERTIFICATION OF APPROVAL
I certify that I have read Classification, Vegetation-Environment Relationships, and
Distribution o f Plant Communities on Southeast Farallon Island, California by Jamie
Lee Hawk, and that in my opinion this work meets the criteria for approving a thesis
submitted in partial fulfillment of the requirement for the degree Master of Arts in
Geography: Resource Management and Environmental Planning at San Francisco State
University.
Professor
Jaime Jahncke, Ph.D.California Current Director, Point Blue Conservation Science
CLASSIFICATION, VEGETATION-ENVIRONMENT RELATIONSHIPS,
AND DISTRIBUTION OF PLANT COMMUNITIES ON
SOUTHEAST FARALLON ISLAND, CALIFORNIA
Jamie Lee Hawk San Francisco, California
2015
We present the plant communities of Southeast Farallon Island and describe their
relationships to environmental variables and disturbance factors. We sampled a total of
42 vegetation plots containing 26 taxa with a stratified design across the 29-hectare (72-
acre) island. To classify the herbaceous communities we applied agglomerative
hierarchical clustering, while the influence of site parameters was obtained using
Nonmetric Multidimensional Scaling (NMDS) ordination. A total of five plant
communities were classified, including two native plant assemblages (Spergularia
macrotheca type and Lasthenia maritima type) and three invaded communities
(Tetragonia tetragonioides type, Plantago coronopus type, and Mixed vegetation type).
The strongest gradients in vegetation composition can be explained by solar heat load,
dominance of substrate type, and edaphic factors (soil pH, salinity, depth). Physical
disturbance and proximity to anthropogenic land use also influence plant community
composition. A map of the classified vegetation types and additional mapping units were
created to better understand current patterns in vegetation and assist in long-term
management of the island’s resources. Southeast Farallon Island is the largest seabird
breeding colony south of Alaska and the U.S. Fish & Wildlife Service is planning for
intensive habitat restoration, therefore, a clear understanding of native and invaded plant
communities and vegetation-environment relationships is required.
I certify that the Abstract is a correct representatior of the content of this thesis.
Chair, Thesis Committee / } Date
ACKNOWLEDGEMENTS
It is a sincere pleasure to express my deep sense of thanks and gratitude to my
primary advisor and mentor Dr. Barbara A. Holzman. Her dedication and keen interest in
the subject had been a primary driver in the completion of this work. Immense thanks are
also owed to Drs. Ellen Hines and Jaime Jahncke for timely advice and candid
communication.
I thank profusely all the staff and interns at Point Blue Conservation Science and
the U.S. Fish & Wildlife Service for making this research possible, with special
recognition of Russ Bradley, Pete Warzybok, Ryan Berger, Gerry McChesney, and
Jonathan Shore for their input and support in all phases of this work.
I owe a deep sense of gratitude to the field crewmembers for their assistance in
data collection and overall good humor: Dan Adams, Richard Chasey. Patrick Daly, Josh
Nuzzo, Owen Parker, Brian Peterson, Thad Shelton, and David Zimmerman.
This research was supported in part by the SFSU Department of Geography &
Environment Steven Pease Memorial Award. The U.S. Fish & Wildlife Service and Point
Blue Conservation Science provided logistical support, vessel transportation, and
lodging. Dr. Holzman and the SFSU Department of Geography & Environment afforded
food and field equipment throughout the study period.
Lastly, I am extremely thankful to my parents, Michael and Sue Hawk, and my
partner, Owen Parker, for their encouragement and support over the years.
TABLE OF CONTENTS
List of Tables.......................................................................................................................... vii
List of Figures........................................................................................................................ viii
List of Appendices................................................................................................................... ix
Introduction................................................................................................................................ 1
Methods........................................................................................................................................
Study area.......................................................................................................................8
Vegetation survey....................................................................................................... 12
Environmental variables.............................................................................................14
Data analysis................................................................................................................17
Type description key...................................................................................................19
Mapping techniques................................................................................................... 20
Accuracy assessment................................................................................................. 21
Spatial data attribution and metadata........................................................................ 22
Results..........................................................................................................................................
Taxonomic overview .......................................................................................24
Classification............................................................................................................... 25
Ordination................................................................................................................... 28
Vegetation types..........................................................................................................30
Vegetation m ap...........................................................................................................35
Map accuracy.............................................................................................................. 38
Invasive species modifier........................................................................................... 41
Disturbance and invasive species.............................................................................. 43
Discussion................................................................................................................................47
Conclusion............................................................................................................................... 58
References................................................................................................................................ 59
Appendices............................................................................................................................... 71
LIST OF TABLES
Table Page
1. Soil salinity classes.................................................................................................... 15
2. Soil pH classes........................................................................................................... 15
3. Anthropogenic disturbance categories..................................................................... 15
4. Seabird burrow density classes................................................................................. 15
5. Synoptic table of classified vegetation types.......................................................... 26
6. Diagnostic species of classified vegetation types................................................... 27
7. Correlation between axes and environmental variables......................................... 29
8. Summary table of mapping units..............................................................................36
9. Error matrix of user and producer accuracies..................................................38
10. Summary table of Tetragonia tetragonioides modifier.......................................... 41
LIST OF FIGURES
Figures Page
1. Map of study area...................................................................................................... 9
2. Map of vegetation sampling plots locations............................................................13
3. Dendrogram of classified vegetation types............................................................. 25
4. NMDS ordination diagrams........................................................................................29
5. Vegetation map of Southeast Farallon Island......................................................... 37
6. Map of accuracy assessment points................................................................... 40
7. Herbicide treatment effect within Tetragonia tetragonioides type....................... 42
8. Map of non-native vegetative cover within classified plots.................................. 43
9. Anthropogenic disturbance categories recorded per plot.......................................44
LIST OF APPENDICES
Appendix Page
1. Plant species inventory, 1892 to 2015....................................................................71
2. Vegetation type descriptive key..............................................................................74
3. Metadata for vegetation map feature class.............................................................84
4. Data matrices for vegetation cover and environmental variables........................ 97
ix
1
INTRODUCTION
Invasive non-native plant species have become an increasing threat to biodiversity
worldwide (Mack et al. 2000; Mooney & Hobbs 2000). Mediterranean climate regions
(Kottek et al. 2006) are considered to be one of the more vulnerable ecosystems to
introduced plants (Rejmanek & Randall 1994; Randall et al. 1998; Gaertner et al. 2009;
Underwood et al. 2009), and islands even more so (Lloret et al. 2005; Kueffer et al.
2010). Islands have experienced extreme changes in land cover triggered by human
settlement, contributing to ecological degradation and biotic invasion (Oppel et al. 2011).
Human occupancy on most Californian islands has led to the introduction of non-native
mammals such as sheep, rabbits, and rodents (McChesney and Tershy 1998). These
animals depredate island vegetation by herbivory (e.g. Donlan et al. 2002), seed
consumption (Smith et al. 2002; Jones & Golightly 2006), and soil erosion (Brumbaugh
1980; Johnson 1980; Pinter & Vestal 2005), leading to a reduction in native plant cover
and diversity, and subsequent non-native plant invasion (Klinger et al. 1994). Land
rehabilitation efforts on degraded islands are underway worldwide (Glen et al. 2013)
including eradication of introduced animals and active or passive ecosystem restoration
(Beltran et al. 2014, and references therein).
The Farallon Islands of Central California are currently in the planning stages for
proposed house mouse (Mus musculus) eradication (USFWS 2013) and have ongoing
seabird habitat restoration activities (USFWS 2009), requiring baseline vegetation data to
assess the efficacy of current and future management actions. To facilitate vegetation
2
regeneration in degraded areas, an understanding of native and non-native plant
communities is needed. Quantitative investigation of plant communities based on
sampling species composition and abundance aids in the detection and subsequent
monitoring of non-native invasive species (Huebner 2007), classification of vegetation
into distinct types (Schwabe & Kratochwil 2011), and explanation of underlying
environmental gradients (Kent 2012). Vegetation survey, multivariate analysis
(classification and ordination), and vegetation mapping provide essential tools for
delimiting the complex and abstract vegetation continuum (Moravec 1989), providing
focus for biological conservation, environmental management, and climate change
research (Chytry et al. 2011).
Vegetation composition and underlying environmental gradients are poorly
understood for the approximate 15,000 offshore islands, islets and rocks colonized by
seabirds in western North America (USFWS 2005). Islands commonly contain some
level of endemism due to unique edaphic conditions, climate, and geographic isolation
(Philbrick 1980; Steadman 1995), and native plants perform a range of ecological
functions with respect to soil processes and wildlife interaction. Vegetation composition
affects the quality of seabird nesting habitat (Hornung 1981; USFWS 2005; Cadiou et al.
2010), and in turn, seabirds directly and indirectly affect plant community patterns and
dynamics (reviewed in Ellis 2005).
Seabirds can exert high pressure on ecosystems and influence plant biomass,
species richness, and community composition, particularly on islands, which are both
3
very vulnerable to disturbance and often house large seabird colonies (Dean et al. 1994;
Baumberger et al. 2012). Seabirds significantly alter edaphic conditions and plant
communities by chemical change and physical disturbance. Seabirds deposit marine
allochthonous input into terrestrial systems, including prey remains, carcasses, feathers,
eggshells and guano (Polis & Hurd 1996), leading to high levels of phosphate, nitrate,
and ammonium deposition (Dean et al. 1994; Wainright et al. 1998; Anderson & Polis
1999; Bancroft et al. 2005a). High levels of guano contribute to low soil pH and inhibit
vegetative growth by suppressing nutrient absorption in many species (Odasz 1994;
Wainwright et al. 1998). This influx of nutrients, however, may facilitate growth of
guano-tolerant and omithocoprophilous plant species (Omduff 1965; Rajakaruna 2004).
Seabirds trample vegetation and uproot seedlings to build nests, making
propagation difficult for most plants (Gillham 1956a; Dean et al. 1994). This physical
disturbance may explain why plant species with a fast-growing life history strategy thrive
on seabird islands (sensu Grime 1977; Vidal et al. 2000). Burrowing seabirds further alter
below-ground atmospheric, edaphic, and hydrologic conditions on a micro-scale, thereby
creating niche zones for plants with particular physical traits such as deep roots or
succulence (Gillham 1956a; Bancroft et al. 2005a). Physical disturbance caused by
seabirds agitates and exposes soil, leading to high rates of non-native plant introduction
(e.g. Vidal et al. 2003; Baumberger et al. 2012). Furthermore, seabirds (gulls in
particular) are important agents of seed dispersal (Gillham 1956b, 1970; Magnusson &
4
Magnusson 2000; Calvino-Cancela 2011; Padilla et al. 2012) and thereby influence plant
recruitment.
Seabirds of the California Current System (CCS) (USFWS 2005) require
particular plant characteristics and adequate vegetative cover for nesting habitat. Surface-
nesting seabirds such as gulls and terns require low-growing plants to enable visibility
and roosting activity. Areas lacking vegetation with highly exposed soil are considered
unsuitable habitat for the brown pelican, ring-billed gull, Western gull, and glaucous
winged gull (USFWS 2005). Below-ground burrowing seabirds such as storm-petrels and
auklets depend on stable soil (Gillham 1956a; Furness 1991; Bancroft et al. 2005b;
Cadiou et al. 2010), primarily a function of root growth, to ensure burrow persistence and
to reduce entrance infill or collapse events (Hornung 1981). Animal disturbance and plant
invasions have led to extreme changes in edaphic conditions and the subsequent
destruction of several burrowing seabird colonies in California (Takekawa et al. 1990;
Carter et al. 1992; McChesney & Tershy 1998), with invasive plant species and a general
lack of vegetation cover identified as contributing factors. Common characteristics of
problematic non-native plant species on seabird nesting islands include vertical
prominence, dense sprawl, and shallow roots, contributing to a decrease in visibility and
take-off ability, heightened burrow density, and soil instability, respectively (Furness
1991; USFWS 2005).
Harsh maritime factors influence vegetation community assemblage in coastal
areas. Exposure to high winds hampers vegetative growth due to excessive drying or
5
mechanical effects (Lortie & Cushman 2007; Ogura & Yura 2008; Onoda & Anten 2011)
and salt spray further influences plant physiology and community patterns (Boyce 1954;
Barbour & DeJong 1977; Barbour 1978; Ogura & Yura 2008), likely explaining the
abundance of halophytic (salt-tolerant) species (Flowers et al. 1986). Persistent cloud
shading and summer fog drip reduce drought stress (Fischer et al. 2009; Vasey et al.
2012), and combined with these unique maritime factors, contribute to the development
of unique plant alliances with restricted distributions along the California Coastline
(Sawyer et al. 2009).
Small islands in central and northern California vary in geology, ecology,
geographic isolation, and land use history, but vegetation surveys (Thomas 1967; Coulter
1978; Ripley 1980; Sawyer 1984; Ornduff and Vasey 1995) nonetheless illustrate a semi
related flora. Most island species are characteristic of the California Coastal Scrub and
Vancouverian Coastal Dune and Bluff macrogroups of national and state classification
systems (Faber-Langendoen 2007; Sawyer et al. 2009), which are synonymous with
Munz’s (1959, 1968) Coastal Strand and Coastal Sage Scrub plant communities,
respectively. Native taxa recorded among the surveyed islands include Amsinckia spp.,
Calamagrostis nutkaensis, Calandrinia ciliata, Claytonia perfoliata, Crassula connata,
Dudleya spp., Erigeron glaucus, Elymus mollis, Lasthenia maritima, and Spergularia
macrotheca (nomenclature follows Baldwin et al. 2012). Invasive non-native plant
species are similarly found in mainland communities and include Bromus diandrus,
6
Chenopodium spp., Cirsium vulgare, Hordeum murinum, Lepidium didymium, Plantago
spp., Rumex spp., Sonchus spp., and Tetragonia tetragonioides.
While these island vegetation surveys provide useful species checklists with some
physiognomic classification, they lack quantitative abundance data and distribution
parameters. The same is true for Southeast Farallon Island, the most significant seabird
breeding colony south of Alaska and largest island in Central California. Southeast
Farallon Island was visited by naturalists at the turn of the 19th century (Blankinship and
Keeler 1892; Ray 1904) and again 70 years later (Omduff 1961a; Coutler 1971; Coulter
1978). These early surveys increase our inventory of the historical flora, but contain only
general observations with little attempt to classify the plant communities and analyze
their vegetation patterns. Pinney (1965) describes ‘major vegetal associations’ in relation
to rabbit foraging importance and provides a rather detailed hand-drawn map of the five
subjectively described plant associations. Manuwal (1974), an ornithologist, divides
Southeast Farallon Island into nine Cassin’s auklet habitats that include a vegetation
parameter (i.e., vegetated depressions, deep soil grassy plain, and grassy plain), but the
author does not provide specific species, abundance data, or a map (although area was
calculated for each type). Coulter provided species lists between 1985 and 2001 (unpubl.)
to the managing agencies. Coulter and Irwin (2005, unpubl.) summarized more recent
plant introductions and provide qualitative observations of vegetation patterns and
distribution.
7
Our study aims to provide the first comprehensive quantitative vegetation
classification of the existing vascular plant communities on Southeast Farallon Island and
describe their relationships with environmental gradients, including geologic features,
microtopography, edaphic conditions, and physical disturbance. A map of the classified
vegetation types is provided to better understand plant community distribution and
provide a snapshot of baseline vegetation conditions. The combined results elucidate
external factors that support non-native plant dominance and illustrate potential effects on
burrowing seabird habitat, supporting long-term adaptive management of the island’s
resources.
8
METHODS
Study area
The Farallon Islands are located in the Pacific Ocean approximately 48 km (30
mi) west of San Francisco, California and 32 km (20 mi) south of Point Reyes. They are
comprised of four rocky island groups: Noonday Rock, North Farallones, Middle
Farallon, and South Farallones. The South Farallon group includes Southeast Farallon
Island, the largest and only inhabitable island, West End, and adjacent rocks and islets
(Figure 1). The 29-hectare (72-acre) Southeast Farallon Island (37°42’ N, 123°0’ W) is
characterized by a marine-cut terrace with several steep crags and talus slopes. The
highest point is Lighthouse Hill that stands approximately 105 m (343 feet) above sea-
level. Southeast Farallon Island is separated from West End by the narrow Jordan
Channel, making West End inaccessible for research.
The temperature remains cool throughout the year, with average maximums of
14°C (58°F) in the summer and 12°C (54°F) in the winter, with warmest temperatures in
early autumn (Schoenherr et al. 1999). Precipitation averages 63 cm (25 in.) annually and
peaks over winter months. No standing or running fresh water occurs on the island with
the exception of puddles and seepage areas during the rainy season. The California
Current aids in blanketing the island in heavy fog throughout the summer and is not
accounted for in precipitation measures.
9
F isherm an’s \ Bay
Lighthouse! Hill
+105 m
w e s «cE N D - SO U T H E A ST
[ FARALLON IS L A N D ^
SOUTHFARALLON
ISLAN D S
0 km
MaintopBay
B re a k e rC ove
123 00 W
addle Rock
37°42'N
B u i ld in g /s t r u c t u r e
Figure 1 Map of study area, Southeast Farallon Island, California (37°42’ N, 123°0’ W).
The parent geologic material of Southeast Farallon Island is primarily granitic
with some quartz diorite (Hannah 1951; Schoenherr et al. 1999). Minor soil layering
occurs in the low-lying Marine Terrace, comprising guano, granitic sand, bone fragments,
and other decomposing detritus, which can accumulate up to 20 cm thick (Vennum et al.
10
1994). Cassin’s auklet (Ptychoramphys aleuticus) and rhinoceros auklet (Cerorhinca
monocerata) burrows are abundant across the island (Ainley & Boekelheide 1990) and
are primarily concentrated in deep soils atop the Marine Terrace and talus slopes of
Lighthouse Hill (Carter et al. 1992; Warzybok et al. 2006).
The dominant plant species on Southeast Farallon Island is the native annual
Lasthenia maritima (maritime goldfields), an endemic to offshore seabird nesting islands
and sea stacks from Central California to the northern tip of Vancouver Island, British
Columbia (Omduff 1961b; Omduff 1966; Crawford et al. 1985; Vasey 1985). As an
omithocoprophilous plant, L. maritima can withstand soil conditions typical of seabird
colonies (Omduff 1965), but little is known of its environmental thresholds (Desrochers
& Dodge 2003). The peak of vegetative growth (March-April) coincides with the
beginning of the seabird breeding season when L. maritima is collected by cormorants
and gulls for ground nest building material (Ainley & Boekelheide 1990). The senesced
debris is later utilized as hiding cover for gull chicks (USFWS 2009). Vegetation on
Southeast Farallon Island is entirely herbaceous with the exception of two
Hesperocyparis macrocarpa (Monterey cypress) trees and several Malva arborea (tree
mallow) shrubs originally planted for landscaping near the living quarters. Single
specimens of Pinus radiata (Monterey pine) and Coprosma repens (creeping mirrorplant)
also persist on the eastern side of the island, origin unknown.
Rapid changes in land use and the introduction of plant and animal species began
in the late 1700s (White 1995), when an influx of people, supplies and livestock enabled
11
accidental and intentional introductions of many non-native plants. A feral European
rabbit population decimated native vegetation (Pinney 1965) until its eradication in 1975
(White 1995). Several ornamentals were planted as garden varieties and some grasses
likely transported within animal feed (Coulter 1971). The non-native house mouse
population may also play a role in seed dispersal (Jones & Golightly 2006). As a result,
the number of introduced species outnumbers natives 3:1 today, and invasions prevail in
disturbed and ruderal portions of the island, most markedly on the Marine Terrace and
south-facing slopes of Lighthouse Hill.
The Farallon National Wildlife Refuge Weed Management Plan (Irwin & Buffa
2004, unpubl.) outlines an adaptive management protocol for the removal and control of
primary invasive species Tetragonia tetragonioides (New Zealand spinach) and Malva
parviflora (cheeseweed) and several secondary non-natives. Intensive hand-pulling and
selective herbicide treatment have targeted primary invasive plants since 1990, but due to
budgetary and staffing constraints treatment intensity varies and eradication is far from
complete.
The Farallon National Wildlife Refuge (Refuge) was established in 1909 as a
preserve and breeding ground for seabirds and marine mammals, and originally included
North and Middle Farallon Islands, with the South Farallones being added to the Refuge
in 1969. The Farallon Islands host thirteen breeding seabird species with some 300,000
birds nesting and roosting on Southeast Farallon Island annually (DeSante & Ainley
1980; Warzybok & Bradley 2011). Today the USFWS has cooperative agreements with
12
Point Blue Conservation Science (formerly Point Reyes Bird Observatory) to assist with
wildlife monitoring, facilities management, and protection of the Refuge. Due to the
steep rocky shoreline and sensitivity of wildlife, the Refuge remains closed to public
access.
Vegetation survey
Data on vegetation composition and cover were obtained between 2013 and 2014
from permanent plots established for long-term vegetation research. Plot locations were
chosen based on vegetation stratification and accessibility, and avoided sensitive wildlife
congregations and the de facto wilderness area on the northern side. In total, 42 circular
plots were established with a diameter of 10 m (78.5 m2), totaling approximately 1% of
the island surface (Figure 2). Absolute cover and frequency data for all vascular plants
were recorded in the field using the point-intercept method (Knapp 1984) whereby
intercept data (species, substrate type) were collected along two random transects at an
interval of 0.5 m. Vegetation was surveyed during the optimal growing season (March-
April, 2013-2014) to reflect the time of maximum vegetation development. A total of 26
taxa were recorded within the plots (see Appendix 1 for historical species inventory) and
plants that were difficult to identify to species level were grouped into lower resolution
complexes (i.e., Malva spp. group). Taxonomical identification and status follows the
second edition of The Jepson Manual (Baldwin et al. 2012). Point data were converted to
absolute cover percentages (Sawyer et al. 2009) for further analysis and averaged over
both years to account for temporal variation and seasonality.
13
Lighthouse Hill 105 m
B reak#,C ove
MiroungaBay
Figure 2 Map of vegetation sampling plot locations (n=42). Diagram (not to scale) illustrates hypothetical azimuths of two transects within the 10-m diameter plot boundary. The point intercept method captures species and substrate codes at a 0.5-m interval along each transect and are averaged to obtain overall plot composition.
© 2
01
5,
Jam
ie
Ha
wk
14
Environmental variables
Environmental data include elevation, slope, solar heat load index (McCune &
Keon 2002), substrate (type and cover %), edaphic characteristics (soil depth, pH,
salinity), and disturbance. Plot locations and elevation were derived from differentially
corrected XYZ values collected by a Trimble GeoXH GPS unit with sub-meter accuracy.
Slope (0-90°) and aspect (0-360°) were assessed in the field. Potential annual direct
incident radiation, an index of heat load, was calculated using McCune and Keon’s
(2002) formula that takes into account latitude, aspect and slope. Substrate categories
(rock, bare ground, litter, impervious surface) and cover percentages were extracted from
the vegetation survey data. Soil depth (cm) was averaged over 10 subsamples per plot.
Soil electrical conductivity (EC, a proxy for salinity) and pH were measured in the lab
using an YSI Model 5560 EC probe and Hannah HI 99121 pH meter, respectively. Two
soil samples per plot were collected from the rhizosphere, dried, and sieved (2 mm sieve)
for analysis. Soil salinity and pH were determined using a 1:1 soil to water suspension
(sensu USDA 2001). Soil salinity (EC1:1) values are reported in dS/m units and discussed
in relation to Smith and Doran’s (1996) salinity classes (Table 1). Soil pH values are
compared to standard USDA classes (Table 2). Presence of anthropogenic disturbance
categories (Table 3) were recorded and summed for each plot. Auklet burrows were
counted within each plot and divided by plot area (78.5 m2) to determine burrow density.
Burrow density classes (Table 4) are relative within-island comparisons and required a
minimum difference of seven burrows per plot.
15
Table 1 Soil salinity classes and relationship between EC1:1 and ECe values.
EC1:1(dS/m)
ECe(dS/m) Salinity class Microbial activity
0 -0 .9 8 0 - 2 . 0 Non-saline Few organisms affected
0.99-1 .71 2 .1 -4 .0 Slightly saline Selected microbial processes altered (nitrification/dentrification)
1.72-3.16 4^ 1 OO © Moderately saline Major microbial processes altered (respiration/ammonification)
3 .17-6 .07 8 .1 -1 6 .0 Strongly saline Salt tolerant microorganisms predominate (fungi, actinomycetes, bacteria)
6.08+ 16.0+ Very saline A select few halophytic organisms are active
Adapted from USDA’s (2001) Soil Quality Test Kit Guide. EC1:1 values are derived from a 1:1 soil to water suspension method, whereas ECe values are derived from the saturated paste extract method. Conversions from ECe to EC1:1 were performed using the regression equation (y=2.75 x -0.69) developed by Hogg & Henry (1984). For reference, distilled water is approximately 0.002 dS/m, while seawater is approximately 50 dS/m.
Table 2 Soil pH classes (www.nrcs.usda.gov, accessed April 1, 2015)
Class pH value
Ultra acid 1 .8 -3 .4
Extremely acid 3 .5 -4 .4
Very strongly acid 4 .5 -5 .0
Strongly acid 5.1 -5 .5
Moderately acid 5 .6 -6 .0
Slightly acid 6 .1 -6 .5
Neutral 6 .6 -7 .3
Slightly alkaline 7 .4 -7 .8
Moderately alkaline 7 .9 -8 .4
Strongly alkaline 8 .5 -9 .0
Very strongly alkaline 9 .1 -1 1 .0
Table 3 Anthropogenic disturbance categories.
Categories (n=10)
Building Historic foundation
Structure Rock wall
Trail Monitoring box
Utility pipe Herbicide evidence
Concrete Debris
Table 4 Seabird burrow density classes.
Class Density (/m2)
Non-burrowed 0.00 - 0.09
Slightly burrowed 0 .10-0 .19
Moderately burrowed 0 .20-0 .29
Strongly burrowed 0 .29-0 .39
Very burrowed 0.40+
16
Several limitations likely contribute error to our study and some minor caveats
should be considered. Firstly, the exclusion of vegetation sampling plots from sensitive
wildlife areas (e.g. marine mammal colony), the protected wilderness zone, and unsafe
areas (gulches, cliffs) may exclude particular plant assemblages and extreme
environmental variables from our data. The outmost perimeter and northern side of
Southeast Farallon Island, in particular, are underrepresented in this study. Second,
environmental variable data are likely affected by seasonal-temporality. Since our
fieldwork was conducted in early spring between the marine mammal and seabird peak
breeding seasons (to decrease impact to wildlife), recorded soil pH and salinity values
may differ from year-round and long-term averages (USDA 2001). Third, seabird burrow
counts may underestimate true totals. While auklets typically return to burrows each year
(Manuwal 1974), winter plant growth, burrow collapse, and minimal freshly excavated
soil likely bias counting efforts, albeit systematically. Furthermore, the ratio of entrances
to actual burrows is probably not 1:1 (as there may be multiple burrow entrances or
unused burrows) and may differ for different bird species (Warham 1990). Therefore, our
burrow entrance counts are correlated with seabird burrow density, but the relationship
with seabird density may be weaker. Lastly, the term “impervious surface” refers to most
anthropogenic features on the island (e.g. buildings, concrete slabs, compacted trail).
These surfaces were not tested for permeability and the term is therefore used in the
general sense.
17
Data analysis
A plot-vs-species matrix using percent cover values of each of the 26 taxa was
created. The data were transformed logarithmically in order to reduce skewness and
kurtosis and to compress high values (McCune & Grace 2002; Kent 2012). Species
richness (S), Shannon-Wiener diversity index (Tf), and evenness (J) indices were
calculated for each plot (Whittaker 1972).
Multivariate analysis was applied to the matrix within the R statistical
environment (version 3.0.0, http://www.R-project.org). Hierarchical agglomerative
clustering was used with Bray-Curtis as the dissimilarity measure. Unweighted Pair-
Groups Method using Arithmetic Mean (UPGMA; Sokal & Michener 1958), also known
as group averaging, was used as the method for type formation. The UPGMA linkage
method is well-supported in the analysis of ecological data (Clarke 1993; McCune &
Grace 2002; Kent 2012) as a space-conserving technique that forms spherical groups
(McCune and Grace 2002). The cophenetic distance (Sneath & Sokal 1973) between all
observations was calculated to determine whether estimated and observed dissimilarities
are correlated, thereby ensuring the classification dendrogram is an appropriate summary
of the data. A Multi-Response Permutation Procedure (MRPP) (Mielke & Berry 2007)
was used to test for statistical significance between priori defined types using the mrpp
function in the vegan package (version 2.2-1, http://vegan.r-forge.r-project.org/) for R.
Diagnostic species of plant communities were determined using the indicator
value index (IndVal) method (Dufrene & Legendre 1997; Chytry et al. 2002). IndVal is
18
based on species relative abundance and fidelity in each type, a method recommended for
sparsely populated matrices (Mouillot et al. 2002; McCune & Grace 2002). IndYal
analyses were performed with function duleg of the LabDSV package (version 1.6-1,
http://ecology.msu.montana.edu/labdsv/R) in the R statistical environment. Default
options were used including 1000 randomizations and 0.05 error probability level.
Species with IndVal scores higher than 0.45 and test significance lower than 0.05 were
deemed to be diagnostic.
To support the results of the hierarchical classification and to analyze
relationships between environmental factors and the distribution pattern of plant
communities, non-metric multidimensional scaling (NMDS) analyses were performed
using vegan. The metaMDS procedure as recommended by Minchin (1987) was
employed including a maximum of 100 random starts in search of the stable solution with
the second run starting from previous best solution. The Bray-Curtis dissimilarity for
ordination, rather than Euclidean distance, was used because we are interested in the
compositional dissimilarity between the sites rather than in raw differences in abundance
of one species or another (Faith et al. 1987; McCune & Grace 2002). A two-dimensional
solution of NMDS was used because change in stress value (goodness of fit) was minor
with subsequent dimensions as shown by a scree plot. Correlation (r2) was calculated
between fitted vectors and the ordination using the envfit function of vegan. A
permutational MANOVA using distance matrices procedure tested for significance of
environmental variables among classified types using the adonis function of vegan.
19
Type description key
The reference key to vegetation type descriptions (Appendix 2) models that of A
Manual o f California Vegetation, 2nd ed. (MCV) (Sawyer et al. 2009), the California
expression of the U.S. National Vegetation Classification System (NVCS) (Faber-
Langendoen 2007; FGDC 2008; Jennings et al. 2009). Latin binomials of diagnostic
(indicator) species are separated by hyphens in type names, indicating a similar
herbaceous stratum. Plants listed first in the description define and typify the vegetation
type, with MCV glossary terms used to characterize the vegetation layer: absolute cover,
relative cover, continuous, intermittent, sparse, among others (Sawyer et al. 2009). A
Membership Rules section defines dominant species (>40% absolute cover), co-dominant
species (15-40% absolute cover each), character species (distinct maximum
concentration, typically lower cover), and sparse species (<10% cover). The Habitat
Characteristics section describes biological and environmental conditions (e.g. topo-
edaphic characteristics, disturbance regime) and general location of where the type is
found (including a small inset map). A Remarks section includes additional information
about the vegetation type and/or physical traits of dominant, co-dominant and/or
characteristic species. A Management Considerations section is provided where
applicable. A set of representative photos is provided for each type that capture localized
variation in plant composition and substrate type. No efforts to rank or synonymize types
with other classification alliances (e.g. MCV, NVCS) are made at this time.
20
Mapping techniques
The extent and distribution of mapping units were mapped using a combination of
ground-based GPS, altitudinal vantage point, and on-screen digitizing methods. Mapping
units comprise classified vegetation types (including sub-units and categories for some
types), specific species stands (primarily non-herbaceous), bare ground, and
anthropogenic features. Classified vegetation type mapping sub-units and mapping
categories, while not necessarily evident in the classification, were mapped to indicate
unique substrate conditions and dichotomous plant assemblages, respectively. The
geographic locations of 42 vegetation plots and 14 additional training points were logged
with a Trimble GeoXH GPS unit to sub-meter accuracy. Other vegetation patches,
obvious type edges, and prominent on-ground features (e.g. trails, foundation comers)
were also mapped with the GPS unit.
These baseline data files were brought into ArcGIS (version 10.2, ESRI,
Redlands, CA, US) and analyzed against 1-meter National Agricultural Imagery Program
(NAIP) digital orthoimagery (USDA-FSA Aerial Photography Field Office, Salt Lake
City, UT, US). The flight that acquired the image was conducted in May 2012 when
annual vegetation began to senesce. Distinct vegetation community polygons were
digitized on screen (“heads up”) at an average 1:1,000 scale for the Marine Terrace and
other flat areas, but shadows prevented digitizing for most steep hillsides. Altitudinal
vantage point mapping (sensu Weislander 1935) was completed for these areas and
included the use of field maps printed with pre-digitized polygons (assigned and labeled
21
with unique FID codes to relate them to the database), coloring pens, and binoculars. No
exact minimum mapping unit was defined, but imagery resolution prevented mapping
polygons less than 25 m2. Field mapping could not be completed in or adjacent to
sensitive wildlife populations, therefore sparse vegetation may be present along the rocky
island perimeter but is undetectable by orthoimagery interpretation and therefore
excluded from the final dataset. Topology was enforced for the final vector feature class
(shapefile) to ensure proper spatial relationships (Theobald 2001).
Accuracy assessment
As recommended by the U.S. Geological Survey-National Park Service (USGS-
NPS) Vegetation Mapping Program (VMP) (Grossman et al. 1994), map accuracy was
assessed using the standard confusion matrix approach, which indicates the percent of
correctly and incorrectly mapped units in binary form (Congalton 1991). Requirements
for the VMP specify 80% accuracy for each map unit representing classified plant
communities. Only classified vegetation type mapping units were assessed for accuracy
(sub-mapping units were dissolved into the parent type) and other static mapping units
(e.g. anthropogenic features) were individually checked for accuracy outside the formal
assessment. The number of polygons visited per vegetation type depended on its total
mapped area, therefore widespread types required more assessment polygons. Polygons
were randomly chosen for assessment, but with logistic constraints (i.e. polygon size
>100m2 and away from sensitive wildlife).
22
Accuracy assessment (AA) surveyors navigated to the polygon centroids using a
Trimble GeoXH GPS unit without prior knowledge of type assignment, but were aware
of polygon boundaries, anthropogenic features, and AA data point locations. The AA
surveyor assessed plant community of respective polygon and assigned a provisional type
name using the classification key (Appendix 2). Dominant species, environmental data
(topographic position, aspect, slope, proximity to features), and confidence in
classification were recorded in the field. For each AA data point, the field-assigned
vegetation type code was compared to the corresponding polygon code. All mismatches
were reviewed to see if there were any false errors (Faber-Langendoen 2007), resulting in
either a match or true error. The final binary data were used to create the error matrix and
assess overall thematic map accuracy.
Spatial data attribution and metadata
Vegetation classification type, dominant, co-dominant, and character species, and
T. tetragonioides category codes were input for each polygon based on those created
during the mapping phase. Specific management needs related to the concern over the
status and trends of primary invasive species required the inclusion of a primary category
for the non-native T. tetragonioides, along with an attribute modifier that described a
categorical estimate of T. tetragonioides cover for areas containing the species. If T.
tetragonioides was interpreted as the dominant species (>40%) for a polygon, that
polygon was assigned the specific classified vegetation type category. Other areas that
23
contained T. tetragonioides were assigned a value (#) corresponding to <5% cover (1), 5-
10% cover (2), or >10% cover (3).
The final map layer follows the U.S. National Vegetation Classification standard
(FGDC 2008) whereby tabular attributes and metadata meet standardized requirements.
Metadata includes information about study (date, season), plots (number, locations), field
methods, and classification methods (Appendix 3).
24
RESULTS
Taxonomic overview
A total of 26 taxa (25 species, 1 genus group) were recorded among the 42
vegetation plots on Southeast Farallon Island (Table 5). The taxa represent twelve
botanical families (Baldwin et al. 2012): Asteraceae (5 species), Poaceae (5),
Caryophyllaceae (3), Chenopodiaceae (3), Malvaceae (3+), Geraniaceae (2), Aizoaceae
(1), Brassicaceae (1), Plantaginaceae (1), Polygonaceae (1), Portulacaceae (1), and
Urticaceae (1).
Native species include Lasthenia maritima (maritime goldfields), Spergularia
macrotheca (sticky sandspurry), Claytonia perfoliata (miner’s lettuce), Amsinckia
spectabilis (seaside fiddleneck), and Bromus carinatus1 (California brome), accounting
for 19 percent of the total species richness. Most species are considered non-native to
California and include Tetragonia tetragonioides (New Zealand spinach), Malva
parviflora (cheeseweed), Plantago coronopus (cutleaf plantain), Lepidium didymum
(lesser swine cress), Chenopodium murale (nettle leaf goosefoot), Bromus diandrus
(ripgut brome), and Hordeum murinum (hare barley), among others. Of the 21 non-native
species recorded in vegetation plots, one-quarter are currently listed on the Cal-IPC
invasive plant database (http://www.cal-ipc.org/paf/, accessed on March 1, 2015) as
having limited or moderate ecological impact to California’s wildlands (Cal-IPC 2006).
1 Coulter (1978) apparently identified this species as Bromus maritimus by photograph. Limited specimens prohibited us from determining whether this native grass is indeed B. maritimus, a former varietal of B. carinatus (B. carinatus var. maritima).
25
Classification
The UPGMA cluster analysis divides the 42 plots into five vegetation types
(Figure 3). A high cophenetic correlation (r2 = 0.83) indicates the dendrogram
successfully reproduces observed (Bray-Curtis) dissimilarities. The MRPP results
indicate the clusters are significantly different (PO.OOl), have high within-group
homogeneity (A = 0.418), and are tightly formed (observed 8 = 0.392, expected 8 =
0.674). Frequency (F%) and absolute cover (C%) of each species relative to types
elucidates cluster formation (Table 5). Indicator species analysis identifies twelve
significant (P<0.05) diagnostic species, with IndVal scores ranging from 45 to 94 (Table
6). Spergularia macrotheca type (SpmaT) and Lasthenia maritima type (LamaT) are
native plant communities, whereas Tetragonia tetragonioides type (TeteT), Plantago
coronopus type (PlcoT), and Mixed vegetation type (MixedT) are non-native stands.
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Figure 3 Dendrogram of classified vegetation types. Agglomerative hierarchical clustering (UPGMA method) o f 42 vegetation plots (26 taxa) produced five statistically significant (P<0.05) groups.
26
Table 5 Synoptic table of classified vegetation types. F = relative frequency; C = relative absolute cover. The abbreviations H, G or S after a species name stands for herb, grass or shrub. * significant (P<0.05)
Descriptive || Environmental Data (mean±SD) SpmaT LamaT TeteT PlcoT M ixedT
Number of plots 3 19 9 4 7Species richness (S') 5.0±0.6 4.4±2.2 6.0±3.3 11.8±3.6 9.0±1.7Diversity ( / / ’) 0.86±0.33 0.69±0.46 1.09±0.66 1.93±0.36 1.81±0.13Evenness (,J) 0.56±0.19 0.43±0.24 0.61±0.19 0.79±0.06 0.83±0.07
Potential solar radiation (MJ/cm2/yr) 0.82±0.0 0.76±0.15 0.98±0.09 0.82±0.01 0.82±0.01Rocky substrate (%)* 5±6 22±18 12±12 4±4 5±2Bare ground (%) 19±6 15±10 4±2 2±1 11±10Litter (%)* o±o 1±2 1±1 5±4 9±3Soil pH 5.3±0.3 5.0±0.8 5.2±0.6 4.9±0.7 5.6±0.89Soil EC1;1 [salinity] (dS/m) 0.813±0.328 1.640±2.131 0.387±0.223 0.484±0.328 0.516±0.315Soil depth (cm)* 8.7±3.3 7.5±3.7 7.5±4.4 11.2±2.8 13.9±2.9Burrow density (/m2) 0.06±0.11 0.06±0.10 0.12±0.10 0.07±0.04 0.19±0.15Anthropogenic disturbances (#) l.Oil.O 2.3±1.8 2.7±2.1 1.8±1.5 4.2±1.7
Species Code F% |C% F% |C % F% | C% F% | C% F% | C%
Amsinckia spectabilis (H) Amsp 0 10 0 1 0 11 | 6 25 | 6 43 |2
Anagallis arvensis (H)*> Anar 0 10 5 | 1 0 | 0 25 11 0 10Bromus carinatus (G) Brea 0 10 5 | 5 0 1 0 0 10 14 11Bromus diandrus (G)*> f Brdi 010 16 | 5 78 | 7 100 1 9 100118Chenopodium murale (H)*> Chmu 0 10 11 | 2 11 | 4 25 | 1 43 |2Claytonia perfoliata (H) Clpe 10013 63 | 4 44 | 13 100 | 12 5 7 14Cotula australis (H)*> Coau 010 0 | 0 0 | 0 25 | 1 0 10Erodium cicutarium (H)<*f Erci 010 5 | 1 11 | 1 25 14 43 19Erodium moschatum (H)<* Ermo 010 0 | 0 56 | 4 25 16 5 7 18Festuca bromoides (G )* Febr 010 0 1 0 11 | 2 75 | 1 0 |0Hordeum murinum (G)#> t Homu 0 10 21 | 6 44 | 6 100116 7 1 15Lasthenia maritima (H) Lama 10016 100 | 45 56 | 13 100 16 100| 15Lepidium didymum (H)*> Ledi 1001 5 37 | 4 33 | 2 50 | 1 43 13Malva arborea (S)*> Maab 010 0 | 0 0 | 0 0 10 1414Malva spp. (H)<* Masp 010 0 1 0 22 | 2 25 | 3 43 17Plantago coronopus (H)*> Pico 0 10 11 1 7 11 | 6 100127 2 9 13Poa annua (G)*> Poan 0 10 5 | 1 0 | 0 0 10 0 |0Rumex crispus (H)*>t Rucr 0 10 0 | 0 0 1 0 010 1417Senecio vulgaris (H)<* Sevu 0 10 0 1 0 0 1 0 50 | 1 0 |0Sonchus asper (H)<* Soas 010 0 1 0 0 1 0 0 10 1412Sonchus oleraceus (H)*> Sool 010 5 | 2 0 1 0 100 12 0 |0Spergularia macrotheca (H) Spma 100153 58 | 8 1111 75 | 6 1412Spergularia media (H)*> Spme 33 12 26 | 2 0 1 0 0 10 0 10Stellaria media (H)<* Stme 010 32 | 2 33 | 1 100 14 7 1 17Tetragonia tetragonioides (H)*>t Tete 33 124 26 | 9 100 1 51 25 | 7 1416Urtica urens (H)<* Urur 010 16 | 1 67 | 6 25 12 10017
❖Non-native to California f Invasive according to California Invasive Plant Council
27
Table 6 Diagnostic species of classified vegetation types. The indicator value index (IndVal) method (Dufrene and Legendre 1997; Chytry et al. 2002) determined diagnostic species. Values were multiplied by 100 and are presented in descending order with significant values (P<0.05) shaded in grey. See Appendix 1 for full species list and Appendix 2 for type description key.
SpmaT LamaT TeteT PlcoT MixedT
Diagnostic species of Spergularia macrotheca type
Spergularia macrotheca 83 5 0 6 0Lepidium didymum 57 6 0 0 5Spergularia media 18 12 0 0 0
Diagnostic species of Lasthenia maritima typeLasthenia maritima 8 53 5 8 21Poa annua 0 5 0 0 0
Diagnostic species of Tetragonia tetragonioides typeTetragonia tetragonioides 5 0 77 0 0
Diagnostic species of Plantago coronopus typeSonchus oleraceus 0 0 0 94 0Plantago coronopus 0 0 0 92 0Hordeum murinum 0 0 5 66 12Festuca bromoides 0 0 0 61 0Senecio vulgaris 0 0 0 50 0Claytonia perfoliata 12 7 10 45 6Stellaria media 0 0 0 40 35Cotula australis 0 0 0 25 0Anagallis arvensis 0 0 0 21 0
Amsinckia spectabilis 0 0 0 13 11
Diagnostic species of Mixed vegetation type
Urtica urens 0 0 21 0 62Bromus diandrus 0 0 13 28 53Erodium cicutarium 0 0 0 5 32Malva spp. 0 0 0 5 31Erodium moschatum 0 0 17 5 29Chenopodium murale 0 0 0 0 23Malva arborea 0 0 0 0 14Rumex crispus 0 0 0 0 14Sonchus asper 0 0 0 0 14Bromus carinatus 0 0 0 0 5
28
Ordination
Supporting the UPGMA classification, the NMDS ordination for the survey
dataset unambiguously partitions the five vegetation types (Figure 4). The greatest
reduction in stress is achieved with a two-dimensional solution (stress=0.18, non-metric
R2=0.97). Visual inspection of the ordination show non-native vegetation types (TeteT,
PlcoT, MixedT) cluster in the left and bottom sides of the diagram, whereas native
vegetation types (LamaT, SpmaT) cluster in the right and top sides. There are significant
(P<0.05) correlations between environmental gradients and the ordination solution (Table
7). Species distributions along NMDS axes chiefly respond to a topographical gradient
(NMDS Axis 1) defined by solar radiation (slope/aspect), rocky substrate cover, bare
ground cover, and soil salinity. The solar radiation variable separates plots on south-
facing slopes (TeteT) from plots on cooler, rocky slopes and lowland areas (LamaT).
Lowland plots are further partitioned following an increasing salinity gradient. Soil depth
and litter content variables define the vertical axis (NMDS Axis 2). Plots dominated by
perennial, succulent species (SpmaT) are separated from plots primarily composed of
annual herbs and grasses (PlcoT, MixedT) as represented by the litter content variable. A
soil depth gradient further separates the former group from the latter in ordination space,
as SpmaT is primarily distributed on shallow, gravelly soils while PlcoT and MixedT are
found on deep soils in the southeastern area of the island.
29
Figure 4 Distribution o f sample plots (a) and plant species (b) in NMDS ordination space (stress=0.18, non-metric R2=0.97). Plots (n=42) are symbolized by classified vegetation type. Vectors of significant (P<0.05) environmental variables are fitted to the ordination solution, with arrow length scaled by correlation. Axis 1 illustrates a topographic-salinity gradient and Axis 2 reflects a litter content-soil depth gradient. Species centroids are denoted by 4-letter codes (first two letters of genus and species; see Table 5). In the case of an overlap, priority was given to labels with high cover species by using the orditorp command in the vegan package for R , with sparse species designated by a red Axes range from -1.5 to 1.5 and plots are centered on 0,0.
Table 7 Vectors o f significant (P<0.05) environmental variables in the NMDS ordination. Directional cosines of NMDS axis 1 (NMDS1) and 2 (NMDS2), correlation coefficient r2, and significances are provided. *:P<0.05, **:P<0.01, ***:P<0.001.
N M D S1 NM DS2 r2 P-value
Solar radiation (MJ/cm2/yr) -0.94 0.35 0.32 **
Rocky substrate cover (%) 0.99 0.08 0.13 *
Bare ground cover (%) 0.78 0.62 0.28 **
Soil salinity (jiS/cm) 0.99 0.03 0.15 *
Soil depth (cm) -0.25 -0.97 0.18 **
Litter content cover (%) -0.30 -0.95 0.38 ***
30
Spergularia macrotheca type (SpmaT) (Appendix 2A)
The most tightly formed UPGMA division (5 = 0.2556) separates three
Spergularia macrotheca type (SpmaT) plots from the remaining vegetation types of
Southeast Farallon Island. The primary diagnostic species is S. macrotheca (IndVal=83,
see Table 6), whose absolute cover ranges from 43 to 60 percent and is considered the
dominant species of SpmaT. Lepidium didymum is the other significant (P<0.05)
diagnostic species (IndVal=57) but retains low cover (2-7%) and is therefore considered a
characteristic species of SpmaT. Sparse species (<10%) include L. maritima, C.
perfoliata, Spergularia media, and T. tetragonioides. Species richness (5=4-5 ) and
diversity (H —0.65-1.2) are each low in SpmaT, and native species dominate the
vegetative cover (83±17%, range=63-97%). SpmaT plots are nearly void of senesced
plant debris (litter cover=0%), have consistently moderate soil exposure (bare ground
cover= 12-26%), and have zero to moderate rocky cover (0-12%). Soils are characterized
as moderately deep (6.8-12.5 cm), non-saline to slightly saline (EC1:1=0.581-1.189
dS/m), and very strongly acidic to moderately acidic (pH=5.0-5.7). Seabird burrow
density is zero (n=2) to moderate (0.18/m2, n=l) and anthropogenic disturbance is
minimal (0 to 3 categories recorded). SpmaT is distributed on the Western Marine
Terrace and along the island perimeter atop rocky outcrops and sandy flats.
Lasthenia maritima type (LamaT) (Appendix 2B)
The largest UPGMA division (n=19) separates Lasthenia maritima type (LamaT)
plots from the remaining vegetation data. The primary diagnostic species is L. maritima
31
(IndVal=53), whose absolute cover values range from 20 to 80 percent and is a dominant
species among all plots. Co-dominant species include C. perfoliata, L. didymum, S.
macrotheca, and T. tetragonioides. Other species with sparse cover include B. diandrus,
H. murinum, P. coronopus, Spergularia media, Stellaria media, and U. urens. Species
richness (5=1-9) and diversity (H ’=0.00-1.36) are the lowest compared to other
vegetation types. Native species dominate total vegetative cover (88±13%, range=59-
100%) and three LamaT plots are void of any non-native species. LamaT plots are low in
senesced plant debris (litter cover=0-5%), have slightly to heavily exposed soil (bare
ground cover=l-38%), and vary in rockiness (rock cover=l-64%). Soils are moderately
thin to deep (3.3-17.1 cm), non-saline to very saline (EC1:1=0.283-8.756 dS/m), and are
extremely acidic to neutral (pH=4.1-6.9). Seabird burrow density values range from zero
to high (0.00-0.34/m2) and anthropogenic disturbance is variable (0-8 categories
recorded). LamaT is distributed throughout most of Southeast Farallon Island and is
found on rocky outcrops, steep crags, and north-facing slopes of Lighthouse Hill, and is
also found on concave portions of the Marine Terrace and in areas adjacent to marine
mammal colonies. Topo-edaphic conditions and disturbance values are therefore variable.
Tetragonia tetragonioides type (TeteT) (Appendix 2C)
The second-largest UPGMA division (n=9) separates the Tetragonia
tetragonioides type (TeteT) from the remaining vegetation data. The primary diagnostic
species is T. tetragonioides (IndVal=77) whose absolute cover ranges from 24 to 83
percent and is the dominant species of the type. A frequent co-dominant species is L.
32
maritima. Characteristic species are B. diandrus, Erodium moschatum (white-stemmed
filaree), and U. urens that vary in cover (see Table 5). Other frequent (>33% plots)
species are sparse: C. perfoliata, H. murinum, L. didymum, and Stellaria media. Species
richness (S =2-12) and diversity (H -0.22-2.20) are moderate compared to other types.
Non-native species dominate total vegetative cover (83±13%, range=67-100%) and three
TeteT plots have zero cover of native species. TeteT plots contain very low senesced
plant debris (litter cover=0-4%), little exposed soil (bare ground cover=l-7%), and have
variable rock cover (=0-35%). Soils are shallow to deep (3.7-17.7 cm), the least saline
(EC1:1=0.106-0.564 dS/m), and range from extremely to moderately acidic (pH=4.3-5.8).
Seabird burrow density values are widely ranged (0.01-0.29/m2) and anthropogenic
disturbance variable (1-6 categories recorded). TeteT is distributed on the south-aspect
face and talus slopes of Lighthouse Hill atop rocky substrate and sandy soil.
Plantago coronopus type (PlcoT) (Appendix 2D)
The most diverse (mean H ’=1.09) UPGMA division separates four Plantago
coronopus type (PlcoT) plots from the remaining vegetation. PlcoT is characterized by
six diagnostic species (see Table 6), with two identified as very strong indicator species:
P. coronopus (IndVal=92) and S. oleraceus (IndVal=94). Other diagnostic species
include H. murinum (IndVal=66), Festuca bromoides (brome fescue) (IndVal=61),
Senecio vulgaris (old man of spring) (IndVal=50), and C. perfoliata (IndVal=45),
confirming PlcoT is a highly mixed but unique vegetation community. There are no
dominant species to characterize PlcoT as not a single species has an absolute cover
33
greater than 40 percent. Instead, there are four co-dominant species: P. coronopus (20-
35%), H. murinum (4-26%), B. diandrus (1-18%), and C. perfoliata (1-18%).
Characteristic species are S. oleraceus, F. bromoides, and S. vulgaris because, although
absolute cover of each is low (<5%), they have strong statistical fidelity (Chryty et al.
2002) and help typify PlcoT. Species richness (5=9-17) and diversity (H —1.62-2.41) are
the highest of all classified vegetation types. Non-native species dominate total vegetative
cover (74±13%, range=57-88%). PlcoT plots have little senesced plant debris (litter
cover=l-5%), very low exposed soil (bare ground cover=l-2%), and little rock cover (=0-
8%). Soils are moderately deep (6.9-12.6 cm), non-saline to slightly saline (EC1:1=0.263-
0.965 dS/m), and extremely to moderately acidic (pH=4.3-5.7). Burrow density is low to
moderate (0.03-0.12/m2) and anthropogenic disturbance minimal (0-1 categories
recorded). PlcoT is distributed on the Eastern Marine Terrace atop sandy loam with high
organic matter.
Mixed vegetation type (MixedT) (Appendix 2E)
The most heterogeneic (8 = 0.503) UPGMA division separates seven Mixed
vegetation type (MixedT) plots from the remaining vegetation. Diagnostic species are B.
diandrus (IndVal=53) and U. urens (IndVal=62), but 17 additional species frequent this
type in varying cover (see Table 5), illustrating the type is a heavily mixed and variable
community. MixedT is characterized by two distinct vegetation compositions (categories
on the vegetation map): annual grassland and non-native herbaceous (3 and 4 plots,
respectively). The annual grassland category (MixedT-g, n=3) is dominated by B.
34
diandrus whose absolute cover ranges from 19 to 39 percent. Co-dominant species of
MixedT-g are H. murinum (0-14%) and L. maritima (12-21%). MixedT-g is often
adjacent to PlcoT but is distinguished by the near absence of P. coronopus (0-5% cover)
and co-dominance of L. maritima. The non-native herbaceous category (MixedT-h) lacks
any dominant species as not a single species has an absolute cover greater than 40
percent. Co-dominant species of MixedT-h include Erodium spp., L. maritima, Malva
spp., Stellaria media, and U. urens. Characteristic species include A. spectabilis, C.
murale, and R. crispus as they are rarely recorded outside the type.
In general, MixedT plots are consistently high in species richness (5=7-11) and
diversity (H —1.61-1.99). Non-native species dominate MixedT plots (71±11%,
range=51-80), albeit to a lesser degree than TeteT and PlcoT. MixedT plots have
moderate senesced plant debris (litter cover=4-12%), low to high levels of exposed soil
(bare ground cover=2-24%), and low rock cover (2-7%) in all but one outlier plot
(=48%). Soils are shallow to deep (4.6-17.6 cm), non-saline to slightly saline
(EC1:1=0.160-1.068 dS/m), and very strongly acidic to neutral (pH=4.8-6.7). Burrow
density ranges from moderate to very high (0.04-0.44/m2) and anthropogenic disturbance
low to high (2-7 categories recorded). MixedT plots are distributed on the Marine Terrace
interior, along the island perimeter, and atop Lighthouse Hill, thereby explaining the wide
range in edaphic characteristics. In particular, MixedT-g plots are located atop
moderately deep and burrowed soils of the Eastern Marine Terrace, whereas MixedT-h
plots are distributed atop the deepest and most heavily burrowed soils island-wide.
35
Vegetation map
The final vegetation map identifies thirteen vegetation mapping units in addition
to two non-vegetated layers (bare, anthropogenic) (Figure 5). A list of the mapping units
and the percent of the island covered for each is provided (Table 8). Total area mapped is
18 ha (-180,000 m2) (63% of the island surface) comprising 222 polygons. The most
extensive plant community is LamaT and covers 60% of the mapped area. Included are
two mapping sub-units of LamaT (“lush” and “bare”; Table 8) that were mapped
separately to illustrate extreme differences in substrate type and habitat. The “lush” sub
unit (LamaT-1) refers to concave areas with dense stands of L. maritima (>50% absolute
cover). The “bare” sub-unit (LamaT-b) depicts areas with high soil exposure (bare
ground cover > 25%). Two categories of MixedT (“grassland” and “herbaceous”)
differentiate annual grass-dominated regions from non-native herbaceous areas. One
outlier plot classified as TeteT has very high species richness (=12) and low T.
tetragonioides cover (24%) relative to other TeteT plots, therefore, the respective
polygon is mapped as MixedT-h. Four non-herbaceous species define separate mapping
units, as well as one continuous patch of Rumex acetosella. Anthropogenic areas cover
approximately four percent (35 polygons) of the total mapped area and include trails,
structures, buildings, and ruderal features (e.g. foundations, concrete). Coastal cliff areas
likely have sparse coverage of halophytic species (e.g. S. macrotheca), but we were
unable to sample or map these areas due to wildlife sensitivity and inadequate imagery.
36
Table 8 Summary table of mapping units. Polygon size was calculated in ArcGIS (WGS84, UTM ION)
Mapping unit Databasecode
U of polygon
Min. size (m2)
Max. size (m2)
Avg. size (m2)
Total area (m2)
Lasthenia m aritim a type LamaT 65 25 8,478 1,157 77,493
Lasthenia m aritim a type, “lush” mapping sub-unit LamaT-1 9 52 4,907 1,246 11,216
Lasthenia m aritim a type, “bare” mapping sub-unit LamaT-b 10 211 3,750 1,602 16,017
Spergularia m acrotheca type SpmaT 20 60 2,405 745 14,145
Tetragonia tetragonioides type TeteT 15 109 3,823 1,202 18,033
Plantago coronopus type PlcoT 11 16 5,408 853 9,385
Mixed vegetation type, “grassland” category MixedT-g 16 42 2,017 633 10,124
Mixed vegetation type, “herbaceous” category MixedT-h 30 52 2,100 497 13,424
Coprosm a repens mapping unit* CoreMU 1 n/a n/a n/a 19
H esperocyparis m acrocarpa mapping unit* HemaMU 2 93 98 96 191
M alva arborea mapping unit* MaarMU 1 n/a n/a n/a 205
Pinus radiata mapping unit* PiraMU 1 n/a n/a n/a 103
Rum ex acetosella mapping unit RuacMU 1 n/a n/a n/a 160
Bare soil mapping unit BareMU 5 29 412 170 849
Anthropogenic mapping unit AnthroMU 35 7 2,064 228 7,990
T o ta l 179,354
*Non-herbaceous vegetation mapping unit
37
123°00'W
37°42'N
Lasthenia m aritima type
Spergularia m acrotheca type
Tetragonia tetragonioides type
1 Piantago coronopus type
Mixed vegetation type, annual grassland
Mixed vegetation type, herbaceous*
Non-herbaceous vegetation**
Bare soil
I Anthropogenic feature
Figure 5 Vegetation map of Southeast Farallon Island, California. The mapping sub-units of the Lasthenia maritima type are not symbolized due to scale.
*Mixed herbaceous category includes RuacMU.
**Non-herbaceous category includes CoreMU, HemaMU, PiraMU, and MaarMU.
38
Map Accuracy
Due to the small area (29 ha) of Southeast Farallon Island and limited distribution
of most classified vegetation types, 45 data sample points (Figure 6) were required for a
formal accuracy assessment (AA) (Grossman et al. 1994). We evaluated producer’s
accuracy (errors of omission), which is the probability that the map actually represents
what was found on the ground, and users’ accuracy (errors of commission), which is the
probability that a test data point has been mapped correctly. The overall thematic
accuracy of classified vegetation type mapping units is 90% (Table 9). Mean producer’s
accuracy for the five units is 91.6%, while user’s accuracy averaged slightly lower at
90.8%.
Table 9 Error matrix of user and producer accuracy for classified vegetation type mapping units. A class accuracy standard of 80% (Grossman et al. 1994; Jennings et al. 2009) was exceeded for all five units.
Reference Data
SpmaT LamaT TeteT PlcoT MixedT TOTALS User’sAccuracy
SpmaT 10 1 11 91%
LamaT 19 1 1 21 91%
TeteT 1 6 7 86%
PlcoT 4 4 100%
MixedT 1 6 7 86%
TOTALS 10 22 7 4 7 50
Producer’sAccuracy 100% 86% 86% 100% 86%
Overall Accuracy (10+19+6+4+6)750 = 90%
39
Inspection of the errors shows that most inconsistencies occur among LamaT
polygons with co-dominant species. Plant phenology varied greatly between ground
truthing (spring 2014, zero to early bloom) and map AA (spring 2015, full bloom to early
senescence). The AA surveyor’s on-ground perspective therefore differed from the
validator’s, leading to opposing conclusions on assigning a vegetation type for five (9%)
of the AA test data points (see Table 9). Three LamaT polygons were incorrectly mapped
as SpmaT, TeteT, and MixedT by the orthoimagery interpreter and have since been
corrected in the dataset. Two LamaT polygons were assigned as either TeteT or MixedT
by the A A surveyor due to the increased cover most herbaceous species in 2015, but were
kept as LamaT in the dataset and noted of its invaded composition.
Given that the primary source of error appears to be related to the confusion of
seasonal co-dominance, we are confident that our overall accuracy is quite high. That
said the final vegetation map represents a temporal snapshot of several annual-dominated
types. The extent and location of plant communities will likely shift year-to-year and may
drastically change over time due to the ephemeral nature of annual plants, climate change
effects, and resource management impact.
40
MaintopBay
37°42'N
123 00'W
B reak
Lasthenia m aritima type
Spergularia m acrotheca type
V Tetragonia tetragonioides type
A | Plantago coronopus type
Mixed vegetation type, annual grassland
O Mixed vegetation type, herbaceous*
Non-herbaceous vegetation**
Bare soil
I Anthropogenic feature
A c c u r a c y —a s s e s s m e n t
p o in t- V e g e t a t io n
s a m p l in gp lo t
Figure 6 Map of accuracy assessment (AA) points.
20
15
, Ja
mie
H
aw
k
41
Invasive species modifier
Polygons dominated by T. tetragonioides (i.e. TeteT mapping units) account for
approximately 10% of the mapped area (Table 10). Additional polygons that have a T.
tetragonioides modifier, indicating some amount of the species is present, represent
another 30 percent of the mapped area. Nearly 70 percent (5 hectares) of this latter
category consists of T. tetragonioides occurring in LamaT and SpmaT, indicating the
invasive species is a direct competitor with the native communities on Southeast Farallon
Island.
Table 10 Summary of area mapped with Tetragonia tetragonioides modifier.
T. tetragonioides modifier Area (m2) Proportion of mapped area
TeteT mapping unit 18,033 10%
3- Severe* 16,634 9%
2- Moderate 18,445 10%
1- Minimal 38,344 21%
73,423 40%
1 = Minimal: Generally less than 5% cover of T. tetragonioides in the polygon.
2 = Moderate: Approximately 5-10% cover of T. tetragonioides over most o f the polygon.
3 = Severe: Over 10% cover of T. tetragonioides is in the polygon, often a co-dominant to other vegetation.
* In this table T. tetragonioides modifier “severe” does not include polygons in the TeteT mapping unit.
An estimated 95 percent of T. tetragonioides plants are sprayed with herbicide
annually, with hand-pulling occurring opportunistically (Irwin and Buffa 2004, unpubl.).
While our vegetation surveys and field mapping efforts were conducted before annual
herbicide spraying and all 42 plots were spared from treatment (some accidental
overspray reportedly occurred), the extent and impact of control efforts are unknown and
no clear boundaries of treatment regime or intensity exist. That said, TeteT may be more
42
widespread and T. tetragonioides more dominant than our map and data suggest, and the
type and species distribution may significantly change with continued eradication efforts.
Short-term benefits of herbicide treatment are evident within our vegetation
survey data. For example, the absolute cover of T. tetragonioides increased seven-fold
(from 10 to 70%) by the second year of herbicide restriction in five plots on Lighthouse
Hill (Figure 7). Furthermore, species richness decreased by 60 percent and native species
(L. maritima, C. perfoliata, A. spectabilis, S. macrotheca) were nearly absent by 2014.
Indeed there is strong evidence to support annual herbicidal treatment targeting T.
tetragonioides on Lighthouse Hill, and with consistent and effective treatment the species
may be eradicated from Southeast Farallon Island.
Figure 7 Herbicide treatment effect within Tetragonia tetragonioides type. Relative absolute cover of 5 sample plots on Lighthouse Hill were compared between 2013 and 2014. The figure on the left shows survey data one year after herbicide spray restriction, and the right-hand figure shows survey data two years after herbicide restriction. Native species (Amsp, Clpe, Spma; Table 1) were absent by 2014 with the exception of L. maritima.
Urur
2013 2014
43
Disturbance and invasive species
Non-native species are present in 93 percent of the sampling plots (Figure 8).
Overall vegetative cover (excluding substrate) is dominated (>50%) by invasive species
in nearly half the plots. Plots with zero cover of native species (n=3) are classified as
TeteT, whereas predominately (or entirely) native plots are within LamaT or SpmaT.
1 23 '00’W
37 42’N
Total vegetative cover*
Native - o - Exotic
Lasthenia m aritima type
Spergularia m acrotheca type
Tetrogonia tetragonio ides type
§ Plantago coronopus type
Mixed vegetation type, annual grassland
Mixed vegetation type, herbaceous
1 Anthropogenic feature
*Excludes substrate
V e g e t a t io ns a m p l in gp lo t
Figure 8 Map of non-native vegetative cover (excludes substrate) in 42 plots on Southeast Farallon Island.
© 2
01
5,
Jam
ie
Ha
wk
44
One hundred percent (42 plots) of the vegetation samples show some evidence of
disturbance (wildlife or anthropogenic) within the immediate vicinity of the plot
boundary. The most common disturbance is caused by humans (93%, 39 plots) with
monitoring boxes, trails, and rock walls the most commonly recorded categories (Figure
9). Plots with heavy anthropogenic disturbance (5+ categories, n=6) have high species
richness (7.3±2.7), a larger ratio of non-native species (3.8:1), and a greater proportion of
vegetative cover of non-native plants (67±29%). These heavily disturbed plots are
classified as MixedT, TeteT, or LamaT (n=2 per type). While 70 percent of all plots are
located within 25 m of a trail or walkway, the plots most heavily disturbed by humans
have a trail within or directly adjacent (<5m) to its boundary.
M onitorin g boxes j
Trail \
Rock wall j
Debris
H erbicide
C on crete
Stru cture
Foundation
Utility p ipe
Building
10
Number of plots
15
SpmaT
LamaT
TeteT
PIcoT
MixedT
20
Figure 9 Anthropogenic disturbance categories recorded per plot.
45
Seabird burrows were recorded in 76 percent of the vegetation sample plots in
varying densities (0.03-0.45/m2). Plots with relatively high burrow density (>0.20/m2,
n=8) are classified as LamaT, MixedT, and TeteT and are located on the Marine Terrace
and talus slopes of Lighthouse Hill. Similar to plots with heavy anthropogenic
disturbance, these densely burrowed plots have high species richness (6.3±2.7), a larger
ratio of non-native species (mean-2.4:1), and a greater proportion of vegetative cover of
non-native plants (55±34%). These burrowed plots have deep soils (11.2±4.1 cm) and
moderate litter cover (4±4%), and with the exception of one outlier plot near the island
perimeter, soils are extremely to strongly acidic (pH=4.8±0.6) and non-saline
(EC1:1=0.537±0.435 dS/m).
Dense wildlife colonies (marine mammal and murre) directly impact five plots
located along the outermost perimeter of the island. All colony plots are classified as
LamaT and have very low species richness (2.7±1.5), an even ratio of non-native to
native species (1:1), and little proportion of non-native vegetative cover (3±3%). These
colony plots have moderately deep soils (8.9±5.7) with very high cover of rocky substrate
(22±18%) and bare ground (22±15%). Soils are strongly acidic to neutral (pH=5.3±1.0)
and are slightly to very saline (EC1:1=4.012±3.172 dS/m).
Plots lacking any anthropogenic disturbance and/or seabird burrowing are
classified as native plant communities (SpmaT, LamaT) and have low frequency and
minimal cover of non-native species. Plots with zero anthropogenic disturbance
categories (n=3) are located on the Western Marine Terrace and have low species
46
richness (4.7±1.2) and low non-native vegetative cover (6±3%). Plots with zero seabird
burrow counts (n=10) are located on cool, rocky slopes and thin-soiled lowland areas
(e.g. Western Marine Terrace). These plots have low species richness (3.7±1.7) and low
non-native vegetative cover (5±4%).
47
DISCUSSION
Native plant communities
The Lasthenia maritima type (LamaT) may be defined as the constant community
on Southeast Farallon Island. The wide distribution illustrates a tolerance for varying
degrees of edaphic conditions and disturbance. As an ornithocoprophilous native plant
species (Ornduff 1965), L. maritima has botanical records from various seabird colonies
along the coast of Western North America. Vasey (1985) noted the range for the species
strongly corresponds to the flight pattern of the Western gull, and that cypselae (achene-
like fruit) have often been found embedded in the feathers of dead birds. Plants adapted
to life on seabird-nesting islands are uniquely adapted to handle guano-derived soils high
in Nitrogen and Phosphorous that are often acidic and physically disturbed (Ellis 2005).
The environmental tolerances of L. maritima are unknown, however its unique edaphic
adaptations suggest a remarkable biology (Desrochers & Dodge 2003). On Southeast
Farallon Island, for example, L. maritima grows in some of the most acidic, saline and
disturbed soils island-wide.
Major marine mammal haul-out areas and dense seabird congregations overlap
with LamaT around the island perimeter. High inputs of ammonia and heavy trampling
could explain the ‘scorched earth’ effect, with extensive bare ground (“wallows”), limited
species richness, and little microbial activity common effects (Smith 1978). Wildlife
participating in sea-going activity and the continuous input of salt spray supplies soluble
salts to colony zones and result in extremely saline soil conditions (Smith 1978). Plots
48
within or adjacent to wildlife colonies on Southeast Farallon Island contain all of these
descriptors, with L. maritima typically the only species able to withstand such harsh
environmental conditions.
Spergularia macrotheca is a halophytic (salt-tolerant) species (Flowers et al.
1986) that is widely distributed in coastal environments, wetlands, and alkaline sinks in
California (Baldwin et al. 2012). The species has a tolerance for extreme soil salinity
(Okusanya & Unger 1984) and is a perennial herb with succulent, glandular leaves and a
stout taproot (Baldwin et al. 2012). The indicator value for this species reached its
maximum in sampling plots on the upper Marine Terrace (adjacent to Maintop Bay, see
Figure 1) where the low-growing S. macrotheca blankets rocky outcrops and thin-soiled
areas. The S. macrotheca type (SpmaT) is nearly void of senesced plant debris, likely
reflecting its perennial life history, the absence of annual grasses, and/or low physical
disturbance. Westerly winds are high in the SpmaT region and likely contribute to
drought conditions and sea spray effects typical of the coastal strand (Barbour 1978).
Soils are slightly saline (see Table 5), suggesting a salinity gradient may affect its
distribution on Southeast Farallon Island. Isolated patches of S. macrotheca are
distributed along the island perimeter (see Figure 5) where maritime effects are strongest,
but we were unable to sample these soils and therefore cannot gauge its salinity tolerance
on the island.
49
Non-native plant communities
The Tetragonia tetragonioides type (TeteT) is one of three invaded plant
communities on Southeast Farallon Island. The plant is recognizable by its fleshy
triangular-ovate leaves and dense, sprawling growth form (Baldwin et al. 2012). T.
tetragonioides is a weed of international distribution (Gray 1997) and commonly invades
coastal areas and many islands in California (e.g. Knapp et al. 2009). The species T.
tetragonioides has a tolerance for hot and dry conditions (Neves et al. 2005; Masakazu et
al. 2008). Observational evidence suggests its broad leaves collect fog drip and shade the
soil below, enabling the annual plant to behave perennially on Southeast Farallon Island
(pers. comm. 2015, Pete Warzybok, biologist). TeteT dominates the south face and talus
slopes of Lighthouse Hill where potential solar radiation (McCune & Keon 2002) values
are high and soils are shallow, reflecting its tolerance for low soil moisture. As a known
halophyte (Wilson et al. 2000; Neves et al. 2005, 2006, 2008; Yousif et al. 2010) T.
tetragonioides has an extreme salinity threshold (Hasanuzzaman et al. 2014), however,
TeteT unexpectedly dominates areas on Southeast Farallon Island where soil salinity is
lowest (see Table 5). Furthermore, T. tetragonioides co-dominates three of the least-
saline plots of LamaT (0.328 and 454 dS/m) and SpmaT (0.585 dS/m). This phenomena
may be indicative of the desalination capability of T. tetragonioides (Hasanuzzaman et al.
2014) whereby ions are extracted from the soil and stored in its succulent leaves (Neves
et al. 2005).
50
The Plantago coronopus type (PlcoT) is the most diverse community and is
characterized by very several strong, albeit non-dominant, indicator species (see Table 6).
P. coronopus is an important component in this type and is recognized by its basal rosette
of purple-green leaves and spikes of inconspicuous flowers (Baldwin et al. 2012). As a
halophyte, P. coronopus can withstand saline soils (Blacquiere & Lambers 1981; Koyro
2006) and is distributed throughout most disturbed areas of the U.S., including coastal
bluffs and salt marshes (DiTomasso & Healy 2007; Baldwin et al. 2012). A perennial
plant, P. coronopus can live up to twelve years and its spikes with intact capsules often
persist through winter (DiTomasso & Healy 2007). PlcoT grows in dense patches where
P. coronopus and other low-growing herbs (e.g. C. perfoliata, S. oleraceus) and grasses
(e.g. H. murinum, F. bromoides) form a thick fibrous mat of vegetative growth atop
rocky, moderately deep soils in the Eastern Marine Terrace.
The remaining community may be defined as the most loosely-defined non-native
plant community on Southeast Farallon Island as is therefore named: Mixed vegetation
type (MixedT). MixedT is characterized by two distinct vegetation compositions: annual
grassland and non-native herbaceous. B. diandrus and U. urens are each indicator species
for MixedT, but the former better represents the grassland category (MixedT-g) while the
latter helps characterize the herbaceous category (MixedT-h). The European annual grass
B. diandrus has long straight awns and sharp florets (Baldwin et al. 2012) and is ranked
as a moderate invasive species in California (Cal-IPC 2006). B. diandrus is commonly
associated with disturbed soils that have relatively high water and nitrogen availability,
51
moderate ammonium concentration (Hoopes & Hall 2002), and moderate salinity (Kolb
& Alpert 2003), possibly reflecting why MixedT-g dominates deep soils of the Eastern
Marine Terrace. MixedT-h comprises numerous non-native and cosmopolitan species
common to disturbed areas in California, including two plants ranked as limited invaders
to California (E. cicutarium, R. crispus; Cal-IPC 2006). The proximity of MixedT-h to
impervious trails, buildings, and structures suggests anthropogenic disturbance and water
run-off are important distributional factors. The native plant A. spectablis thrives among
the non-native herbaceous category and L. maritima is a co-dominant in all MixedT plots,
therefore invasive plant control efforts should proceed with caution.
Edaphic constraints
Our study elucidates several topo-edaphic gradients that affect dominance of
native and non-native plant species on Southeast Farallon Island, including soil salinity
and pH. Microenvironmental gradients of salt spray and soil salinity (calculated by
electrical conductivity, EC) have been measured and noted as one of the controlling
factors in the distribution of coastal plants (Barbour 1978). Generally speaking, soil with
ECi-i values higher than 0.980 dS/m are considered saline (see Table 1) and are only
suitable for plants with some level of salt tolerance (USDA 2001). Growth inhibition
under saline conditions as compared with non-saline conditions is partly due to shortage
in energy (Blacquiere & Lambers 1981). NaCl transport, root respiration, and repair of
salt damage require extra energy, and glycophytes therefore have high mortality in saline
environments (Barbour 1978; Hasanuzzanman et al. 2014). As expected, soil salinity
52
(measured as electrical conductivity, EC) is very high near marine mammal and murre
colony outlier plots (4.012±3.173 dS/m) on Southeast Farallon Island where wildlife,
seawater inundation, and salt spray directly contribute soluble salts to the environment.
The highest EC values were recorded in native LamaT and SpmaT communities,
suggesting the salinity gradient plays a role in their community structures. Otherwise
soils are non-saline to very slightly saline across the island (0.625±0.400 dS/m, excluding
colony plots), factors contributing to habitat suitability for the numerous non-native
glycophytic plants.
Acidic soils are typical of seabird colonies because alkaline guano increases soil
acidity as it decomposes (Ellis 2005) as demonstrated by other soil studies within seabird
colonies (e.g. McCain 1975; Magnusson & Magnusson 2000; Mulder & Keall 2001;
Smith 2003; Durrett et al. 2014). As expected, soil pH is generally acidic on Southeast
Farallon Island (5.1±0.7) and, based on USDA soil reaction classes (see Table 2),
recorded values range from “ultra acid” to “neutral”. The highest pH values were
recorded in the wildlife colony plots, suggesting extreme soil salinity stymies microbial
activity (see Table 2) and therefore decreases the decomposition rate of alkaline guano
(Gillham 1956b; Smith 1978), resulting in higher pH values. Although soil pH is not a
statistically significant variable of the NMDS ordination, the general trend is typical of
guano-rich soils in seabird colonies.
A more thorough chemical and structural analysis of the island soil complex (e.g.
nutrient levels, guano indices, hydric regime) is needed to further interpret soil salinity
53
and pH results and to investigate related vegetation patterns. Our study illustrates L.
maritima can tolerate soils with high salinity (max EC1:1=8.756 dS/m) and acidity (min
pH= 4.1) and dominates areas with both shallow and deep soils (3 to 17 cm), thereby
explaining its constancy across the island. Southeast Farallon Island provides a unique
opportunity to research plant species responses to extreme edaphic conditions typical of
seabird colony islands (Ellis 2005). Furthermore, determining species environmental
thresholds aid in predicting plant invasions and are particularly significant for vulnerable
areas such as islands (Kueffer et al. 2010).
Island diversity
The total species richness is lower compared to the richness recorded in mainland
coastal alliances (Sawyer et al. 2009) and somewhat larger oceanic islands (Junak et al.
1995; Moody 2001). Our study recorded a significantly high percentage of non-native
(80%) and Cal-IPC ranked invasive (25%) plant species on Southeast Farallon Island, a
large proportion for an island of its small size (29 ha) and isolation (~40 km).
Potential phenomena affecting island invasibility include anthropogenic history,
disturbance, environmental heterogeneity, community structure, propagule pressure,
species traits (invasiveness), and stress (Alpert et al. 2000), factors that undoubtedly
interact and likely explain the large proportion of non-native plants Southeast Farallon
Island. Community structures lacking native endemic plant diversity and without strong
interactions between species are more susceptible to invasion (Alpert et al. 2000). More
diverse native communities theoretically use resources more completely and reduce their
54
availability to potential invaders, thereby strengthening native competition and reducing
replacement rates (Tilman 1997). Only five native species were recorded in our
vegetation sampling data for Southeast Farallon Island (Table 1; see Appendix 1 for full
species inventory), with L. maritima dominating the majority of the plots. Southeast
Farallon Island has little habitat diversity due to its small size (29 ha) and elevation range
(0-105 m), thereby lacking the topographic change required for greater spatial variability
in precipitation, wind, temperature, and fog regimes. Furthermore, harsh maritime
conditions likely increases propagule pressure and geographic isolation decreases the
colonization rate of many mainland plant species. Some native endemics were possibly
eliminated by humans prior to systematic botanical surveys, which did not begin on
Southeast Farallon Island until the late 1800s (Blankinship & Keeler 1892). Therefore,
the native plant communities on Southeast Farallon Island (SpmaT, LamaT) lack
diversity, suggesting a high susceptibility to invasion by non-native plants.
Disturbance
Islands with extensive histories of anthropogenic disturbance are commonly
plagued by biotic invasion (Kueffer et al. 2010). Our study supports the notion that
disturbance, particularly past and current land use, is one of the most influential factors in
the frequency of plant invasion. Vegetation types containing evidence of prior
anthropogenic disturbance (foundations, rock walls, debris) and current land use
(buildings, monitoring boxes) have high non-native plant occurrence and cover.
Furthermore, zones adjacent to impervious trails and surfaces are particularly high in
55
non-native herbaceous cover (e.g. MixedT-h mapping category) likely due to seed
dispersal and the accumulation of precipitation runoff. In general, the correlation of
anthropogenic disturbance with the occurrence of non-native plant species is consistent
throughout most vegetation types.
Auklet burrowing is also related to non-native species occurrence and dominance,
albeit to a lesser degree. Bioturbation contributes to seed bank agitation and subsequent
non-native plant germination (Ellis 2005). While other edaphic characteristics contribute
to site invasibility of burrowed areas (depth, moisture, nutrients), soil excavation and
exposure likely play an important role in non-native plant establishment and dominance.
The ordination analysis detected a burrow density gradient (albeit not statistically
significant; P=0.07) possibly affecting the ruderal vegetation types on the Marine
Terrace. Burrow density is lowest in SpmaT and PlcoT areas where soils are generally
rocky and shallow, whereas burrow density is high among the other types as long as soils
depth is adequate.
That said, a plot with very high burrow density (=0.34/m2) is within a lush L.
maritima patch on the north side of the island. This area is consistently high in burrow
density (Warzybok et al. 2006) as deep soil and oceanic access provides ideal habitat
characteristics (USFWS 2005), with this zone is designated as de facto wilderness by the
U.S. Fish & Wildlife Service. Anthropogenic disturbance is negligible on the north side
of Southeast Farallon Island and observational evidence suggests the area has few non
native species present. Targeted research within the wilderness zone could illustrate the
56
true effects of disturbance, natural or otherwise, on vegetation communities of Southeast
Farallon Island.
Implications for management
Vegetation classification and fme-scale mapping efforts provide numerous
benefits to land management, including the development of a common language, the
contribution to ecological understanding, the identification of plant communities prone to
invasion or habitat degradation, and the provision of baseline environmental and
vegetation conditions. These benefits enable management efforts to be more effective in
their conservation tactics, facilitate long-term research, and monitor change over time
(Grossman et al. 1998).
A primary goal of the USFWS and Point Blue Conservation Science is to restore
lost or degraded seabird habitat by eradication or control of invasive vegetation proven to
have negative impacts to nesting or roosting sites on Southeast Farallon Island (USFWS
2005; USFWS 2009). Our study provides preliminary evidence that auklets burrow
densely (>0.20/m2) within most plant communities on Southeast Farallon Island (even
those dominated by non-native species) as long as soil depth is adequate (>10 cm) and
rocky substrate minimal. Burrow counts were unexpectedly high underneath dense stands
of T. tetragonioides and B. diandrus on the Marine Terrace and talus slopes of
Lighthouse Hill, potentially indicating soil moisture and root depth compensate for the
lack of other habitat characteristics. The perennial nature and dense growth form of T.
tetragonioides may provide a microhabitat of cool and humid atmospheric conditions
57
relative to outside summer temperatures (Gillham 1956a). The thin, long root systems
(>15 cm) of B. diandrus (DiTomasso & Healy 2007) may stabilize burrow walls and
prevent entrance collapse (Gillham 1956a; Hornung 1981; Furness 1991; Bancroft et al.
2005b; Cadiou et al. 2010). These non-native species may provide short-term habitat
benefits, but observational evidence suggests impenetrable mats of T. tetragonioides
eventually blocks burrow entrances and annual grasses decrease auklet mobility,
subsequently increasing predation risk by gulls (pers. comm. 2015, Pete Warzybok,
biologist). Targeted fine-scale and long-term research is required to draw any firm
conclusions of non-native vegetation impacts (positive or negative) to seabird burrowing
habitat, and Southeast Farallon Island provides an ideal system to study seabird-
vegetation relationships.
A seed bank analysis on Southeast Farallon Island (Chasey 2015, unpubl. data)
illustrates that a plethora of viable non-native seeds await germination in the majority of
our 42 sample plots. Since seeds are likely recruited by humans and colonial avifauna
(e.g. Western gull) alike, controlling seed transport is nearly impossible. Therefore,
understanding the physical factors contributing to site invasibility and knowing the
composition of the underlying seed bank are critical steps in planning resource
management tactics. By focusing non-native species control efforts on areas adjacent to
trails and walkways, managing agencies U.S. Fish & Wildlife Service and Point Blue
Conservation Service can more effectively maintain the integrity of native communities
on Southeast Farallon Island.
58
CONCLUSION
In this study, our classification provides the first quantitative description of
Southeast Farallon Island vegetation and invasive plant infestation levels, providing a
highly accurate (90%) vegetation map to assess plant community patterns and targeted
invasive species. Not unexpectedly, the largest grouping of sample plots (45%) was
classified into the L. mar/Ywza-characterized vegetation type (LamaT). As an
omithocoprophilous native plant species (Omduff 1965), L. maritima dominates the
majority of Southeast Farallon Island and thrives in a wide range of habitats. Our
multivariate approach allowed the various degrees of ecological and floristic similarity to
be represented within the five classified vegetation types. The vegetation on Southeast
Farallon Island represents a strict category of herbaceous vegetation that can withstand
the harsh climate, unique edaphic characteristics, and disturbance regime of a seabird
colonized oceanic island with a long history of human influence. The island offers an
exceptional opportunity to identify ecosystem characteristics beneficial to non-native
plant species and our study poses numerous avenues of further ecological research.
59
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Appendix 1 Plant species inventory, 1892-2015. Nomenclature follows The Jepson Manual, 2nd Edition (Baldwin et al. 2012) therefore some Latin binomials may not match original documents. Species recorded in one or more inventory are provided.
SpeciesBlankinship
& Keeler 1892
O rnduff1961
Coulter1971
Coulter1978
Coulter1985-
2001**
Coulter & Irwin 2005***
2013-2015
Amsinckia spectabilis • • • • • •
Anagallis arvensis*
Avena barbata* f
72
SpeciesBlankinship
& Keeler 1892
O rnduff1961
Coulter1971
Coulter1978
Coulter1985-
2001**
Coulter & Irwin2005***
2013-2015
Lasthenia maritima • • • • • • •
Leontodon saxatilis*
Lepidium didymum*
Malva arborea*
Malva neglecta*
Malva parviflora*
Malva pseudolavatera*
Medicago polymorpha* |
Melilotus indicus*
Montia fontana
Oxalis pes-caprae*t
Polygonum aviculare ssp. depressum *
Polypogon monspeliensis
Polystichum munitum
73
SpeciesBlankinship
& Keeler 1892
O rnduff1961
Coulter1971
Coulter1978
Coulter1985-
2001**
Coulter & Irwin2005* * *
2013-
2015
Spergularia media* • • • • • •
Stell aria media* • • • • • •
Tetragonia tetragonioides* t • • • • •
Trifolium bifidum var. decipiens •
Trifolium fucatum • • •
Trifolium microcephalum •
Trifolium variegatum • •
Trifolium sp. • •
Urtica urens * • • • • •
Zantedeschia aethiopica • • • • •
* Non-native to California
t Invasive according to California Invasive Plant Council
**Coulter provided unpublished species lists to the U.S. Fish & Wildlife Service in 1985, 1988, 1991, 1997 & 2001 .
***Coulter & Irwin’s (2005) report to the U.S. Fish & Wildlife Service is the most recent unpublished document about vegetation on Southeast Farallon Island.
74
Appendix 2A Vegetation type descriptive key. Cover refers to relative absolute cover values (averagedamong type plots, does not average zeros). Characteristic species typically have lower absolute cover (5-15%) but help typify the vegetation type.________________________________________________________
1. Spergularia macrotheca type (SpmaT)
MEMBERSHIP RULES
Diagnostic species (P>0.05): Spergularia macrotheca, Lepidium didymum
Dominant species (40-100% cover) Spergularia macrotheca
Co-dominant species (15-40% cover) n/a
Characteristic (variable cover) Lepidium didymum
Sparse species (<10% cover) Claytonia perfoliata, Lasthenia maritima, Poly carpon tetraphyllum, Spergularia media, Tetragonia tetragonioides
HABITAT CHARACTERISTICS The Spergularia macrotheca type (SpmaT) is found in thewestern half of the upper Marine Terrace where soil is thin and gravelly and westerly winds are high, contributing to drought conditions, sea spray, and subsequent salinized soils. As a perennial succulent species, the SpmaT region is nearly void of senesced plant debris, which may also be indicative of annual grass absence and low seabird burrowing activity. The total cover of S. macrotheca ranges from 43 to 60 percent and nearly blankets rocky outcrops throughout the SpmaT region.
Soil depth (cm): 8.7±3.3
Soil pH: 5.3±0.3
Soil salinity (EC1:1, dS/m): 0.813±0.328
REMARKS S. macrotheca is a halophytic (salt-loving) species that canwithstand saline environments. Wildlife sensitivity prohibited us from surveying vegetation and sampling soils near marine mammal colonies, but observational evidence suggest S. macrotheca grows in small clumps throughout these areas.
MANAGEMENT CONSIDERATIONS Tetragonia tetragonioides is abundant throughout SpmaT,therefore herbicide should be applied with precision as to not affect surrounding native plant community.
75
1. Spergularia macrotheca type (SpmaT)
TYPE PHOTOS
Photo credit: Holzman, 2015
Photo credit: Holzman, 2015
Photo credit: Holzman, 2015
Photo credit: Holzman, 2015
Photo credit: Holzman, 2015
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2. Lasthenia maritima type (LamaT)
Appendix 2B Vegetation type descriptive key. Cover refers to relative absolute cover values (averagedamong type plots, does not average zeros). Characteristic species typically have lower absolute cover (5-15%) but help typify the vegetation type.
MEMBERSHIP RULES
Diagnostic species (P>0.05):
Dominant species (40-100% cover)
Co-dominant species (15-40% cover)
Lasthenia maritima
Lasthenia maritima,
Spergularia macrotheca, Lepidium didymum, Tetragonia tetragonioides
Characteristic species (variable cover) n/a
Sparse species (<10% cover) Bromus diandrus, Claytonia perfoliata, Hordeum murinum, Plantago coronopus. Spergularia media, Stellaria media, Ur tic a urens
HABITAT CHARACTERISTICS Lasthenia maritima type (LamaT) is widely distributed on rockyoutcrops and steep crags throughout most of Southeast Farallon Island, but is also found on concave portions of the Marine Terrace and north-facing slopes of Lighthouse Hill. In general, LamaT areas are fairly rocky but a subset of highly vegetated LamaT plots (n=5) are characterized by a near-continuous cover of L. maritima (>50% absolute cover). These lush plots are found in concave and deep-soiled (>10 cm) areas and are ideal for seabird burrowing habitat. Another subset of LamaT plots (n=6) are unique in that bare ground is extensive (>25% cover), suggesting the presence of a disturbance regime by either wildlife or anthropogenic land use. Several o f these exposed LamaT plots are adjacent to major sea lion haul out areas and murre congregations where high inputs of ammonia and heavy trampling could explain the ‘scorched earth’ effect common to land surrounding dense colonies. Soil salinity is extremely high (mean=6.380 dS/m) in these colony plots and restricts growth of nearly all plants but L. maritima (e.g. S. macrotheca, C. murale)
Soil depth (cm): 10.2±4.9
Soil pH: 5.0±0.8
Soil salinity (EC1:1, dS/m): 1.640±2.131
REMARKS L. maritima has no published environmental tolerances.
77
2. Lasthenia maritima type (LamaT)
TYPE PHOTOS
Photo credit: Chasey, 2015
Photo credit: Chasey, 2015
Photo credit: Holzman, 2015
Photo credit: Chasey, 2015
Photo credit: Chasey, 2015
78
Appendix 2C Vegetation type descriptive key. Cover refers to relative absolute cover values (averagedamong type plots, does not average zeros). Characteristic species typically have lower absolute cover (5-15%) but help typify the vegetation type.
3. Tetragonia tetragonioides type (TeteT)
MEMBERSHIP RULES
Diagnostic species (P>0.05): Tetragonia tetragonioides
Dominant species (40-100% cover) Tetragonia tetragonioides
Co-dominant species (15-40% cover) Lasthenia maritima
Characteristic species (variable cover) Bromus diandrus, Erodium moschatum, Hordeum murinum,Urtica urens
Sparse species (<10% cover) Claytonia perfoliata, Lepidium didymum, Stellaria media
HABITAT CHARACTERISTICS Tetragonia tetragonioides type (TeteT) is predominantly foundon the south face and talus slopes of Lighthouse Hill, indicating tolerance for thin soil and hot and dry conditions. The species has markedly high cover in TeteT classified plots, ranging from 24 to 83 percent. TeteT soils are consistently the least-saline on Southeast Farallon Island.
Soil depth (cm): 7.5±4.4
Soil pH: 5.2±0.6
Soil salinity (EC1:1, dS/m): 0.387±0.223
REMARKS Observational evidence suggests the broad leaves o f T.tetragonioides collect fog drip and shade the soil below, increasing soil moisture and enabling the annual plant to behave perennially. While T. tetragonioides is a known halophyte with an extreme salinity threshold, the species dominates areas on Southeast Farallon Island where soil salinity is low. Low salinity values may be a result of the T. tetragonioides’ capability to remove salts from the soil by accumulating ions in its plant tissue.
MANAGEMENTCONSIDERATIONS
This species is targeted for annual herbicide treatment, therefore the extent of TeteT may be more widespread than depicted on the inset map.
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3. Tetragonia tetragonioides type (TeteT)
TYPE PHOTOS
Photo credit: Chasey, 2015 Photo credit: Holzman, 2015
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Appendix 2D Vegetation type descriptive key. Cover refers to relative absolute cover values (averagedamong type plots, does not average zeros). Characteristic species typically have lower absolute cover (5-15%) but help typify the vegetation type.
4. Plantago coronopus type (PlcoT)
MEMBERSHIP RULES
Diagnostic species (P>0.05): Plantago coronopus, Sonchus oleraceus, Hordeum murinum, Festuca bromoides, Senecio vulgaris, Claytonia perfoliata
Dominant species (20-100% cover) n/a
Co-dominant species (10-20% cover) Plantago coronopus, Hordeum murinum, Bromus diandrus, Claytonia perfoliata
Characteristic species (variable cover) Sonchus oleraceus, Festuca bromoides
Sparse species (<10% cover) Lasthenia maritima, Lepidium didymum, Senecio vulgaris, Spergularia macrotheca, Stellaria media
HABITAT CHARACTERISTICS The ruderal Plantago coronopus type (PlcoT) is characterizedby six diagnostic species and high species richness. PlcoT is distributed on thin and matted soils of the marine terrace and easily recognized by the combined presence of three species. The perennial P. coronopus is the dominant species and recognized by its basal rosette of purple-green leaves and spikes of inconspicuous flowers (20-35% cover). The annual grass H. murinum has feather-like heads atop decumbent to erect stems (4-26% cover). The annual S. oleraceus has glabrous foliage with large terminal lobes on the lower leaves and clustered heads of yellow composite flowers. S oleraceus retains low total cover (1-4%) but has strong statistical fidelity in this type.
Soil depth (cm): 11.2±2.8
Soil pH: 4.9±0.7
Soil salinity (EC1:1, dS/m): 0.484±0.328
REMARKS
MANAGEMENT CONSIDERATIONS Soil depth is adequate for burrowing on a microscale, in somePlcoT plots, but observational evidence suggests fibrous root structures of H. murinum. Without adequate soil accumulation and access, auklet burrow density is lowest (mean=0.07/m2) compared to other vegetation types.
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4. Plantago coronopus type (PlcoT)
TYPE PHOTOS
Photo credit: Holzman, 2015
Photo credit: Holzman, 2015Photo credit: Holzman 2015
Photo credit: Holzman, 2015Photo credit: Holzman, 2015
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5. Mixed vegetation type (MixedT)
Appendix 2E Vegetation type descriptive key. Cover refers to relative absolute cover values (averagedamong type plots, does not average zeros). Characteristic species typically have lower absolute cover (5-15%) but help typify the vegetation type.________________________________________________________
MEMEBERSHIP RULES
Diagnostic species (P>0.05):
Dominant species (15-100% cover)
Co-dominant species (10-15% cover)
Bromus diandrus, Ur tic a urens
Bromus diandrus,
Lasthenia maritima, Urtica urens
Characteristic species (variable cover) Amsinckia spectabilis, Erodium cicutarium, Erodiummoschatum, Malva spp.
Sparse species (<10% cover) Chenopodium murale, Claytonia perfoliata, Hordeum murinum, Lepidium didymum, Plantago coronopus, Stellaria media
HABITAT CHARACTERISTICS The Mixed vegetation type (MixedT) is a heavily mixed and highly variable community. Soils have a wide range in salinity and pH due to varying geographic conditions. MixedT is characterized by two distinct vegetation compositions: annual grassland and non-native herbaceous. Three MixedT plots are dominated by B. diandrus (30±10% cover), and to a lesser extent H. murinum (0-15% cover), grasses that primarily grow atop thick and burrowed soils of the eastern Marine Terrace. MixedT plots characterized by dense stands of herbaceous non-natives such as C. murale, Erodium spp., Malva spp., and U. urens are found in close proximity to impervious trails and buildings, suggesting anthropogenic disturbance and water run-off are important distributional factors.
Soil depth (cm): 13.9±2.9
Soil pH: 5.6±0.89
Soil salinity (EC1:1, dS/m): 0.516±0.315
REMARKS B. diandrus is commonly associated with soils having relatively high water and nitrogen availability, moderate ammonium concentration (Hoopes & Hall 2002), and high salinity (Kolb & Alpert 2003), likely explaining its general invasive behavior and proliferation in deep soils on the island.
MANAGEMENTCONSIDERATIONS
The native plant Amsinckia spectablis thrives among the nonnative herbaceous category and Lasthenia maritima is a codominant in all MixedT plots (15±3% cover), therefore invasive plant control efforts should proceed with caution.
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5. Mixed vegetation type (MixedT)
TYPE PHOTOS
Photo credit: Holzman, 2015
Photo credit: Holzman, 2015
Photo credit: Holzman, 2015
Photo credit: Holzman, 2015
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Appendix 3 Metadata for vegetation map feature class.
Page 1 of 13
VEG_VegetationMap__SFSU_final_pyFile G eodatabase Feature C lass
Thumbnail Not Available
Tagsvegetation, plant community, vegetation type map, numerical classification, Southesat Farallon Island, San Francisco,
California
Sum m ary
This dataset was created to determine the extent and distribution of classified vegetation types and other land cover units on Southeast Farallon Island, California. Polygon mapping techniques included ground-based GPS, altitudinal vantage point, and on-screen digitizing methods. The geographic locations of 42 permanent vegetation plots and 14 additional training points were logged with a Trimble GeoXH GPS unit to sub-meter accuracy. Other standalone vegetation patches, obvious type edges, and prominent on-ground features (e.g. trails, foundation comers) were also mapped with the GPS unit. These baseline data files were brought into a GIS program (ArcMap 10.2, ESRI 2014) and analyzed against 1-meter National Agricultural Imagery Program (NAIP) digital orthoimagery (USDA-FSA) for horizontal accuracy. The flight that acquired the image was conducted in May 2012 when annual vegetation began to senesce. Distinct vegetation community polygons were digitized on screen ("heads up") at an average 1:1,000 scale for the Marine Terrace and other flat areas, but shadows prevented digitizing for most steep hillsides. Altitudinal vantage point mapping was completed for these areas and included the use of field maps printed with predigitized polygons (assigned and labeled with unique FID codes to relate them to the database), coloring pens, and binoculars. No exact minimum mapping unit was defined, but imagery resolution prevented mapping polygons less than 25 m2. Topology was enforced for the final vector feature class (shapefile) to ensure proper spatial relationships.
Description
Final version of the Vegetation Map feature class (shapefile) for Southeast Farallon Island, California.
Credits
Hawk, J.L. 2015. Classification, vegetation-environment relationships, and distribution of plant communities on Southeast Farallon Island, California. M.A. thesis, San Francisco State University, San Francisco, CA, US.
Use lim itations
While efforts have been made to ensure that these data are accurate and reliable within the state of the art, the author cannot assume liability for any damages or misrepresentation caused by any inaccuracies in the data or as a result of changes to the data caused by system transfers.
ExtentW est -123.006460 E ast -122.999757 North 37.700905 South 37.695769
Scale RangeMaximum (zoom ed in) 1:5,000 Minimum (zoom ed out) 1:50,000
ArcGIS Metadata ►
Topics and Keywords ►
* C o n t e n t t y p e Downloadable DataE x p o r t t o FGDC CSDGM XML f o r m a t a s R e s o u r c e D e s c r i p t i o n No
P l a c e k e y w o r d s Southeast Farallon Island, Farallon National Wildlife Refuge, San Francisco County, California, United
file :///C: AJsers/Jamie/AppData/Local/T emp/arc3 ADD/tmpCBEB .tmp.htm_________________ 5/13/2015
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Page 2 of 13
States
T h e m e k e y w o r d s vegetation type, plant community, classification
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* T it l e VEG_VegetationMap_SFSU_final_pyA l t e r n a t e t it l e s Vegetation Map of Southeast Farallon IslandC r e a t io n d a t e 2014-05-01 00:00:00 P u b l ic a t io n d a t e 2015-06-01 00:00:00
P r e s e n t a t io n fo r m a t s * digital mapF G D C g e o s p a t ia l p r e s e n t a t io n fo r m a t vector digital data
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R e s p o n s i b l e p a r t y
I n d iv id u a l 's n a m e Jamie HawkO r g a n iz a t io n ’s n a m e San Francisco State UniversityC o n t a c t 's p o s it io n Graduate Student C o n t a c t 's r o l e originator
C o n t a c t in f o r m a t io n ►
Ph o n e
V o i c e (408)307-9435
Ad d r e s s Type postalD e l iv e r y p o in t 1600 Holloway Avenue C it y San FranciscoA d m in is t r a t iv e a r e a CA P o s t a l c o d e 94132 C o u n t r y USe - m a il a d d r e s s j l h a w k @ m a i l . s f s u . e d u
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R e s p o n s i b l e p a r t y
I n d iv id u a l 's n a m e Barbara Holzman O r g a n iz a t io n ’s n a m e San Francisco State UniversityC o n t a c t 's p o s it io n Professor C o n t a c t 's r o l e point of contact
C o n t a c t in f o r m a t io n ►
Ph o n e
V o ic e (415)338-7506
Ad d r es s Ty pe postalD e l iv e r y p o in t 1600 Holloway Avenue C i t y San FranciscoAd m in istr a tiv e a rea CA Po sta l c o d e 94132 Co un try USe -m ail a d d r es s b h o lz m a n @ m a il.s fsu .e d u
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D a t a s e t l a n g u a g e s * English (UNITED STATES)D a t a s e t c h a r a c t e r s e t utf8 - 8 bit UCS Transfer Format
file:///C:/Users/Jamie/ADDData/Local/TemD/arc3ADD/taDCBEB.tmahtm 5/13/2015
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S t a t u s completedS p a t ia l r e p r e s e n t a t io n t y p e * vector
S p a t ia l r e s o l u t io n
D a t a s e t 's s c a l e
S c a l e d e n o m in a t o r 1000
• P r o c e s s in g e n v ir o n m e n t Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS 10.2.2.3552
C r e d it s
Hawk, J.L. 2015. Classification, vegetation-environment relationships, and distribution of plant communities on Southeast Farallon Island, California. M.A. thesis, San Francisco State University, San Francisco, CA, US.
ArcGIS item p ro p e r t ie s
* Na m e VEG_VegetationMap_SFSU_final_py ♦ S i z e 0 . 0 0 0
* Lo c a t io n file:/A\JAMIE-PC\Users\Jamie\Documents\FarallonIslands\GIS_data\SEFI_GIS_M ASTER.gdb* A c c e s s p r o t o c o l Local Area Network
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Extents ►
E x t e n t
D e s c r ip t io n
The dataset extent includes the vegetated surface Southeast Farallon Island, California, or approximately 63% of the island. Wildlife sensitivity and safety concerns prohibited sampling and mapping along the island perimeter, but observational evidence suggests little to no vegetation covers these areas.
G e o g r a p h ic e x t e n t
Bo u n d in g r e c t a n g l e
E x t e n t t y p e Extent used for searching* W e s t l o n g it u d e -123.006460* E a s t l o n g it u d e -122.999757* No r t h l a t it u d e 37.700905* S o u t h l a t it u d e 37.695769* E x t e n t c o n t a in s t h e r e s o u r c e Yes
T e m p o r a l e x t e n t
B e g in n in g d a t e 2012-06-01 00:00:00 E n d in g d a t e 2015-04-01 00:00:00
E x t e n t in t h e it e m ’s c o o r d in a t e s y s t e m
* W e s t l o n g it u d e 499430.516478* E a s t l o n g it u d e 500021.438697* S o u t h l a t it u d e 4172060.863180* No r t h l a t it u d e 4172630.690752* E x t e n t c o n t a in s t h e r e s o u r c e Yes
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Po in t o f c o n t a c t
I n d iv id u a l ’s n a m e Jamie HawkO r g a n iz a t io n ’s n a m e San Francisco State UniversityC o n t a c t ’s p o s it io n Graduate StudentC o n t a c t ’s r o l e originator
C o n t a c t in f o r m a t io n ►
Ph o n e
V o ic e (408)307-9435
A d d r e s s
T y p e postalD e l iv e r y p o in t 1600 Holloway Avenue C it y San FranciscoA d m in is t r a t iv e a r e a CA Po s t a l c o d e 94132
file:///C:/Users/Jamie/AppData/Local/Temp/arc3ADD/tmpCBEB.tmp.htm_________________ 5/13/2015
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C o u n t r y USe -m a il a d d r e s s [email protected] f s u . e d u
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Po in t o f c o n t a c t
I n d iv id u a l 's n a m e Barbara Holzman O r g a n iz a t io n 's n a m e San Francisco State UniversityC o n t a c t 's p o s it io n Professor C o n t a c t ’s r o l e point of contact
C o n t a c t in f o r m a t io n ►
Ph o n e
V o ic e (415)338-7506
A d d r e s s
TY p e postalD e l iv e r y p o in t 1600 Holloway Avenue C it y San FranciscoA d m in is t r a t iv e a r e a CA Po s t a l c o d e 94132 C o u n t r y USe -m a il a d d r e s s [email protected] f s u . e d u
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R e s o u r c e m a in t e n a n c e
U p d a t e f r e q u e n c y not planned
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Resource Constraints ►
C o n s t r a in t s
L im it a t io n s o f u s e
While efforts have been made to ensure that these data are accurate and reliable within the state of the art, the author cannot assume liability for any damages or misrepresentation caused by any inaccuracies in the data or as a result of changes to the data caused by system transfers,
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Spatial Reference ►
A r c G IS c o o r d in a t e s y s t e m
* T y p e Projected* G e o g r a p h ic c o o r d in a t e r e f e r e n c e GCS WGS 1984* P r o j e c t io n WGS_1984_UTM_Zone_10N* C o o r d in a t e r e f e r e n c e d e t a il s
Pr o j e c t e d c o o r d in a t e s y s t e m
W e l l - k n o w n id e n t if ie r 32610 X o r ig in -5120900 Y o r ig in -9998100 XY s c a l e 450445547.3910538 Z ORIGIN -100000 Z s c a l e 10000 M ORIGIN -100000 M s c a l e 10000 XY t o l e r a n c e 0.001 Z t o l e r a n c e 0.001 M t o l e r a n c e 0.001 H ig h p r e c is i o n true L a t e s t w e l l - k n o w n id e n t if ie r 32610W e l l - k n o w n t e x t PROJCS["WGS_1984JJTM_Zone_10N",GEOGCS[,,GCS_WGS_1984",DATUM
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["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0], UNIT ["Degree",0.0174532925199433]], PROJECTION [ ’Transverse_Mercator"], PARAMETER ["False_EastingH,500000.0],PARAMETER['’False_Northing",0 .0 ],PARAMETER["Central_MeridianV 123.0],PARAMETER["Scale_Factor",0.9996],PARAMETER["Latitude_Of_Origin",0 .0],UNrT["Meter", 1.0],AUTHORITY ["EPSG",32610]]
R e f e r e n c e s y s t e m id e n t if ie r
♦ V a l u e 32610* C o d e s p a c e EPSG • V e r s io n 8 . 2 . 6
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V e c t o r ►* Le v e l o f t o p o l o g y f o r t h is d a t a s e t geometry only
G e o m e t r ic o b j e c t s
F e a t u r e c l a s s n a m e VEG_VegetationMap_SFSU_final_py* O b j e c t t y p e composite* O b j e c t c o u n t 222
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F e a t u r e c l a s s n a m e VEG_VegetationMap_SFSU_final_py* F e a t u r e t y p e Simple* G e o m e t r y t y p e Polygon* Ha s t o p o l o g y FALSE* F e a t u r e c o u n t 222* S p a t ia l in d e x TRUE* L in e a r r e f e r e n c in g FALSE
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Geoprocessing history ►
P r o c e s s
P r o c e s s n a m e
D a t e 2013-04-04 15:41:17T o o l l o c a t io n c:\program files (x86)\arcgis\desktopl0.1\ArcToolbox\Toolboxes\Data Management Tools.tbx\ProjectC o m m a n d i s s u e d
Project Vegetation\GlS_VegPatchesS:\FarallonIslands\Vegetation\FieldData\VegTypeMapping\GIS_VegPatches_project.shp PROJCS [ ’ WGS_1984_rJTM_Z one_iON', GEOGCS [' GCS_WGS_1984 », DATUM[ *D_WGS_1984 •, SPHEROID [’WGS_1984•,6378137.0,298.257223563!],PRIMEMf•Greenwich’,C .C],UNIT [’Degree’,0.0174532925199433:],PROJECTION[’Transverse_Mercator’3, PARAMETER ['False_Easting*, 500000.0],PARAMETER[1False_Northing*,0.0],PARAMETER[*Central_Merldian', - 123.0], PARAMETER['Scaie_Factor’,0.9996],PARAMETER['Latltude_Of_Origin’,0.0],UNIT['Meter',1.0]] # GEOGCS['GCS_WGS_1984',DATUM['D_WGS_1984’fSPHEROID[’WGS_1984',6378137.0,298.257223563: ], PRIMEM [’Greenwich’, 0.Oj, UNIT[’Degree’,0.0174532925199433]]
In c lu d e in l in e a g e w h en e x p o rt in g m e ta d a ta No
P r o c e s s
P r o c e s s n a m e
D a t e 2013-07-23 13:56:58T o o l l o c a t io n c:\program files (x86)\arcgis\desktopl0.0\ArcToolbox\Toolboxes\Data Management Tools.tbx\MergeC o m m a n d i s s u e d
Merge Vegetation\GIS_VegPatches_project;Vegetation\GPS_VegPatches_projectC:\Users\Jamie\Documents\FarallonIslands\Vegetation\FieldDataWegTypeMapping\_MASTER_VegPatches.shp "Id "Id" true true false 6 Long 0 6 ,First,#,Vegetation\GIS_VegPatches_project,Id,-1,- 1,Vegetation\GPS_VegPatches_project,Id,-1,-1;Zone "Zone" true true false 50 Text 0 0 ,First,#,Vegetation\GIS_VegPatches_project,Zone,-1,-1,Vegetation\GPS_VegPatches_project,Zone,-1,- l;Zone_Desc "Zone_Desc" true true false 50 Text 0 0 ,First,#,Vegetation\GIS_VegPatches^project,ZoneDesc,-1,-1,VegetationNGPS VegPatches project, ZoneDesc,-1,-1;Dominant "Dominant" true true false 50 Text 0
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Page 6 of 13
0 ,First,#,Vegetation\GIS_VegPatchesjproject,Dominant,-1, -1,Vegetation\GPS_VegPatches_project, Dominant,-1,-l;CoDominant "CoDominant" true true false 5C Text 0 0 ,First,#,Vegetation\GIS_VegPatches_project,CoDominant,-1,-1,Vegetation\GPS_VegPatches_project,CoDominant,-1,-1?SubDom "SubDom" true true false 50 Text 0 0 ,First,#,Vegetation\GIS_VegPatches_project,SubDom,-1,-1, Vegetation\GPS_VegPatches_project, SubDom, -1,-l;Coimment "Comment" true true false 50 Text 0 0 ,First,#,Vegetation\GIS_VegPatches__project,Comment,-1,-1;Acreage "Acreage" true true false 13 Float 0 0 ,First,#,Vegetation\GIS_VegPatches_project,Acreage,-1,-1,Vegetation\GPS_VegPatchesjproject,Acreage,-1,-l;Method "Method" true true false 5C Text D 0 ,First,#,Vegetation\GIS_VegPatches_project,Method,-1,-1,Vegetation\GPS_VegPatches_project,Method,-1,-l;TransctNum "TransctNum" true true false 5C Text C 0 ,First,#,Vegetation\GPS_VegPatches_project,TransctNum,-1,-1;Slope "Slope" true true false 4 Short 0 4 ,First,♦,Vegetation\GPS_VegPatches_project,Slope,-1,-1,-Aspect "Aspect" true true false 4 Short 0 4 ,First,#,Vegetation\GPS_VegPatches_project,Aspect,-1,~i;OtherSpec "OtherSpec" true true false 50 Text 0 C ,First,#,Vegetation\GPS_VegPatchesjproject,OtherSpec,-l,-l;Photo "Photo" true true false 4 Short 0 4 ,First,♦,Vegetation\GPS_VegPatches_project,Photo,-1,-l;Collector "Collector" true true false 5C Text C 0 ,First,#,Vegetation\GPS_VegPatches_project,Collector,-1,-1"
In c lu d e in l in e a g e w h en e x p o rt in g m e ta d a ta No
P r o c e s s
P r o c e s s n a m e
D a t e 2015-05-13 18:17:47T o o l l o c a t io n c:\program files (x86)\arcgis\desktopl0.2\ArcToolbox\Toolboxes\Data Management Tools.tbx\CalculateFieldC o m m a n d i s s u e d
CalculateField VEG_VegetationMap_SFSU_v3_py Id [OBJECTID; VB #I n c l u d e in l in e a g e w h e n e x p o r t in g m e t a d a t a No
Hide Geoprocessing history ▲
Distribution ►
D is t r i b u t io n fo r m a t
* Na m e File Geodatabase Feature Class V e r s io n 20150601
T r a n s f e r o p t io n s
* T r a n s f e r s i z e 0.0 00
Hide Distribution A
Fields ►
D e t a il s f o r o b j e c t VEG_VegetationMap_SFSU_final_py ►
* T y p e Feature Class* Row c o u n t 222 D e f in it io n
Final vegetation map of Southeast Farallon Island
D e f in it io n s o u r c e
Hawk, J.L. 2015. Classification, vegetation-environment relationships, and distribution of plant communities on Southeast Farallon Island, California. M.A. thesis, San Francisco State University, San Francisco CA, US.
Field O B JE C T ID ►* A l ia s OBJ ECTID* D a t a t y p e OID* W id t h 4* P r e c i s i o n 0* S c a l e 0* F ie l d d e s c r ip t io n
Internal feature number.
* D e s c r i p t i o n s o u r c e Esri
* D e s c r i p t i o n o f v a l u e sSequential unique whole numbers that are automatically generated.
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Page 7 of 13
Hide Field OBJECT!D A
F ie ld Shape ►* A l i a s Shape* D a ta typ e Geometry* W id th 0* P r e c is io n 0* S c a le 0* F ie ld d e s c r ip t io n
Feature geometry.
* D e s c r ip t io n s o u r c e
ESRI
* D e s c r ip t io n o f v a lu e s
Coordinates defining the features.
Hide Field Shape A
F ie ld Id ►* A l i a s Id* D a ta typ e Integer* W id th 4* P r e c is io n 0* S c a le 0 F ie ld d e s c r ip t io n
An integer value of the OBJECTID column.
D e s c r ip t io n s o u r c e
ESRI
Ra n g e o f v a l u e s Min im u m v a l u e 1
Ma x im u m v a l u e 222
Hide Field Id A
F i e l d Zone ►* A u a s Zone* D a t a t y p e String* W id t h 50* Pr e c is io n 0* S c a l e 0 F i e l d d e s c r ip t io n
A text string of alpha characters abbreviating the mapping unit description.
D e s c r ip t io n s o u r c e Hawk 2015
L i s t o f v a l u e s
V a l u e AnthroMUD e s c r ip t io n Anthropogenic mapping unitE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e BareMUD e s c r ip t io n Bare soil mapping unitE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e Core MUD e s c r ip t io n Coprosma respens mapping unitE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e HemaMUD e s c r ip t io n Hesperocyparis macrocarpa mapping unitE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
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Page 8 of 13
V a l u e LamaTD e s c r i p t io n Lasthenia maritima typeE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e LamaT-bD e s c r i p t i o n Lasthenia maritima type, bare sub-unitE n u m e r a t e d d o m a in v a l u e d e f i n i t i o n s o u r c e Hawk 2015
V a l u e LamaT-lD e s c r i p t io n Lasthenia maritima type, lush sub-unitE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e MaarMUD e s c r i p t i o n Malva arborea mapping unitE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e MixedT-gD e s c r i p t i o n Mixed vegetation type, grassland categoryE n u m e r a t e d d o m a in v a l u e d e f i n i t i o n s o u r c e Hawk 2015
V a l u e MixedT-hD e s c r i p t io n Mixed vegetation type, herbaceous categoryE n u m e r a t e d d o m a in v a l u e d e f i n it io n s o u r c e Hawk 2015
V a l u e PiraMUD e s c r i p t io n Pinus radiata mapping unitE n u m e r a t e d d o m a in v a l u e d e f i n it io n s o u r c e Hawk 2015
V a l u e PIcoTD e s c r i p t i o n Plantago coronopus typeE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e RuacMUD e s c r i p t i o n Rumex acetosella mapping unitE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e SpmaTD e s c r i p t i o n Spergularia macrotheca typeE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e TeteTD e s c r i p t i o n Tetragonia tetragonioides typeE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
Hide Field Zone k
F i e l d Zone_Desc ►* A l ia s Zone_Desc ♦ Da t a t y p e String* W i d t h 50* Pr e c i s i o n 0* S c a l e 0 F ie l d d e s c r ip t io n
A text string fully describing each mapping unit code (aka zone column).
D e s c r i p t i o n s o u r c e Hawk 2015
C o d e d v a l u e sN a m e o f c o d e l is t Full titles of each mapping unit code S o u r c e Hawk 2015
Hide Field Zone_D esc A
F ie l d Dominant ►* A l ia s Dominant ♦ Da t a t y p e String♦ W id t h 50
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Page 9 of 13
* Pr e c is io n 0* S c a l e 0 F i e l d d e s c r ip t io n
A text string representing the dominant plant species (four-letter code is determined the first two letters of the genus and species). Other codes may include BARE (bare ground), ROCK (rocky substrate), IMPV (impervious surface), and Mixed (variable species cover).
De s c r ip t io n s o u r c e
Hawk 2015
C o d e d v a l u e s
Na m e o f c o d e l i s t List of dominant plant species (>40% absolute cover)S o u r c e Hawk 2015
Hide Field Dominant A
F i e l d CoDom inant ►» A l ia s CoDom inant* D a t a t y p e String* W id t h 50* Pr e c is io n 0* S c a l e 0 F ie l d d e s c r ip t io n
A text string representing the co-dominant plant species (four-letter code is determined the first two letters of the genus and species). Other codes may include BARE (bare ground), ROCK (rocky substrate), IMPV (impervious surface), and Mixed (variable species cover).
D e s c r ip t io n s o u r c e
Hawk 2015
C o d e d v a l u e s
Na m e o f c o d e l i s t List of co-dominant plant species (25-40% absolute cover)S o u r c e Hawk 2015
Hide Field CoDominant A
F i e l d SubDom ►* A l ia s SubDom* D a t a t y p e String* WIDTH 50* Pr e c is io n 0* S c a l e 0 F ie l d d e s c r ip t io n
A text string representing the sub-dominant plant species (four-letter code is determined the first two letters of the genus and species). Other codes may include BARE (bare ground), ROCK (rocky substrate), IMPV (impervious surface), and Mixed (variable species cover).
D e s c r ip t io n s o u r c e
Hawk 2015
C o d e d v a l u e s
Na m e o f c o d e l i s t List of sub-dominant plant species (10-25% absolute cover)S o u r c e Hawk 2015
Hide Held SubDom A
F ie l d Comment ►* A l ia s Comment* D a t a t y p e String* WIDTH 50* Pr e c is io n 0* S c a l e 0 F ie l d d e s c r ip t io n
Text string with general comments and field notes
D e s c r ip t io n s o u r c e
Hawk 2015
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Page 10 of 13
D e s c r ip t io n o f v a l u e s
Each record in the feature class has a unique value in this column
Hide Field Comment A
F ie ld Acreage ►* A l ia s Acreage • D a t a t y p e Single* W id t h 4* Pr e c is io n 0* S c a l e 0 F ie ld d e s c r ip t io n
Single number measuring the area of each polygon (acres).
D e s c r ip t io n s o u r c e
ESRI
D e s c r ip t io n o f v a l u e s
Each record in this feature class has a unique values in this column
Hide Field Acreage A
F ie ld Method ►* A u a s Method* D a t a t y p e String* W id t h 50* Pr e c is io n 0* S c a l e 0 F i e l d d e s c r ip t io n
Text string describing the method of polygon creation.
D e s c r ip t io n s o u r c e Hawk 2015
L i s t o f v a l u e s
V a l u e Digitized in GISD e s c r ip t io n Polygons were digitized on-screen ("heads up") in GIS using NAIP 2012 orthoimagery.E n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e Field mapped with GPSD e s c r ip t io n Polygons were mapped on the ground using a Trimble GeoXH GPS unit.E n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
Hide Field Method A
F ie ld OtherSpec ►* A l ia s OtherSpec* D a t a t y p e String* W id t h 50* Pr e c is io n 0* S c a l e 0 F i e l d d e s c r ip t io n
A text string representing the other plant species (four-letter code is determined the first two letters of the genus and species). Other codes may include BARE (bare ground), ROCK (rocky substrate), IMPV (impervious surface), and Mixed (variable species cover).
D e s c r ip t io n s o u r c e Hawk 2015
C o d e d v a l u e s
Na m e o f c o d e l i s t List of other plant species (<10% absolute cover) S o u r c e Hawk 2015
Hide Field OtherSpec A
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F ie ld Shape_Length ►* A l ia s Shape_Length* Da t a t y p e Double* W id t h 8* Pr e c is io n 0* S c a l e 0* F i e l d d e s c r ip t io n
Length of feature in internal units.
* D e s c r ip t io n s o u r c e
Esri
* D e s c r ip t io n o f v a l u e s
Positive real numbers that are automatically generated.
Hide Field Shape_Length a
F ie ld Shape_Area ►* A l ia s Shape_Area* D a t a t y p e Double* W id t h 8* Pr e c is io n 0* S c a l e 0* F i e l d d e s c r ip t io n
Area of feature in internal units squared.
* D e s c r ip t io n s o u r c e
Esri
* D e s c r ip t io n o f v a l u e s
Positive real numbers that are automatically generated.
Hide Field Shape Area A
F ie ld Tete_ModiFier ►* A l ia s Tete_Modifier* D a t a t y p e String* W id t h 50* Pr e c is io n 0* S c a l e 0 F i e l d d e s c r ip t io n
A categorical estimate of Tetragonia tetragonioides cover for areas containing the species.These values are rough estimates for spring time cover of TETE. An herbicide treatment effect likely contributes to the underestimation the breadth and intensity of TETE presence on the island.
D e s c r ip t io n s o u r c e
Hawk 2015
L i s t o f v a l u e s
v a l u e 1D e s c r ip t io n <5% absolute cover of TETEE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e 2D e s c r ip t io n 5-10% absolute cover of TETEE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e 3D e s c r ip t io n > 10% absolute cover of TETEE n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
V a l u e TeteTD e s c r ip t io n Classified Tetragonia tetragonioides vegetation type (>25% cover)
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Page 12 of 1* '
E n u m e r a t e d d o m a in v a l u e d e f in it io n s o u r c e Hawk 2015
Hide Field Tete_ Modifier A
F ie ld A r e a _ m _ s q ►* A l ia s Area_m_sq ♦ D a t a t y p e Single* W id th 4* Pr e c is io n 0* S c a l e 0 F ie ld d e s c r ip t io n
Sinqle number measurinq the area of each p o l y g o n (squared meters).
D e s c r ip t io n s o u r c e
ESRI
D e s c r ip t io n o f v a l u e s
Each record in this feature class has a unigue values in this column.
Hide Field Area_m _sq A
Hide Details for object VEG_ VegetationMap_SFSU_final_py A
Hide Fields A
Metadata Details ►
* M e ta d a ta la n g u a g e English (UNITED STATES)* M e ta d a ta c h a r a c t e r s e t utf8 - 8 bit UCS Transfer Format
S co p e o f th e d a ta d e s c r ib e d by t h e m e ta d a ta * dataset S co p e name * dataset
* L a s t u p d ate 2015-05-13 .
A r c G IS m e t a d a t a p r o p e r t i e s
Me t a d a t a f o r m a t ArcGIS 1.0 S t a n d a r d o r p r o f il e u s e d t o e d i t m e t a d a t a FGDC Me t a d a t a s t y l e FGDC CSDGM Metadata
C r e a t e d i n A r c G I S f o r t h e it e m 2015-05-13 20:21:18 La s t m o d if ie d in A r c G I S f o r t h e it e m 2015-05-13 20:29:19
A u t o m a t ic u p d a t e s
Ha v e b e e n p e r f o r m e d YesL a s t u p d a t e 2015-05-13 20:29:19
Hide Metadata Details A
Metadata Contacts ►
M e t a d a t a c o n t a c t
I n d iv id u a l ' s n a m e Jamie HawkO r g a n iz a t io n ’s n a m e San Francisco State UniversityC o n t a c t 's p o s it io n Graduate Student C o n t a c t 's r o l e originator
C o n t a c t in f o r m a t io n ►
Ph o n e
V o ic e (408)307-9435
A d d r e s s
T y p e postalD e l iv e r y p o in t 1600 Holloway Avenue
file.7//C:/Users/Jamie/AppData/Local/Temp/arc3ADD/tmpCBEB.tmp.htm 5/13/2015
96
C it y San FranciscoA d m in is t r a t iv e a r e a CA Po s t a l c o d e 94132 C o u n t r y USe -m a il a d d r e s s [email protected]
Hide Contact information A
Hide Metadata Contacts A
Metadata Maintenance ►
Ma in t e n a n c e
U p d a t e f r e q u e n c y not planned
Hide Metadata Maintenance A
FGDC Metadata (read-only) ▼
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Page 13 of 13
5/13/2015
97
Appendix 4A Data matrix of vegetation sampling data (26 taxa, 42 plots), absolute cover (%) values. Data represents the average of combined plot data from spring seasons of 2013 and 2014.
PL
OT
Am
sp
Ana
r
Bre
a
Brd
i
Chm
u
Clp
e
Coa
u
Erc
i
Erm
o
Feb
r
Hom
u
Lam
a
Led
i
Maa
r
Mas
p
Pico
Poan
Ruc
r
Sevu
Soas
Sool
Spm
a
Spm
e
Stm
e
Tet
e
Uru
r
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610 © ©© © <N©
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©<N©
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© © ©©
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© © © © © © © © © © ©©
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© © © © © 0.24 © © © © © © © © © © © © © ©
i> © © © © © © © © © © ©
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©
OO © © © © ©900 © © © © © © © © © © © © © © © © © ©
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w* © © o © ©
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42 41 40 39 38 37
0 0 0.06 0.02 0.06 0
0 0 0 0 0 0
0.05 0 0 0 0 0
0 0.31 0.17 0.1 0.1 0
0 0 0 0.05 0 0
0 0.05 0.04 0 0 0
0 0 0.01 0 0 0
0 0.07 0.04 0.17 0 0
0 0.26 0.06 0 0.01 0
0 0 0.02 0 0 0
0 0 0.04 0 0 0
0.19 0.12 0.04 0.14 0.07 0
0 0 0.01 0 0.01 0
0 0 0 0 0 0
0 0 0 0 0 0
0 0 0.19 0 0 0
0 0 0 0 0 0
0 0 0 0.07 0 0
0 0 0.01 0 0 0
0 0 0 0.02 0 0
0 0 0.01 0 0 0
0.02 0.02 0.01 0 0 0
0 0 0 0 0 0
0.02 0 0.04 0 0 0
0 0 0.07 0 0.31 0.79
0 0.05 0.02 0.07 0.06 0.07
35 34 33 32 31
0 0 0.02 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0.02 0.02 0.02
0 0 0 0 0
0.02 0.02 0.01 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0.02 0.04 0
0 0 0 0 0
0 0 0.02 0.02 0
0.02 0.1 0.15 0.18 0
0.07 0.02 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0.6 0.57 0 0.01 0
0.02 0 0 0 0
0 0 0.06 0.02 0
0 0 0 0.3 0.74
0 0 0.07 0.02 0.1
36
0
0
0
0
00.01
00
000
0.39
0
0
0
0
0
0
0
0
0
0.01
0
0.02
0
0
30 29 28 27
0 0 0 0
0 0.01 0 0
0 0 0 0
0.08 0.01 0.13 0
0 0 0 0
0.2 0.01 0.02 0
0 0 0 0
0 0 0.01 0
0.03 0 0.07 0
0 0 0 0
0.01 0.05 0 0
0 0.39 0.19 0
0 0.18 0 0.05
0 0 0 0
0 0 0.01 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0 0 0
0 0.02 0 0
0 0 0 0
0.54 0 0.39 0.83
0 0.01 0.01 0
25 24 23 PLOT
0 0 0 Amsp
0 0 0 Anar
0.01 0 0 Brea
0.39 0.11 0.01 Brdi
0.01 0.02 0 Chmu
0 0.02 0.14 Clpe
0 0 0 Coau
0 0.01 0 Erci
0 0 0 Ermo
0 0 0 Febr
0.14 0.1 0.26 Homu
0.17 0.38 0.06 Lama
0.01 0.01 0.01 Ledi
0.04 0 0 Maar
0.01 0 0 Masp
0.05 0.01 0.35 Pico
0 0 0 Poan
0 0 0 Rucr
0 0 0 Sevu
0 0 0 Soas
0 0 0.01 Sool
0 0.01 0.08 Spma
0 0 0 Spme
0.02 0 0.02 Stme
0 0 0 Tete
0.04 0 0 Urur
26
0
0
0
0.01
0
0.2
000
0.02
0.1
0.11000
0
0
0
0
0
0
0
0
0.01
0.49
0
99
Appendix 4B Data matrix of environmental variables (11 variables, 42 plots).
PLOT ELEV SLOPE SOLAR ROCK BARE LITT DEPTH BURRd pH EC ANTHRO1 12.1 1 0.82 0.07 0.05 0.12 11.2 0.08 6.7 0.306 42 9.9 0 0.81 0.06 0.23 0.11 15.8 0.11 6.6 0.5555 23 13.1 1 0.82 0.25 0.13 0.04 5.3 0.04 4.5 0.454 84 9.4 8 0.85 0.31 0.1 0 4.9 0.00 4.4 1.443 15 18.9 6.5 0.87 0.19 0.11 0.02 9.8 0.11 4.4 1.259 16 23.4 3 0.79 0.45 0.25 0.05 5.3 0.00 5.6 8.756 27 15.6 7 0.89 0.04 0.14 0.02 11.9 0.00 4.5 0.283 18 20.8 13 0.72 0.24 0.13 0.02 10.2 0.34 4.1 0.3535 29 10.2 2 0.78 0.14 0.25 0.02 6.9 0.00 6.8 0.423 210 10.0 3 0.76 0.26 0.33 0.01 4.5 0.00 5.2 4.005 211 15.0 7 0.70 0.02 0.38 0 17.1 0.11 4.4 0.8295 212 21.1 11 0.86 0.2 0.14 0 4.1 0.00 4.8 0.883 313 16.4 2 0.83 0.11 0.05 0 5.1 0.05 5.8 1.454 214 11.2 0 0.81 0.11 0.07 0.01 6.7 0.20 4.4 1.443 0
1 15 11.4 1 0.82 0.48 0.14 0 4.6 0.00 4.4 1.443 016 10.7 3 0.84 0.04 0.13 0 6.7 0.03 4.6 0.328 117 14.1 1 0.82 0 0.17 0 12.5 0.18 5.3 0.5805 218 8.7 1 0.82 0.06 0.01 0.01 6.9 0.08 4.2 0.42 419 8.4 1 0.82 0.02 0.07 0.12 17.7 0.45 4.8 0.602 720 11.3 0 0.81 0 0.04 0.04 17.7 0.08 5.8 0.5645 221 9.5 1 0.82 0 0.01 0.1 12.6 0.08 4.6 0.289 222 7.1 1 0.82 0.04 0.04 0 12.6 0.23 6.9 5.0265 123 7.8 0 0.81 0 0.02 0.02 11.2 0.11 5.2 0.965 124 10.4 4 0.78 0.26 0.06 0 9.3 0.01 5.0 0.6855 325 10.9 0 0.81 0.04 0.02 0.05 11.4 0.04 4.8 1.0675 526 14.0 10 0.93 0.01 0.05 0 9.5 0.29 5.0 0.1995 127 14.1 22 1.04 0.05 0.07 0 9.5 0.06 4.6 0.203 228 12.9 6 0.88 0.11 0.02 0.02 6.9 0.01 5.4 0.106 129 13.8 3 0.84 0.01 0.3 0 10.3 0.09 4.5 0.359 530 24.3 17 1.00 0.12 0.01 0 6.5 0.13 5.2 0.183 131 38.2 16 0.99 0.07 0.05 0.02 5.9 0.25 4.3 0.593 632 57.5 32 1.08 0.35 0.04 0 4.4 0.13 4.4 0.398 433 79.3 40 1.09 0.48 0.1 0.04 4.6 0.04 5.0 0.86 534 14.6 3 0.82 0.02 0.26 0 6.8 0.00 5.0 1.1885 035 14.2 1 0.82 0.12 0.14 0 6.7 0.00 5.7 0.671 136 45.7 47 0.41 0.46 0.1 0 3.5 0.01 5.1 0.3115 337 32.2 28 1.07 0.1 0.02 0.02 3.7 0.05 5.8 0.732 138 20.1 18 1.01 0.31 0.05 0.02 3.7 0.03 5.8 0.5065 639 13.6 1 0.82 0.05 0.24 0.07 15.8 0.20 5.1 0.4065 440 13.8 2 0.83 0.08 0.02 0.05 13.3 0.03 5.7 0.2625 141 13.7 1 0.82 0.05 0.02 0.05 11.4 0.25 5.7 0.1595 342 98.8 62 0.30 0.64 0.07 0 3.3 0.00 4.8 1.4035 4
