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Developing Biological Criteria for the Recovery of Florida Scrub-Jay Populations on Public Lands in Brevard County: Patterns of Fire History, Habitat Fragmentation, Habitat Use
and Demography.
Final Report to Endangered Species Office, U. S. Fish and Wildlife Service, Jacksonville, FL
1999
Breininger, D. R., D. M. Oddy, M. L. Legare, and B. W. Duncan
Dynamac Corporation
Dyn-2
Kennedy Space Center, FL 32899
Contract No. 1448-40181-97-C-002
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Abstract
This colorbanding and demographic study of Florida scrub-jays (Aphelocoma coerulescens) began in December 1996. The study is focused on quantifying population dynamics on public lands as they are being acquired for conservation and making recommendations for recovery of the populations. Specific objectives were to: a) collect demographic data, b) establish an accurate baseline of population status, c) evaluate habitat quality, and d) and make suggestions to aid recovery. In 1998, additional funding was provided by the Florida Fire Science Team to study catastrophic wildfire effects at Buck Lake. The objectives included the quantification of Florida scrub-jay habitat suitability before (1943) and after (1994) human activities greatly reduced the natural fire regime and compare these to 1999 conditions one year after the catastrophic wildfires of 1998. One purpose of these studies was to evaluate how maps of wildfires could be used to quantify the habitat fragmentation effects of wildfires.
All but one of the study sites were in public ownership or were proposed for conservation acquisition. South Brevard has the most scrub sites in public ownership that have an abundance of Florida scrub-jays. More scrub conservation land acquisition has been directed towards South Brevard on the Florida mainland where large scrub-jay populations occur. The reduction in fire frequency is most severe within North Brevard so that the lower abundance of jays in North Brevard is the result of habitat degradation and not necessarily habitat potential.
Extensive surveys were conducted in 1993 to support the Statewide Surveys and the Brevard County Scrub Conservation and Development Plan which was not implemented. The study sites had 150 pairs during 1993 and declined to 64 pairs in 1999. This represented a population growth rate (R) of 0.865 or an average population decline of 13.5% per year. The rate of decline threatens the recovery potential because the population growth rate under optimal conditions is not likely to result in rapid population recovery.
Population declines would have been steeper if there had not been significant immigration into the study sites. Immigration into study sites was not unexpected because the sites included the densest aggregations of remaining Florida scrub-jays in the region. The study sites were locations where dispersing Florida scrub-jays had greater chances to breed than surrounding areas, partially because the study sites were of higher quality than their surroundings because of their habitat size, composition, and contiguity.
The above rate of population decline was slightly influenced by a presumed statewide epidemic (1997-1998) that resulted in a greater than normal mortality rate. Florida scrub-jay breeder survival is high during most years except during short, rare episodes of high mortality. Data from all years clearly indicated that the most important cause for decline was poor habitat quality that resulted from the disruption of natural fire regimes. Lower reproductive success and survival was comparable to other studies that have shown that Florida Scrub-Jays cannot persist in habitats that are subject to fire regimes that are infrequent. All studies indicate that Atlantic coast populations need a more frequent fire regime than previously believed because vegetation grows faster on the coast. The effects of individual wildfires vary greatly depending on the characteristics of individual fires and the recent history of fire and population patterns at sites where fires occur.
Recovery team efforts indicated that the metapopulation in South Brevard was the fourth largest metapopulation in the species range and would be expected to be the fourth largest if all
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habitat that is proposed for conservation is restored to optimal conditions. Although some of the habitat once proposed for conservation is likely to be destroyed, more habitat has been found than originally estimated. Ongoing studies indicate that metapopulation size was underestimated by 15-30 pairs in 1993 because private ranchland that is now under public ownership or soon to be acquired was not inventoried.
Organizations involved in management have proceeded from a primary acquisition mode to one that includes fire management. Much progress was made in the past year towards restoration and management. Previous wildfires in north and south Brevard have also improved habitat. However, nearly all territories have patches of tall scrub and these conditions have long-term mortality rates that exceed reproductive success rates, at least on Merritt Island. No studies of colorbanded Florida scrub-jays have yet demonstrated that Florida scrub-jays can persist in areas where there always is an abundance of tall scrub.
Florida scrub-jays had not recolonized some restored areas which were below their carrying capacity. The habitat quality of most occupied habitat remained poor so that there was not a large production of new potential breeders. Exchanges among subpopulations were infrequent for females and extremely rare for males so that local population dynamics were more relevant than metapopulation dynamics. Forests hindered dispersal and separated many restored areas from occupied territories that produced potential breeders. A gradual territorial budding process was hypothesized as one mechanism for reestablishing Florida scrub-jays in restored areas where jays have been extirpated. This process is predicted to be slow and relies on contiguity between restored areas and occupied areas. Florida scrub-jays have been demonstrated to initiate new territories by processes other than budding, but these are also uncommon. Therefore, forest barriers between occupied and restored habitat should be expeditiously eliminated where the forests are artifacts of human activities.
Expediting most recovery actions would improve the chances of successful recovery and decrease extinction probabilities. The reason for this is that managing to reduce the level of Florida scrub-jay decline is likely to have greater success than trying to increase populations that have become very few in number. Much restoration is needed for recovery in most landscapes. Restoration includes mechanical cutting of scrub that remained unburned for long periods, frequent fire, and tree thinning. Data from this study was routinely applied by organizations. Restoration progress increased in the past 12 months as management organizations acquired fire management staff.
Adaptive management must be coupled with scrub-jay demography data given variations in fire behavior and vegetation responses to management. Habitat mapping applications are generally to coarse to provide the information needed for management and predicting population responses. Many questions remain concerning the demographic success associated with the variation of habitat conditions that approach but do not achieve optimal habitat suitability. It is unlikely that every territory will be restored to optimal conditions so that reproductive success will exceed mortality in some areas so that it will be important to determine the distributions of optimal habitat necessary for recovery. These questions are the focus of future studies as the study expands into newly acquired areas and continues in areas that are now being subject to habitat management actions.
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Executive summary
Geography and Florida Scrub-Jay Populations.
The Florida scrub-jay (Aphelocoma coerulescens) is Florida’s only endemic bird and
is threatened with extinction by rapid human population expansion and the lack of
frequent fires. Brevard County has two (South Brevard and Merritt Island/Cape
Canaveral) of the four largest Florida scrub-jay populations that remain (Figure 1).
Nearly all of the Merritt Island/Cape Canaveral barrier island population of Florida scrub-
jays occurs on federally owned lands in north Brevard. Many of these occur in habitat of
low elevation or in areas that require extensive habitat restoration. Our studies began
on Merritt Island and Cape Canaveral and much of our understanding was developed
from a decade of ecological studies on these properties. We compare many of our
results to the 30-year study of Florida scrub-jays on Archbold Biological Station which
occurs in central Florida on the Lake Wales Ridge.
The mainland of North Brevard also has potential to be one of largest populations
but this region has a long history of infrequent fire resulting in excessively overgrown
habitat. Public lands are sparsely distributed on the mainland in North Brevard and
these have few Florida scrub-jays. The Seminole Ranch, which might soon be acquired
by the St. Johns River Water Management District, occurs in a larger landscape where a
couple dozen Florida scrub-jays still remain. Central Brevard still has a few dozen
families but few of these occur on public lands and recent rapid human development has
greatly diminished the opportunity to have a large population. Another metapopulation
in Brevard occurs on South Brevard’s beaches but this population is rapidly declining
and has little potential for long-term population persistence.
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Cape Canaveral Air Station
Merritt Island National Wildlife Refuge Kennedy Space Center
South Brevard Barrier Island
Sebastian Buffer Expansions in Indian River County (yellow)
Tico and Dicerandra
Rockledge Scrub Vierra Mitigation
Figure 1. Florida Scrub-Jay Habitat in Brevard and North Indian River Counties. Scrub Shown as Red.
Buck Lake .
South Brevard Metapopulation
Sebastian Habitat Conservation Plan
. Seminole Ranch
Miles 0 8 16 24
North
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The recent and planned purchases by the Brevard County Environmentally
Endangered Lands Program, St. Johns River Water Management District, and Florida
Department of Environmental Protection will provide for several large scrubby flatwoods
reserves in South Brevard County. However, these tracts require much restoration and
management. Trees have increased in densities as a result of fire suppression in most
areas. Shrub heights and densities have greatly increased resulting in a loss of
openings that Florida scrub-jay populations need to be demographically successful.
Forests have replaced many savannas comprised of scrub, flatwoods, and marshes.
Once these habitats have been degraded, a few prescribed fires often do not readily
restore scrub to conditions suitable for the native species of conservation concern.
Colorbanding studies are essential for measuring management success or failure
because there is limited data on how habitat and predation differences influence
demographic success across the range of conditions that Florida scrub-jays currently
occupy.
Objectives.
This colorbanding and demographic study of a metapopulation of Florida scrub-jays
(Aphelocoma coerulescens) began in December 1996 in South Brevard County. The
U.S. Fish and Wildlife Service (USFWS) funded the study at the direction of Dawn
Zattau, Jacksonville. The study sites included Malabar, Valkaria, Babcock, Micco,
Jordan, St. Sebastian River State Buffer Reserve vicinity (Sebastian Buffer), and Palm
Bay (Figure 2). These comprised most of the Florida scrub-jays found within South
Brevard in 1993 during statewide population surveys (Figure 3). Buck Lake, in North
Brevard, was added as a study site in 1999 at the direction of Dale Wade (U.S. Forest
Service) and Sue Grace (U.S. Geological Survey) as part of the Florida Fire Science
Team investigations (Figure 4).
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Figure 2. Study Sites and Xeric Oak Scrub in South Brevard County
I-95
Micco
Road
Grant
Road
Valkaria
Road SR
51 4
Xeric Oak Scrub Malabar Study Site Jordan Study Site North
Palm Bay Study Site Valkaria Study Site Babcock Study Site Micco Study Site Sebastian Buffer Study Site
0 2 4 6 Miles
Indian River Lagoon Barrier Island Atlantic Ocean Sebastian River Florida Mainland
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Figure 3. Florida Scrub-Jay Habitat Occupancy and Xeric Oak Scrub in South Brevard County During 1993 Statewide Census
I-95
Micco Road
Grant Road
Valkaria Road
SR 5
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Xeric Oak Scrub
Indian River Lagoon
Barrier Island
North
Atlantic Ocean
Sebastian River
Florida Mainland
Roads
0 2 4 6 Miles
Areas Occupied by Florida Scrub-Jays
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Figure 4. Florida Scrub-Jay Populations and Xeric Oak Scrub in the Vicinity of Buck Lake
Buck Lake
Seminole Ranch
Fox Lake
Occupied Florida Scrub-Jay Polygons During Statewide Census
Xeric Scrub North
Miles0 2 4 6
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All study sites were in public ownership or were proposed for conservation
acquisition, except for the urban population in Palm Bay. The urban Palm Bay
population was included because it once had a large population that might serve as a
source of immigrants to conservation lands once they are restored and because it is
important to quantify the demographics of a variety of urban populations. The public
lands were managed by the Brevard County Environmentally Endangered Lands
Program (EELs), Florida Department of Environmental Protection (DEP), and St. Johns
River Water Management District (SJRWMD). Many of the sites had only recently been
acquired and many of the Florida scrub-jay families still occurred on both public and
private lands.
In South Brevard, the objectives were: collect data on juvenile production, yearling
production, juvenile survival, breeder survival, helper survival, pair bond fidelity, sex
ratio’s, delayed breeding characteristics, dispersal distances, and territory sizes.
Objectives were also to use this data to support recovery efforts by establishing metrics
for recovery based on habitat quantity, quality, and arrangement. Objectives were also
to quantify how demographic success varies with habitat quality and make site-specific
acquisition and management recommendations to aid recovery efforts in an adaptive
management context.
At Buck Lake, additional objectives included the comparison of habitat suitability
changes before extensive fire suppression (1940s) and after 50 years of fire
suppression. Objectives also included investigating the effects of the 1998 catastrophic
wildfires on habitat suitability and the population dynamics of a relatively isolated Florida
scrub-jay population in order to investigate the potential effects of catastrophic fires in
landscapes fragmented by humans.
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Results
Potential Population Size and Connectivity In South Brevard, Florida scrub-jays were color-banded from 81 families. Fifty of
these families occurred in existing or proposed conservation areas or adjacent public
lands. Large areas of potentially optimal oak scrub were not inhabited by Florida scrub-
jays because at least two of three habitat features were marginal. There were too few
openings among scrub oaks, too many trees, and too many tall shrubs in most areas.
Mean territory size was greater than previously reported, probably because scrub-jays
were below their carrying capacity.
Restoration can double the number of families in existing or proposed areas.
Several other fragments that might be acquired could provide another 10-20 families.
Several sites occur across the C54 Canal in Indian River County and are connected to
the South Brevard metapopulation through the Sebastian Buffer. These sites include
the southern half of Sebastian Buffer, the Carson Platt Ranch (anticipated acquisition),
Sebastian Airport, and adjacent Indian River County conservation areas. These sites
are likely to increase the metapopulation by at least 30 families; therefore potential
metapopulation size for conservation areas could be at least 160 families with extensive
land acquisition and restoration. These conservation areas would comprise an Atlantic
Coastal Ridge population and a Ten Mile Ridge population with little connection to one
another and other significant subpopulations in Florida.
Movements of Florida scrub-jays among subpopulations are relevant to planning
management and mitigation strategies across space and time. We found few
exchanges of females between Atlantic Coastal Ridge and Ten Mile Ride populations.
Even within ridge systems, population dynamics within clusters were most influenced by
population processes within the cluster because exchanges among clusters were
infrequent. Most replacement breeders following a breeder death came from the same
population cluster. There was immigration, however, of unbanded individuals to the
study site adding uncertainty to our increasing understanding of metapopulation
dynamics.
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The Buck Lake population was comprised of 3 families and was probably isolated or
nearly isolated from other populations. We hypothesized Buck Lake could support at
least 12 families and could be connected to a large scrubby flatwoods landscape several
miles south (near South Lake), where the SJRWMD expects to buy much land. A large
amount of scrub that occurs south of Buck Lake and west of Fox Lake is private
property. The Seminole Ranch may soon be acquired by SJRWMD. EELs have
submitted areas adjacent to Seminole Ranch to CARL for acquisition. Much restoration
and fire management, however, will be needed to reduce the relatively high extinction
risk of these populations because of a long history of habitat degradation related to fire
suppression.
Demographic Success The study populations declined by almost 40% between 1993 and 1997 (Table 1).
Another steep decline occurred between 1997 and 1998 when an apparent statewide
epidemic affected all but the Sebastian Buffer population and the Tel 4 population on
Merritt Island. The breeding population did not decrease as sharply in 1998. The
breeding population increased in some sites in 1999 but these increases were not
because reproductive success exceeded mortality in the sites. The 1999 nesting
season produced an unusually large number of juveniles as evidence of high annual
variability. However, the survival of these young jays in a unusually productive year is
predicted to be low because of poor habitat quality that makes them vulnerable to
predation by Cooper’s Hawks (Accipiter cooperii). Field observations make it clearly
evident that dense tree layers and tall shrubs make it difficult for jays to spot these
predators.
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TABLE 1. Changes in Florida scrub-jay population sizes in Brevard County mainland study sites. Numbers represent the number of breeding pairs during April.
1993 1997 1998 1999
Malabar 10 4 2 2
Jordan 24 11 9 8
Valkaria 24 26 18 20
Babcock 7 6 3 2
Micco 15 3 2 4
Palm Bay 53 26 17 13
Sebastian Buffer 11 13 13 12
Reserve
Buck Lake 6 Unknown 5 3
Reproductive success has been generally lower than needed for population
persistence in the South Brevard County mainland metapopulation. Reproductive
success has also been lower than needed for population persistence in the South
Brevard County barrier island metapopulation, the Merritt Island population and the
Cape Canaveral population. The poor reproductive success is typical for habitats that
include tall scrub. Most Florida scrub-jay territories average 10 ha or larger in South
Brevard. Because of large territories, some tall scrub tends to be present in most
Florida scrub-jay territories in areas once subject to fire suppression. Even small
amounts of tall scrub, high pine densities, or forests can result in poor demographic
success in Florida scrub-jay territories. Restoration of such areas will probably take
frequent repeated fires and adaptive management coupled to monitoring data.
Mean family size was lower than those reported in previously published studies.
These lower numbers resulted from years of poor demographic success associated with
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poor habitat quality. Survival measures in South Brevard were lower than previously
published data and probably resulted from an epidemic that resulted in a catastrophic
loss of Florida scrub-jays from many areas in Florida from September 1997 through April
1998. Survival measures were also low because of poor habitat quality and vulnerability
to hawk predation.
Management The U.S. Fish and Wildlife Service, conservation land acquisition organizations, and
environmental consultants have used these results to evaluate and plan mitigation and
conservation land acquisition strategies. Acquiring xeric oak scrub and adjacent swale
marsh and palmetto-dominated habitats will continue to enhance long-term persistence
probabilities of Florida scrub-jays and many other species uniquely adapted to these
habitat types.
Aggressive management and restoration can correct poor habitat quality that
resulted from the disruption of natural fire patterns. Habitat restoration has the potential
to at least double the Florida scrub-jay population at most sites. Restoring habitat to
increase population size will increase the abilities of populations to withstand epidemics
and other catastrophes. Frequent fire is needed at all study sites for long-term
persistence of Florida scrub-jay populations. Management and restoration will benefit
most species that make central Florida’s biological diversity unique.
The EELs, SJRWMD, and DEP have used the data from this study to perform
management at Sebastian Buffer, Valkaria, Micco, and Buck Lake. Nearly all areas
need frequent fires to restore the sites to conditions needed for population persistence.
Data from this study indicate that Malabar and Jordan study sites need immediate
burning and have been targeted as priorities once meteorological conditions improve.
The number of families is greatly declining at Malabar and Jordan and few individuals
are available nearby to immigrate into the tracts. Because males rarely move among
habitat fragments, we hypothesize that fragments will rarely be recolonized by breeding
pairs once males are extirpated from the fragments, unless other occupied fragments
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are less than a kilometer apart and fragments are not separated by forest or open water.
Translocation of jays might be needed to recover habitat fragments that are restored
after acquisition. Options for recovery of isolated fragments, such as Buck Lake, are
limited and translocation might be needed once the sites are restored to optimal habitat
conditions.
This study and related studies indicate that scrub-jays in urban areas are unlikely to
persist because of poor habitat quality and the difficulty in burning urban fragments, an
abundance and type of predators in the urban matrix, and road mortality. So far results
from this study suggest that jays from many urban areas may not move to restored
areas and may die out in urban areas without translocation. There is no reason to
consider translocation if potential territories are not restored to optimal conditions.
Sites adjacent to areas occupied by Florida scrub-jays might be colonized rapidly,
but forests between restored sites and occupied sites might limit recolonization by
Florida scrub-jays. Population modeling has predicted slow population recovery even
when restoration tracts are adjacent to areas occupied by Florida scrub-jays. The limiting
effects of slow population recovery and poor habitat quality between potential donor and
recipient sites are apparent at Valkaria where a wildfire and timbering program restored
large areas but recolonization has been excessively slow and most habitat remains
unoccupied. Many Florida scrub-jays occur within a kilometer of the restored areas but
are probably unaware of the habitat potential of the restored areas. Management of
Valkaria Airport and Golf Course should be initiated as soon as possible because of their
role in connectivity and abundance of many existing Florida scrub-jay families.
This study provided habitat specific data previously unavailable for the areas
surveyed. It also provided data on vital rates associated with habitat conditions common
to the Atlantic coast and increased the sample size of populations subject to rare
catastrophic events (i.e., epidemics). Data from this study were frequently used for
public education, to initiate management activities, and prioritize land acquisition. This
study continues under a new contract where we are expanding to all other newly
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acquired public lands in Brevard County and north Indian River County that are not on
Merritt Island National Wildlife Refuge or Cape Canaveral Air Station.
Interpreting habitat loss and habitat fragmentation effects from wildfires using fire maps
Land use mapping and wildfire mapping applications are likely to be too coarse for
accurate predictions of Florida scrub-jay population dynamics. Habitat features that
influence populations are often smaller than individual minimum mapping units used for
most mapping applications. Wildfires can have short-term negative effects because
they burn large areas extensively. Florida scrub-jays need some unburned patches of
scrub to provide acorns and cover for nesting and escaping predators. However, the
amount of scrub needed is generally small compared to the extent of scrub that has
remained unburned for too long. All but the smallest populations can withstand
catastrophic fire events. Usually small populations are not at their carrying capacity
because of long term population declines attributed to reduced fire frequencies so that
unburned habitat is often available adjacent to burned areas. However, this habitat is
generally of poor quality because it has been unburned for long periods. Wildfires might
more often have positive effects within several years of a fire because they reduce tree
densities and shrub height and increase the abundance of natural openings resulting in
an improvement in habitat suitability across a longer period than occurs from the short-
term reduction in habitat suitability. Wildfires probably have a greater probability of
increasing the connectivity of populations than decreasing the connectivity because they
reduce tree densities that impede dispersal. Generally, prescribed fires and salvage
logging operations to reduce the probability and severity of wild fires are likely to have
positive effects on scrub-jay populations. Specific sections in this document describe
management recommendations in detail.
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Table of Contents
Page
Abstract 2
Executive summary 4
Table of Contents 17
1.0 Introduction: the need for the study 18
2.0 Objectives 21
3.0 Methods 23
4.0 Results 30
5.0 Discussion 58
6.0 Natural Resource Management Implications 63
7.0 Implications for Land Acquisition 77
8.0 Conclusions 80
Acknowledgments 81
Appendix A. The Importance of Habitat Management 82
Appendix B. Definition of Optimal Habitat Conditions 84
Appendix C. Fire Management Prescriptions for Achieving
Optimal Habitat Condition 88
Appendix D. The Use of Mechanical Techniques 90
Literature Cited 91
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1.0 Introduction
Most populations of the Florida scrub-jay (Aphelocoma coerulescens) are
threatened with extinction along the Atlantic coast because of habitat destruction,
degradation, and fragmentation. Although rapid urban developments greatly threaten
the population viability of the Florida scrub-jay, habitat degradation from the lack of
frequent fires also threatens most populations (Woolfenden and Fitzpatrick 1984, 1991;
Breininger et al. 1996b,1998, 1999). The site tenacity and low dispersal abilities of the
species magnify the significance of habitat destruction and degradation (Stith et al.
1996; Root 1998; Stith 1999).
The recent purchases by the Brevard County Environmentally Endangered Lands
Program (EELs), St. Johns River Water Management District (SJRWMD), and Florida
Department of Environmental Protection (DEP) provide several large scrubby flatwoods
reserves. Additional purchases have been proposed. Proposed and recent land
acquisition efforts in Brevard and Indian River Counties could provide habitat that can
contribute to several of the most important metapopulations of the Florida scrub-jay
(Stith 1999). However, these tracts require much restoration and management (Swain
et al. 1995, Boyle 1996).
Much remains to be learned about how to restore scrubby flatwoods that have been
subjected to soil disturbances, fire suppression, and habitat fragmentation. A few
prescribed fires often do not readily restore scrub to conditions suitable for the native
species of conservation concern once scrubby flatwoods have been degraded
(Schmalzer et al. 1994; Breininger et al. 1996a, b; Duncan and Breininger 1998;
Schmalzer and Boyle 1998; Duncan et al. 1999).
Colorbanding studies are essential to measure management success. It is not
possible to measure dispersal and survival without banding. Florida scrub-jays can
reside within source areas, where reproduction exceeds mortality, and sink areas where
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reproduction is less than mortality (Breininger et al. 1995). Jay densities are not always
indicative of demographic success (Breininger et al. 1998, in press). Monitoring sinks
without colorbanding the jays may not reveal a serious problem until it’s too late to
recover the population (Howe et al. 1991, Pulliam and Danielson 1991, Pulliam et al.
1992, Pulliam 1996). Florida scrub-jays may immigrate into population sinks if sink
areas are of better quality than those currently occupied. This can continue until there
are no jays left to serve as a source of immigrants. Reproductive success must result in
reproduction of new potential breeders; this reproduction must equal or exceed breeder
mortality for populations to recover (Pulliam et al. 1992, Breininger et al. 1995).
Although much is known about Florida scrub-jay population demography in large
tracts of optimal habitat, little is known about the demographic parameters of Florida
scrub-jays under habitat conditions that are suboptimal. The details of habitat quality
arrangements are critical because Florida scrub-jay population persistence is very
sensitive to habitat quality (Breininger et al. 1999). All available demographic data
indicates that Florida scrub-jays have mortality that exceeds reproductive success under
marginal and moderately suitable habitat conditions (Woolfenden and Fitzpatrick 1984,
1991; Breininger et al. 1995, 1998, in press). The amounts and proportions of optimal
habitat needed for long-term persistence must be known for reserve management and
acquisition. It is unrealistic for all habitat to be in optimal condition at once so that natural
landscapes are likely to have a source-and-sink population structure that varies spatially
and temporally.
Most demographic studies have emphasized individual study areas and not the
dynamics among subpopulations. Population processes, such as immigration among
subpopulations, can influence population persistence in population sinks or reduce
demographic success because of density dependent survival (Pulliam 1996). Data is
generally lacking concerning the ability of Florida scrub-jays to persist and undergo
population recovery in scrub that is fragmented. Data is needed on the influence of
population status (e.g., occupancy, density), habitat quality, habitat arrangements, and
matrix habitats (nonscrub) on dispersal rates. Theoretical predictions of metapopulation
20
dynamics and source-and-sink dynamics do not apply to actual Florida scrub-jay
population dynamics under some conditions of habitat quality and arrangement
(Breininger 1999). For example, Florida scrub-jays tend not to move from large scrub
landscapes into habitat fragments within suburban areas (Thaxton and Hingtgen 1996).
Therefore, large patches of high quality scrub might be sources of individuals to some
types of population sinks (Breininger et al. 1995) but not others (Thaxton and Hingtgen
1996, Breininger 1999).
Florida scrub-jay populations are unable to persist in most or all urban and suburban
landscapes (Breininger 1999, R. Bowman pers. comm.) although many individuals occur
in areas where human land uses make long-term population persistence unlikely (Stith
et al. 1996). Much habitat within potential reserves is unoccupied or is not at carrying
capacity (Swain et al. 1995). It is important to quantify the tendencies of jays to move
from areas that are not going to be acquired for conservation into areas that are
acquired and restored. Metapopulation dynamics might be system-specific because
population sizes might be limited by either sex (Breininger 1999). Slightly higher
mortality rates by females but lower dispersal tendencies by males limit the application
of simple dispersal relationships in predicting population dynamics of fragmented
systems (Breininger 1999). Adaptive management strategies coupled to demographic
data of colorbanded jays is needed because of complex population responses to
fragmentation, uncertainties in demographic responses to habitat variation, variable fire
behavior patterns, and site-specific variation in vegetation responses.
Habitat and predation differences influence demographic success among
populations (Breininger et al. 1995; 1996a, b; 1998). Therefore, colorbanding studies
are critical in a variety of geographic areas to determine the consequences of
extrapolating from one study site to another and one geographic region to another.
Catastrophic wildfires ravaged parts of Florida in 1998 and resulted in an increase in
project activities to investigate recent and historical habitat and Florida scrub-jay habitat
suitability changes at Buck Lake. Wildfires differ from prescribed fires when they occur
under meteorological conditions that are too extreme for prescribed fire. This is
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particularly true in recent times where fuels have accumulated to greater levels than
probably occurred before humans suppressed fires and fragmented the landscape
minimizing the ability for most fires to burn across large areas. Buck Lake provided an
example of a landscape where the Florida scrub-jay population became nearly isolated
from other populations because of habitat destruction and habitat degradation
associated with a reduction of fire frequency. Extreme wildfires have the potential to
temporarily reduce habitat suitability because all scrub oaks burn and jays have nowhere
to find suitable scrub oak cover. Furthermore, these fragments might not be recolonized
once scrub oaks recover. Extreme wildfires also have the potential to restore habitat
conditions and increase the connectivity of populations. We already had two sites that
were burned by the 1998 wildfires and one (Valkaria) burned by an extreme 1997
wildfire prior to funding by the Florida Fire Science Team. We also had numerous sites
under long-term investigation that were subject to many prescribed fires.
2.0 Objectives
The short-term goals of this project were to:
a) provide demographic data (e.g., juvenile production, yearling production,
juvenile survival, breeder survival, helper survival, pair bond fidelity, sex ratio’s,
delayed breeding characteristics, dispersal distances); and
b) initiate establishment of an accurate baseline of habitat occupancy and
population status, and
c) evaluate habitat quality and make management suggestions that aid
recovery, and
d) provide data needed to prioritize endangered lands acquisition and mitigation
strategies.
Long-term goals were to quantify data needed to define the following information:
a) the abilities of Florida scrub-jays to colonize restored and uninhabited
habitat, and
b) the influence of habitat arrangements on population dynamics, and
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c) population persistence probabilities of alternative recovery strategies, and
d) population parameter values needed for monitoring and maintaining viable
populations in the reserves, and
e) landscape and habitat quality inventory criteria that identify areas of
demographic success (where potential breeder production equals or exceeds
breeder mortality), and
f) site-specific data to land managers on the results of their restoration activities,
and
g) site-specific data to land managers on habitat management needs following
initial restoration efforts.
The following additional objectives were related to work performed as part of the
Florida Fire Science Team studies:
a) quantify changes in the amount of suitable habitat for Florida scrub-jays
before (1943) and after the widespread reduction in fire frequencies (1994), and
b) quantify changes in the amount of suitable habitat for Florida scrub-jays
before the wildfires (but after the prescribed fire management period (e.g., 1998))
with the amount of suitable habitat after the wildfires (e.g. 1999), and
c) quantify potential habitat, and
d) test whether areas occupied by Florida scrub-jays differ from unoccupied
areas regarding fire history and habitat quality, and
e) evaluate the utility of fire and habitat maps for predicting and interpreting
wildfire effects.
3.0 Methods
The following methods emphasize the attainment of short-term goals. Methods for
attaining long-term goals are under development by the investigators in collaboration
with their colleagues to perform U.S. Fish and Wildlife Service recovery team and NASA
long-term monitoring program objectives. The methods below replicate and supplement
23
methods used during the first year of the study (Breininger and Oddy 1998). These
methods are based on long-term studies that have undergone critical scientific peer
review (e.g., Woolfenden and Fitzpatrick 1984, 1991, 1996 ; Breininger et al. 1995,
1996, 1998, 1999; Duncan et al. 1996, 1999; Breininger 1999).
In January 1997, the study began with sites that were already in partial ownership
for purposes of conservation; these included Valkaria, Malabar, and Micco. We added
the Babcock site, following permission to study jays on these private lands because it
was proposed for acquisition. We added the St. Sebastian River State Buffer Reserve
(Breininger 1998a) and urban areas of Palm Bay (Breininger 1998b) in July of 1997.
Jordan was acquired and added as a study site in November of 1997. Buck Lake was
added during February of 1999.
3.1 Capture, colorbanding, and census.
Initial studies involved repeated censusing to quantify the number of Florida scrub-
jay territories occupying the site. During this time, we exposed scrub-jays to raw peanut
bits to prepare them for capture. Once jays became familiar with peanuts, we baited
Potter traps but kept the trap doors wired open. Once many jays were entering traps,
we began the capture process. In addition to Potter traps, drop traps were used to
capture some jays unwilling to enter Potter traps. Mist nets were used to capture jays
unwilling to enter either trap. Captured jays were banded with a unique combination of
one silver and two colorbands. Once captured, the primary coverts were carefully
examined to distinguish individuals less than one-year-old from older jays.
Breeders were identified based on dominance behaviors, intensity of territory
defense, and nesting activities. Nests were opportunistically found and visited once per
week to measure clutch size, fledgling production, and signs of predation. Our efforts
were to focus on banding as many territories as possible, rather than the intensive
24
systematic nest searches that we often perform. Juveniles were tallied among all
territories in July.
3.2 Territory mapping
Territory mapping was conducted from April through May. Normally, boundaries
were delineated to within a few meters by initiating disputes between families
(Woolfenden and Fitzpatrick 1984, Breininger et al. 1995). All published studies have
involved areas where all scrub was rigorously contested and occupied by jays
(Woolfenden and Fitzpatrick 1984, Breininger et al. 1995). Territory disputes did not
occur in some large expanses of mesic flatwoods and extensively burned areas that
were adjacent to areas occupied by scrub-jays. In some cases, we mapped boundaries
based on areas where jays were observed from areas where no scrub-jays were
observed without witnessing disputes between families.
3.2 Habitat studies
Scrub habitat coverages developed for the Brevard County Scrub Conservation and
Development Plan (SCDP; Swain et al. 1995) were obtained as ARC/INFO coverages.
Coverages were projected to UTM NAD83. High resolution digital orthophoto quads
(DOQs) were obtained for all study areas. The DOQs were available across wide areas
and provided consistent, convenient, high quality templates for managing and displaying
spatial data using readily available software (e.g., ArcView, ARC/INFO) on most
hardware platforms (e.g., Windows 95 or Unix). Using the DOQs as templates provided
a mechanism to view thematic layers with digital photography as a background and
facilitated the development to techniques that could be used at other scrub sites. All
habitat maps were registered to DOQs. Imagery from 1943 was obtained to
qualitatively describe habitat changes in the last 50 years. Observations of Florida
scrub-jay occupancy revealed that the existing scrub maps were not inaccurate for
describing habitat use by Florida scrub-jays at the local scale (Breininger and Oddy
1998). New habitat layers were created by screen digitizing new ARC/INFO coverages
25
using the DOQs as backgrounds. Habitat coverages were created for all sites except
the urban areas of Palm Bay.
An ARC/INFO coverage was developed for each site (except Palm Bay) and
included the following attributes: (1) habitat type, (2) tree cover, (3) height, and (4)
presence/absence of openings among scrub oaks. Habitat types included: scrub,
ruderal grass, marsh, permanent forest, disturbed grass/shrubland, water, human
cultural features, and unsuitable pasture (Table 2). Scrub included: oak scrub (> 50 %
scrub oak cover), palmetto-oak scrub (5 – 50 % scrub oak cover), and palmetto scrub (<
5 % scrub oak cover; Table 3). Permanent forest included pine and hardwood forests
that were present in 1943 or scrub that became forest and existed as disjunct landscape
areas that did not justify restoration to scrub. Forests within disjunct landscapes
comprised sites that probably would not be within a scrub-jay reserve and areas that
probably would not be important to connect reserves. Forested scrub, which became
forest by 1994 because of fire suppression and habitat fragmentation, could become
suitable to Florida scrub-jays after restoration. Forested scrub was classified as scrub
and not forest in the habitat layer; forested scrub included areas with pine and oak
canopies. Tree density classes included: savanna (< 15 % tree cover), woodland (15 -
65% tree cover), and forest (> 65% tree cover). Forest here referred to permanent
forest or forested scrub. Height mapping classes included: (1) short scrub (< 120 cm
tall), (2) a mosaic of short (< 120 cm tall) and optimal scrub (120 - 170 cm tall), and (3)
tall scrub (> 170 cm tall) which could have included a mixture of tall scrub and other
height classes.
Imagery from 1943 was scanned, georeferenced, and used to map the habitat
features above at Buck Lake using methods. Digital 1998 wildfire boundary files were
obtained from the SJRWMD. These files were compiled at the Emergency Operations
Center, State of Florida. The boundaries were mapped from a variety of sources, such
as infra-red imagery contracted by Federal Emergency Management Administration,
U.S. Forest Service flights, and NOAA's GOES weather satellite.
26
Table 2. Definitions of habitat mapping categories.
Habitat type Description
Scrub Oak scrub and palmetto-lyonia with or without a
tree canopy; potentially suitable scrub-jay habitat;
includes forested areas today that were scrub in
the 1943 landscape.
Ruderal grass Bahia grass or open sandy areas with sparse
vegetation <15 cm tall.
Marsh Wetlands dominated by herbaceous vegetation.
Forest Dense tree canopy not restorable to scrub-jay
habitat; hammocks, swamps, and scrub with a
dense tree canopy that is not adjacent to a
potential scrub-jay reserve.
Disturbed grass/shrubland Human disturbed areas with shrubs and grass
such as pasture land that could be suitable for
scrub-jays.
Water Lakes, ponds, and lagoon waters.
Human cultural features Roads, buildings, and surrounding ruderal grass.
Unsuitable pasture Pasture with no shrubs; trees sometimes present.
27
Table 3. Definitions of Florida scrub-jay habitat quality features within scrub polygons.
Feature Description Habitat Quality
Oak cover:
Oak scrub Scrub with > 50 % oak cover. optimal
Palmetto-oak Palmetto-lyonia with 5 – 49 % oak cover. suboptimal
Palmetto Palmetto-lyonia without oaks. suboptimal
Open space:
Present Mosaic of open sandy areas among oaks. optimal
Absent Continuous shrubs or dense grass > 15 cm tall suboptimal
Tree cover:
Savanna 0 – 15 % tree canopy cover. optimal
Woodland 16 – 65 % tree canopy cover. suboptimal
Forest > 65 % tree canopy cover. suboptimal
Height categories:
Short Large areas (> 10 ha) completely burned suboptimal
(< 120 cm tall) within the last 3 - 5 years.
Optimal mosaic Patches of scrub oaks at optimal height optimal
(120 – 170 cm) without patches of tall scrub
(> 170 cm) larger than 0.4 ha.
Tall Tall scrub or a mosaic of other height suboptimal
categories that include tall scrub patches > 0.4 ha.
28
The minimum mapping unit was 0.4 ha (1 acre). The above habitat components were
needed to evaluate habitat suitability (Duncan et al. 1995, Breininger et al. 1998a,
1998b). Every territory was also classified into one of four fire history classes (Table 4)
(Breininger et al. in press).
TABLE 4. Height classes of Florida Scrub-Jay territories.
Height class
Short.
Description
Entire territory was < 120
cm tall.
Minimum mapping units
No patch taller than 120 cm
was > 0.4 ha (1.0 acre).
Short/optimal mix. Territory was a mix of
short and optimal scrub
(120 - 170 cm tall) and
had no tall scrub (> 170
cm tall).
At least 1 patch of optimal
scrub was > 0.4 ha and at least
1 patch of short scrub was >
0.4 ha. No patch of tall scrub
was > 0.4 ha.
Tall mix. Territory was mix of tall
scrub and short and/or
optimal scrub.
At least 1 patch of tall
scrub was > 0.4 ha. At least 1
patch of short or optimal scrub
was > 0.4 ha acre.
Tall. Entire territory was >
170 cm tall.
No scrub < 170 cm tall was
> 0.4 ha.
29
4.0 Results
The number of territories investigated changed during the study because of study
site expansion and population decline (Table 5, Table 6). Two hundred and fifty Florida
scrub-jays were banded. Most families that occurred within the study site and that
remained unbanded had all or large portions of their territories on private lands where
we could not observe many of their activities. Most families that remained unbanded
occurred within the Emerson cluster of territories in the urban Palm Bay study tract
where jays were unusually wary.
TABLE 5. Florida scrub-jay territories under investigation in Brevard County mainland
study sites. Numbers represent the number of breeding pairs during April where we
colorbanded individuals and quantified their reproductive success.
1997 1998 1999
Malabar 4 2 1
Jordan 5 5 4
Valkaria 26 18 20
Babcock 5 3 2
Micco 3 2 4
Palm Bay 26 17 13
Sebastian Buffer Reserve 12 13 12
Buck Lake 0 0 3
30
TABLE 6. Changes in Florida scrub-jay population sizes in South Brevard County study sites.
1993 a 1997 1998 1999
Malabar 10 4 2 2
Jordan 24 11 9 8
Valkaria 24 26 18 20
Babcock 7 6 3 2
Micco 15 3 2 4
Palm Bay 53 26 17 13
Sebastian Buffer 11 12 13 12
Reserve
Atlantic Coastal Ridge 13 > 6 b > 6 b > 6 b
south of Valkaria
Ten Mile Ridge between 12 > 6 b > 6 b > 6 b
Babcock and Micco
Total of all areas 169 > 101 > 71 > 71
a Data summarized by Swain et al. (1995) and Stith et al. (1996).
b Data is incomplete because all areas on private lands were not surveyed.
Family size, survival, and reproductive success were lower than previously published
results (Table 7). Mean family sizes in 1998 and 1999 do not identify that there were
also many Florida scrub-jays seen floating about the study area without having
membership to any particular territory. Demographic success was lowest at Babcock
(Table 8).
31
TABLE 7. Florida scrub-jay demography on the Brevard mainland compared to other published studies.
Mainland Urban South Kennedy Archbold
Brevard Palm Brevard Space Center a (1969-1986)
Reserves Bay Beaches
1997-1999 1997-1999 1997-1999 T4 study HC study Periodically Unburned
site site burned
1989-1993 1988-1993
Family 2.5 2.2 2.2 3.2 2.8 3.00 b Not reported
Size
Breeder 0.77 0.45 0.79 0.76 0.80 0.81 c 0.72 c
survival d
Helper 0.70 0.33 0.48 0.72 0.73 0.74 b Not reported
survival d
Juveniles 0.74 0.77 0.41 0.96 0.47 1.23 c 0.80 c
/pair
Yearlings 0.31 0.53 0.22 0.62 0.32 0.68 c 0.36 c
/pair d
a Data from Breininger et al. (1996).
b Data from Woolfenden and Fitzpatrick (1984).
c Data from Woolfenden and Fitzpatrick (1991).
d Excludes years when a presumed epidemic occurred
32
TABLE 8. Demographic comparisons among Brevard study sites, 1997 - 1999.
Malabar Valkaria Jordan Palm Babcock Micco Buffer Buck
Bay Lake
Family size
1997 2.5 2.6 2.2 2.1 3.0 2.7 a 2.2 n/a
1998 2.0 2.3 2.6 2.3 2.7 2.0 2.6 n/a
1999 3.0 2.6 3.2 2.9 2.0 2.75 2.9 2.0
Breeder survival
1997 0.33 0.49 n/a 0.65 0.20 n/a n/a n/a
1998 0.67 0.81 0.70 0.38 0.50 0.50 0.85 n/a
Juveniles / pair
1997 0.50 0.73 1.20 0.96 1.00 0.00 0.83 n/a
1998 0.00 0.39 0.60 0.47 0.00 2.00 1.38 n/a
1999 0.00 1.40 3.5 0.85 1.00 2.25 1.5 0.67
Yearlings / pair
1997 0.50 0.12 0.40 0.62 0.00 0.00 0.42 n/a
1998 0.00 0.39 0.40 0.35 0.00 1.00 0.54 n/a
Mean demographic
Performance / pair b
1997 -0.67 -0.94 n/a -0.04 -1.60 n/a n/a n/a
1998 -1.00 -0.05 -0.2 -0.65 -1.60 0.0 0.23 n/a
a Breeder survival and demographic success sample size includes only two
pairs because of inability to capture one pair.
b Number of yearlings produced minus the number of breeders that died.
33
Most breeders were not paired together between the 1997 and 1998 nesting
seasons because of high breeder mortality in contrast to more stable bonds between
1998 and 1999 (Table 9). Most pairs were not consistently paired together in Palm Bay
which had unusually high mortality across much of 1998.
The ratio of male-to-female helpers was 2.3 for 1997 and 3.5 for 1998. One-year-
olds frequently bred in Palm Bay but not in the other study sites (Table 10)
Female breeder survival was 0.34 and male breeder survival was 0.62 in 1997. The
difference in survival was significant (log-likelihood test p = 0.006). Female breeder
survival was 0.67 and male breeder survival was 0.71 in 1998. The difference in survival
was not significant (log-likelihood test p = 0.71). Survival for breeders with helpers was
0.39 and 0.56 for breeders without helpers in 1997. The difference in survival was not
significant (log-likelihood test p = 0.56). Survival for breeders with helpers was 0.81 and
0.62 for breeders without helpers in 1998. The differences in survival was significant
(log-likelihood test p = 0.04).
Juvenile production was 0.87 for breeders with helpers and 0.80 for breeders
without helpers in 1997. The differences in juvenile production was not significant
(Mann Whitney U test p = 0.55). Juvenile production was 0.81 for breeders with helpers
and 0.54 for breeders without helpers in 1998. The difference in juvenile production was
not significant (Mann Whitney U test p = 0.45). Yearling production was 0.13 for
breeders with helpers and 0.45 for breeders without helpers in 1997. The difference in
yearling production was not significant (Mann Whitney U test p = 0.19). Yearling
production was 0.43 for breeders with helpers and 0.38 for breeders without helpers in
1998. The difference in yearling production was not significant (Mann Whitney U test p =
0.81).
34
TABLE 9. Pair bond stability in South Brevard
Both survived One breeder died One breeder Both Divorce and remained and the other died and the died
paired bred with other did not together replacement breed
Malabar
1997 -1998 0 3 1 0 0
1998-1999 0 2 0 0 0
Jordan
1998-1999 2 3 0 0 0
Valkaria
1997-1998 8 8 1 9 0
1998-1999 14 0 1 3 0
Palm Bay
1997-1998 9 4 0 7 1
1998-1999 3 8 0 2 0
Babcock
1997-1998 0 2 0 3 0
1998-1999 0 2 0 0 0
Micco
1998-1999 0 1 0 0 0
Buffer
1998-1999 9 4 0 0 0
35
TABLE 10. Breeding status of known one-year-olds.
Help Breed
Malabar
1998 1 0
1999 0 0
Jordan
1998 2 0
1999 2 0
Valkaria
1997 6 1
1998 3 1
1999 4 1
Palm Bay
1998 6 11
1999 0 0
Micco
1999 2 1
Buffer
1998 6 2
1999 7 0
Mean natal dispersal distances for females was 1.7 km. Mean natal dispersal
distance for males was 0.8 km. Two females were involved in two long distance
dispersals that involved movements between the Atlantic Coastal Ridge to the Ten Mile
Ridge. One of these was a helper of unknown breeding experience that moved from
Valkaria to Micco. Another was a first-year helper that went from Valkaria to Sebastian
Buffer and then moved back to Valkaria where it became a novice breeder. This latter
36
jay did not become a resident at Sebastian Buffer so that its reported natal dispersal
distance was short relative to the long distance moved between ridge systems. Twenty-
three Florida scrub-jays immigrated into the study sites from unknown areas between
1997-1999 (Table 11).
TABLE 11. Source and destinations of Forty-four Florida Scrub-Jays that filled breeding vacancies between 1997-1999 a.
From: To To To To Palm To To To Malabar Jordan Valkaria Bay Babcock Micco Sebastian
Buffer Malabar 2 1
Jordan 1
Valkaria 1 13 1
Palm Bay 18
Babcock 3
Micco
Sebastian 4
Buffer
a excludes twenty-three unbanded Florida scrub-jays that immigrated into the study
sites from unknown areas.
Mean territory sizes for all territories from all study sites was 21 ha (Figure 5).
Nearly all territories included tall scrub (Table 12). One hundred and fifty-two territories
could be supported within the initial study sites if all scrub was acquired and restored to
optimal Florida scrub-jay habitat (Table 13).
37
0 - 75.0
- 55.0
- 35.0
15.0
Figure 5. Distribution of territory sizes in South Brevard.
65.45.0
25.05.0 -
Num
ber o
f Ter
ritor
ies
(199
7-19
99) 60
50
40
30
20
10
0
Std. Dev = 16.93 Mean = 21.3 N = 121.00
Territory Size (Hectares)
38
TABLE 12. Distribution of height classes among territories.
Valkaria Malabar Babcock Micco Jordan Buffer Palm Buck
Bay Lake
All short
1997 0 0 0 0 0 0 0 n/a
1998 0 0 0 0 0 0 0 n/a
1999 0 0 0 0 0 0 0 0
Short/optimal mix
1997 0 0 0 0 0 1 0 n/a
1998 0 0 0 0 0 0 0 n/a
1999 0 0 0 0 0 0 0 0
Tall mix
1997 16 3 2 2 1 11 2 n/a
1998 10 0 3 2 1 13 0 n/a
1999 8 1 2 4 1 12 0 3
All tall
1997 10 1 3 1 4 0 24 n/a
1998 8 2 0 0 4 0 17 n/a
1999 11 0 0 0 4 0 13 0
39
TABLE 13. Potential Florida Scrub-Jay habitat reserves in South Brevard County.
Malabar Valkaria Babcock Jordan Micco Buffer Totals
Potential 116 371 81 289 207 484 1548
habitat
(ha) a
Potential 11 37 8 29 20 48 152
number of
territories b
a Potential habitat was based on oak scrub and palmetto-oak scrub or habitat that
could be restored to oak or palmetto-oak scrub.
b Assuming 10 ha as a mean territory size.
All Florida scrub-jay territories included oak or palmetto-oak scrub (Figures 6-22).
Areas without scrub oaks and within 600 meters of scrub oaks were often occupied by
Florida scrub-jays.
Results from Fla Fire Science Team: include 10 figures
40
Figure 6. 1997 Florida Scrub-Jay Territories and Scrub at Malabar
Oak Scrub North Kilometers
Palmetto-Oak 0 0.25 0.50 Palmetto Scrub 1997 Florida Scrub-Jay Territories at Malabar
41
Figure 7. 1998 Florida Scrub-Jay Territories and Scrub at Malabar
Oak ScrPalmettoPalmetto1998 Flo
.
ub NorthKilometers -Oak 0 0.25 0.50 Scrub rida Scrub-Jay Territories at Malabar
42Figure 8. 1999. Florida Scrub-Jay Territories and Scrub at Malabar
Oak Scrub North Kilometers
Palmetto-Oak 0 0.25 0.50 Palmetto Scrub 1999 Florida Scrub-Jay Territories at Malabar
43
Figure 9. 1998 Florida Scrub-Jay Territories and Scrub at Jordan
North
Oak Scrub Palmetto-Oak Scrub
Kilometers Palmetto Scrub 0 0.5 1.0 1.5 1998 Florida Scrub-jay Territories at Jordan
44
Figure 10. 1999 Florida Scrub-Jay Territories and Scrub at Jordan
North
Oak Scrub Palmetto-Oak Scrub
Kilometers Palmetto Scrub 0 0.5 1.0 1.5 1999 Florida Scrub-Jay Territories at Jordan
Scale 1: UNDEFINEDScale 1: UNDEFINEDScale 1: UNDEFINED
Figure 11. 1997 Florida Scrub-Jay T
Oak Scrub
Palmetto-Oak 0
Palmetto Scrub 1997 Florida Scrub-Jay Territories
45
erritories and Scrub at Valkaria
North
Kilometers 1 2
at Valkaria
Scale 1: UNDEFINEDScale 1: UNDEFINEDScale 1: UNDEFINED
46
Figure 12. 1998 Florida Scrub-Jay Territories and Scrub at Valkaria
North
Oak Scrub Palmetto-Oak Scrub Kilometers
0 1 2Palmetto Scrub 1998 Florida Scrub-Jay Territories at Valkaria
Scale 1: UNDEFINEDScale 1: UNDEFINEDScale 1: UNDEFINED
47
Figure 13. 1999 Florida Scrub-Jay Territories and Scrub at Valkaria
North
Oak Scrub
Palmetto-Oak Scrub Kilometers0 1 2
Palmetto Scrub 1999 Florida Scrub-Jay Territories at Valkaria
48
Figure. 14. 1999. Florida Scrub-Jay Territories in Palm Bay Urban Study Sites
North
Palm Bay Study Area
Emerson Cluster Kilometers 0 1 2
Babcock Cluster
49
Figure 15. 1997 Florida Scrub-Jay Territories and Scrub at Babcock
North
Oak Scrub Palmetto-Oak Scrub Kilometers
0 0.25 0.50Palmetto Scrub 1997 Florida Scrub-Jay Territories at Babcock
50
Figure 16. 1998 Florida Scrub-Jay Territories and Scrub at Babcock
North
Oak Scrub Palmetto-Oak Scrub Kilometers
0 0.25 0.50Palmetto Scrub 1998 Florida Scrub-jay Territories at Babcock
51
Figure 17. 1999 Florida Scrub-Jay Territories and Scrub at Babcock
North
Oak Scrub Palmetto-Oak Scrub Kilometers
0 0.25 0.50Palmetto Scrub 1999 Florida Scrub-Jay Territories at Babcock
52
Figure 18. 1997 Florida Scrub-Jay Territories and Scrub at Micco
NorthOak Scrub Kilometers
Palmetto-Oak 0 0.25 0.50 Palmetto Scrub 1997 Florida Scrub-Jay Territories at Micco
53
Figure 19. 1998 Florida Scrub-Jay Territories and Scrub at Micco
NorthOak Scrub Kilometers
Palmetto-Oak 0 0.5 Palmetto Scrub 1998 Florida Scrub-Jay Territories at Micco
54
Figure 20. 1999 Florida Scrub-Jay Territories and Scrub at Micco
NorthOak Scrub
Kilometers Palmetto-Oak 0 0.5 Palmetto Scrub 1999 Florida Scrub-Jay Territories at Micco
55
Figure 21. 1998 Florida Scrub-Jay Territories and Scrub at Sebastian Buffer
North
Oak Scrub Palmetto-Oak Kilometers
0 2 4Palmetto Scrub 1998 Florida Scrub-Jay Territories
56
Figure 22. 1999 Florida Scrub-Jay Territories and Scrub at Sebastian Buffer
North
Oak Scrub Palmetto-Oak Kilometers
0 2 4Palmetto Scrub 1999 Florida Scrub-Jay Territories at Sebastian Buffer
57
5.0 Discussion
We investigated 81, 60, and 59 territories respectively for 1997, 1998 and 1999. At
least seven other families occurred on private lands adjacent to our study tracts in 1997.
Peripheral surveys revealed at least another 12 territories between Malabar and
Sebastian Buffer between 1997 and 1999. A few areas were too large to survey from
roads so that there undoubtedly were additional families in the South Brevard scrub-jay
population which therefore must have had greater than 100 territories in 1997.
Purchases for the St. Sebastian River State Buffer Reserve extended into Indian River
County and were close enough to be part of the Florida scrub-jay population in South
Brevard. These areas included greater than 12 territories (personal communication,
Keith Fisher, SBR). Observations of DOQs for the planned Carson Platt acquisition
suggest a dozen more territories will become part of St. Sebastian River State Buffer
Reserve. Another dozen families are included in a habitat conservation plan for North
Indian River County. These jays in South Brevard County and North Indian River
County represented the largest concentrations of Florida scrub-jays on the mainland of
the Atlantic coast (Stith et al. 1996, Stith 1999). These are also the largest
concentration of jays outside the Merritt Island/Cape Canaveral, Ocala, and the Lake
Wales Ridge making the South Brevard/North Indian River County population the fourth
largest population.
Although the geographical extent of our studies increased, the number of territories
decreased because of steep population declines. South Brevard populations declined
by almost 1/3 between 1993 and 1997 and greater than 50% between 1993 and 1998.
These data correspond to population declines predicted using population models and
vital rates that correspond with tall scrub or scrub that is a mix of tall and shorter scrub
(Breininger et al. 1996b, Breininger et al. 1999). The large Florida scrub-jay population
on Merritt Island has been declining by almost 50% per decade (Breininger et al. 1996b).
Evidence suggests that the Cape Canaveral population has also undergone a significant
decline and this decline is expected to continue because Cape Canaveral is dominated
58
by tall scrub (Stevens et al. 1998). Therefore Florida scrub-jays of the Atlantic coast are
likely to become endangered with extinction if these declines continue.
Mean family size was lower than most previously published studies and probably
resulted from poor demographic success. The mean family sizes in the urban Palm Bay
area were essentially identical to those found in another urban population headed
towards extinction (Breininger 1999). Survival measures were also lower than published
data and probably resulted from an epidemic that resulted in a catastrophic loss of
Florida scrub-jays from many areas in Florida (G. Woolfenden, R. Bowman, and J.
Fitzpatrick personal communication). Other Brevard populations, but not all, suffered
catastrophic losses from August 1997 to April 1998 (Breininger, Oddy, Larson, Smith
unpublished data; T. Stevens, S. Legare, R. Schaub personal communication). These
catastrophic events are of short duration and have low annual probabilities (Woolfenden
and Fitzpatrick 1984, 1991). Nearly all juveniles died during the previous Archbold
epidemic, but some survived to become yearlings in South Brevard and Merritt Island
(Breininger, Oddy, Larson, Smith, and Stolen unpublished data). The reasons for the low
survival rate for the urban Palm Bay area in 1998 are unknown. Many of the Palm Bay
breeder deaths in 1997 occurred during March 1998 whereas most deaths in the
remaining South Brevard population occurred in October of 1997. Most of the Palm Bay
deaths in 1998 occurred throughout the year so that the presumed epidemic by itself is a
poor explanation for low survival in Palm Bay.
Juvenile and yearling production rates were lower in South Brevard than previously
reported rates in frequently burned scrub. Lower reproductive success is expected for
areas that have an abundance of scrub that is tall because it is unburned for at least 20
years (Woolfenden and Fitzpatrick 1984, 1991; Breininger 1992; Schaub et al. 1992;
Breininger et al. 1995, 1996a, 1998a, 1998b). The urban Palm Bay population had
much greater reproductive success than the South Beach urban population (Breininger
1999). Reproductive success was not greater than the mortality rate at all study sites
except Sebastian Buffer in 1998. Sebastian Buffer had vital rates that were similar to
those needed for long-term population persistence. The mean family sizes suggest that
59
a population decline had previously occurred in the Sebastian Buffer population. This
study is still too short to make conclusions about the relative stability of the Sebastian
Buffer population.
Unlike 1997 results in South Brevard, most Florida scrub-jay pairs remain together
between successive breeding seasons and it is rare for both breeders to die during the
same year (Woolfenden and Fitzpatrick 1984, Breininger et al. 1996a). Stability in South
Brevard pair bonds was as expected during 1998 for sites that did not have unusually
high breeder mortality. As expected, a surviving breeder usually found a breeder to
replace a mate that died in South Brevard (Woolfenden and Fitzpatrick 1984, Breininger
et al. 1996a). Divorce was rare in South Brevard which is typical (Woolfenden and
Fitzpatrick 1984, Breininger et al. 1996a). For Palm Bay, an abundance of Florida
scrub-jays that were not affiliated with any particular territory was unusual. Perhaps
floaters were attributed to two consecutive years of high breeder mortality and therefore
a chaotic disruption of normal sociobiology.
The number of male helpers greatly exceeded the number of female helpers. This
was previously reported along the Atlantic coast where mortality exceeded reproductive
success and male breeder survival exceeded female breeder survival (Breininger et al.
1996a). Slightly more male helpers occur at Archbold because female helpers tend to
disperse further and at earlier ages so that female helpers have slightly higher mortality
rates than male helpers (Woolfenden and Fitzpatrick 1984). Female breeders had lower
survival than male breeders did in South Brevard. Female breeders tended to have
lower survival than males at KSC (Breininger et al. 1996a) but not Archbold (Woolfenden
and Fitzpatrick 1984). Demographic patterns are influenced greatly by small differences
in breeder survival (McDonald and Caswell 1993, Breininger et al. 1999).
Breeders with helpers had greater reproductive success than breeders without
helpers, although these differences were inconsistent. Pairs with helpers often had
greater reproductive success at KSC and Archbold (Woolfenden and Fitzpatrick 1984,
Mumme 1993, Breininger et al. 1996a). Differences in breeder survival for breeders with
60
and without helpers were also inconsistent in contrast to Archbold (Woolfenden and
Fitzpatrick 1984) but not KSC. Reasons for inconsistency in the differences in
demographic success might include sample sizes, stochasticity, and even habitat
effects.
Except in Palm Bay, most one-year-olds did not breed in South Brevard, although a
larger percentage bred in South Brevard than at Archbold (Woolfenden and Fitzpatrick
1984). The frequency of breeding by one-year-olds and the duration of delayed
breeding are related to demographic success (Breininger et al. 1996a, Breininger 1999).
Florida scrub-jays in declining populations have greater chances to breed than Florida
scrub-jays in stable populations.
One female Florida scrub-jay from Valkaria dispersed to become a breeder at Micco.
Another Florida scrub-jay at Valkaria ventured to Sebastian Buffer before returning to
Valkaria to become a breeder. These two long distance dispersals indicated that
Atlantic Coastal Ridge and Ten Mile Ridge Florida scrub-jay populations were connected
although they might function independently. Most breeding vacancies were filled by jays
that resided within the same cluster although immigration from unknown areas
complicated this analyses. Considerable potential habitat occurs outside the study sites
especially east and north of Micco. It is unlikely that the study sites and other large
areas of potential habitat will function as sources to habitat fragments because there is
generally a net movement of jays from fragments into larger natural areas (Thaxton and
Hingtgen 1995). Even among habitat fragments that are of poor habitat quality, there
can be a net movement from smaller to larger tracts because the larger tracts are a
source of mates as extinction occurs within the smaller fragments (Breininger 1999).
Therefore, immigration into the study tracts is anticipated as long as there are jays
residing outside these large tracts. However, sex differences in dispersal limit
recolonization of unoccupied habitat once it is restored if there is no adjacent source of
males which move less frequently among clusters (Breininger 1999). This is evident in
several areas in Valkaria that were burned by the catastrophic wildfire or timbered during
subsequent habitat restoration efforts.
61
Mean dispersal distances in South Brevard may be longer than means at Archbold
because of the fragmented nature of some of the scrub (Thaxton and Hingtgen 1996).
Mean dispersal distances are 0.3 km for male and 1.0 km for female Florida scrub-jays
in contiguous habitat at Archbold (Woolfenden and Fitzpatrick 1984). Mean dispersal
distances are 1.9 km for male and 8.1 km for female jays originating from territories in
suburban areas (Thaxton and Hingtgen 1996). Mean dispersal distance from natal
territories are 1.0 km for males and 8.1 km for female jays within a fragmented urban
population on Brevard’s barrier island (Breininger 1999). The mean dispersal distances
reported herein are likely to change as the sample sizes increase.
Mean territory sizes were much larger than previously recorded in study tracts where
all scrub was occupied and habitat was saturated to carrying capacity (Woolfenden and
Fitzpatrick 1984; Breininger et al. 1995, 1998, in press). Many territories in South
Brevard were within the typical range. However, many territories were also very large.
One reason for large territory sizes was that there was much unoccupied habitat so that
Florida scrub-jays families were probably able to occupy more habitat than possible if
there had been greater competition for space. Also many territories were adjacent to
mesic flatwoods that lacked enough scrub oaks to be occupied by other families of
scrub-jays. These families too may have been able to occupy more habitat than possible
if competition for space had been greater. Other habitat conditions might also have
required jays to occupy larger areas than has been found in previous studies. For
example, some areas in the Sebastian Buffer area have high pine densities so that
these areas may have been enclosed within territories but may have actually received
little or no use. Relationships between family size, population density, territory size, and
territory quality have long been known to involve confounding relationships that need
greater investigation (Woolfenden and Fitzpatrick 1984).
Much oak scrub was not inhabited by Florida scrub-jays because at least two of
three habitat features (open space, tree cover, shrub height) were marginal (Breininger
and Oddy 1998). Most territories were suboptimal because two or more habitat features
62
were suboptimal (Breininger and Oddy 1998). These habitat features have explained
habitat occupancy patterns and demographic success in other studies (Westcott 1970;
Woolfenden 1974; Cox 1984, 1987; Woolfenden and Fitzpatrick 1991; Schaub et al.
1992; Breininger et al. 1991a, 1995, 1996a, 1996b, 1998a, in press).
The methods used to estimate potential carrying capacity relied on only the oak and
palmetto-oak scrub. The advantages of this approach are that it is easily repeatable and
does not rely on expert opinions or complex rules. However, it ignores some ruderal and
palmetto scrub habitats that contribute to population size depending on their landscape
context.
6.0 Natural Resource Management implications
The following summarizes recommendations that resulted from this study while
incorporating results from related scrub studies that are summarized in greater detail
within Appendices A, B, C, and D. It is important to note that the organizations have
recently been staffed with fire managers who have rapidly been managing the newly
acquired public lands. The following summarizes discussions that have occurred with
these managers. Planning and often actual implementation has often already occurred.
Limitations based on weather, urban surroundings, equipment and manpower remain
but a local interagency working group is being initiated to address these issues.
Progress has been made since completion of the first annual report that indicated that
rapid progress is essential or else extinction will occur (Breininger and Oddy 1998).
6.1 General Recommendations
Florida scrub-jay habitat acquisition and management actions should not be
restricted to xeric habitats but should include palmetto-dominated habitats that have
scrub oaks and palmetto-dominated and swale marsh habitats adjacent to xeric oak
habitats (Breininger et al. 1991a, 1995, 1998; Duncan et al. 1995). Many applications
have not identified all suitable and occupied habitat. Scrub oak polygons used by
63
Florida scrub-jays are often smaller than minimum mapping units used by most habitat
mapping applications. We showed that scrub oak polygons do not need to be explicitly
mapped (Breininger and Oddy 1998). Saw palmetto polygons that contain scrub oaks
can be used to identify habitat that is likely to be occupied (Breininger and Oddy 1998).
It is easy to distinguish these “ mixed “polygons from saw palmetto polygons that do not
contain scrub oaks. Although Florida scrub-jays spend most of their time in oak scrub
patches, they defend and use saw palmetto scrub adjacent to scrub oak patches
(Breininger et al. 1995, 1998). Human alteration of the palmetto and swale marsh matrix
disrupts fire patterns, alters prey and predator composition, and removes habitat that
may become optimal after fires (Fitzpatrick et al. 1991, Breininger et al. 1995). Other
scrub animals (e.g., gopher tortoises, gopher frogs, and indigo snakes) also do not
restrict their use to oak scrub patches (Breininger et al. 1991b, 1994; Smith et al. 1997;
Legare, Smith, Breininger unpublished data). Massive numbers of amphibians breed in
the swale marshes and spend their lives in scrub; these are important food for Florida
scrub-jays (Moler and Franz 1987).
6.2 General Fire Management Recommendations
The landscape that surrounds oak scrub should burn more frequently (e.g., every 3
years) than oak scrub. Scrub oak patches often burn less often than adjacent palmetto-
dominated habitats and swale marshes (Breininger et al. unpublished manuscript).
Failure to burn the matrix frequently enough can result in a loss of openings and the
development of too many tall shrubs and trees (Breininger et al. in press). Once
openings are lost, it may take many fires to get them back (Schmalzer et al. 1994).
Open sandy areas are critical for long-term Florida scrub-jay population persistence
(Woolfenden 1974, Duncan et al. 1996, Breininger et al. 1998). Open sandy areas are
also important to other scrub plants and animals (Campbell and Christman 1982,
Hawkes and Menges 1996).
The frequency for burning oak scrub should be based on habitat structure with no
reliance on any rotations previously established for these habitats. Habitat structural
64
criteria should be used to evaluate burning needs and not fire frequencies (Breininger et
al. in press) because there is site-specific variation in response to fire because of
variation in soils, nutrients, water table, and previous fire history (Abrahamson and
Hartnett 1990; Breininger and Schmalzer 1990; Myers 1990; Schmalzer and Hinkle
1992a, 1992b; Menges and Kohfeldt 1995; Hawkes and Menges 1996).
Observations from historical photographs show that pine densities have greatly
increased which is consistent with regional patterns of habitat change associated with
the disruption of natural fire patterns (Duncan et al. 1996, 1999). Elsewhere, we found
that the presence of patches of tall oaks greater than 0.4 hectare (1 acre) had negative
impacts on demography (Breininger et al. in press). Large (e.g., 0.4 ha) or long (> 100
m) patches of tall shrubs may interfere with the jay’s visual sentinel system, which is
adapted for predator detection and territorial defense (McGowan and Woolfenden 1989).
It may take many specifically focused fires to reduce the number of tall patches to
conditions where Florida scrub-jay populations can persist for long periods. A few small
clumps of tall oaks or pines will not interfere with visibility and can serve as useful posts
for sentinels.
Florida scrub-jays need some scrub oaks that are 120 – 170 cm tall for nesting and
to have enough acorns during winter periods of low insect abundance (DeGange et al.
1989). Maintenance of some scrub should not be difficult given the fragmentation of
fuels resulting from human landscape modification. Several restoration fires will be
needed to get most of the scrub burned. Fires that follow the initial restoration fires
should be mosaics. It is reasonable to assume that at least one small fire will be needed
at each site on an annual basis for many years to restore the landscapes and reduce
hazardous fuel loadings.
Frequent fires will benefit species adapted to Brevard ecosystems. Such
management practices will reduce the risk of catastrophic wildfires thus making future
habitat management easier because of the reduction in fuels. These activities will be
consistent with the habitat requirements of other native species that make the local
65
biological diversity unique (Webber 1935; Speake et al. 1978; Means and Campbell
1981; Auffenberg and Franz 1982; Campbell and Christman 1982; Abrahamson 1984;
Abrahamson and Hartnett 1990; Breininger and Schmalzer 1990; Layne 1990; Myers
1990; Breininger et al. 1991b; Robbins and Myers 1992; Breininger and Smith 1992;
Schmalzer and Hinkle 1992a, 1992b; Breininger et al. 1994; Ostertag and Menges 1994;
Florida Natural Areas Inventory 1995; Hawkes and Menges 1995, 1996; Menges and
Kohfeldt 1995; Glitzenstein et al. 1995).
6.3 Site Specific Recommendations
Frequent fire is needed at all study sites for the long-term persistence of Florida
scrub-jay populations. Most sites will need to be dominated by restoration actions rather
than management strategies that would be used if the sites already were in optimal
condition. The following focuses on macrohabitat management needs of restoring large
patches of tall shrubs (>170 cm tall) to a mosaic of short (<120 cm ) and optimal height
(120-170 cm) and reducing hardwood and pine trees in scrub to a couple trees per acre.
Our recommendations should not be applied to pine in areas important to red-cockaded
Woodpeckers. Disturbed woody wetlands that were formerly swale marshes should also
be extensively burned to return them to marsh habitats but these are not explicitly
addressed herein but will be addressed more explicitly in later reports. The return of
openings is important but may or may not readily occur following initial restoration
efforts. Openings are critical components but are not addressed specifically herein
because we assume they might return in most areas following initial restoration and
frequent fire applications.
66
Figure 33. Fire Management Needs at Malabar
North Kilometers
0 0.25 0.50 0.75
Scrub needing prescribed fire
67
The habitats mapped below extended past the boundaries of areas that were
already in public ownership and include areas targeted for acquisition. Figures 33-38 do
not explicitly identify existing public lands from those that are privately owned. Some of
the private lands are being used for mitigation but many are outside the jurisdiction of
natural resource management. Efforts are in progress to acquire digital files of site
boundaries. Most existing digital files represent areas proposed for acquisition and do
not reflect the dynamics of the land acquisition. Aerial photography has not yet been
acquired and used to map all habitat changes resulting from management and wildfires
that have occurred. Efforts have been made only to approximate these changes.
Extensive imagery acquisition, detailed mapping, and Global Positioning System
measurements of all management actions are outside the scope of the existing work.
Therefore, the figures below are only general descriptions of fire management needs.
Areas identified below include tall oak scrub (>170 cm tall) and palmetto-dominated
habitats that need burning. Palmetto-dominated areas might not have had mean shrub
heights exceeding 170 cm. These were included if they have not burned in many years
because frequent burns are part of their natural state and jays seem to use them most
when they are frequently burned. Some areas identified below include areas that had
incomplete burns or had been unburned for a long time before the last fire. The figures
represent immediate fire needs and do not identify areas that will need burning in a few
years that do not need burning at present.
68Figure 34. Fire Management Needs at Jordan
North
0 0.5 1.0 1.5 Kilometers
Scrub needing prescribed fire
69
Figure 35. Fire Management Needs at Valkaria
NorthKilometers
0 0.5 1.0 1.5
Scrub that needs prescribed fire
70
Figure 36. Fire Management Needs at Babcock
NorthKilometers 0 0.5 1.0
Scrub that needs prescribed fire
71
Figure 38. Fire Management Needs at Sebastian Buffer
Kilometers North 0 2 4
Scrub that needs prescribed fire
72
Figure 33-38 can be compared with the territory maps (Figures 6-21) above to
determine whether mosaic fires or complete fires are needed for a particular area.
Areas that are greatly below carrying capacity or that are unoccupied should be burned
to reduce 70-90% of the fuels. Areas that are occupied at average densities of 1 pair
per 10 hectares or greater should be burned as mosaics so that a hectare of oak scrub
remains unburned in each territory. Generally, it is better to risk burning too much than
too less. Generally, an area burned too little will still be a population sink for many
years. Generally, an area burned too much will only be a sink for only a few years.
These generalities refer to fires of <100 hectares. Large, extensive fires (hundreds of
hectares and consuming 90% of the fuels) are not recommended for areas approaching
carrying capacity. The recent burn at Micco was an example where the knowledge of
existing jay distribution in relation to carrying capacity and the knowledge of site
surroundings represented a circumstance where a large extensive fire was advisable
and successfully implemented.
6.3.1 Malabar. Nearly all scrub is too tall but the site is surrounded by human development and has
great fuel loadings. The first burn is planned soon but it will probably not be extensive
enough to enhance population recovery. Nearly all of the scrub at this site should be
burned because so few families remain. This site is not closely connected to other jay
populations because of surrounding human developments and extensive forestation
attributed to infrequent fire. The number of scrub-jay families using this site is
precariously close to extinction. Successful recolonization probabilities for males might
be too low for population recovery if extinction occurs. The lack of continuity with other
jay subpopulations probably means that a population in this area will be effected mostly
by it own population dynamics so that maximizing population size in this fragment is
probably essential for it to have a population that can sustain itself. There is some
habitat that could be acquired or managed between Malabar and Jordan that has
potential to establish continuity that might increase the viability of the Malabar
population.
73
6.3.2 Jordan. Nearly all scrub is too tall and has great fuel loadings. The first burn is planned
soon but it will probably not be extensive enough to enhance population recovery. There
are also mitigation lands south of the existing EELs purchase that need management.
These areas not only provide habitat for at least three jay families but are important
because they connect the EELs site to Valkaria Airport scrub. Although nearly all the
scrub needs burning, a sequence of fires is needed every year to have mosaic fires in
order to leave some scrub for each of the remaining families. An exception is the scrub
between the powerlines and railroad tracts where jay families only occur along the
periphery. This area should receive a hot fire that consumes nearly all the habitat
present.
6.3.3 Valkaria. Much scrub that burned in the Valkaria wildfire will be optimal habitat within a couple
years. The timbering that occurred adjacent to this area also resulted in much habitat
improvement. However, much of this area is unoccupied. Forests that were once scrub
or marshes separate this area from many areas occupied by Florida scrub-jays. A
territorial budding process might be needed to recover these areas. Therefore, all
forested and overgrown potential habitat, in public ownership bordering this area should
be restored quickly to encourage recolonization.
For 1999, 13 of 19 Florida Scrub-Jay territories in the Valkaria area overlapped
Valkaria airport and golf course indicating the importance of these sites to recovery of
the population in the conservation reserve being established at Valkaria. The Valkaria
airport is one of the few areas in Brevard with broad extensive scrub oak ridges that
have not been developed. Nearly all of the airport and golf course property is overgrown
and could be optimal following several prescribed fires and tree density reduction.
Discussions have identified that habitat improvements would greatly improve safety of
aircraft operations and that planned safety enhancements could enhance habitat
suitability. The initial Florida Inland Navigation District (FIND) spoil disposal proposed
74
site would greatly impact the establishment of a large contiguous jay population.
Numerous cooperative discussions have been held to move this site to the periphery
and these efforts need to continue until a solution is complete.
6.3.4 Palm Bay. Nearly all jays reside within small scrub fragments among a suburban landscape
resulting in little land management potential. Liberty Park is the only public lands that
can provide habitat but this park is very small. There are two scrub tracts east of
Babcock (just north and south of Valkaria Road) that are probably large enough to
support 3-6 families but this area would be separated from the nearest large proposed
conservation area (Babcock) by a kilometer of dense forest. No fire management
recommendations are proposed for this population.
6.3.5 Babcock. Most of the Babcock site needs burning and pine thinning. A problem with this site
is that it is in fragmented ownership. However, the scrub at this site is less degraded
than many sites so that the establishment of openings should not be difficult. Nearly all
scrub that is in mitigation ownership should be burned providing it is logistically possible
to do this. Habitat destruction continues along the edges of this proposed EELs site.
6.3.6 Micco. Nearly all of the Micco tract north of Micco Road that is important for jays has been
burned. Some cutting of trees is needed along the north edges of the site. The area
south of Micco Road needs extensive restoration but this is not of immediate priority
although it is very important for maintaining long-term continuity with the Buffer Reserve.
The area southwest of the intersection of Micco Road and the powerlines should be
burned within a couple of years and eventually all of the area to the west of the
powerlines should be restored to a pine savanna. The scrub east of the EELs tract and
west of I-95 is very important for acquisition but is largely overgrown.
75
6.3.7 Buffer. The Corrigan Ranch area is in better condition than all other public lands in Brevard.
Other ownerships that have been acquired have generally had overgrown scrub and
have many challenging restoration needs. This report addresses only areas north of the
C54 Canal; areas south of the C54 Canal will be addressed in subsequent reports.
Even the Corrigan Ranch section has much overgrown scrub along edges, particularly
along the C54 Canal just east of the powerlines and in the southeast corner of the
property. The southeast corner of the property is one of the larger xeric areas and
probably was once a mosaic of scrub and longleaf pine-wiregrass. Restoration to this
condition would enhance jay habitat suitability. Much degraded habitat also occurs
along the north property line east of I-95. This area could probably support many
families but is currently unoccupied and is not a critical linkage to other subpopulations
and therefore is a lower priority than other management needs. The north area west of
I-95 is overgrown but represents a large contiguous scrub landscape. Natural resource
managers demonstrated their abilities to restore a large landscape quickly using a
combination of mechanical techniques and fire when provided with the necessary
resources.
6.3.8 Buck Lake. Wildfires, prescribed fires, tree thinning, and rollerchopping have restored much of
the landscape. However, some areas remain tall and need cutting and prescribed fire.
One area has especially large oaks that need cutting to allow an extensive, contiguous
landscape. This area is an area where the few remaining families have contiguous
boundaries and therefore needs treatment. Buck Lake is isolated or nearly isolated from
other populations so that it is essential to restore as much potential habitat as possible
to provide the greatest chances for population persistence.
.
7.0 Implications for Land Acquisition.
Recommendations are restricted to study site vicinities in this report. Study site
expansions are planned for Rockledge and Tico during the next year so that additional
recommendations will appear in subsequent reports.
76
7.1 South Brevard
The acquisition and mitigation activities occurring in South Brevard have the
potential to conserve one of the largest populations of one of North America’s most
unique birds. Acquisition is planned to continue at Valkaria, Micco, and Jordan. This
study recommends the acquisition of large expanses of xeric oak and surrounding
palmetto-dominated habitats and swale marshes. This not only is important for Florida
scrub-jay populations but for sustaining other species of conservation concern. Red-
cockaded woodpecker studies at the Buffer Reserve demonstrate that there are more
red-cockaded woodpeckers remaining and more potential habitat remaining than once
believed. However, recovering a viable population will require acquisition of large
contiguous landscapes. Sustaining a regional indigo snake population also requires a
large reserve network. Sustaining a viable jay population might also require larger
reserves than given for the reasons other than described below. The consequences of
faunal collapse and ecosystem degradation might have greater impacts to jay
populations than we understand. Fish crows, grackles, and mourning doves can reach
very high population numbers in habitat fragments surrounded by urban areas
(Breininger pers. obs.). Fish crows and grackles are potential predators of scrub-jay
nests and young. Mourning dove aggregations in scrub tracts attract Cooper’s Hawks
that can reside in urban-dominated landscapes and detecting and escaping predation by
these predators appears to consume most of the time of jays residing in these tracts
(Breininger pers. obs.). Furthermore, fire managers emphasize their difficulty in burning
in urban-dominated landscapes.
Florida scrub-jay territories along roads tend to be population sinks (Mumme
unpublished). Large reserves have many advantages for Florida scrub-jays (Fitzpatrick
et al. 1991). Florida scrub-jays are particularly vulnerable to predation by hawks,
particularly Cooper’s hawks, along the Atlantic coast (Breininger et al. 1996a). Florida
scrub-jays have a well-developed sentinel system for early detection of these predators
in open landscapes (McGowan and Woolfenden 1989). Florida scrub-jays living in
77
families that are surrounded by other families are safer than Florida scrub-jays living
along edges that have no early warning regarding the presence of a hawk.
Young Florida scrub-jays generally spend a few years with their parents until
breeding vacancies become available nearby (Woolfenden and Fitzpatrick 1984,
Breininger et al. 1996a). These nonbreeders help their parents raise new generations of
young and help in predator detection. Florida scrub-jay breeding pairs with helpers have
better demographic success than breeding pairs without helpers (Woolfenden and
Fitzpatrick 1984, Breininger et al. 1996a). Helpers that live in families surrounded by
other families have more chances to monitor breeding vacancies without leaving their
families than helpers that live in isolated families. Helpers in fragmented populations
have lower survival than helpers in landscapes with many contiguous families (Thaxton
and Hingtgen 1995, Breininger unpublished manuscript). Helpers in fragmented areas
must take greater risks to monitor areas for breeding opportunities.
There is great uncertainty concerning metapopulation dynamics in highly fragmented
systems so that several risk management strategies should be implemented given that
the South Brevard population is one of the largest and most important rangewide
metapopulations (Stith 1999). Low dispersal tendencies by males implies that it also
important to consider that at least short-term population dynamics of reserves might be
dominated by local population factors. Florida scrub-jay population viability increases
greatly between 20 and 100 pairs and large populations have much better ability to
withstand catastrophic events and persist than smaller populations (Breininger et al.
1996b, 1999). It is important to enlarge proposed conservation plans so that both the
Atlantic Coastal Ridge and Ten Mile Ridge populations are at the largest size possible
(>60 pairs). The SCDP included plans to connect the two populations south along the
Atlantic Coastal Ridge to Sebastian River. However, the population along the Atlantic
Coastal Ridge south of Valkaria is excessively fragmented so that it might also be useful
to acquire several of the large unfragmented, high quality mesic flatwoods landscapes
north and south of Grant Road. Florida scrub-jays will disperse through mesic flatwoods
that are frequently burned. Mitigation banks for gopher tortoises and wetlands could be
78
located in these areas. Large connected reserves will also benefit indigo snakes,
bobcats, and river otters (Harris and Gallagher 1989) and be more practical to manage
than a system of many small and scattered reserves.
Many of the recommendations for acquisition to increase scrub ecosystem viability
have been adopted by EELs as priorities although funding will probably not be sufficient
for all acquisitions and acquisition depends of the willingness of landowners to sell their
properties. These include acquiring the remainder of Valkaria, Jordan Boulevard, Micco
and new acquisitions from Babcock scrub south to Micco Site.
7.2 North Brevard
The SCDP (Swain et al. 1995) and statewide regional planning efforts (Fitzpatrick et
al. 1995) advocated an archipelago of scrub reserves along the entire range of Brevard
County. Continued human development make this difficult, if not impossible to obtain.
However, sustaining a few relatively isolated mainland populations is feasible. A large
population can be sustained in North Brevard but much acquisition is needed. North
Brevard has one of the potentially largest state populations and one of the most
vulnerable population to extinction without much acquisition (Stith 1999). The purchase
of Buck Lake and anticipated purchases of Seminole Ranch by SJRWMD provides two
small subpopulations that are within a couple kilometers of each other but separated by
habitat fragments of little value except for a planned mitigation purchase north of
Seminole ranch. Much potential scrub-jay habitat occurs south of Seminole Ranch and
west of South Lake and Fox Lake. Acquisition of these additional areas could increase
the size of the protected Seminole Ranch population by 6-12 families. The CARL
program itself developed a proposed package to connect many of the conservation
lands north of Buck Lake. Some scrub is within this area but is fragmented sparsely
occupied by scrub-jays. There is habitat for many families immediately adjacent to the
north boundary of Buck Lake. This relatively small area is critical to increase the
potential size of the Buck Lake population.
79
8.0 Conclusions
Florida scrub-jay populations have been declining because of poor habitat quality.
Reproductive success and survival were low because of poor habitat quality and
because of an epidemic that resulted in a catastrophic loss of Florida scrub-jays.
Implementation of proposed land acquisitions could result in the fourth largest Florida
scrub-jay population across the remaining range. However, the acquisition and
restoration processes must move faster than the rates of jay population decline.
Aggressive management and restoration can correct poor habitat quality that resulted
from the widespread disruption of natural fire patterns. Management and restoration will
benefit most species that contribute to central Florida’s unique biological diversity.
Wildfire can have short-term and long-term effects that sometimes differ from one
another; beneficial and detrimental effects also tend to be case-specific. A wildfire fire
can reduce demographic success for several years if all scrub is burned and could
increase extinction probabilities if that population is already small and isolated.
However, a wildfire is also likely to result in an improvement in habitat conditions
immediately if it burned as a mosaic at the local scale or after a few years or if it burns
lots of tall shrubs and kills many trees. Large expanses of burned areas can reduce
population connectivity over the short-term but can increase connectivity if these areas
had become forests because of the disruption of natural fire patterns. Measures to
salvage timber after fires will probably benefit scrub-jays as long as they do not result in
excessive soils disturbance that reduces palmetto cover making it difficult for fire to carry
following the recovery of scrub oak vegetation. The application of prescribed fires and
timbering to reduce fire hazards of unburned areas is likely to improve conditions for
scrub-jay demographic success and dispersal. If areas are densely occupied by scrub-
jays, the management activities should attempt to leave one hectare patches of scrub for
every territory and these patches should be in open landscapes rather than along the
edge of a forest.
This study contributed to an overall understanding of Florida scrub-jay demography
and social behavior in a manner that will facilitate the recovery process. Demographic
80
rates need to be replicated across a range of habitat management and habitat quality
conditions. Although there is much similarity in biology between Atlantic coast and
Archbold populations, there are also distinctions that are relevant to the quantification of
important parameters needed to evaluate extinction risk.
Acknowledgments
We thank Dawn Zattau and the U. S. Fish and Wildlife Service for their support in
funding the study. We also that Anne Birch, Tami Robinson, and others from the
Brevard County Environmentally Endangered Lands Program. We thank Lisa Smith of
Smith Environmental Services and Zeke Nations of Endangered Lands Management
Company for assisting us with access issues. We thank Jennifer McMurtray of the St.
Johns River Water Management District for assistance with access issues. We thank
Keith Fisher, Susan Carl, and others from the Florida Department of Environmental
Protection for various support. We thank Anna Smith and Brian Toland for their field
assistance. We thank Ross Hinkle and Paul Schmalzer for reviewing this report.
Appendix A: The Importance of Habitat Management
Optimal Florida scrub-jay habitat, defined by conditions when reproductive success
exceeds mortality, is maintained by relatively frequent fires (Woolfenden and Fitzpatrick
1984, 1991; Breininger et al. 1995, in press). In most scrub landscapes that support
scrub-jay habitat, humans have disrupted natural fire patterns so that fires no longer
burn or are allowed to burn across landscapes.
Infrequent fire is one of the greatest threats to population persistence making
restoration and prescribed fire management one of the most important components of
the Florida scrub-jay recovery plan. Many Florida scrub-jays occur in habitat conditions
where their long-term persistence is doubtful although their persistence in these areas
can last many years (Swain et al. 1995, Stith et al. 1996, Root 1998, Breininger and
Oddy 1998, Breininger et al. 1999). A primary cause for Florida scrub-jay decline is poor
81
demographic success associated with reductions in fire frequency (Woolfenden and
Fitzpatrick 1984, 1991; Schaub et al. 1992; Stith et al. 1996; Breininger and Oddy 1998;
Breininger et al. 1996a, 1996b, 1999, in press). The reduction in fire frequency is
associated with increases in shrub height, decreases in open space, increases in tree
densities, and the replacement of scrub and marshes by forests (Duncan and Breininger
1998, Schmalzer and Boyle 1998, Duncan et al. 1999). These habitat trajectories result
in declines in habitat use and demographic success (Woolfenden and Fitzpatrick 1984,
1991; Breininger et al. 1995, 1998, in press). The number of breeding pairs can decline
by 50% every 5-10 years (Woolfenden and Fitzpatrick 1991, Breininger and Oddy 1998,
Breininger et al. 1999, B. Toland unpublished data).
Much of the reduction in fire frequency began before the 1960s (Duncan et al. 1999)
so that the degraded habitat conditions preceded the careers of natural resource
managers and voters that participate in land management decisions. It is important to
restore and manage all potential habitat within scrub reserves but this is not always a
popular decision with managers or the uniformed public. However, Florida’s only
endemic bird is unlikely to persist without such management. Sand pines and large
oaks have often replaced open scrub savannas that were frequently burned prior to the
1960s. Aerial photography in the 1940s is available for nearly every location and
provides information for determining habitat potential (Duncan and Breininger 1998;
Duncan et al. 1996, 1999).
Soils disturbance, fragmentation of habitats, and fire suppression result in scrub
patches that are difficult to burn except under circumstances in which fires are difficult to
control. Reestablishing openings and other characteristics of optimal habit might take
long periods and require techniques not yet established. Many scrub landscapes occur
in smoke sensitive areas and have accumulated fuel loadings that make it difficult to
manage all conservation lands for optimal habitat conditions.
Habitat requirements of species that are dependent on scrubby flatwoods provide
information on habitat conditions that existed for thousands of years. A limited quantity
of information can be extracted from population studies of native habitat specialists,
82
vegetation studies, historical photographs, or from observations of how often humans
can burn a habitat type. Combining these observations provides our best hope for
estimating natural fire cycles. Because of human landscape alterations, many declining
populations are small and fragmented and will not persist without the careful attention of
natural resource managers (Auffenberg and Franz 1990, Woolfenden and Fitzpatrick
1991, Quintana-Ascencio and Menges 1996, Breininger et al. in press). At least some
scrubby flatwoods landscapes need fire rotations shorter than previously advocated in
order to manage for habitat conditions required by habitat specialists.
It is important to identify management goals based on habitat conditions and
arrangement. There is variation in vegetation responses to fire because of variation in
soils, nutrients, water table, fire intensity, and previous fire history (Abrahamson and
Hartnett 1990; Breininger and Schmalzer 1990; Myers 1990; Schmalzer and Hinkle
1992a,b; Menges and Kohfeldt 1995; Hawkes and Menges 1996). More intense fires,
resulting from longer periods without fire, can create more openings in Lake Wales
Ridge scrubs than Atlantic coast scrubs (Menges and Hawkes 1998). Because site
variability influences recovery from fire, natural resource managers should adjust fire
frequency and intensity in individual landscapes by using height, openings, tree cover,
and other structural features to assist in determining burning objectives for a particular
site.
Fuel moisture, local weather, ignition, and suppression techniques influence the
amount of habitat that burns (Rothermal 1983, Doren et al. 1987, Dye 1991). Therefore,
fire management plans must consider fire behavior of previous fires and vegetation
responses. Therefore, it is difficult to write fire prescriptions and detailed management
plans for long periods so that habitat management programs should be based on spatial
and temporal goals in habitat quality, close monitoring of scrub-jays and habitat
conditions, and adaptive management.
Other species of conservation concern not restricted to scrubby flatwoods also need
frequent fire (e.g., gopher tortoise [Gopherus polyphemus], indigo snake [Drymarchon
83
corais couperi], Florida mouse [Podomys floridamus], red-cockaded woodpecker
[Picoides borealis], loggerhead shrike [Lanius ludovicianus], and Bachman’s sparrow
[Aimophila aestivalis]; Means and Campbell 1981, Auffenberg and Franz 1992, Speake
et al. 1978, Layne 1990, James et al. 1997). Several reptiles of conservation concern
(e.g. Eumeces egregius lividus, Neoseps reynoldsi) also need sandy openings in xeric
habitats, such as oak scrub (Christman 1992 a, b). We know of no species restricted to
scrubby flatwoods that prefer unburned habitats. Birds that prefer unburned scrubby
flatwoods are species that are common across much of eastern North America
(Breininger and Smith 1992). Some xeric scrubs, such as rosemary (Ceratolia ericoides)
scrub or sand pine (Pinus clausa) scrub have plants and bryophytes adapted to longer
fire intervals (Menges and Kohfeldt 1995, P. Schmalzer pers. comm.).
Appendix B Definition of Optimal Habitat Conditions
Florida scrub-jays need large, open landscapes for long-term population persistence
(Woolfenden and Fitzpatrick 1984, 1991). Modeling studies suggest that most habitat
must be optimal for population recovery and that extinction risk declines rapidly between
20 and 100 breeding pairs if all habitat is optimal (Breininger et al. 1999). Optimal
Florida scrub-jay landscapes need to include “focal” patches that have optimal
characteristics within a “matrix” of habitat that does not lower the suitability of the focal
patches.
B.1 Landscape Characteristics
The landscape attributes of optimal habitat can be described as low and open with
low densities of pine trees (Woolfenden and Fitzpatrick 1984, 1991). Florida scrub-jays
do not use forests and avoid areas near forests (greater than 65% tree cover; Breininger
et al. 1995). Nest predation is a primary factor influencing the Florida scrub-jay’s
preference for landscapes dominated by frequently burned scrub (Schaub et al. 1992).
Vegetation that characterizes open (recently burned) scrub allows scrub-jays to monitor
a large area while providing refuge and the opportunity for Florida scrub-jays to be
84
inconspicuous in their activities. Florida scrub-jays may not be effective at deterring
predators once the predator has found the nest. However, mobbing may alter the
course of foraging predators. The fragmentation of scrub landscapes results in an
increase of woodlands and forests (Duncan et al. 1999). Disturbances related to human
development, fire suppression, and other disruptions of natural fire patterns have made
many edges of habitat fragments unsuitable for jays. Landscapes, fragmented by
woodlands, forests, and tall shrubs, no longer allow Florida scrub-jays to scan large
areas for predators which may be important for the Florida scrub-jay’s visual sentinel
system, which is adapted for predator detection (McGowan and Woolfenden 1989).
Florida scrub-jays subdivide the landscape into 10 ha parcels when the habitat
approaches optimal conditions (Woolfenden and Fitzpatrick 1984, 1991; Breininger et al.
1995, in press). Within each parcel there should be at least a hectare of oak scrub that
is 120-170 cm tall (Breininger et al. in press). Most remaining oak scrub should be
shorter than 120 cm and have many openings. No studies have been published that
show that Florida scrub-jays have reproductive success rates that equal or match
mortality rates in habitat that does not meet the above criteria. The mosaic of optimal
height oak scrub and short oak scrub will be dynamic because of the fire frequency.
Saw palmetto and herbaceous swale marshes often dominate Florida scrub-jay
territories and should be short (<120 cm; Breininger et al. 1995, 1998, in press).
No scrub should remain unburned for 20 years unless evidence conclusively
demonstrates that the area naturally was unburned for long periods. Territories that are
dominated by scrub unburned for >20 years usually are sinks where mortality exceeds
reproductive success (Woolfenden and Fitzpatrick 1984, 1991). Optimal height is
sometimes described as being 1-3 meters tall. However, Florida scrub-jays territories
are usually sinks in areas where there are many patches that exceed 170 cm in height
along Florida’s Atlantic coast (Breininger et al. in press). Some sink areas are expected
among areas that are sources where reproductive success exceeds mortality (Breininger
et al. 1995, 1998, in press). This source-and-sink structure was natural and unavoidable
given the landscape arrangements of oak scrub among saw palmetto and burn patterns.
85
However, reproductive success must exceed mortality in the population for population
persistence. The ratios of source and sink habitat for viable populations have not been
demonstrated and might be population specific.
B.2 Focal Habitat Patches
Optimal Florida scrub-jay habitat occurs as patches (focal habitat) with the following
attributes (Duncan et al. 1995, Breininger et al. 1998):
a) 10-50% of the oak scrub comprised of bare sand or sparse herbaceous
vegetation,
b) greater than 50% of the shrub layer comprised of scrub oaks,
c) a mosaic of oak scrubs that occur in optimal height (120-170 cm) and shorter,
d) less than 15% pine canopy cover, and
e) greater than 300 m from a forest.
Florida scrub-jays have adapted to frequent fires by defending large territories
increasing the probability of having enough patches in optimal condition within a territory
at any given time (Woolfenden and Fitzpatrick 1984, 1991; Breininger et al. 1995). Oak
scrub represents the potential focal habitat, but not all of it is necessarily in optimal
condition at the same time. Patches of oak scrub vary in quality depending on the time
since fire. Tall oaks impede the ability to spot predators whereas short oaks can still
provide numerous foraging opportunities (Breininger et al in press).
B.3 Matrix Habitat
Much potential Florida scrub-jay habitat occurs as patches of oak scrub within a
matrix of little-used habitat of saw palmetto and herbaceous swale marshes (Breininger
et al. 1991, 1995). These native matrix habitats provide prey for Florida scrub-jays and
habitat for other species of conservation concern. The flammability of native matrix
habitats is important for spreading fires into oak scrub that often burns poorly. Saw
palmetto, gallberry, and grasses, which dominate saw palmetto and marshes, are more
86
flammable and accumulate fuel more rapidly than scrub oaks (Abrahamson 1984;
Abrahamson and Hartnett 1990; Myers 1990; Schmalzer et al. 1991; Schmalzer and
Hinkle 1992a). Degradation or replacement of native matrix habitats with habitat
fragments and industrial areas adds predators of Florida scrub-jays, such as fish crows,
that are rare in most regularly burned (every 3 years), native matrix habitats (Breininger
and Schmalzer 1990, Breininger and Smith 1992). Matrix habitats often develop into
woodlands and forests when there is a disruption of fire regimes. These woodlands and
forests are not suitable for Florida scrub-jays, decrease the habitat suitability of nearby
scrub, and further disrupt fire patterns.
87
Appendix C. Fire Management Prescriptions for Achieving Optimal Habitat
Recommended fire return intervals have included 8-25 years (Florida Natural Areas
Inventory 1990), 10-20 years (Fitzpatrick et al. 1991), and 5-20 years (Menges and
Hawkes 1998). Periods of 20 years without fire in oak scrub and scrubby flatwoods
along Florida’s Atlantic Coast result in an increase in shrub height and tree densities and
a loss in openings (Duncan et al. 1999). Many of these changes are difficult or
impossible to reverse by only prescribed fire (Schmalzer and Boyle 1998). Therefore, the
upper bounds for fire intervals in scrubby flatwoods are too long for many scrubby
flatwoods sites along the Atlantic Coast (Breininger et al. in press). Many Atlantic Coast
sites appear to have much faster recovery rates than Lake Wales Ridge sites (E.
Menges, P. Schmalzer pers. comm.).
Florida scrub-jay habitat use is low in areas without natural openings (Woolfenden
and Fitzpatrick 1984, 1991; Breininger et al. 1995, 1998). Almost one third of common
plant species on the Lake Wales Ridge are specialized to occupy openings (Menges
and Hawkes 1998). No plant species are specifically adapted to long-unburned scrubby
flatwoods (Menges and Kohfeldt 1995). Although fire intensity, season, and history
influence the loss of openings after fires, most openings do not persist in scrubby
flatwoods for more than a few years after fires (Schmalzer and Hinkle 1992a, Hawkes
and Menges 1996). Frequent fires in mesic flatwoods that burn into oak scrub are one
possible mechanism to retain openings in oak scrub. The most xeric scrub oak sites
retain openings for long periods.
Florida scrub-jay mortality exceeds reproductive success where there are no
patches of oaks at optimal height (120-170 cm) or where scrub is too tall (> 170 cm;
Breininger et al. in press). Scrub height models predict that oaks grow to 120 cm within
10 years after a fire, and that oaks grow taller than 170 cm within 20 years of a fire
(Duncan et al. 1995). Many questions remain regarding fire management because
Florida scrub-jays need frequent fires to maintain openings, yet they need enough oaks
88
that are unburned for at least 10 years to provide cover for nests and to escape
predators (Woolfenden and Fitzpatrick 1984, Breininger et al. in press).
Fitzpatrick et al. (1991) state that individual patches should burn every 10-20 years
when managing oak scrub. This rotation is consistent with optimal Florida scrub-jay
habitat suitability, and often the relationships between the height of scrub oaks and time
since fire (Schmalzer and Hinkle 1992a,b; Duncan et al 1995; Breininger et al. 1998).
However, some scrubs recover very quickly so that and need a fire interval much shorter
than every 10 years because they become too tall and dense to be regularly used by
Florida scrub-jays (Schaub, Breininger, Schmalzer unpublished data). Scrub oaks have
dominated areas that were once open sandy areas and these are often not reduced in
density by a few fires. Therefore, some oak scrub must burn very often to reestablish
openings. Oak scrub that burns often might best be in areas immediately adjacent to
more flammable mesic flatwoods vegetation.
Fitzpatrick et al. (1991) recommended the use of patchy fires so that no more than
25% of the scrub burns in a single fire. Therefore, four patchy fires are needed within
landscapes every 10-20 years. The rotation for mesic flatwoods is every 2-5 years
(Stout and Marion 1993). Therefore frequent mosaic fires that burn much of the mesic
flatwoods and only occasionally burn oak scrub patches thoroughly might provide the fire
regime needed at many sites.
Lightning associated with thunderstorms, which most frequently occur during the
growing season (April-September), causes most natural fires (Robbins and Myers 1992,
Davidson and Bratton 1986). Typical winter prescribed fire conditions are drier than
typical growing season fire conditions except during droughts, which occur at irregular
intervals approximately 20 years apart (Davidson and Bratton 1986). Prescribed fires
often occur in the winter, which may partially explain why natural openings have not
returned. Winter fires do not reduce oak cover as effectively as growing-season fires in
north Florida sandhill vegetation (Platt et al. 1991, Glitzenstein et al. 1995). However,
the importance of growing-season fires in maintaining openings in scrub is unknown (P.
89
Schmalzer and E. Menges, pers. comm.). Many growing-season fires may be needed to
restore openings to scrub unburned for >20 years. Single hot growing-season fires often
do not result in openings that last longer than 1-2 years. This is particularly true for
scrubs that have been subject to fire suppression (Schmalzer pers. comm.; Breininger
and Duncan, pers. obs.). Growing season fires should eventually be emphasized but
fire managers often must burn whenever possible given the narrow windows of
opportunity that many fire managers face and large areas of scrub that need frequent
fire. Frequent fires should be used throughout the year until the amount of scrub that is
too tall and dense is reduced.
Appendix D. The Use of Mechanical Techniques
Many areas that have been unburned for long periods can no longer be burned
under prescribed conditions (Schmalzer and Boyle 1998). To manage habitat and
reduce fuel loads, these areas must be mechanically treated prior to the application of
fire. Monitoring data indicates that mechanical treatment followed by burning can be
used to develop a habitat structure that can be maintained by prescribed fire (Schmalzer
and Boyle 1998). Mechanical treatments must be careful not to result in too much soils
disturbance so that too much saw palmetto scrub is lost. Excessive soils disturbance
can have long lasting effects on scrub that make it difficult to burn for many decades
(Breininger and Schmalzer 1990, Duncan et al. 1999). Excessive soils disturbance can
also increase exotics such as Brazilian Pepper that require control.
Restoration activities must also be directed towards restoration of landscapes.
Restoration efforts can fail to enhance Florida scrub-jay demographic success
(Breninger and Schaub unpublished data) if they occur as small patches in a landscape
that has burned infrequently and if subsequent fires do not occur often enough in
surrounding areas. Florida scrub-jays will use cut and burned areas soon after
restoration, but adjacent areas can became overgrown and unsuitable. Although some
scrub must be left for existing families, it is important to not have most of the landscape
90
remain in a state with tall oaks and restored scrub. Areas that are left for existing Florida
scrub-jay families should be short and not adjacent to forests so that scrub-jays can see
predators in time to evade capture. All habitat can be treated in sites no longer occupied
by Florida scrub-jays.
Openings might be difficult to reestablish because scrub oak stem densities are
great in previously cut areas so that it is necessary to conduct many frequent fires in
areas that have been mechanically cut and burned. It is important to use fire to develop
a complex mosaic of openings among scrub oaks rather than rely on simple edges that
can be systematically searched by predators. It is important to manage for optimal
conditions across landscapes because Florida scrub-jays can rigorously compete for the
best habitat within landscapes dominated by marginal habitat and this competition can
impact demographic success (Breininger and Oddy unpublished data).
Literature Cited
Abrahamson, W. G. 1984. Species Responses to Fire on the Florida Lake Wales
Ridge. American Journal of Botany 7:9-21.
Abrahamson, W. G., and D. C. Hartnett. 1990. Pine Flatwoods and Dry Prairies. Pages
103-149 in R. L. Myers and J. J. Ewell, editors. Ecosystems of Florida. University
of Central Florida Press, Orlando, Florida.
Auffenberg, W. and R. Franz. 1982. The Status and Distribution of the Gopher Tortoise
(Gopherus polyphemus). Pages 95-126 in R.B. Bury, editor. North American
Tortoises: conservation and ecology. U.S. Fish and Wildlife Service Research
Report 12.
Bergen, S. 1994. Characterization of fragmentation in Florida Scrub Communities. M.
S. Thesis. Florida Institute of Technology, Melbourne, Florida.
Boyle, S. R. 1996. A Landscape Approach to Florida Scrub-jay (Aphelocoma
coerulescens) Habitat Use in Brevard County, Florida. M. S. Thesis, Florida
Institute of Technology, Melbourne, Florida. 134 pp.
91
Breininger, D. R. 1992. Habitat Model for the Florida Scrub Jay on Kennedy Space
Center. NASA Technical Memorandum 107543.
Breininger, D. R. 1998a. Recovery of Atlantic Coast Florida Scrub-Jay Populations: St.
Sebastian River Buffer Reserve. Report to U.S. Fish and Wildlife Service.
Breininger, D. R. 1998b. Florida Scrub-Jay Demography in the Palm Bay Urban
Metapopulation. Report to U.S. Fish and Wildlife Service.
Breininger, D. R. 1999. Florida Scrub-Jay Demography and Dispersal in a Fragmented
Landscape. Auk 116:520-527.
Breininger, D. R. and D. M. Oddy. 1998. Developing Biological Criteria for the Recovery
of Florida Scrub-Jay Populations on Public Lands Report to U.S. Fish and
Wildlife Service.
Breininger, D. R., and P. A. Schmalzer. 1990. Effects of Fire and Disturbance on Plants
and Animals in a Florida Oak/Palmetto Scrub. American Midland Naturalist
123:64–74.
Breininger, D. R., and R. B. Smith. 1992. Relationships Between Fire and Bird Density
in Coastal Scrub and Slash Pine Flatwoods in Florida. American Midland
Naturalist 127:223–240.
Breininger D. R., B. W. Duncan, and N. J. Dominy. Unpublished manuscript.
Relationships Between Fire Frequency and Vegetation Type in Pine Flatwoods of
East Central Florida.
Breininger, D. R., M. A. Burgman, and B. M. Stith. 1999. Influence of Habitat,
Catastrophes, and Population Size on Extinction risk on Florida Scrub-Jay
Populations. Wildlife Society Bulletin 27:810-822.
Breininger, D. R., M. J. Provancha, and R. B. Smith. 1991 a. Mapping Florida Scrub Jay
Habitat for Purposes of Land-use Management. Photogrammetric Engineering
and Remote Sensing 57: 1467-1474.
Breininger, D. R., P. A. Schmalzer and C. R. Hinkle. 1991b. Estimating Occupancy of
Gopher Tortoise (Gopherus polyphemus) Burrows in Coastal Scrub and Slash
Pine Flatwoods. Journal of Herpetology 25: 317-321.
92
Breininger, D. R., P. A. Schmalzer, and C. R. Hinkle. 1994. Gopher Tortoise (Gopherus
Polyphemus) Densities in Coastal Scrub and Slash Pine Flatwoods in Florida.
Journal of Herpetology. 28: 60-65.
Breininger D. R., V. L. Larson, B. W. Duncan, R. B. Smith. 1998. Linking Habitat
Suitability to Demographic Success in Florida Scrub-jays. Wildlife Society Bulletin
26:118-128.
Breininger D. R., V.L. Larson, D. M. Oddy, R. B. Smith. In press. How Does Variation in
Fire History Influence Florida Scrub-jay Demographic success? In press: Fire
Effects on Rare and Endangered Species Conference. International Association
of Wildland Fire, Fairfield, Washington.
Breininger, D. R., V. L. Larson, D. M. Oddy , R. B. Smith and M. J. Barkaszi. 1996a.
Florida Scrub-jay Demography in Different Landscapes. Auk: 112:617-625.
Breininger, D. R., V. L. Larson, B. A. Duncan, R. B. Smith, D. M. Oddy, and M.
Goodchild. 1995. Landscape Patterns in Florida Scrub Jay Habitat Preference
and Demography. Conservation Biology 9: 1442-1453.
Breininger, D. R., V. L. Larson, R. Schaub, P. A. Schmalzer, B. W. Duncan, D. M. Oddy,
R. B. Smith, F. Adrian and H. Hill, Jr. 1996b. A Conservation Strategy for the
Florida Scrub-jay on John F. Kennedy Space Center/Merritt Island National
Wildlife Refuge: an initial scientific basis for recovery. NASA Technical
Memorandum 111676.
Burgman, M. A., D. R. Breininger, B. W. Duncan, and S. Ferson. In press. Setting
Reliability Bounds on Habitat Suitability Indices. Ecological Applications.
Burgman, M. A. S. Ferson, & H. R. Akcakaya. 1993. Risk Assessment in Conservation
biology. Chapman and Hall, London.
Campbell, H. W. and S. P. Christman. 1982. The Herpetological Components of
Florida Sandhill and Sand pine Scrub Associations. Pages 163-171 in N. J.
Scott, Jr., editor. Herpetological Communities. U. S. Fish and Wildlife Service
Wildlife Research Report 13.
Cox, J. A. 1984. Distribution, Habitat, and Social Organization of the Florida Scrub Jay,
with a Discussion of the Evolution of Cooperative Breeding in New World Jays.
Dissertation. Zoology Department, University of Florida, Gainesville, Florida.
93
Cox, J. A. 1987. Status and Distribution of the Florida Scrub Jay. Florida Ornithological
Society Special Publication Number 3. Gainesville, Florida.
Davidson, K. L. and S. P. Bratton. 1986. The Vegetation History of Canaveral National
Seashore. CPSU Technical Report 22. U. S. National Park Service Cooperative
Studies Unit, Institute of Ecology, University of Georgia, Athens. 75 pp.
DeGange, A. R., J. W. Fitzpatrick, J. N. Layne, and G. E. Woolfenden. 1989. Acorn
Harvesting by Florida Scrub Jays. Ecology 70:348-356.
Doren, R. F., D. R. Richardson, and R. E. Roberts. 1987. Prescribed burning of the
Sand Pine Scrub community: Yamato scrub, a test case. Florida Scientist
50:184-192.
Duncan, B. A. and D. R. Breininger. 1998. Quantifying Habitat Change: modeling
historical and current Florida Scrub-Jay habitat suitability. GIS/LIS Proceedings,
Dallas, Texas.
Duncan, B. W., S. Boyle, P. A. Schmalzer, and D. R. Breininger. 1996. Spatial
Quantification of Historic Landscape Change within Two Study Sites on John F.
Kennedy Space Center. Proceedings of 16th Annual ESRI Conference. May 20–
24, 1996.
Duncan, B. W., D. R. Breininger, P. A. Schmalzer, and V. L. Larson. 1995. Validating a
Florida Scrub Jay habitat suitability model, using demography data on Kennedy
Space Center. Photogrammetric Engineering and Remote Sensing 56:1361-
1370.
Duncan, B. A., S. Boyle, D. R. Breininger, and P. A. Schmalzer. 1999. Landscape
Ecology. Coupling Past Management Practice and Historical Landscape Change
on John F. Kennedy Space Center. Landscape Ecology 14:291-309.
Dye, R. 1991. Use ofFfiring Techniques to Achieve Naturalness in Florida Parks.
Proceedings of the Tall Timbers Fire Ecology Conference 17:353-360.
Fitzpatrick, J. W., G. E. Woolfenden, and M. T. Kopeny. 1991. Ecology and
Development-related Habitat Requirements for the Florida Scrub Jay
(Aphelocoma c. coerulescens). Florida Game and Fresh Water Fish Commission
Nongame Wildlife Report No. 8. Tallahassee, Florida. 49pp.
94
Florida Natural Areas Inventory. 1995. Tracking Lists of Special Plants, Lichens,
Invertebrates, Vertebrates, and Natural Communities. Tallahassee, Florida.
Glitzenstein, J. S., W. J. Platt, and D. R. Streng. 1995. Effects of Fire Regimes and
Habitat on Tree Dynamics in North Florida Longleaf Pine Savannas. Ecological
Monographs 65:441-476.
Harris, L. D., and P. B. Gallagher. 1989. New Initiatives for Wildlife Conservation: the
need for movement corridors. Pages 11-34 in G. MacKintosh, ed. Preserving
communities and corridors. Defenders of Wildlife, Washington, D.C.
Hawkes, C. V. and E. S. Menges. 1995. Density and Seed Production of a Florida
Endemic, Polygonella Basirama, in Relation to Time Since Fire and Open Sand.
American Midland Naturalist 133: 138-148.
Hawkes, C. V. and E. S. Menges. 1996. The Relationship Between Open Space and
Fire for Species in a Xeric Florida Shrubland. Bulletin of the Torrey Botanical
Club 123:81-92.
Howe, R. W., G. J. Davis, and V. Mosca. 1991. The Demographic Significance of
"Sink" Populations. Biological Conservation 57:239-255.
James, F. C., C. A. Hess, and D. Kufrin. 1997. Species-centered Environmental
Analysis: indirect effects of fire history on red-cockaded woodpeckers. Ecological
Applications7:118-129.
Layne, J. N. 1990. The Florida Mouse. Pages 1-21 in C.K. Dodd, Jr., R. E. Ashton, Jr.,
R. Franz, and E. Wester, editors. Burrow Associates of the Gopher Tortoise.
Proceedings of the 8th annual meeting of the Gopher Tortoise council. Florida
Museum of Natural History, Gainesville.
McDonald, D. B. and H. Caswell. 1993. Matrix Methods for Avian Demography. Current
Ornithology 10:139-184.
McGowan, K. J., and G. E. Woolfenden. 1989. A Sentinel System in the Florida Scrub
Jay. Animal Behavior 37:1000-1006.
Means, D. B. and H. W. Campbell. 1981. Effects of Prescribed Burning on Amphibians
and Reptiles. Pages 89-90 in G. W. Wood, editor. Prescribed Fire and Wildlife in
Southern Forests. Belle W. Baruch Forest Science Institute, Georgetown, South
Carolina.
95
Menges, E. S. and N. Kohfeldt. 1995. Life History Strategies of Florida Scrub Plants in
Relation to Fire. Bulletin of the Torrey Botanical Club 122:282-297.
Moler, P. E., and R. Franz. 1987. Wildlife Values of Small, Isolated Wetlands in the
Southeastern Coastal Plain. Pages 234-238 in R. R. Odom, K.A. Riddleberger,
and J.C. Ozier, editors. Proceedings of the Third Southeastern Nongame and
Endangered Wildlife Symposium. Georgia Department of Natural Resources,
Athens, Georgia.
Myers, R. L. 1990. Scrub and High Pine. Pages 150-193 in R. L. Myers and J. J. Ewell,
editors. Ecosystems of Florida. University of Central Florida Press, Orlando,
Florida.
Mumme, R. L. 1993. Do Nonbreeders Increase Reproductive Success: An
Experimental Analysis the Florida Scrub Jay? Behavioral Ecology and
Sociobiology 31:319-328.
Ostertag, R. and E. S. Menges. 1994. Patterns of Reproductive Effort with Time Since
Last Fire in Florida Scrub Plants. Journal of Vegetation Science 5:303-310.
Platt, W. J. , J. S. Glitzenstein, and D. R. String. 1991. Evaluating Pyrogenicity and its
Effects on Pine savannahs. Proceedings of the Tall Timbers Fire Ecology
Conference 17:143-162.
Quintana-Ascencio, P. F. and Menges, E. S. 1996. Inferring Metapopulation Dynamics
from Patch-level Incidence of Florida Scrub Plants. Conservation Biology
10:1210-1219.
Pulliam, H. R. 1996. Sources and sinks: Empirical Evidence and Population
consequences. Pages 45-70 In O. L. E. Rhodes, Jr., R. H. Chesser, and M. H.
Smith. Population Dynamics in Ecological Space and Time. University of
Chicago Press, Chicago.
Pulliam, H. R., and B. J. Danielson. 1991. Sources, Sinks, and Habitat Selection: a
Landscape Perspective on Population Dynamics. American Naturalist 137:s50-
s66.
Pulliam, H. R., J. B. Dunning, and J. Liu. 1992. Population Dynamics in Complex
Landscapes: a Case Study. Ecological Applications 2:165-177.
96
Robbins, L. E., and R. L. Myers. 1992. Seasonal Effects of Prescribed Burning in
Florida: a review. Miscellaneous Publication No. 8. Tall Timbers Research, Inc.,
Tallahassee, Florida.
Root, K. V. 1998. The Effects of Habitat Quality, Connectivity, and Catastrophes on a
Threatened Species. Ecological Applications 8:854-865.
Schaub, R., R. L. Mumme, and G. E. Woolfenden 1992. Predation on the Eggs and
Nestlings of Florida Scrub Jays. Auk 109:585-593.
Schmalzer , P. A. and S. R. Boyle. 1998. Restoring Long-unburned Oak-saw palmetto
Scrub Requires Mechanical Cutting and Prescribed Burning. Restoration and
Management Notes 16:96-97.
Schmalzer, P. A., and C. R. Hinkle. 1992a. Recovery of Oak-saw palmetto after Fire.
Castanea 57:158–173.
Schmalzer, P. A., and C. R. Hinkle. 1992b. Species Composition and Structure of Oak-
saw palmetto Scrub Vegetation. Castanea 57:220–251.
Schmalzer, P. A., C. R. Hinkle, and J. L. Mailander. 1991. Changes in Community
Composition and Biomass in Juncus Roemerianus Scheele and Spartina bakeri
Merr. marshes one year after a fire. Wetlands 11:67-86.
Schmalzer, P. A., D. R. Breininger, F. Adrian, R. Schaub, and B. W. Duncan. 1994.
Development and Implementation of a Scrub Habitat Compensation Plan for
Kennedy Space Center. NASA Technical Memorandum 109202.
Smith, R. B., D. R. Breininger and V. L. Larson. 1997. Home Range Characteristics of
Radiotagged Gopher Tortoises on Kennedy Space Center, Florida. Chelonian
Conservation and Biology 23:358-362.
Speake, D. W., J. A. McGlincy, and T. A. Colvin. 1978. Ecology and Management of
the Eastern Indigo Snake in Georgia: a progress report. Pages 64-73 in R. R.
Odum and L. Landers, editors. Proceedings of Rare and Endangered Wildlife
Symposium, Georgia Department Natural Resources Game and Fish Division
Technical Bulletin WL4.
Stevens, T., R. Bowman, and J. Hardesty. 1998. Status and Distribution of the Florida
Scrub-jay (Aphelocoma coerulescens) at Cape Canaveral Air Station, Florida.
45th CES/CEV, Patrick Air Force Base, FL.
97
Stith, B. M., J. W. Fitzpatrick, G. E. Woolfenden, and B. Pranty. 1996. Classification
and Conservation of Metapopulations: a case study of the Florida scrub jay.
Pages 187-216 In D.R. McCullough (ed.) Metapopulations and wildlife
Conservation. Island Press, Ca.
Stith, B. M. 1999. Metapopulation Viability Analysis of the Florida Scrub-jay
(Aphelocoma coerulescens): a statewide assessment. Final Report to U.S. Fish
and Wildlife Service, Jacksonville, FL. Contract 1448-40181-98-M324.
Swain, H., P. A. Schmalzer, D. R. Breininger, K. Root, S. Bergen, S. Boyle, S.
MacCaffree, S. Heflick, and T. Gregory. 1995. Consultants report to the Brevard
County Habitat Conservation Plan. Brevard County, Florida.
Thaxton, J. E. and T. M. Hingtgen. 1996. Effects of Suburbanization and Habitat
Fragmentation on Florida scrub-jay Dispersal. Florida Field Naturalist 24:25-37.
Webber, H. J. 1935. The Florida Scrub, a Fire-fighting Association. American Journal
of Botany 22:344-361.
Westcott, P. A. 1970. Ecology and Behavior of the Florida Scrub Jay. Dissertation.
Zoology Department, University of Florida, Gainesville, Florida.
Woolfenden, G. E. 1974. Nesting and survival in a population of Florida Scrub Jays.
Living Bird 12:25-49.
Woolfenden, G. E., and J. W. Fitzpatrick. 1984. The Florida Scrub Jay: demography of
a cooperative-breeding bird. Princeton Univ. Press, Princeton, New Jersey.
Woolfenden, G. E., and J. W. Fitzpatrick . 1991. Florida Scrub Jay ecology and
Conservation. Pages 542-565 in Bird population studies (C. M. Perrins, J. D.
Lebreton, and G. J. M. Hirons, Eds.). Oxford Univ. Press, New York.
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