PLANT SPECIES, HABITAT, AND SITE INFORMATION FOR FERN ...people.oregonstate.edu/~wilsomar/PDF/WCL_WES_93.pdf · 1Plant nomenclature follows Hitchcock et al., 1969, unless otherwise

PLANT SPECIES, HABITAT, ANDSITE INFORMATION FOR FERN RIDGE RESERVOIR

A Component of the Project toDevelop Management Guidelines for Native Wetland Communities

Submitted to

Waterways Experiment Station Soil Conservation ServiceArmy Corps of Engineers Portland, Oregon

Vicksburg, Mississippi

Submitted by

Dr. Mark V. WilsonKathy P. Connelly

Lisa E. LantzRestoration Ecology and Plant Conservation Biology

Cooperative Project,Department of Botany and Plant Pathology, and

Department of Rangeland Resources

Oregon State University

March 31, 1993

SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

LITERATURE REVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Natural history of the Willamette Valley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Description of Fern Ridge sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5The wetland prairie community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5The upland prairie community . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Special status plant species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Lomatium bradshawii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10Erigeron decumbens var. decumbens. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Aster curtus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Montia howellii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Horkelia congesta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Cyperus rivularis var. rivularis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18Sidalcea cusickii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Microcala quadrangularis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Calochortus uniflorus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Sagittaria latifolia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Lupinus sulphureus ssp. kincaidii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23Sidalcea campestris . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Lathyrus holochlorus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

FIELD STUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27STUDY SITES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Plant Community Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Studies of Lomatium bradshawii and Erigeron decumbens var. decumbens . . . . . . . . . . . 31RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Plant community studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Community descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Fire effects on cover and diversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35Rare plant distributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Studies of Lomatium bradshawii and Erigeron decumbens var. decumbens . . . . . . . . . . . 37Lomatium bradshawii . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Erigeron decumbens var. decumbens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

SUMMARY

This report presents information on the sensitive habitats and rare plant species at Fern

Ridge. Fern Ridge, a project administered by the Army Corps of Engineers, contains valuable

wetland prairie and upland prairie habitats. Wetland prairies support 10 rare plant species;

upland prairies support 4 rare plant species. These species occur within 11 management units at

Fern Ridge. The report describes for each species its taxonomic and legal status, appearance,

distribution, and population biology. The ecological dependence of rare species on other

organisms or on special habitats dictates an ecosystem approach to management.

Ecological succession from grassland to forest is the primary threat to prairie habitats and

the rare species they support. Prescribed burning is a promising management technique for

arresting succession. This report summarizes results from a series of prescribed burning

experiments conducted within two wetland prairie sites at Fern Ridge. Fire sometimes promoted

cover and diversity of native species. In other circumstances, fire increased the cover of non-

native and woody species. Fire enhanced seed production in Lomatium bradshawii, a rare

species of special concern.

The report presents a series of general recommendations for managing the rare prairie

habitats and plant species at Fern Ridge. These include developing a habitat monitoring

program, improving rare plant species monitoring, supporting ecological management research,

managing entire ecosystems, continuing the prescribed burning experiments, and monitoring any

other prescribed prairie burning. Specific recommendations will be presented in a another

report.

Wilson, Connelly, and Lantz - 2 - Fern Ridge

INTRODUCTION

The management responsibilities of the U.S. Army Corps of Engineers include the

stewardship and management of its wetlands and other biological resources. Managers often

have little experience to draw upon in their stewardship of these resources. Gathering

information therefore plays an essential step in developing management guidelines. The goal of

this report is to present existing information on the important plant species and habitats of Fern

Ridge, a project near Eugene, Oregon, administered by the Army Corps of Engineers. Fern

Ridge contains two of the rarest habitats in western Oregon, native wetland and upland prairies.

These natural areas support several plant species either listed or included as candidates under the

federal Endangered Species Act.

This report presents four types of information about the biological resources at Fern Ridge.

First, it describes the Fern Ridge site, including the distribution of sensitive habitats and rare

plant species. Second, it reviews existing information on wetland and upland prairie habitats,

including species composition, diversity, and physical environment. Third, it reviews existing

information on 13 rare plant species at Fern Ridge, including legal and taxonomic status, habitat

requirements, life history characteristics, reproductive biology, and species interactions. Fourth,

it documents the responses of habitats and rare species at Fern Ridge to the management tool of

prescribed burning.

In this report, we also use the information on habitats, species, and prescribed burning to

make general recommendations for managing the biological resources at Fern Ridge.

Subsequent reports will detail management recommendations, using the management guideline

methodology presented in Wilson and Lantz (1992).

1Plant nomenclature follows Hitchcock et al., 1969, unless otherwise noted.


LITERATURE REVIEW

METHODS

We collected the material in this report by searching existing sources for information on

the rare plant species and habitat types found at Fern Ridge. The published literature contains

little information, so we examined unpublished material from the Bureau of Land Management

(Eugene), the Plant Systematics and Conservation Biology Program of the Oregon Department

of Agriculture (ODA), the Oregon Natural Heritage Program, The Nature Conservancy, and the

Oregon State University (OSU) Herbarium. In addition, we gathered information from several

knowledgeable individuals: Edward Alverson, Deborah Clark, Karen Finley, Dr. Richard Halse,

Dr. Paul Hammond, Rick Hayes, Dr. Cheryl Ingersoll, Thomas Kaye, Keli Kuykendall,

Catherine Macdonald, and Dr. Robert Meinke. Names and addresses of these individuals are

included as Appendix I.

We also obtained specific information on the location of the rare species and habitats at

Fern Ridge from maps prepared by MaryAnn Weber and Richard Hayes of the U.S. Army Corps

of Engineers. We used these maps to estimate soil types and the areas covered by rare plant

populations. The Corps also supplied some population monitoring data for Aster curtus1,

Erigeron decumbens var. decumbens, and Lomatium bradshawii.

RESULTS

Natural history of the Willamette Valley

Western Oregon's Willamette Valley runs about 220 km from near Portland, in the north,

to near Eugene, in the south. The valley is a structural depression consisting largely of wide

alluvial flats occasionally separated by low hills. These flats are bordered to the west by the


sandstone and shale foothills of the Coast Range and to the east by the basaltic foothills of the

Cascade Mountains (Thilenius 1968).

While the Willamette Valley itself has never been glaciated, it has been inundated many

times by meltwater floods from the Columbia River (Thilenius 1968; Orr et al. 1992). In

addition, before flood control dams were built in the 1960's, the Willamette River and its

tributaries periodically flooded their banks (Savonen 1988). As a result, much of the level valley

floor is covered with silts, sands, and clays, which have poor drainage qualities (Savonen 1988).

The valley climate is characterized by mild, wet winters and hot, dry summers, with a

precipitation deficit in the driest months of July and August (Moir and Mika 1972). In some

areas, the combination of wet winters and poorly drained soils has resulted in seasonal flooding.

Records from the nineteenth century report that the bottomlands near present-day Eugene were

sometimes covered by up to three feet of water in the wet season (Savonen 1988).

Although the climate of the Willamette Valley is characteristic of the humid forest region

(Moir and Mika 1972), early European settlers encountered an area dominated by prairies and

oak savannas (Smith 1949; Habeck 1961; Johannessen et al. 1971). Based on the accounts of

early settlers, these grasslands were maintained by annual fires set by the Native Americans

(Sprague and Hansen 1946, Smith 1949, Habeck 1961, Johannessen et al. 1971, Boyd 1986).

With European settlement, these fires were suppressed and much of the highly productive

prairies were lost to agriculture and urbanization.

Many of the remaining grasslands are being lost through succession. Most Willamette

Valley prairies are considered seral communities that have been maintained by fire or other

human activities (Franklin and Dyrness 1973). With fire suppression, trees (Quercus garryana,

Fraxinus latifolia, Pseudotsuga menziesii, Acer macrophyllum, Arbutus menziesii) and shrubs

(Rhus diversiloba, Crataegus spp., Rosa spp.) were able to establish (Johannessen et al. 1971;

Habeck 1962; Towle 1982). Therefore, unlike in much of the United States, pioneer settlement

in the Willamette Valley led to an increase in forest cover (Towle 1982). As a result of these


changes, less than 1% of the original grassland remains intact (Johannessen et al. 1971). The

Nature Conservancy (1983) has listed Willamette Valley prairies as one of the most endangered

habitats in the state.

In general, the original grasslands of the Willamette Valley can be divided into two types:

wetland prairies and upland prairies. The wetland prairies are found in areas of the valley floor

with poorly drained alluvial soils that often experience flooding during the winter months.

Upland prairies are found on better drained soils and often intergrade with areas of oak savanna.

Description of Fern Ridge sites

The land managed by the Army Corps of Engineers at Fern Ridge Reservoir includes areas

of both wetland and upland prairie.

The wetland prairie community. The wetland prairies of concern to the Corps are found

primarily along the eastern shore of the reservoir in the Amazon Dike No. 2, Royal Amazon, and

Fisher Butte Management Units (Figure 1). Additional wetland areas are found along Coyote

Creek in the West Coyote Management Unit, intermingled with upland prairie in the South

Marsh Management Unit, and near Clear Lake Road in the Kirk Pond Management Unit. In

general, these areas are in close proximity to Fern Ridge Lake, and they experience some

inundation during the wet season (November to April).

The highest quality wetland prairie areas are probably found at Rose Prairie, just north of

the Amazon Channel, and at Fisher Butte. These areas are set aside as Research Natural Areas.

Other high quality prairies can be found just south of the Amazon Channel and just south of

Royal Avenue. Some of the wettest areas directly adjacent to the lake's eastern shore are being

invaded by reed canarygrass (Phalaris arundinacea). This aggressive exotic may increase in

abundance if manipulations are made to raise reservoir pool levels (R. Hayes, pers. comm.).


The original extent and vegetation of Willamette Valley wet prairies remains somewhat

unclear. Most flat areas with hydric soils that occur below 400 feet were probably once wet

prairies (Savonen 1988). These seasonally flooded areas were probably dominated by

bunchgrasses, particularly Deschampsia cespitosa (Frenkel and Heinitz 1987; Savonen 1988).

Other typical species may have included Danthonia californica, Beckmannia syzigachne,

Agrostis exarata, Alopecurus aequalis, Eragrostis hypnoides, and Juncus spp. (Moir and Mika

1972; Habeck 1961; Nelson 1919).

While early settlers initially inhabited drier parts of the Willamette Valley that were

immediately suitable for farming, the wet prairies were eventually plowed, drained, and planted

(Savonen 1988). The few wet prairies that remain are being invaded by exotic species, such as

Holcus lanatus (Moir and Mika 1972; Lippert and Jameson 1964) and woody vegetation. In the

absence of fire, the climax community of these wet bottomlands may be ash (Fraxinus latifolia)

forest (Moir and Mika 1972). Therefore, if wet prairies are to be preserved, some effort must be

taken to control woody plants.

In general, Willamette Valley wetland prairies are typified by a high water table and

occasional ponding during the wet season. The soils at the Fern Ridge wetland prairie sites are

mapped as Natroy silty clay loam; Dayton silt loam, clay substratum; Noti loam; Linslaw loam;

and Pengra silt loam (SCS 1987). These soils are all of alluvial origin and generally deep and

poorly drained. From November to May, they are subject to long periods of flooding (SCS

1987).

Studies done at Fisher Butte and Rose Prairie indicate that some areas are submerged for at

least six months out of the year (K. Finley, pers. comm.). Other areas may only experience

pooling of water between tussocks of grass in the wettest months. In many areas of the wetland

prairies, the soils are anaerobic and reduced for long periods that roughly coincide with periods

of flooding (K. Finley, pers. comm.).


The Nature Conservancy has tried prescribed fire to control Fraxinus latifolia and Pyrus

communis at their Willow Creek wet prairie preserve (Acker 1991). While this program was

successful in killing tree canopies (especially for trees with a diameter breast height of less than

15 cm), the trees resprouted. In fact, trees that were burned more severely (based on maximum

tree scorch height), resprouted more vigorously (Acker 1991). Therefore, prescribed fire alone

does not appear to be an effective control for these two tree species. It is not yet known how fire

may affect other woody species.

The upland prairie community. Upland prairie habitats are found in various parcels

surrounding the Fern Ridge reservoir. For the most part, these soils are better drained with no

standing water. Two areas of remnant upland prairie can be found on the north shore of the lake

in the Kirk Pond, Shore Lane, and Amazon Dike No. 2 Management Units (Figure 1). The

Shore Lane and Amazon Dike No. 2 units host the rare Fender's blue butterfly (Hammond and

Wilson 1993), a candidate for listing under the Endangered Species Act. All three units

encompass old agricultural fields that are being invaded by blackberries (Rubus spp.) and Scot's

broom (Cytisus scoparius). The Army Corps of Engineers has implemented a mowing regime in

some of these upland prairies to control invaders. The vegetation of Gibson Island might also be

classified as upland prairie, but the area has become choked with woody vegetation. Additional

upland prairies can be found in the Zumwalt Park area, along the eastern shore of the Jean's

Peninsula Management Unit, and intermingled with wetland prairies in the South Marsh and

Applegate Management Units. The latter area is a known nesting ground for the rare western

pond turtle (Clemmys marmorata marmorata, a candidate for listing under the Endangered

Species Act), but places along McCutcheon ditch are becoming choked with Scot's broom.

Little specific information is currently available on the upland prairie community at Fern

Ridge. In fact, only a small amount of descriptive information is available for Willamette Valley

upland prairies, in general. Therefore, all descriptions are strictly conjecture, since agriculture,


urbanization, and natural succession to forests have so altered the upland prairie community

(Franklin and Dyrness 1973).

The species composition of the upland prairies is thought to have contained several native

grass and forb species (Table 1). Euro-American settlers introduced many new plants to the

Willamette Valley, and some of these species have become naturalized and widespread (Table

1). As early as 1919, about half of the grass species near Salem were introduced (Nelson 1919).

Many of these exotic species have become dominant in areas.

At Fern Ridge, upland prairies are found on soils mapped as McBee silty clay loam,

Stiewer loam, Salkum silt loam, Veneta loam, Linslaw loam, Pengra silt loam, Noti loam, and

Natroy silty clay (SCS 1987). These soils are all of alluvial origin. The first four soil types

listed above are all at least moderately deep and well-drained. The latter three soil types are

poorly drained (SCS 1987). However, it is not known if some of the upland prairie soil is

actually poorly drained, or if the soil maps are of too coarse a scale to accurately depict the soils

under a small area.

Some attempts have been made to manage upland prairies, both as natural areas and

pasture land. At The Nature Conservancy's Wren Prairie Preserve, west of Corvallis, a

controlled burn was carried out in 1984. Monitoring data from the following year indicate that

the native species responded well to fire, but the exotic species also responded well, often with a

greater magnitude (Magee 1986). Recruitment of annual exotic species was substantially greater

in areas that had been burned (Magee 1986). Magee (1986) recommended that burning be

discontinued at Wren until the long-term effects have been monitored. However, one year of

observation after a single fire probably does not represent the response of the community over

longer periods or to repeated fires. Elsewhere in this report we present results from experimental

burns at Fern Ridge.

Attempts have also been made to employ mowing treatments to control some exotic

species. Turner (1969) studied the effects of grazing and mowing on an Elymus caput-medusae-


dominated pasture outside of Corvallis. He found that mowing in late May or early June

drastically reduced the amount of E. caput-medusae (medusahead). In addition, without the

competition from medusahead, Danthonia californica increased in both vigor and reproductive

output, and, after two years of mowing, D. californica closed the stand to medusahead. The

ecological dominance of the area thus shifted from annual to perennial grassland. Mowing may

also control some encroaching shrubs, such as Rosa spp. (Turner 1969), but it should not be

viewed as a panacea. Detailed vegetation composition of a site must be made prior to

management implementation; some sites, with few native perennials present, may have little

opportunity for improvement even if aggressive annual exotics are controlled (Turner 1969). In

addition, mowing may have detrimental impacts on some rare and endangered plants.

Special status plant species

The Willamette Valley native grasslands are home to many endemic plant species.

However, loss of prairie habitat to agriculture, urbanization, and natural succession to forests has

nearly led to the extirpation of several Willamette Valley species. At least thirteen rare plant

species are known to occur at Fern Ridge. This list includes species native to both the upland

and wetland habitats.

The following section describes for each rare plant species its taxonomic status, legal

status, appearance, geographical distribution, habitat requirements, reproduction biology, seed

biology, herbivores, competitive ability, locations within Fern Ridge, and presence of monitoring

data. Not all types of information are available for all species. The management units

mentioned in this summary are shown in Figure 1; distributions in management units are

included in Table 2.


Lomatium bradshawii. Lomatium bradshawii (Rose ex Math.) Math. & Const. is, as a

state and federally listed endangered species (Oregon Natural Heritage Program 1991), perhaps

the rarest of the Fern Ridge species.

Commonly known as Bradshaw's desert parsley or Bradshaw's lomatium, Lomatium

bradshawii is a 20 cm to 50 cm tall perennial herb in the parsley family (Apiaceae). The plant

has light yellow flowers, arranged in umbels, and corky-winged fruits. The flowers are

subtended by bracts, which are singly or doubly divided into threes; this trait differentiates it

from all other Lomatium species (Eastman 1990).

An endemic of the Willamette Valley, Lomatium bradshawii is currently limited to the

clay soils of wet, bottomland prairies from near Salem to the area around Eugene (Hitchcock et

al. 1969). The species' habitat is characterized by heavy, sticky plastic clay soils with no

significant rock, gravel, or sand (Kagan 1980). Soil samples taken at several populations

showed no L, F, or H horizons and limited litter (Kagan 1980). Iron and black concretions were

present, and the soil was somewhat acidic, with a mean pH of 5.3.

Lomatium bradshawii does not reproduce vegetatively (Kaye 1992a), depending

exclusively on seeds for reproduction. Flowers appear in April or May (Kagan 1980). The plant

produces two kinds of flowers—staminate (male) and hermaphroditic (male and female). The

hermaphroditic flowers are protogynous; their styles are exerted while the stamens and petals are

still curved inward, meaning that the stigmas are receptive before the stamens shed pollen (Kaye

1992a). The first umbel of a given plant will have a majority of male flowers, and later umbels

will have a higher proportion of hermaphroditic flowers (Kaye 1992a). The majority of the

flowers produced are staminate. Kagan (1980) found that most (69%) of plants examined had all

staminate flowers, and all hermaphroditic umbels had at least 50% staminate flowers.

Presumably, such a breeding system helps to promote cross-pollination. Insects, including

solitary bees (Andrena sp., Melanostoma sp., Tenthredinidae sp.), wasps (Ichneumonidae sp.),


flies (Mesograpta marginata, Paragus sp., Sphaerophoria sp., Xylota sp.), and beetles (Lebia

moesta) have been observed carrying pollen between plants of this species (Kaye 1992a). While

most Lomatium species are self-compatible (Kaye 1992a), it is not yet clear whether L.

bradshawii is capable of self-pollination.

The seeds of this species mature in late May or June (Kagan 1980). For all of the sites

studied by Kagan (1980), the mean number of seeds produced per plant was thirteen. Most of

the seeds are wind-dispersed and fall within 1 m of the parent plant (Kagan 1980). However,

since the species grows within the floodplain of creeks and rivers, it may depend on water for

long-distance seed dispersal (Kagan 1980). Its fruits, with their thick corky wings, are buoyant

(Meinke 1980).

Little information is available on the germination requirements of this species. Tests

conducted at the Berry Botanic Garden in Portland estimated viability at 80-90%. However, the

viability and the optimal treatment for germination varied for different populations (USFWS

1991). In the field, seedlings have been observed only in open microsites, but the fates of

individual seeds have never been followed (USFWS 1991). Studies by the Berry Botanical

Garden show that it takes at least three years for Lomatium bradshawii to develop from a seed to

a reproductive individual.

A number of pests have been observed on this species. A Chytridiomycete fungus has

been found exclusively on plants that have set seed (Kagan 1980). Few plants are able to

produce mature seed before the fungus causes them to die back. Spittle bugs (Ceropidae) and

two species of aphids (Aphididae) have also been observed predominantly on plants that have set

fruit. The number of fruits aborted in plants infested with these pests is significantly higher than

the number aborted in uninfested plants (Kagan 1980).

At this time, little is known of the effects of competition on this species. However, based

on its size and native environment, it would seem unlikely to survive encroachment by woody

vegetation. Flowering rates of Lomatium bradshawii seem to drop rapidly with increasing shade

2Patch sizes refer to the total area encompassing the plant population. Densities ofindividuals vary tremendously within patches and from patch to patch.


(E. R. Alverson, pers. comm.), showing the adverse effects of increases in woody plant cover

during succession from grassland to forest.

Populations of L. bradshawii are found in six of the management units at Fern Ridge. The

Kirk Pond Management Unit contains one patch2 of L. bradshawii near the eastern edge of the

unit, which encompasses about 7600 m2. The Amazon Dike No. 2 Unit encompasses four

patches, totalling about 260,000 m2. Data exist for three monitoring grids set up in this

management unit, but they must be interpreted with extreme caution. The data from grid 1-2,

taken from 1988-1992, show no real trends. The highest plant density occurred in 1990 (3.3

plants/m2). The lowest density was found in 1992 (1.13 plants/m2). Grid 1-3 has data only for

1992. Grid 1-4 showed a consistent increase from 0.20 plants/m2 in 1987 to 0.50 plants/m2 in

1990. Only 0.26 plants/m2 were observed in 1992. The Royal Amazon Unit contains 3 patches

of L. bradshawii, mostly in about 680,000 m2 in the eastern portion of the management unit.

Monitoring grid 1-5 showed no obvious trends in the abundance of this plant from 1987-1992;

the density ranged from 0.10 plants/m2 in 1988 to 0.52 plants/m2 in 1990. The data in grid 1-6

show a consistent increase from 0.30 plants/m2 in 1987 to 0.59 plants/m2 in 1990. The Fisher

Butte Management Unit contains nine patches of L. bradshawii concentrated over 323,500 m2 in

the eastern portion of the management unit. The East Coyote Management Unit contains seven

patches of L. bradshawii, covering about 60,000 m2. The West Coyote Management Unit

contains two patches of L. bradshawii covering about 21,000 m2.

Lomatium bradshawii plants were monitored before and after prescribed burns on the

Bureau of Land Management Long Tom Area of Critical Environmental Concern. Flowering

and seed production were higher after the burn, but density was lower. It is difficult to ascribe

these changes to fire alone, since no unburned, control plants were monitored.


Erigeron decumbens var. decumbens. Erigeron decumbens Nutt. var. decumbens is listed

by the State of Oregon as endangered, and is a C1 candidate at the federal level, meaning that the

U.S. Fish and Wildlife Service (USFWS) has sufficient information to support a proposal to list

the taxon as endangered or threatened under the Endangered Species Act (Oregon Natural

Heritage Program 1991). Also known as the Willamette daisy, pacific fleabane, or meadow

erigeron, E. decumbens var. decumbens is a 15 cm to 45 cm tall perennial herb with linear based

leaves, about 10 cm to 20 cm long. The flowers are arranged in daisy-type heads, which contain

20 to 50 purple-pink outer (ray) flowers and yellow central (disk) ones (Eastman 1990). The

plant is a member of the sunflower family (Asteraceae).

This taxon is endemic to the Willamette Valley. Historically, it was widespread in the

valley, but it is currently restricted to a few sites toward the southern end of the Willamette

Valley (Kagan and Yamamoto 1987). These sites are all bottomland grasslands, which are flat

and often dissected by channels. In general, the habitat for this taxon is characterized by heavy

clay soils.

While the plants have rhizomes, no vegetative spread has been observed in Erigeron

decumbens var. decumbens. Therefore, reproduction probably occurs exclusively through seed

(Kagan and Yamamoto 1987). The taxon flowers in June and July (Hitchcock et al. 1969).

Apparently, at least some pollination is carried out by insects. While no specific pollinators are

known, native butterflies, ground nesting bees, bumblebees, flies, and introduced honeybees

have been seen visiting flowers (Kagan and Yamamoto 1987).

The number of mature seeds found on a single head ranges from 25 to 50 (Kagan and

Yamamoto 1987). To germinate, these seeds require some sort of cold treatment. Germination

tests have indicated that the taxon has a low germination rate (22% to 34%) (Kagan and

Yamamoto 1987). The seeds are wind-dispersed, but since they do not fly well, dispersal

distance is quite restricted (Kagan and Yamamoto 1987).


Little is known about how this taxon interacts with other species. The most that can be

said is that shading by encroaching trees and shrubs apparently causes this species to vanish

(Kagan and Yamamoto 1987).

Erigeron decumbens var. decumbens is found on two of the Fern Ridge management units.

The Fisher Butte Management Unit contains three neighboring patches covering about 630,000

m2 in the eastern portion of the management unit. Monitoring data from 1988-1991 exist for five

grids in the area. Four out of the five grids show a relatively consistent density over time. The

fifth grid (grid 3-5) shows a consistent decline from 0.70 plants/m2 in 1988 to 0.25 plants/m2 in

1991. The East Coyote Management Unit contains three neighboring patches of plants covering

about 38,000 m2 in the eastern portion of the management unit.

Aster curtus. Aster curtus Cronquist, a member of the sunflower family (Asteraceae) is a

candidate for listing as endangered at both the state and federal levels. At the federal level, it is a

C2 candidate, meaning that the USFWS requries additional information to propose listing the

species as endangered or threatened under the Endangered Species Act (Oregon Natural Heritage

Program 1991).

Aster curtus is a 10 cm to 30 cm tall perennial herb, with 3 cm long leaves arranged

alternately on the stem. Commonly known as white-top aster, the flowers of this species are

arranged in heads, and each head may have 1 to 3 white outer (ray) flowers along with a few (9-

21) pale yellowish inner (disk) flowers with purple anthers (Eastman 1990).

This species is known primarily from the prairies of western Washington, but populations

are known in the Willamette Valley. Over most of its range, Aster curtus is found in well-

drained upland prairies (Alverson 1991). However, at the southern extent of its range in Lane

County, it is known to occur in wet Deschampsia cespitosa grassland (Alverson 1991). At sites

such as Fern Ridge, A. curtus is found in clay soils with standing water in the winter.


Aster curtus is rhizomatous, and much of its spread may be vegetative (Clampitt 1987).

However, it also reproduces by seed. The plants flower in July and August (Hitchcock et al.

1969); the flowers are protandrous, with the stigmas expanding through the connate anthers

several days after anthesis (Clampitt 1987). Such a system decreases the likelihood of self-

pollination (Clampitt 1987). The species may also be self-incompatible. In a bagging

experiment, Clampitt (1987) found that bagged inflorescences (where pollinators had been

excluded) produced many fewer mature seeds than open inflorescences, suggesting that self-

pollination does not readily occur. However, no specific insect pollinators are known.

The seeds, which disperse about a month after flowering (Clampitt 1987), are probably

wind dispersed. This species produces about 160 seeds per inflorescence (Clampitt 1987). Aster

curtus seeds germinate under a wide temperature range, but they require light; the seedlings

grow slowly, so they may lack the energy stores to grow through deep layers of soil or litter.

Stratification increases the speed and amount of germination (Clampitt 1987). However, seed

viability is moderate, at about 54% (Clampitt 1987).

Little is known about the effects of disease and predation on this species other than it is

known to be palatable to horses and cattle (Alverson 1987). While its rhizomatous nature

affords some tolerance to grazing, high grazing pressure may lead to the destruction of

populations.

Some experimental work has been done on the effects of competition on this species.

Clampitt (1987) found that competition with all but the feeblest competitor decreased the yield

of Aster curtus to 1/10 of its yield when grown alone. The seedlings of this species grow very

slowly and persist under intense competition, producing plants of low stature that produce

several ramets before flowering.

Aster curtus is found on six of the Fern Ridge management units. The Applegate

Management Unit contains several small patches that are clumped together near the western

edge of the management unit. Together they encompass about 12,000 m2. The Royal Amazon


Management Unit contains one large patch (about 400,000 m2) of A. curtus near the eastern edge

of the management unit. One monitoring grid exits for this unit; data from 1987-1992 indicate

that the number of stems of this species has remained fairly constant at about 10 stems/m2. The

Amazon Dike No. 2 Management Unit contains four patches covering about 300,000 m2 near the

eastern edge of the management unit. Two monitoring grids have been established here. Grid 2-

2 showed a continuous increase in stems from 7.1 stems/m2 in 1986 to 21.3 stems/m2 in 1990.

However, only 12.6 stems/m2 were found in 1992. Grid 2-1 indicated a fairly constant density of

about 24 stems/m2 from 1988-1990. The Fisher Butte Management Unit contains five patches

covering about 48,000 m2 along the eastern portion of the management unit. Three monitoring

grids have been established. However, the data from grids 2-5 and 2-6 are not easily

interpretable. No pattern was evident from 1987-1990 in grid 2-4. The densities ranged from a

low of 22.1 stems/m2 in 1988 to a high of 44.1 stems/m2 in 1989. The Kirk Pond Management

Unit contains three patches covering about 40,000 m2 in the northeastern portion of the

management unit. The South Marsh Management Unit contains a single patch covering about

27,000 m2 in the southern portion of the management unit.

Montia howellii. Montia howellii Wats., also known as Howell's montia, is a candidate for

listing as endangered at both the state and federal levels. At the federal level, it is a C2 candidate

(Oregon Natural Heritage Program 1991).

A very small, low-growing annual in the purslane family (Portulacaceae), Montia howellii

has alternate leaves that are strap-shaped with spoon-shaped ends (Hitchcock et al. 1969). M.

howellii is generally only visible in the early spring before other plants begin to grow.

This species is found in moist lowland areas west of the Cascades from British Columbia

to northwest California (Hitchcock et al. 1969). In Oregon, most of the populations are found on

moist and vernally wet portions of roads (Kaye 1992b). Other M. howellii sites in the Pacific

Northwest are along rivers or streams (Kagan 1989). The road soils of the Oregon populations


consist of heavy clay with poorly drained sub-soils, which are probably identical to the soils of

the adjacent Deschampsia caespitosa prairie (Kagan 1989).

As an annual, Montia howellii is completely dependent on reproduction from seed.

Hitchcock et al. (1969) report that the plant flowers from April to May. In Oregon, however, the

plant can reproduce very early; it is often in flower in February (Kagan 1989). This species is

mostly self-pollinating, often with cleistogamous flowers, which never open for cross-pollination

(Kagan 1989). Some open (chasmogamous) flowers may be cross-pollinating, but no insects

have been observed (Kagan 1989).

On average, plants produce 4-5 flowers, and each flower produces 2-3 seeds (Kagan 1989).

The large seeds appear to be gravity-dispersed. The seeds do float, however, so they may also be

dispersed by water. Montia howellii seeds require cold temperatures (


1989 by the Oregon Natural Heritage Program estimated the total Kirk Park population at 10,000

to 25,000 plants. The West Coyote Management Unit contains a single patch of about 12,000 m2

in the southeastern portion of the management unit.

Horkelia congesta. Horkelia congesta Dougl. ex Hook, commonly known as shaggy

horkelia, is a candidate for listing at the state level (Oregon Natural Heritage Program 1991).

A member of the rose family (Rosaceae), this taprooted perennial usually has several stems

reaching 20 cm to 40 cm in height. The narrow leaves found at the base of the plant are 3 cm to

8 cm long and divided into toothed leaflets. The flowers are cream-colored (Hitchcock et al.

1969).

The plants found in western Oregon are of the subspecies congesta, which can be found

from Washington to Douglas Counties. This taxon flowers from April to June and apparently

depends on seed for reproduction (Hitchcock et al. 1969). However, very little else is currently

known about this taxon. More information may be available in late 1993 or 1994, as the taxon

will be studied by T. N. Kaye of the Oregon Department of Agriculture.

Horkelia congesta ssp. congesta is found on four of the Fern Ridge management units.

The Fisher Butte Management Unit contains five patches covering about 150,000 m2 in the

eastern portion of the management unit. The Amazon Dike No. 2 Management Unit contains

two patches covering about 630,000 m2 in the eastern portion of the management unit. The

Royal Amazon Management Unit contains two patches covering about 690,000 m2 in the eastern

portion of the management unit. The Kirk Pond Management Unit contains two patches

covering about 2800 m2.

Cyperus rivularis var. rivularis. Cyperus rivularis Kunth var. rivularis is more

commonly known as shining flatsedge or shining cyperus. This taxon is not currently a

candidate for listing at either the state or federal level. However, it is monitored by the Oregon

Natural Heritage Program on List 3, meaning that more information is necessary to determine if


the species is threatened or endangered in Oregon or throughout its range (Oregon Natural

Heritage Program 1991).

A member of the sedge family (Cyperaceae), Cyperus rivularis is a 5 cm to 20 cm tall

tufted annual with a few narrow leaves borne near the base of the plant (Hitchcock et al. 1969).

According to Hitchcock et al. (1969), the species is widespread in the United States and southern

Canada, but it is more common eastward. The species is also found south to South America.

However, it is rarely collected in the Pacific Northwest. In general, the species is found along

streambanks and in other wet, low places of valleys and lowlands.

No information is available for this plant in Oregon. Information from West Virginia

(Strausbaugh and Core 1964), South Dakota (VanBruggen 1976), and Missouri (Steyermark

1963) suggests that the species flowers sometime between July and October. However, no other

information is currently available.

Four patches of Cyperus rivularis var. rivularis are found covering about 32,000 m2 of the

Kirk Pond Management Unit.

Sidalcea cusickii. Sidalcea cusickii Piper, commonly known as Cusick's checker-mallow,

is not currently a candidate for listing at either the state or federal level. However, it is

monitored by the Oregon Natural Heritage Program on List 4, meaning that the species is one of

concern but is not currently threatened or endangered (Oregon Natural Heritage Program 1991).

This species is a member of the mallow family (Malvaceae). A hollow-stemmed

perennial, this plant can reach 150 cm in height. The flowers, which have 1.5 cm long rose-pink

petals, grow in dense racemes. The leaves at the base of the stem are cleft in 7 to 9 lobes, while

the upper leaves may be narrow and bractlike (Eastman 1990). This species is endemic to the

southern Willamette Valley and the Coquille and Umpqua river valleys. According to records on

file at the OSU Herbarium, the plant is generally found in heavy wet soils and gravelly loam, in

open fields and along roadsides.


Sidalcea cusickii is rhizomatous and can also reproduce from seed. This gynodioecious

plant produces flowers from May to June (Hitchcock et al. 1969); some flowers are perfect, with

stamens and pistils, while others are strictly female (Halse et al. 1989). The female flowers are

generally smaller. The showy flowers indicate insect pollination. For the genus Sidalcea, the

prime pollinator is Diadasia nigrifrons, a specialist bee that visits no other genera (Moldenke

1981).

Little work has been done specifically on Sidalcea cusickii. However, its relative, S.

nelsoniana, is better known and may be similar in some respects. Studies done on S. nelsoniana

have found that the seeds require scarification for germination (CH2M Hill 1986). Passage

through an animal gut, fungal or bacterial action, or fire might fulfill this requirement in nature.

In addition, weevils are known predators for S. nelsoniana. The larval stage of the butterfly

Vanessa anabella Fields (Lepidoptera: Nymphalidae) also feeds largely on the leaves of

Sidalcea species and other members of the Malvaceae (CH2M Hill 1986). However, the extent

of the damage this insect may inflict on Sidalcea cusickii is not known.

Sidalcea cusickii is found on two of the Fern Ridge management units. The Fisher Butte

Management Unit contains a single patch covering about 12,000 m2 near Highway 126. The

Kirk Pond Management Unit contains a single patch covering about 7600 m2 near Clear Lake

Road.

Microcala quadrangularis. Microcala quadrangularis (Lam.) Griseb., commonly called

timwort, is not currently a candidate for listing at either the state or federal level. However, it is

monitored by the Oregon Natural Heritage Program on List 2 because it is threatened with

extirpation within Oregon (Oregon Natural Heritage Program 1991).

A member of the gentian family (Gentianaceae), this small annual herb plant reaches 3 cm

to 8 cm in height and has narrow leaves located mainly at the base. The yellowish flowers have

four petals, which are usually closed, except in bright sunlight (Hitchcock et al. 1969).


This species is found in the Willamette and Umpqua Valleys, where it grows in prairies

and open, moist flats. In California, the species is found in thick clay (Hitchcock et al. 1969); it

is probably found in clay soils of the Willamette Valley, as well. While the species is rare in

Oregon, it is more abundant elsewhere.

As an annual, the plant, which flowers from March to June, is completely dependent upon

seed for reproduction. However, little else is currently known about this species.

A single patch of Microcala quadrangularis, covering about 85,000 m2, occurs in the

Fisher Butte Research Natural Area. It is also present in low abundance in the Rose Prairie

Research Natural Area.

Calochortus uniflorus. Calochortus uniflorus Hook. & Arn. is a member of the lily

family (Lilaceae). Commonly known as the Monterey mariposa or the large-field sego lily, this

species, was once considered for listing but is no longer monitored by any agency in Oregon.

Calochortus uniflorus grows from a bulb and has a short stem that may barely extend

above the ground surface. The leaves at the base range from 10 cm to 40 cm long, with parallel

veins. The flowers have petals, which often have a purple spot and a few hairs near the center

(Hitchcock et al. 1969).

This species is found west of the Cascade and Sierra Nevada Mountains, where it ranges

from the vicinity of Eugene south to Monterey, California (Hitchcock et al. 1969). Reproduction

is by bulb or seed, but no other information is currently available about the biology of this

species.

Two patches of Calochortus uniflorus, covering about 5800 m2, occur in the Fisher Butte

Research Natural Area. It is also present in low abundance in the Rose Prairie Research Natural

Area.


Sagittaria latifolia. A member of the water-plantain family (Alismataceae), Sagittaria

latifolia Willd. is more commonly known as wapato, broadleaf arrowhead, or duck potato. This

species was considered for listing but it is not longer monitored by any agency in Oregon.

This herbaceous perennial grows from 30 cm to 120 cm tall. Its leaves are arrow-shaped

with parallel veins, and its flowers have three round, white petals with bright yellow anthers

(Eastman 1990).

Sagittaria latifolia grows in mud or quiet shallow water. The species was once very

common in the wet marsh areas of the Willamette Valley and the Columbia River; however, it

was nearly extirpated as a result of habitat destruction. In protected areas, populations of the

plant are reviving (Eastman 1990). While relatively rare in Oregon, this plant is very abundant

in the central and eastern United States, where it is found in ditches, ponds, lakes, and swampy

areas. The plant is also common on the Pacific coast from Vancouver Island to central

California, and it can be found in Arizona through Mexico and Central America to northern

South America, and in the West Indies and Hawaii (Hitchcock et al. 1969).

A strongly rhizomatous species, Sagittaria latifolia is capable of spreading clonally or by

seed. Flowering occurs from July to September (Hitchcock et al. 1969). The species is largely

dioecious in the northern part of its range (Wooten 1971); the majority of plants are either male

or female, but the plants can also be monoecious, with male and female flowers on the same

inflorescence (Muenchow and Delesalle 1992). The pollination mechanism is not known, but

the species is known to be self-compatible (Muenchow and Delesalle 1992).

A female flower produces hundreds of achenes (Muenchow and Delesalle 1992), and seed

viability has been estimated at greater than 80% (Wooten 1971). Seeds from monoecious plants

germinate readily when placed in water. However, seeds from dioecious plants appear to require

some form of cold treatment (Wooten 1971). It seems that seeds from dioecious populations

produce some form of germination inhibitor, while there is no inhibitor in seeds from


monoecious plants. Therefore, reproduction appears to be predominantly vegetative in dioecious

populations and sexual in monoecious populations (Wooten 1971).

Little information is available on herbivory on Sagittaria latifolia in Oregon. In Ohio,

however, weevils of the genus Listronotus are common on Sagittaria latifolia (Muenchow and

Delesalle 1992). The male plant tissue seems to attract the weevils. Adult weevils can feed and

oviposit on Sagittaria latifolia. Basal, male flowers, which open earlier, are more likely to

bloom successfully, since herbivory is highest among the slowest buds. Less insect damage

occurs on wetter sites (Muenchow and Delesalle 1992). No information is available on the

effects of competition on this species.

Sagittaria latifolia occurs in five of the Fern Ridge management units. The South Marsh

Management Unit contains two patches covering about 79,000 m2 in the southwest portion of the

management unit. The Jean's Peninsula Management Unit contains two patches covering about

59,000 m2 along the eastern shoreline of the peninsula. The Royal Amazon Management Unit

contains seven scattered patches covering about 1600 m2. The West Shore Management Unit

contains a single patch covering about 6100 m2 along the central shoreline of the management

unit. The Fisher Butte Management Unit contains many patches scattered through the western

half of the management unit. These patches encompass about 34,000 m2.

Lupinus sulphureus ssp. kincaidii. Lupinus sulphureus Dougl. ssp. kincaidii (Smith)

Phillips is commonly known as Kincaid's lupine. This taxon is a candidate for listing at the state

and federal levels. At the state level, it is being actively reviewed for probable listing as

threatened (R. Meinke and T. Kaye pers. comm.). At the federal level, it is a C2 candidate

(Oregon Natural Heritage Program 1991).

A member of the pea family (Fabaceae), this perennial herb grows 30 cm to 100 cm tall.

Its leaves are palmately divided into narrow leaflets that are creased in the middle. The


underside of the leaves are covered with silvery, white hairs. The flowers, which are pea-shaped

and purplish-blue, grow in 10 cm to 20 cm tall racemes (Eastman 1990).

This taxon is endemic to the open, upland prairie habitat of the Willamette Valley and

south into Douglas County (Hitchcock et al. 1969, P. Hammond pers. comm., K. Kuykendall,

pers. comm.). In general, its habitat is characterized by south-facing slopes and clay soils that do

not dry out until July.

Kincaid's lupine can spread vegetatively or by seed. Some individuals may be very long-

lived (at least 25 years in one excavated individual; M. V. Wilson, unpublished data). Its flowers

appear from April to June (Hitchcock et al 1969). The plant appears to require an insect

pollinator. T. N. Kaye (pers. comm.) found that bagged inflorescences produced no seed,

suggesting that the species is self-incompatible. Several insects have been observed pollinating

this plant, including Bombus mixtus, Dialictus sp., and Apis mellifera (Wilson et al. 1991).

Seed production in this species appears to be low. Studies done in 1990 (Wilson et al.

1991), estimated seed production at 1.6 seeds/fruit, 4.8 seeds/inflorescence, and 6.8 seeds/m2.

However, 1990 may have been a particularly poor year for seed production, since the cool and

overcast spring weather was not favorable for insect pollination.

The seeds are fairly large and probably drop to the ground near the parent plant.

Experiments have indicated that scarification increases germination in this taxon (C. Ingersoll

and D. Clark, pers. comm.). While it is not certain how seeds respond under natural conditions,

very few seedlings have ever been observed (C. Ingersoll, pers. comm.).

Genetic studies (K. St. Hilaire and A. Liston, unpublished data) show low heterozygosity

within populations, similar to values shown by other narrowly distributed plant species.

A major point of interest for this rare plant is the fact that it is a major food source for the

larvae of the rare Fender's blue butterfly (Icaricia icarioides fenderi). More information on

Lupinus sulphureus ssp. kincaidii will be forthcoming in a USFWS status report by K.

Kuykendall.


Lupinus sulphureus ssp.kincaidii is found on two of the Fern Ridge management units.

The Amazon Dike No. 2 Management Unit contains eight patches covering about 61,000 m2 in

the northern portion of the management unit. The Shore Lane Management Unit contains a

single patch covering about 9000 m2 in the southernmost portion of the management unit.

Sidalcea campestris. A member of the mallow family (Malvaceae), Sidalcea campestris

Greene is not currently a candidate for listing at either the state or federal level. However, it is

monitored by the Oregon Natural Heritage Program on List 4 (Oregon Natural Heritage Program

1991).

Sidalcea campestris is commonly known as meadow sidalcea or tall wild hollyhock. It is a

stout perennial herb that can reach 150 cm in height. The leaves at the base of its stem are fan-

shaped with seven to nine lobes. Leaves farther up the stem are smaller and divided into five to

seven pointed, narrow lobes. The flowers, which are pale pink, are arranged in a loose raceme

(Eastman 1990).

Sidalcea campestris is found strictly in the Willamette Valley, from Portland south to the

vicinity of Eugene, where it is found in dry fields and along roadsides (Hitchcock et al. 1969).

This species grows in well-drained gravelly soils to rather wet clay (Kemp et al. 1978).

Historically, S. campestris was common in Willamette Valley grasslands. However, habitat loss

through agriculture and urbanization have limited it almost exclusively to fence rows and

roadsides (Kemp et al. 1978). The species has adapted well to human disturbance; it is very

common along roadsides and fence rows, where it can survive alongside European weeds (Halse

and Glad 1986). However, S. campestris is not found in woody or shaded sites (Meinke 1980;

Halse pers. comm.).

This species can reproduce both vegetatively and from seed. From May to July, this

gynodioecious plant produces flowers (Hitchcock et al. 1969); some flowers are perfect, with

stamens and pistils, while others are strictly female (Halse et al. 1989). The showy flowers


indicate insect pollination. For the genus Sidalcea, the prime pollinator is Diadasia nigrifrons, a

specialist bee that visits no other genera (Moldenke 1981). S. campestris is a prolific bloomer

that produces many fruits and seeds in a long raceme (Meinke 1980). Many populations may

consist of vegetatively reproducing clones, since seedling establishment would seem unlikely in

dense, unburned vegetation (Meinke 1980).

Little work has been done specifically on Sidalcea campestris. However, its relative, S.

nelsoniana is better known and may be similar in some respects. Studies done on S. nelsoniana

have found that the seeds require scarification for germination (CH2M Hill 1986). Passage

through an animal gut, fungal or bacterial action, or fire might fulfill this requirement in nature.

The hard, tough seed coats of S. campestris are similar to those found in some legumes that are

known to be fire-stimulated (Meinke 1980). Weevils are known predators for S. nelsoniana.

The larval stage of the butterfly Vanessa anabella Fields (Lepidoptera: Nymphalidae) also feeds

largely on the leaves of Sidalcea species and other members of the Malvaceae (CH2M Hill

1986). However, the extent of the damage this insect may inflict on Sidalcea campestris is not

known.

Four patches of Sidalcea campestris, covering about 57,000 m2 along Clear Lake Road,

occur in the Kirk Pond Management Unit.

Lathyrus holochlorus. Lathyrus holochlorus (Piper) Hitchc. is commonly called thin-

leaved pea-vine. This member of the pea family (Fabaceae) is not currently a candidate for

listing at either the state or federal level. However, it is monitored by the Oregon Natural

Heritage Program on List 4 (Oregon Natural Heritage Program 1991).

Lathyrus holochlorus is a perennial herb with angled stems that reach 30 cm to 100 cm in

length. The leaves, consisting of 8 to 12 oval leaflets, end in a tendril. The pealike flowers are

whitish (Hitchcock et al. 1969).


This species is endemic to the Willamette Valley, where it is found from Lane County to

near Portland (OSU Herbarium file). In general, the species grows in moist loam.

Capable of reproducing by rhizomes, as well as by seeds, the species flowers from May to

July (Hitchcock et al. 1969). The flowers produced are protandrous, with the stigmas developing

after the anthers (Broich 1983). This system decreases the likelihood of self-pollination. In fact,

evidence suggests that this plant is obligately outcrossed with a genetic incompatibility (Broich

1983). Some small populations monitored for 2-4 years have failed to produce seed in spite of

observed pollinators. These populations probably represent one self-incompatible clone (Broich

1983). Observed pollinators are mostly large bees of the genera Bombus, Osmia, and

Synhalonia, along with butterflies. These bees are generally strong fliers that can forage over

large distances (Moldenke 1976).

Seed reproduction appears to be limited by the availability of compatible pollen, as well as

seed predation by "pea weevils." In many populations, few good seeds are found (Broich 1983).

Seeds of Lathyrus holochlorus are preyed upon by pea weevils of the family Bruchidae. The

female weevil lays her eggs in or on developing fruits. The larvae then feed on the developing

seeds (Janzen 1969). This predation, along with lack of compatible pollen, often results in few

viable seeds; the seeds produced are either empty or contain a mature insect (Broich 1983).

Nothing is known about the effects of competition on this species.

A single patch of Lathyrus holochlorus occurs within a 9300 m2 area near the Long Tom

River in the Applegate Management Unit.

FIELD STUDIES

INTRODUCTION

This section describes field studies conducted at Fern Ridge on the effects of prescribed

3These field studies were conducted by Kathy Connelly with Boone Kauffman, unlessotherwise noted.

4This report covers general fire effects on vegetation. A complete treatment of fire, fuels, andvegetation is forthcoming (K. Connelly, in prep.).


burns on native ecosystems. These studies3 were conducted as part of a cooperative project

involving the U.S. Army Corps of Engineers, The Nature Conservancy, the Bureau of Land

Management Eugene District, and the Department of Rangeland Resources, Oregon State

University.

The principal objective was to investigate the feasibility of using prescribed fire to

maintain or improve the native species composition of Willamette Valley plant communities.

Natural and prescribed fire by Native Americans has been extremely important in shaping and

maintaining prairie plant communities in this region (Habeck 1961; Johannesen et al. 1971;

Boyd 1986). Over 100 years without fire has allowed trees and shrubs to increase in abundance

dramatically in the remaining prairies. As a result, native populations of grasses and forbs have

declined (Franklin and Dyrness 1973; Frenkel and Heineitz 1987).

We therefore hypothesized that prescribed burns would enhance the native prairie flora by

controlling successional invasion of woody species and by invigorating vegetative and

reproductive growth of these fire-adapted native plant communities. Support for this hypothesis

comes from vegetation monitoring by The Oregon Nature Conservancy Field Office. Prescribed

burns in upland and wetland prairies within their ownership (for example, Willow Creek,

Rattlesnake Butte, Cascade Head and Wren Prairie) appeared to cause a positive response of

native plant species to fire and some reduction of shrub and tree densities (C. Macdonald, pers.

comm.).

The study reported here is the first comprehensive, controlled scientific study of burning in

Willamette Valley prairies. Little is known of the effect fire has on plant communities or on the

species life histories within these prairie communities. No other study4 has quantified fuel loads,


fuel moisture, fire weather, or multiple burns in these ecosystems. Thorough quantification of

fire behavior, fuel dynamics, and vegetation response are paramount for the development of

prescriptions for fires that might perpetuate Willamette Valley prairies and their rare and

endangered plant components.

STUDY SITES

Two study sites were located on lands administered by the U.S. Army Corps of Engineers,

Fern Ridge project, near Eugene, Oregon. Connelly and Kauffman (1991) contains a detailed

description of these sites. The sites will be referred to as the Rose Prairie and Fisher Butte study

sites. Both sites are experiencing tree and shrub invasion and both contain rare and endangered

plant species.

These wetland prairie sites are classified as jurisdictional wetlands, and anaerobic

conditions from waterlogging limit plant growth during the wet winter and spring months.

Drought limits plant growth during the dry summer months. Therefore, the plants that survive in

these habitats must be adapted to extremes in moisture availability that occur during a yearly

cycle. A majority of species are dormant by late fall. Thus, most plants would have been

dormant during the fall, when aboriginal burning likely occurred.

Five plant communities were determined and mapped for both study sites based on

intensive reconnaissance and low altitude aerial photography. Three plant communities were

differentiated at the Rose Prairie study site for analysis. A majority of the Rose Prairie study

area is covered by a Vaccinium caespitosum community, a Rosa nutkana/Anthoxanthum

odoratum community, and a Deschampsia cespitosa-Danthonia californica community (Figure

2).

Two plant communities were differentiated at the Fisher Butte study site. They included a

Rosa nutkana/Deschampsia cespitosa-Juncus nevadensis and a Deschampsia

cespitosa-Danthonia californica community. As these two plant community types intergrade


along an apparent moisture gradient, community transects were placed at extreme ends of the

gradient. Oregon ash (Fraxinus latifolia) was found principally in the Rosa

nutkana/Deschampsia cespitosa-Juncus nevadensis community. Crataegus douglasii, Pyrus

fuscus, and Malus diversiloba were the primary invaders in the Deschampsia

cespitosa-Danthonia californica plant community.

METHODS

During the autumn of 1988, 1989, and 1991, Bureau of Land Management personnel

performed prescribed burns at two study sites on Army Corps of Engineers lands.

Plant Community Studies

Plant community composition plots were evaluated prior to burning in 1988 and during the

spring and summer of 1989 and 1990. We established three permanent 30-m transects in each

plant community within each treatment at both the Fisher Butte and Rose Prairie sites (Figure 2).

We measured the response to fire of plant communities by recording cover and nested frequency

along these transects (Goldsmith et al. 1986; Barbour et al. 1987). Our plot frame size was 50

cm × 50 cm with nested plots of 25 cm × 25 cm and 12.5 cm × 12.5 cm. Permanent plots were

established at each meter mark along the 30 m transect. For all species, frequency was tallied in

each plot size and cover for each species was determined for the 50 cm × 50 cm plot size. For

this document, we utilized only the largest plot size (50 cm × 50 cm) for describing and reporting

changes in frequency values. Cover was determined in the first 15 plots while nested

frequencies were tallied for all 30 plots.

We investigated plant community vegetation response to three treatments:

Treatment 0, Control (no burning)

Treatment 1, Burned in fall of 1988


Treatment 2, Burned in 1988 and 1989

One replicate of each treatment was established at the Rose Prairie site while two replicates of

each burn treatment and one control treatment was established at the Fisher Butte site

Data were collected in 1988 prior to an October prescribed burn. Data were again

collected in spring and summer of 1989 prior to a prescribed burn during September. Data were

collected for a third season during spring and summer of 1990. Plant community plots have not

been collected since 1990.

The PC-Ord program (McCune 1990) was used to calculate species richness from cover

and frequency data.

Studies of Lomatium bradshawii and Erigeron decumbens var. decumbens

Individual Lomatium bradshawii and Erigeron decumbens var. decumbens plants were

measured each spring between 1988 and 1992. For each L. bradshawii plant we recorded height

(from ground to tallest leaf extension), the widest diameter of leaf material (W1), the widest axis

of leaf material perpendicular to W1 (W2), the number of umbels, the number of umbellets, and

the number of developed fruits. For each E. decumbens plant we recorded height (from ground

to tallest flower head), the widest diameter of leaf or flower head material (W1), the widest axis

of leaf or flower head material perpendicular to W1 (W2), and the number of flower buds

produced. Elliptical crown cover area (A) for both species was derived utilizing the formula A =

(π×W1×W2)/4.

We investigated tagged plant responses to three treatments between 1988 and 1992.

Treatments were as follows;

Treatment 0, Control (no burning)

Treatment 1, Burned in 1988 and 1991

Treatment 2, Burned in 1988, 1989, and 1991


One replicate of each treatment was established at the Rose Prairie site while two replicates of

each burn treatment and one control treatment were established at the Fisher Butte site

Data were collected in 1988 prior to an October prescribed burn. Data were again

collected in spring and summer of 1989 prior to a prescribed burn during September. Data were

collected for a third season during spring of 1990. Karen Finley collected data on these tagged

plants in the spring of 1991 before another prescribed fall burn in 1991 and remeasured tagged

plants in the spring of 1992. All data for 1988-1992 have been analyzed for Lomatium

bradshawii. Data collected on the measured attributes of Erigeron decumbens var. decumbens

have been analyzed for 1988-1991, while recruitment data have been analyzed only for 1988-

1990.

A total of 450 individual Lomatium bradshawii plants were tagged at the Rose Prairie and

Fisher Butte sites. For Erigeron decumbens, 300 plants were tagged at the Rose Prairie and

Fisher Butte sites.

Macroplots were established around randomly selected tagged plants to determine

recruitment of Lomatium bradshawii and Erigeron decumbens. L. bradshawii macroplots were

2-m-radius plots while E. decumbens macroplots were 1-m-radius plots. Individual plants within

macroplots were tallied into flowering or non-flowering groups.

Five macroplots per treatment per site were mapped for Lomatium bradshawii during

1988. An additional 5 control macroplots were included during 1989 for a total of 45 macroplots

for this species between the years 1989 and 1992.

For Erigeron decumbens var. decumbens, ten macroplots were evaluated in each of the

five treatment areas at Fisher Butte for a total of 50 macroplots during 1988 and 1989. An

additional five control macroplots were included in the study during 1990.

The cover and frequency values of rare plants were extracted and tallied from the plant

community plot data.


RESULTS

Plant community studies

Community descriptions. The Fisher Butte site had a very `hummocky' terrain with

individual grass plants (particularly Deschampsia cespitosa) occupying soil pedestals.

Pedestaling increased along the increasing moisture gradient.

A Rosa nutkana/Deschampsia cespitosa-Juncus nevadensis community and a

Deschampsia cespitosa-Danthonia californica community were differentiated at Fisher Butte.

Conspicuous dominant native species in both communities at Fisher Butte include Deschampsia

cespitosa, Danthonia californica, Madia glomerata, and Grindelia integrifolia. Holcus lanatus

was a conspicuous non-native found over the entire Fisher Butte site.

Specific dominant native species in the Rosa nutkana/Deschampsia cespitosa-Danthonia

californica community included Carex spp., Juncus nevadensis, Agrostis exarata, Rosa nutkana,

Cardamine penduliflora and Galium spp. Subordinate species that typified the community

included Beckmannia syzigachne, Boisduvalia sp., Brodiaea coronaria, Eleocharis acicularis,

Epilobium spp., Microsteris gracilis, Veronica scutellata, and Eryngium petiolatum. Mentha

pulegium was a conspicuous non-native species; less conspicuous non-native species included

Briza minor, Centaurium umbellatum, and Hypericum perforatum.

Conspicuous native species within the Deschampsia cespitosa-Danthonia californica

community at Fisher Butte included Aster chilensis var. hallii, Eriophyllum lanatum, Microseris

laciniata, Prunella vulgaris, and Sisyrinchium angustifolium. Conspicuous non-natives species

included Agrostis spp., Centaurium umbellatum, and Hypericum perforatum. Less conspicuous

non-natives included Briza minor, Hypochaeris radicata, Leontodon nudicaulis, and

Anthoxanthum odoratum.

The Rose Prairie site tended to be drier than the Fisher Butte site, draining earlier in the

spring. Also, a more prevalent composition of non-native species occurred at this site. Three


plant communities were differentiated at this site: a Rosa nutkana/Anthoxanthum odoratum

community, a Deschampsia cespitosa-Danthonia californica community, and a Vaccinium

caespitosum community.

The Rosa nutkana/Anthoxanthum odoratum community had a thick moss mat (up to 8 cm)

and occupied slightly elevated mounds (up to 50 cm) above the generally level terrain. This

community type contained a large complement of alien plant species which generally occupied

greater than 50 percent of the plant cover. Typical native species included Lotus purshiana,

Heterocodon rariflorum, and Danthonia californica. Dominant non-native species included

Anthoxanthum odoratum, Hypericum perforatum, Holcus lanatus, Plantago lanceolata, Rosa

nutkana, Rumex acetosella, and Briza minor. Less conspicuous non-native species included

Cerastium viscosum, Leontodon nudicaulis, Myosotis discolor, Parentucellia viscosa, Seneceo

jacobaea, and Galium parisiense.

The Deschampsia cespitosa-Danthonia californica community occurred on the northern

portion of the study site. This community tended to be `hummocky' or pedestalled. Dominant

native species included Deschampsia cespitosa, Danthonia californica, Panicum occidentale,

Eriophyllum lanatum, and Grindelia integrifolia. Less conspicuous, though abundant native

species included Camassia quamash, Centunculus minimus, Centaurium muhlenbergii,

Microseris laciniata, Juncus tenuis, and Juncus nevadensis. Conspicuous non-native species

included Agrostis tenuis, Anthoxanthum odoratum, Hypochaeris radicata, and Leontodon

nudicaulis.

The Vaccinium caespitosum community appeared to occupy the same generally level

terrain as the Deschampsia cespitosa-Danthonia californica community, and they had many

species in common. At first glance, the Vaccinium caespitosum community could be roughly

differentiated due to the presence of Vaccinium caespitosum. However, this community

contained a rich assortment of other species not typically observed in the Deschampsia

cespitosa-Danthonia californica community. Numerous terrestrial lichens occurred primarily

5In 1990, cover was recorded only for abundant species. As a result, cover values reportedfor 1990 are underestimates of the true values. Thus, year to year comparisons should be madecautiously, although comparison among treatments in 1990 are still valid.


within the Vaccinium caespitosum community but also occurred to a lesser extent in the Rosa

nutkana/Anthoxanthum odoratum community. Native dominant species of the Vaccinium

caespitosum community included those listed for the Deschampsia cespitosa-Danthonia

californica community as well as V. caespitosum, Aster curtus, Carex spp., Lotus formosissimus,

Prunella vulgaris, Sisyrinchium angustifolium, and Viola adunca. Less conspicuous, though

abundant native species included those species listed for the Deschampsia cespitosa-Danthonia

californica community as well as Aster chilensis var. hallii, Brodiaea coronaria, Comandra

umbellata, Fragaria virginiana, Horkelia congesta, and Rosa nutkana. Comandra umbellata is

a root parasite that appeared to be parasitizing V. caespitosum within this community.

Conspicuous non-native species were the same as those listed for the Deschampsia cespitosa-

Danthonia californica community and additionally contained Hypericum perforatum and Briza

minor.

The Vaccinium caespitosum community is species rich, although biomass is depauperate.

The low aboveground biomass, low stature, and prominence of an ericaceous species in this

community are indicative of an oligotrophic system (Kauffman and Connelly 1988; Frenkel and

Heinitz 1987).

Fire effects on cover and diversity. Burning had no consistent effect on the overall cover5

or diversity of either native or non-native plant species (Figures 3-6). The number of native

species present in plots increased with burning compared to a decline in the unburned plots in the

Rosa nutkana/Anthoxanthum odoratum community at Rose Prairie.

Cover by growth form varied widely between years (Tables 3 and 4). Fire appeared to

increase cover of native species in two cases. Native tree and shrub cover increased in the Rosa

nutkana/Deschampsia cespitosa-Danthonia californica community at Fisher Butte compared to


unchanged cover in unburned, control plots. This tree and shrub cover, although of native

species, may be detrimental to the rest of the community by shading out native grasses and forbs.

(A more detailed analysis of fire effects on trees and shrubs is in preparation by K. P. Connelly.)

Native perennial graminoids increased in the Deschampsia cespitosa-Danthonia californica

community at Rose Prairie in 1990 in both burn treatments but not when unburned. Fire also

changed the cover of three growth forms on non-native species. Non-native annual graminoids

were present in some burned plots (up to 2.1% cover) but were virtually absent from control

plots in all the communities. Non-native annual, biennial, and perennial forbs increased 2-3 fold

after burning in the Rosa nutkana/Anthoxanthum odoratum community, but remained less

common in unburned plots.

Rare plant distributions. Although the plant community sampling was not designed to

document the distributions of rare plant species, individuals of the ten rare species found in

wetland prairies were occasionally encountered. Aster curtus was most abundant in the

Vaccinium caespitosum community at Rose Prairie and in three other communities (Table 5).

Calochortus uniflorus was sampled only in the Deschampsia cespitosa-Danthonia californica

community at Fisher Butte (Table 6). Erigeron decumbens var. decumbens occurred only at the

Fisher Butte site and almost exclusively within the Deschampsia cespitosa-Danthonia

californica community (Table 7). Horkelia congesta occurred in all communities at both sites

although it occurred with most abundance at Rose Prairie within the Vaccinium caespitosum

community (Table 8). Lomatium bradshawii was sampled within the Deschampsia cespitosa-

Danthonia californica communities at Fisher Butte and Rose Prairie and the Vaccinium

caespitosum community at Rose Prairie (Table 9). Microcala quadrangularis was sampled at

both sites but was most abundant at Fisher Butte within the Deschampsia cespitosa-Danthonia

californica community (Table 10).


The Deschampsia cespitosa-Danthonia californica community at Fisher Butte contained

more rare plant species (6) than any of the other communities at either site. The Vaccinium

caespitosum community at Rose Prairie contained just three rare species, but at higher levels of

cover and frequency. The Rosa nutkana/Deschampsia cespitosa-Danthonia californica

community at Fisher Butte contained 3 rare plant species, but at the lowest cover and frequency

of any community.

The effect of fire on these rare plant species is hard to assess from these community data.

Nevertheless, burn treatments appeared to have a beneficial effect on abundance in some cases,

and otherwise mostly neutral effects. Erigeron decumbens frequency was much higher after

burning in the Deschampsia cespitosa-Danthonia californica community compared to controls

(Table 7). Lomatium bradshawii frequency was much higher after the second fire in the

Deschampsia cespitosa-Danthonia californica community at Rose Prairie (Table 9).

Studies of Lomatium bradshawii and Erigeron decumbens var. decumbens

We quantified fire effects on the mortality, flowering, seed production, and vegetative

growth of tagged E. decumbens and L. bradshawii plants . Complete results and analyses have

been presented in previous reports submitted to the Fern Ridge Project of the Army Corps of

Engineers (Connelly and Kauffman 1991; Finley and Kauffman 1992). For this report, we have

summarized data collected from 1988 to 1992 for L. bradshawii and 1988 to 1991 for E.

decumbens var. decumbens for trends due to burn treatments.

Lomatium bradshawii. Flowering and seed production of Lomatium bradshawii increased

dramatically after burning relative to control treatment plants at both Fisher Butte and Rose

Prairie sites (Figures 7 and 8). Seed production was five-times higher in burned plants compared

to controls at Rose Prairie and seven-times higher at Fisher Butte (Figure 8).


Trends in vegetative growth were less distinct. Height growth in burned plants was

roughly the same or lower than in control plants (Figure 9). Crown growth, however, was

generally greater in burned plants compared to control plants, especially at Fisher Butte (Figure

10). Mortality values were variable at the two sites and over the 4 years. Mortality was more

likely to be higher, however, in the control plants (Figure 11).

Density generally declined between 1988 and 1992 in unburned, control plots (Figure 12).

Density in burned plots, however, finished about the same as it had started in 1988. The decline

in density observed between 1990 and 1991 at both sites and with all treatments might have been

caused by the shift from one observer to another at that time.

Overall, these results indicate a fairly positive response of Lomatium bradshawii to the

prescribed burns. There is a clear pattern of increased seed-set for L. bradshawii plants

following prescribed burning. However, vegetative response appears quite variable and may

relate to inherent differences in fertility or microclimatic factors (such as light or moisture

availability) at the two sites. Mortality tended to be low in burned plots.

Erigeron decumbens var. decumbens. Flowering and plant height-growth of E.

decumbens was not clearly enhanced by burning (Figures 13 and 14), although flower production

in burned plants exceeded that in control plants by 1990 and 1991. Crown cover, on the other

hand, was higher in burned plants for all post-fire years (Figure 15). Mortality was initially

higher in burned plants but was low by 1991 for both burn treatments (Figure 16).

Burning had less clear advantages to Erigeron decumbens than it had to Lomatium

bradshawii. Only crown cover and density increased significantly with burning. Flowering and

survival seemed to improve over time, however, in burned plants as compared to control plants.

The density of E. decumbens individuals increased dramatically in burn treatment plots by 1990

(Figure 17).


One explanation for the increased mortality rate and growth suppression patterns that

emerged during some years in burn treatments relative to unburned treatments is that biomass

accumulations resulted in "unnatural" fire conditions. Erigeron decumbens produces somewhat

woody stem growth that does not thoroughly decompose from one growing season to the next.

After more than 100 years without fire, biomass accumulations around the bases of individual

plants would be greater than under a regime of fr

Documents

PLANT SPECIES, HABITAT, AND SITE INFORMATION FOR FERN ...people.oregonstate.edu/~wilsomar/PDF/WCL_WES_93.pdf · 1Plant nomenclature follows Hitchcock et al., 1969, unless otherwise