Adaptive Management for a Coastal Prairie Community

Historically, coastal prairie communities occupied an extensive range from northern California to British Columbia. Today, these communities have been severely fragmented as a result of development, agriculture, recreational use, and invasion from non-native species. With the degradation of these habitats, many plant and animal species have experienced a quick decline, most notably the Oregon silverspot butterfly (Speyeria zerene hippolyta) and its larval and adult food sources, including hookedspur or sand violet (Viola adunca), coast goldenrod (Solidago spathulata), Douglas' aster (Symphyotrichum subspicatum), and edible thistle (Cirsium edule). The silverspot butterfly is listed federally as threatened and in Oregon as endangered, emphasizing the need for protection of remaining habitat as well as restoration and enhancement of potential new sites that encourage expansion of the species. The Institute for Applied Ecology (IAE), the North Coast Land Conservancy, and the Willapa National Wildlife Refuge have teamed up to develop an adaptive management strategy that targets the restoration of 140-acres of coastal prairie by 2020 to create suitable habitat for the reintroduction of the Oregon silverspot butterfly.  This effort is funded by the U.S. Fish and Wildlife Service.

Oregon silverspot butterfly on a coast goldenrod (left) and the larval host plant, sand violet (right).
Butterfly image courtesy of the Oregon Zoo and violet image courtesy of Prairie Moon Nursery.

This targeted restoration effort will help to meet short-term and long-term conservation needs for the butterfly and the associated habitat. Previous studies have tested various management techniques, including prescribed fire, mowing, herbicide application, solarization, grazing, topsoil removal, topsoil inversion, and soil impoverishment, with the desire to mimic non-climatic natural disturbance processes and improve habitat viability (Van Dyke et al. 2004).

This May, the Conservation Research team established a restoration experiment on four different sites to test three site preparation options including topsoil removal, topsoil inversion, and herbicide application. All four sites are located on protected land in a maintenance stage of restoration; three of the sites are located on land owned by the North Coast Land Conservancy in the Clatsop Plains north of Seaside, Oregon and the fourth site is located on the Long Beach Peninsula in Washington on land owned by the Willapa National Wildlife Refuge. The initial site preparation techniques will be followed by seeding and planting of native species. Over the next three years, a combination of management techniques will be implemented to determine the most effective strategy for restoration and maintenance of coastal prairie habitat. These techniques may include seasonal herbicide application, hand-removal of invasive species, and high-intensity grazing, and will be adjusted based on the effectiveness of meeting management objectives.

CR interns Kelsey Copes-Gerbitz (left) and Tobin Weatherson (right) and
Naturalist Denise Giles-Johnson (center) establishing experimental plots.

After initial set-up of the experimental plots, we conducted pre-treatment monitoring of the plant communities, including percent cover of each species present and ground cover classifications. Continued monitoring of the plant communities on an annual basis will help us determine whether the management techniques are leading to desired conditions of high native forb cover (especially of the obligate species on which the Oregon silverspot butterfly depends) and reduced invasive species cover. In turn, the plant community composition will also support the determination of the most appropriate habitats suitable for reintroduction of the Oregon silverspot butterfly. Stay tuned in future years to hear the results of this new experimental project!

CR Interns Andrew Heaston (left), Kelsey Copes-Gerbitz (center), and Crew Leader
Charlotte Trowbridge (right) monitor species cover in the rain at a Clatsop Plains site.

Van Dyke, F., Van Kley, S.E., Page, C.E., and Van Beek, J.G.  2004.  Restoration efforts for plant and bird communities in tallgrass prairies using prescribed burning and mowing.  Restoration Ecology: Vol.12, No. 4, pp. 575-485

Conservation Research in Areas of Critical Environmental Concern

The Conservation Research program at the Institute for Applied Ecology (IAE) frequently conducts research on public lands managed by the Bureau of Land Management. Our focus on rare plants often brings us to Areas of Critical Environmental Concern (ACEC). ACECs are federally designated conservation areas intended to protect the habitats of threatened and endangered species, riparian corridors, archaeological and cultural resources, and unique landscapes. The Conservation Research program at IAE is fortunate to be able to conduct research at a number of these beautiful sites including Upper and Lower Table Rocks near Medford, French Flat near Cave Junction, and Horse Rock Ridge in the Coburg Hills. 
 

Horse Rock Ridge (left). French Flat (right).

The protected status of these critical areas makes them ideal for conservation research. Protection from recreational and economic uses means that long-term monitoring and experimental plots may be established on these sites with relatively little danger of disturbance. These areas are often highly biologically diverse and harbor a variety of unique plant species and assemblages. For example Limnanthes floccosa ssp pumila (dwarf woolly meadowfoam), is endemic to Upper and Lower Table Rocks near Medford. IAE has monitored the effects of grazing and recreation on the population dynamics of Limnanthes on Table Rocks since 2006. Lomatium cookii population demography has been monitored at French Flat since 1990. Active prevention of off-road vehicle access at French Flat has helped to preserve populations of locally endemic Lomatium cookii. Horse Rock Ridge was designated an ACEC in 1984 and has been instrumental to IAE's grassland restoration research. These examples illustrate the importance of Areas of Critical Environmental Concern to conservation and scientific research.Our 2013 interns have enjoyed working in these gorgeous places and are looking forward to visiting more field sites.

 

Dwarf wooly meadowfoam (left) monitored at Medford's Table Rocks (right).

For more information on ACECs in Oregon, visit the BLM website.

Map of ACECs in Oregon (marked in teal). Red circles indicate ACECs visited this year.

False-brome at Maxfield Meadows

Maxfield meadows

Since 2007, IAE has been partnering with the Salem district BLM to restore meadow and oak savanna habitat at Maxfield meadows. The site, located northwest of Corvallis, consists of a variety of meadows and forested areas. Much of the area is a stand of mixed pines with the understory generally characterized by high presence of invasive and exotic forbs.

Among the invasive weeds is false-brome (Brachypodium sylvaticum), which IAE has been attempting to eradicate at the site since 2008. Brachypodium sylvaticum is a highly invasive, perennial European grass which appears to have first been introduced to North America in the Eugene area in the early 1900's. Because of its propensity to dominate habitats that it invades (specifically forest understory), B. sylvaticum has spread rapidly throughout the Pacific Northwest, establishing populations from southern Washington to the bay area of California. As a result, California and Washington have classified B. sylvaticum as a Class A noxious weed, while Oregon maintains its Class B rating.

Named "false-brome" for it's morphological resemblance to members of the Bromus genus, a few key traits can be used for distinguishing False-brome from a true brome. While many bromes are hairy, they lack hairs on the margins of their leaves. Brachypodium sylvaticum on the other hand has distinctly hair leaf margins.

Bromus tectorum leaf margin lacking hairs.
Photo: http://gobotany.newenglandwild.org

B. sylvaticum leaf with hairy margins. Photo: www.portlandoregon.gov

Another identifying trait is the presence or absence of a pedicil (secondary stem holding the flowering head of the grass). In true bromes, the pedicils are conspicuously present, while in false-brome the inflorescence is attached directly to the main stem.

Bromus rigidus inflorescence with pedicils. Photo: linnet.geog.ubc.ca

B. sylvaticum inflorescence attached directly to stem.
Photo: http://www.uni-graz.at

A patch of Brachypodium sylvaticum at Maxfield meadows.

Populations of B. sylvaticum exist throughout the Maxfield site, ranging from just a couple of individuals to patches of 500 square meters or more. Through application of herbicide and hand-pulling, many of the smaller populations at Maxfield meadows have been knocked back or eradicated, while the larger patches show slow progress. In June of 2012, the IAE field crew removed 15 large trash-bags of B. sylvaticum from one of the larger populations located along a stream bank. In April of 2013, we returned to the same stream bank, bracing ourselves for a long day of hand removal. To our surprise, the years of diligent hand-removal had paid off, and the population along the stream had been reduced to just a few, scattered individuals! Invasive species management can often feel like a slow and discouraging struggle, and it was rewarding to see so much progress.

Upcoming management of Maxfield, slated to begin later in 2013, includes a selective timber harvest, burning, and seeding. The goal is to effectively use these techniques to clear and reestablish an oak savannah habitat in what is currently a mixed-pine forest. Following a burn event, the burn area will be seeded with a locally collected mix of native forbs and grasses, with further assessment of exotic present and native success conducted in the subsequent spring. We look forward to sharing future successes at Maxfield.