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Olympia, WA, United States

Fazzino L.,University of Puget Sound | Elizabeth Kirkpatrick H.,University of Puget Sound | Fimbel C.,Nature Conservancy of Washington
Northwest Science | Year: 2011

South Puget Sound prairies are fragmented and degraded, which has a profound effect on plant populations, especially those that are already species of concern, such as Puget balsamroot (Balsamorhiza deltoidea Nutt). Small Puget balsamroot populations may be caused by inadequate pollination via insufficient pollinator services or by low quality pollen. Comparing potential germinants of hand- and naturally-pollinated inflorescences, which takes into account seed set and germination rates, illustrates the extent of pollination limitation on three South Puget Sound prairies on Joint Base Lewis-McChord (7S, Upper Weir, and Johnson). Our results demonstrated that Puget balsamroot is self-incompatible. On all three prairies, hand-pollinated inflorescences produced more potential germinants than naturally-pollinated inflorescences (P < 0.001), indicating that Puget balsamroot is pollen limited. In addition, 7S had a significantly greater number of floral and soil resources than either Johnson or Upper Weir (P < 0.05). However, there were not proportionally more bees found on 7S as compared to Johnson or Upper Weir. Therefore, Puget balsamroot on 7S may be pollen limited because pollinator populations are too small. Determining pollinator population sizes on the south Puget Sound lowland prairies could prove to be useful in determining the relative effects of pollinator limitation and low pollen quality. We suggest that fragmented ecosystems are more susceptible to pollinator limitations than congruent systems because ranges of pollinators no longer adequately overlap to facilitate travel between the ecosystem fragments. © 2011 by the Northwest Scientific Association. Source


Schultz C.B.,Washington State University | Henry E.,Washington State University | Carleton A.,Washington State University | Hicks T.,Washington State University | And 16 more authors.
Northwest Science | Year: 2011

Prairie-oak butterfly species in the Willamette Valley-Puget Trough-Georgia Basin (WPG) ecosystem have declined dramatically due to widespread habitat degradation and loss of prairie-oak ecosystems in the region. Conservation of prairie-oak butterflies offers unique opportunities and special challenges. Here we provide an overview of butterfly conservation in WPG prairies. We begin with a review of the status of at-risk butterfly species in the region, an introduction to five species that are the focus of current conservation efforts: Fender's blue (Icaricia icarioides fenderi), Taylor's checkerspot (Euphydryas editha taylori), mardon skipper (Polites mardon), island marble (Euchloe ausonides insulanus), and Oregon silverspot (Speyeria zerene hippolyta), and a brief review of 10 additional at-risk butterfly species in the ecoregion. We follow with a discussion of three key threats (habitat loss and fragmentation, invasive species, and lack of appropriate disturbance) and four dominant management approaches (fire, herbicides, mowing, and habitat restoration). We discuss current challenges and emerging issues for these species, and focus on invasive species management, understanding basic biology, conserving multiple species, and adapting to climate change. We highlight several success stories from around the region. We conclude that butterfly biologists and land managers in the WPG are in a unique position to conserve the region's threatened prairie butterflies. Facilitating greater communication across the region through organizations such the Cascadia Prairie-Oak Partnership will assist in recovery of the WPG's threatened, endangered and at-risk butterfly species. © 2011 by the Northwest Scientific Association. Source


Dennehy C.,Nature Conservancy of Washington | Alverson E.R.,Nature Conservancy of Oregon | Anderson H.E.,Nature Conservancy of Washington | Clements D.R.,Trinity Western University | And 2 more authors.
Northwest Science | Year: 2011

Invasion by non-native plant species is one of the greatest threats to prairie, savanna, and oak woodland habitats of the Willamette Valley-Puget Trough-Georgia Basin (WPG) ecoregion. Invasive plants can modify the diversity, structure, and function of natural habitats. Effects from non-native invasions have contributed to the decline of many native species found on Pacific Northwest prairie and oak habitats. Even with aggressive management, these unique habitats are severely impacted by nonnative plant invasions. Without management, native species diversity will continue to decline rapidly. Here we provide a list of invasive plants that have extensive detrimental impacts on prairies, savannas, and oak woodlands throughout the ecoregion as a resource for land managers. We provide technical descriptions for the most highly invasive shrubs, grasses, and forbs, current best management practices, and an outlook for the future. When available, we document results from experimental trials. Much of the information presented is based on field observations from experienced land managers. Invasive plants will continue to be a management priority in the WPG for the foreseeable future. Working cooperatively from an ecoregional perspective to track occurrence, develop and implement effective management, and monitor progress is the best platform for successful restoration of the prairies, savannas, and oak woodlands in the WPG ecoregion. © 2011 by the Northwest Scientific Association. All rights reserved. Source


Holman M.L.,Nature Conservancy of Washington | Carey R.G.,Nature Conservancy of Washington | Dunwiddie P.W.,University of Washington
Natural Areas Journal | Year: 2010

Numerous studies describe the biology of invasive plants and control techniques for addressing site-specific infestations. However, few describe the practical steps and components needed to control invasives at larger, more ecologically-meaningful scales. The Skagit Knotweed Working Group was formed in 2000 to control Japanese knotweed (Polygonum cuspidatum Sieb. & Zucc.) and related congeners (knotweed) throughout the upper Skagit River system. Based on our experience, we present several elements that we consider necessary for a successful landscape-scale weed control program: (1) delineation of a clearly defined project area; (2) setting realistic and attainable program goals; (3) the ability to quantify and report measures of control success; (4) engaged partnerships of major public and private landowners; (5) coordination of partner effort to encompass the entire project area; (6) participation of small private landowners; (7) biologically-based, adaptive, and prioritized control strategy; and (8) conducting continuous and rigorous status surveys. We suggest these elements as a framework to overcome challenges to controlling weeds at the landscape scale, using the knotweed control project in the upper Skagit as a case study. Source


Hamman S.T.,Nature Conservancy of Washington | Dunwiddie P.W.,University of Washington | Nuckols J.L.,Nature Conservancy of Oregon | McKinley M.,Nature Conservancy of Washington
Northwest Science | Year: 2011

In Pacific Northwest prairies and oak woodlands, cessation of anthropogenic burning in the mid-1800s resulted in large-scale degradation and loss of habitat due to tree and shrub encroachment. Widespread invasive species, deep thatch accumulations, and extensive moss cover now limit the ability of native plants to germinate and thrive. These changes in habitat structure and function have contributed to the decline of several plant and animal species. Over the past decade, prescribed fire has been increasingly applied throughout the Willamette Valley-Puget Trough-Georgia Basin Ecoregion and used in conjunction with other techniques (herbicide, seeding native species) to restore native habitat with variable results. This variability likely is a result of differential fire intensity, dictated by fuels, weather and application technique, all of which can be controlled for by altering fire season, fire frequency, pre-fire treatments and fire extent. In order to burn at the spatial and temporal scales necessary for effective habitat restoration, however, prescribed burn programs must overcome several socio-political, programmatic and economic challenges. This requires a collaborative approach to prescribed fire training, implementation and research. Future research on fire season, fire frequency, species-specific responses to fire and effects of fire surrogates on ecosystem structure and functioning will help to refine prescribed fire management for maximum effectiveness in prairie and oak woodland restoration. © 2011 by the Northwest Scientific Association. All rights reserved. Source

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