Rare Vascular Plants from Ecology and Conservation of the South Puget Sound Prairie Landscape

The Washington Natural Heritage Program (WNHP) currently tracks eighteen vascular
plant taxa that occur, or have historically occurred, within the South Puget Sound Prairie
Landscape (SPSPL). Six of these occur within grassland habitats and are the subject of
this paper. The species, and their WNHP status, are: Agoseris elata (Sensitive), Aster
curtus (Sensitive), Castilleja levisecta (Endangered), Githopsis specularioides
(Sensitive), Meconella oregana (Threatened), and Sidalcea malviflora var. virgata
(Possibly Extirpated from Washington).

The grassland species in the SPSPL have been under threat since Europeans began
settling the region. Conversion to agriculture, housing and business development, gravel
extraction, grazing, recreational pressure, invasion of non-native species, fire suppression
leading to undesirable plant succession have cumulatively accounted for a phenomenal
loss of habitat for plants native to this ecoregion. What little habitat remains is
increasingly isolated, fragmented, and further degraded.

The state Department of Natural Resources manages three Natural Area Preserves within
the SPSPL that have grassland ecosystems and rare plants: Bald Hill (Githopsis
specularioides), Mima Mounds (Aster curtus), and Rocky Prairie (Aster curtus and
Castilleja levisecta). Fort Lewis, McChord Air Force Base, the Department of Fish and
Wildlife, and Thurston County also manage areas with significant populations of Aster
curtus. However, in order for the combined conservation efforts of agencies and
organizations to be successful, more work is needed. In particular, we need to learn more
about how these ecosystems function, and how the rare species respond to management
activities and disturbances under both natural and disturbed conditions.

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