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Meadow contraction and extinction debt in meadow plants and moths in the Western Cascades
Citation:
Highland, S. AND J. Jones. Meadow contraction and extinction debt in meadow plants and moths in the Western Cascades. Presented at LTER.
Impact/Purpose:
EPA-NRC postdoctoral fellow, in conjunction with a professor of Geosciences at Oregon State University, have produced a poster for an invited presentation at an LTER (Long Term Ecological Research)-wide Science Council Meeting on May 16, 2012 at the HJ Andrews LTER site. The poster details analysis of the impacts of contracting meadows in the western Cascades on herbaceous plants and moths. Data used includes meadow GIS layers created from aerial photos from 2005 and 1949, plant diversity information gathered from 17 0.1 ha Stohlgren-Whitaker plots, and moth diversity information gathered from 98 moth trap samples. Specifically, the data were analyzed to assess the presence of extinction debt in the plants and three feeding guilds of moths. Use of these results can lead to better management of western Cascades forests for biodiversity and to counter potential local extinctions of rare plants and insects.
Description:
Meadows in the western Cascades have contracted and fragmented by approximately 50% in the past 60 years. These habitats occupy only about 5% of the landscape of the western Cascades but are important for the preservation of biodiversity and rare species. This habitat loss and fragmentation can lead to immediate species loss and to time-delayed extinctions, known as the extinction debt. Previous research into extinction debt has mostly been carried out in semi-natural and agricultural lands in Europe, or in habitats heavily impacted by human activities, with few studies in North America or concerning naturally changing habitats. In a study of naturally contracting and fragmenting meadows, we found differences in the extinction debt of plant and insect species depending upon their trophic level and feeding guild. Present day species richness and community structure of herbaceous plants was better explained by past than current meadow area. Similarly, present day species richness of herb-feeding moths was better explained by past meadow area. In contrast, present day species richness of gymnosperm- and angiosperm shrub-feeding moths was better explained by current meadow area. Our results indicate that extinction debts do occur in naturally changing habitats and that delayed reactions in species richness is dependent upon feeding guilds and whether or not landscape alterations are projected to be positive or negative for guild success. Additionally, our results indicate that maintaining the status quo in habitat configurations will not prevent further extinctions.