PARENT SESSION
Oral Session #26: Conservation Ecology: Terrestrial.
Presiding: P. Kleintjes
Tuesday, August 6. 8:00 AM to 11:30 AM. Greenlee Meeting Room, TCC.
Effects of habitat fragmentation on plant-pollinator interactions.
Finer, Matt*,1, Morgan, Martin1, 1 Washington State University, Pullman, WA
ABSTRACT- Perpetuating biodiversity requires the conservation of key ecological processes, in addition to the preservation of core habitat. In terrestrial ecosystems, pollination is a key ecological process. However, widespread habitat fragmentation is threatening native plant-pollinator interactions worldwide. Here, we investigate the effects of extreme habitat fragmentation on plant-pollinator interactions in one of the most endangered ecosystems in America, the Palouse prairie. Using Geranium viscossissimum as a focal organism, we examined how pollinator visitation and diversity and plant female fitness changed with remnant size (small (1 acre) vs. medium (5-10 acres) vs. large (30-40 acres)). We found that both pollinator visitation rate and pollinator diversity declined significantly with decreasing remnant size. We found no significant differences in fruit set, but highly significant differences in seed set between remnant size treatments. We also found that geitonogamous visits (pollinators visiting multiple flowers per plant) were inversely related to remnant size, suggesting smaller remnants might have greater inbreeding. Parallel results were found in a companion study of large vs. small populations of Asclepias speciosa in a scabland ecosystem. These results have several important conservation implications. First, seed set and pollinator visitation and diversity drop sharply in the small remnants, suggesting there may be an important threshold remnant size. Second, even in areas (including protected areas) where the vegetation appears intact (i.e., normal flowering and fruit set), long-term plant reproductive success may be threatened. Finally, restoration and conservation efforts must be ecosystem-level, focusing on key ecological interactions.
KEY WORDS: habitat fragmentation, plant-pollinator interactions, Palouse prairie, population size