Plant/Pollinator Interactions in Fragmented Landscapes
Elle, Elizabeth , Neame, Lisa A. , Gielens, Grahame A. .
Pollinator diversity and wildflower pollen limitation in a fragmented oak-savannah ecosystem.
Habitat loss and the fragmentation of remaining habitat are important drivers of population declines and extinction. Loss of pollinating insect biodiversity has the potential to disrupt the plant-pollinator mutualism and negatively affect plant reproduction. We studied the response of plant and pollinator diversity to habitat fragmentation and measured wildflower pollen limitation in an oak-savannah ecosystem in southwestern British Columbia, Canada. In 19 fragments ranging from 32 to 0.3 ha, there was no overall reduction in pollinator or wildflower diversity in smaller fragments, but fragmentation affected the composition of the pollinator community. Ground nesting species were less abundant and diverse in small fragments, syrphids were more abundant, but other guilds (cavity nesters and cleptoparasites) had no response to reduced fragment size. There was a trend for greater pollen limitation of one species (Camassia quamash) in smaller fragments with lower plant diversity, and for greater pollen limitation in fragments with the highest conspecific stem density. In a follow-up study of pollen limitation in 6 wildflower species in 6 fragments, four out of 16 wildflower/site combinations exhibited significant pollen limitation, and four others had a trend towards pollen limitation. Rather than being linked to overall site characteristics such as fragment size or overall pollinator diversity, pollen limitation may respond to smaller-scale effects: identity of visitors in an interaction web and local (rather than fragment-scale) density of flowering stems. These results suggest that the response of plant-pollinator mutualisms to habitat fragmentation is complex, and will depend on the identities and behavior of the interactors.
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1 - Simon Fraser University, Department of Biological Sciences, 8888 University Drive, Burnaby, British Columbia, V5A 1S6, Canada
2 - Simon Fraser University, Department of Biological Sciences, 8888 University Drive, Burnaby , BC, V5A 1S6, Canada
Presentation Type: Symposium or Colloquium Presentation
Location: 552B/Convention Center
Date: Wednesday, August 4th, 2010
Time: 2:45 PM