Abstract
Context
Agricultural intensification leads to habitat loss and fragmentation, disrupting plant-pollinator interactions directly, through changes in landscape configuration, and indirectly through altered land-use practices. This has detrimental consequences for the persistence of plants, pollinators, and the ecosystem services they provide.
Objectives
We investigated the mechanisms by which environmental and agricultural context impact pollination dynamics and the reproductive success of native plant species in remnant vegetation within an agricultural mosaic. Specifically, we evaluate the direct and indirect effects of landscape fragmentation (patch size and edge effect) and agricultural practices (crop type adjacent to natural remnants) on bee communities and native plants seed production.
Methods
We sampled the pollinator community and conducted pollination experiments on four native annual plant species in the core and edge of nine natural remnants. For each site, we recorded remnant size, adjacent crop type (canola or wheat), and local environmental and biological conditions. We then assessed the relationships between these landscape features, bee communities, pollination services, and the reproductive success of native annual forb species.
Results
Bee abundance was higher in reserves adjacent to canola compared to wheat. However, bee abundance decreased from the core to the edge of remnants adjacent to canola, suggesting a possible pollinator dilution effect. Canola directly and indirectly increased seed production of the focal plant species, mediated by changes in pollinator abundance.
Conclusions
Adjacent crop type, edge effects, and patch size shape plant-pollinator interactions through changes in pollinator abundance, whereas local-scale floral abundance influence pollination dynamics. Our findings indicate that agricultural practices impact the reproductive success of native plants persisting in remnants within an intensively managed agricultural landscape. Further, we show that this effect is mediated by the abundance of generalist insect pollinators in remnant vegetation.