Keystone resources available to wild pollinators in a winter-flowering tree crop plantation

摘要

Homogeneous tree crop plantations can adversely impact wild pollinator communities by limiting the temporal continuity of food and the availability of nesting sites. Identifying how structural differences between plantations and natural vegetation influence pollinator communities is necessary for ecological management of agroecosystems. Communities of potential wild pollinators (native bees, wasps, flies) were compared between monoculture almond plantations and native vegetation in a semi-arid region of southern Australia, before, during and after the late winter almond flowering period. Abundance and richness of each insect group were related to site heterogeneity and keystone structural resources at each site, focusing on food and nesting resources. Relationships with site heterogeneity varied between taxa and across months. Native bee abundance and richness were strongly associated with specific keystone resources, despite showing no association with site heterogeneity. The present study highlights the value of focusing on biologically meaningful resources when investigating relationships between insects and habitat, rather than on generalized heterogeneity metrics. The results suggest that maintaining keystone resources in agroecosystems can support the conservation of insects and ecosystem services, especially in areas where homogeneous agricultural systems overlap dynamic natural ecosystems.