Location: Sunflower and Plant Biology ResearchTitle: Diverse landscapes have a higher abundance and species richness of spring wild bees by providing complementary floral resources over bees’ foraging periods
|GIBBS, JASON - Michigan State University|
|GRATTON, CLAUDIO - University Of Wisconsin|
Submitted to: Landscape Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/22/2015
Publication Date: 8/16/2016
Citation: Mallinger, R.E., Gibbs, J., Gratton, C. 2016. Diverse landscapes have a higher abundance and species richness of spring wild bees by providing complementary floral resources over bees’ foraging periods. Landscape Ecology. 31(7):1523-1535. doi:10.1007/s10980-015-0332-z.
Interpretive Summary: Though landscape simplification and natural habitat loss often negatively affect wild bees, some land-use changes can diversify landscapes to support pollinator communities. We examined the effects of landscape diversity and amount of semi-natural habitat on wild bee abundance and species richness in 35 Wisconsin apple orchards. We also explored whether different habitats provide complementary floral resources for bees. When orchards were surrounded by more diverse landscapes and a greater amount of woodland habitat, wild bee abundance increased. Greater landscape diversity also increased the number of bee species within the orchard. It appears that different habitat types within diverse landscapes supported wild bees both by providing different types of flowers, and also by providing flowers at different times throughout the spring. Our results suggest that diverse landscapes, particularly ones that include both woodlands and grasslands, support wild bees by providing continuous flowers over bee foraging periods and diverse resources to meet different species’ requirements.
Technical Abstract: Landscape simplification and natural habitat loss can negatively affect wild bees. Alternatively, anthropogenic land-use change can potentially diversify landscapes to create complementary habitats that increase overall resource continuity and diversity. We examined the effects of landscape compositional diversity and amount of semi-natural woodland habitat on wild bee abundance and species richness within a pollinator-dependent crop, apples. We also explored whether different habitats within diverse landscapes provide complementary floral resources for bees across space and time. We sampled bees during apple bloom over two years within 35 orchards varying in surrounding landscape diversity and percent woodland at 1 km radii. To assess habitat complementarity, we measured abundance, richness, and community composition of flowers and bees within four common habitats, orchards, annual croplands, woodlands, and grasslands, over three periods from April – June. Wild bee abundance within orchards increased with both landscape diversity and percent woodland, while bee species richness increased only with landscape diversity. Habitats within diverse landscapes had different flower communities with varying phenologies; flowers were most abundant within orchards and woodlands in mid-spring, and then declined over time, while flowers within grasslands marginally increased throughout spring. Different habitat types also had different wild bee communities, and bee abundance within habitats changed over time, possibly due to changing resource availability. Our results suggest that diverse landscape mosaics, particularly ones with both woodland and grassland semi-natural habitat, support wild bees by providing continuous flowers over their foraging periods and diverse niches to meet different species’ requirements.