Pollinator body size mediates the scale at which land use drives crop pollination services

Abstract

Summary1. Ecosystem services to agriculture, such as pollination, rely on natural areas adjacent to farmland to support organisms that provide services. Native insect pollinators depend on natural or semi-natural land surrounding farms for nesting and alternative foraging resources. Despite interest in conserving pollinators through habitat restoration, the scale at which land use affects pollinators and thus crop pollination services is not well understood. 2. We measured abundance of native, wild bee pollinators and the pollination services they provided to highbush blueberry Vaccinium corymbosum L. crops at 16 sites that varied in the proportion of surrounding agricultural land cover at both the field scale (300-m radius) and the landscape scale (1500-m radius). We designed our study such that agricultural land cover at the field scale was uncorrelated with agricultural cover at the landscape scale across sites. We used model selection to determine which spatial scale better predicted aggregate bee abundance, abundance of large versus small bees and crop pollination services. 3. We found that, overall, bees responded more strongly to field-scale than to landscape-scale land cover, but the scale at which land cover had the strongest effect varied by bee body size. Large bees showed a negative response to increasing agricultural cover at both scales, but were most strongly affected by the landscape scale. Small bees were negatively affected by agricultural land cover but only at the field scale, while they had a small positive response to agricultural cover at the landscape scale. 4. Aggregate pollination services from native bees were more strongly influenced by fieldscale agricultural cover, due to the combined effects of both large and small bees responding at that scale. 5. Synthesis and applications. Bee abundance and pollination services were strongly determined by field-scale agricultural cover, suggesting that field-scale set-asides may provide significant benefits to pollination services. Further, we found that pollinators respond differently to land use depending on body size, but all groups of bees benefit from decreasing agricultural cover at the field scale. Therefore, small-scale modifications to habitat can have significant impacts on both pollinator abundance and pollination services to crop plants.

Weeds for bees? A review

“…Furthermore, many different services are provided by many different organisms, even for pollination, and so, many different optimum spatial scales should be expected. These have been shown to vary with body size in wild bees (Benjamin et al 2014). The process of pollination takes place across the landscape scale.…”

“…This figure shows that even if each stakeholder interest seems to be independent from the other, they are indeed related through the plant-pollinator trophic network wild bee diversity, which in turn relies on semi-natural features within the landscape (Steffan-Dewenter and Westphal 2008). However, the spatial scale at which these features affect pollinator abundance and pollination function has not been fully established (Benjamin et al 2014).…”

Landscape and Local Controls of Insect Biodiversity in Conservation Grasslands: Implications for the Conservation of Ecosystem Service Providers in Agricultural Environments

“…Fewer rare bees were also found in these grasslands, with only 7 of the 30 rare species (i.e., those with fewer than 4 occurrences) collected. Given the large foraging ranges of honeybees and bumblebees [45] it may be surprising that lower numbers of these species are driving the association with intensive agriculture at this relatively small scale, but these findings are supported by a recent study that also found a negative response of large-bodied bees to agricultural land cover at a similar scale (300 m radius) [58].…”

Efeito da estrutura da paisagem sobre a diversidade de polinizadores e a efetividade da polinização do café

“…These radii were used in order to consider a wide range of bee flight distances (Araújo et al 2004, Benjamin, Reilly & Winfree 2014. Variables at the landscape and tree levels were uncorrelated with each other.…”

“…These include works in watermelon , sweet cherry , maize (Danner et al 2014), blueberry (Benjamin et al 2014), eggplant (Gemmill-Herren & Ochieng 2008 and coffee . However, in most cases, the analysis of landscape structure was limited to few landscape features, such as the distance to forest patches (Saunders et al 2004, Rickets et al 2004, Carvalheiro et al 2010 or the amount of native habitat (Brosi et al 2008, Le Feón et al 2010.…”