Factors influencing pollinator abundance in indigenous coffee farms of the Nilgiris, Western Ghats, India

Land-use change is a major driver of biodiversity loss, including loss of wild pollinators. We examined pollinators in coffee plantations in Indigenous land holdings in the Nilgiri Biosphere Reserve, Western Ghats (India), where changing agricultural practices and reducing tree shade diversity and cover type may threaten pollinator communities. We assessed pollinator abundance in 10 coffee farms—five of which had the exotic silver oak (<i>Grevillea robusta</i>) as shade trees and five of which had native tree species. We evaluated the effect of (a) tree cover type, (b) distance from the forest edge, and (c) area under coffee cultivation on the cumulative and individual species abundances of five important coffee pollinators: <i>Apis dorsata, A. cerana, A. florea</i>, <i>Tetragonula iridipennis,</i> and <i>Xylocopa</i> sp. We found that the cumulative abundance of all five species and the individual species abundances of three of the species (<i>A. cerana, A. florea,</i> and <i>Tetragonula iridipennis)</i> were positively associated with the area under coffee cultivation. The abundance of <i>A. cerana</i> was also associated with the proximity to the forest edge, with more individuals found in farms closer to the forest. Moreover, the abundances of <i>A. cerana, A. florea</i>, and <i>T. iridipennis</i> were higher, on average, in farms with native tree species, but the relationship was not statistically significant. Overall, our results suggest that maintaining forests near coffee systems could increase insect pollinator abundance (i.e., delivery of pollination services) and maintaining forest cover with native tree species composition could potentially play a role in supporting pollinator habitats as well as providing foraging resources.