Anthropic effects on pollinators in the southernmost limits of subtropical dry forests

AGUILAR R.; CARBONE L.; RAMELLO, P.; ASHWORTH, L.

Congreso; 54th Annual Meeting of the Association for Tropical Biology and Conservation; 2017

Human activities are dominant drivers of currentbiodiversity changes throughout the world. Land use practices such asdeforestation, grazing, and agriculture affect ecosystem structure andfunctioning and regional climate. The southernmost limits of subtropical dryforests have experienced the highest rates of deforestation worldwide over thepast decades, and such landscape changes can alter plant-pollinatorinteractions in different ways. Animal pollinators are responsible for thesexual reproduction of 80% of angiosperms and also play a key rolein fruit/seed production of domesticated species and in the reproduction ofmany useful wild species. Due to the essential ecosystem services provided byanimal pollinators it is particularly important to learn about their dynamicsin such changing environments. Here we assess pollinator richness and abundancein different anthropic scenarios: i) a gradient of habitat fragmentationlandscapes, ii) unburned, high and low fire frequency sites, and iii) agradient of agricultural intensification. Habitat fragmentation strongly reduced richness and abundance of Lepidopteraand Diptera and small solitary bees. More mobile pollinators such ashummingbirds, Bombus spp. however, showed no changes. Apis mellifera, showed anincreased in relative abundance in smaller habitat fragments. Fire frequencyalso elicited species-specific responses of pollinators. Bombus spp. wereequally abundant across sites whereas other pollinators such as Megachile sp.,Notanthidium sp., Trimeria sp. were either reduced in abundance or absent. Wediscuss the implications of these findings for the reproduction of nativeplants species in ubiquitous human-altered landscapes.