Changes in pollinator functional composition and plant –pollinator interaction networks in response to mangrove patch size and surrounding land use

Abstract

Pollinators are declining worldwide as a result of land anthropization. However, several species have shown to be not affected or even benefited, since their responses depend on their functional traits that modulate their adaptability to particular environmental conditions. Pollinator responses may have important consequences on the structure of interaction networks, as the interacting species are sensitive to their counterparts. Despite the great importance that mangrove ecosystems have for human welfare, little is known about what is happening with pollinators' diversity and their interactions with mangrove species. This study investigates landscape effects on pollinator functional composition and their interactions with four dominant mangrove species in the Caribbean coast of Colombia. Pollinators of mangrove species Avicennia germinans, Conocarpus erectus, Laguncularia racemosa, and Rhizophora mangle were classified according to different functional traits and plant-pollinator interaction networks were created, with the aim to explore general patterns and to evaluate the effects of mangrove patch size and the surrounding land uses on pollinator functional composition and plant-pollinator interactions. Pollinator communities were mainly represented by wasps, flies, and bees, with the predominance of small and medium-sized predators, saprophagous, florivorous, no-social, and no-nesting species. Plant-pollinator interactions demonstrated a trend to niche differentiation in C. erectus and R. mangle, high number of interactions and pollinator species, as well as high values of interaction diversity and interaction evenness. Mangrove patch size decreased the richness of ground nesting wasps whereas increased network specialization, and urban size decreased the richness of predators, large-sized species, and ground-nesting wasps.