Niche complementarity among pollinators increases community-level plant reproductive success

Francisco P Molina,Ainhoa Magrach,Ignasi Bartomeus

doi:10.24072/pcjournal.1

Abstract

Declines in pollinator diversity and abundance have been reported across different regions, with implications for the reproductive success of plant species. However, research has focused primarily on pairwise plant-pollinator interactions, largely overlooking community-level dynamics. Here, we present one of the first efforts linking pollinator visitation to plant reproduction from a community-wide perspective using a well-replicated dataset encompassing 16 well-resolved plant-pollinator networks and data on reproductive success for 19 plant species from Mediterranean shrub ecosystems. We find that models including simple visitation metrics are sufficient to explain the variability in reproductive success observed. However, insights into the mechanisms through which differences in pollinator diversity translate into changes in reproductive success require additional information on network structure. Specifically, we find a positive effect of increasing niche complementarity between pollinators on plant reproductive success. This shows that maintaining communities with a diversity of species but also of functions is paramount to preserving natural ecosystems.

Highlights

Pollinators provide key services to plants by facilitating pollen flow (Garibaldi et al 2013)
Our study focuses on understanding whether adding information on selected interaction network structure indices to previously used simple visitation metrics aids in better explaining the differences observed in community-wide reproductive success
We focused on nestedness, a measure of the redundancy in the plants visited by different pollinators, and pollinator niche complementarity, a measure of the complementarity in plant species visited by different pollinator species

Summary

Introduction

Pollinators provide key services to plants by facilitating pollen flow (Garibaldi et al 2013). Declining trends for some pollinator species in some regions (Potts et al 2010; Bartomeus et al 2018) have led researchers to focus on the functional impacts of these changes in pollinator diversity, especially for plant reproductive success (Biesmeijer et al 2006). Many studies have evaluated reproductive success on individual plant species (Albrecht et al 2012; Thomson 2018), and used relatively simple visitation metrics (e.g., the number of pollinator species visiting a plant or the number of visits they perform) to explain the differences observed (e.g., Bommarco et al 2012). Understanding how changes in pollinator diversity and community structure affect ecosystem functioning is a major challenge that requires attention

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Conclusion