Potential landscape-scale pollinator networks across Great Britain: structure, stability and influence of agricultural land cover.

John W Redhead,Michael J.O Pocock,Richard F Pywell,Adam J Vanbergen,Tom H Oliver,Ben A Woodcock,José Marìa Gomez

doi:10.1111/ele.13157

Abstract

Understanding spatial variation in the structure and stability of plant-pollinator networks, and their relationship with anthropogenic drivers, is key for maintaining pollination services and mitigating declines. Constructing sufficient networks to examine patterns over large spatial scales remains challenging. Using biological records (citizen science), we constructed potential plant-pollinator networks at 10km resolution across Great Britain, comprising all potential interactions inferred from recorded floral visitation and species co-occurrence. We calculated network metrics (species richness, connectance, pollinator and plant generality) and adapted existing methods to assess robustness to sequences of simulated plant extinctions across multiple networks. We found positive relationships between agricultural land cover and both pollinator generality and robustness to extinctions under several extinction scenarios. Increased robustness was attributable to changes in plant community composition (fewer extinction-prone species) and network structure (increased pollinator generality). Thus, traits enabling persistence in highly agricultural landscapes can confer robustness to potential future perturbations on plant-pollinator networks.

Highlights

Insect pollinators face many threats that may jeopardise the crucial ecosystem service they provide to crops and wild plants (Vanbergen et al 2013; Gill et al 2016; Potts et al 2016)
Variation in plant and pollinator species richness conformed to known clines across Great Britain (GB)
Our results revealed that national-scale spatial patterns were clearly evident in all network metrics

Summary

Introduction

Insect pollinators face many threats that may jeopardise the crucial ecosystem service they provide to crops and wild plants (Vanbergen et al 2013; Gill et al 2016; Potts et al 2016). The stability of pollinator communities and the service they deliver is mediated by the structure of ecological networks formed by interactions between pollinator and plant species (Vazquez et al 2009; Vanbergen et al 2017). Understanding such networks is important to predict the risks associated with threats to pollinators (Gill et al 2016). Memmott et al 2004; Kaiser-Bunbury et al 2010), climate change Broad geographical patterns in plant–pollinator network properties have been identified across biomes (Olesen & Jordano 2002; Welti & Joern 2015) or within landscapes (Burkle & Alarcon 2011; Carstensen et al 2014; Trøjelsgaard et al 2015; KaiserBunbury et al 2017), these still rely on a comparatively limited number of empirical plant–pollinator networks

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