Abstract

World‐wide declines in pollinators, including bumblebees, are attributed to a multitude of stressors such as habitat loss, resource availability, emerging viruses and parasites, exposure to pesticides, and climate change, operating at various spatial and temporal scales. Disentangling individual and interacting effects of these stressors, and understanding their impact at the individual, colony and population level are a challenge for systems ecology. Empirical testing of all combinations and contexts is not feasible. A mechanistic multilevel systems model (individual‐colony‐population‐community) is required to explore resilience mechanisms of populations and communities under stress.We present a model which can simulate the growth, behaviour and survival of six UK bumblebee species living in any mapped landscape. Bumble‐BEEHAVE simulates, in an agent‐based approach, the colony development of bumblebees in a realistic landscape to study how multiple stressors affect bee numbers and population dynamics. We provide extensive documentation, including sensitivity analysis and validation, based on data from literature. The model is freely available, has flexible settings and includes a user manual to ensure it can be used by researchers, farmers, policy‐makers, NGOs or other interested parties.Model outcomes compare well with empirical data for individual foraging behaviour, colony growth and reproduction, and estimated nest densities.Simulating the impact of reproductive depression caused by pesticide exposure shows that the complex feedback mechanisms captured in this model predict higher colony resilience to stress than suggested by a previous, simpler model. Synthesis and applications. The Bumble‐BEEHAVE model represents a significant step towards predicting bumblebee population dynamics in a spatially explicit way. It enables researchers to understand the individual and interacting effects of the multiple stressors affecting bumblebee survival and the feedback mechanisms that may buffer a colony against environmental stress, or indeed lead to spiralling colony collapse. The model can be used to aid the design of field experiments, for risk assessments, to inform conservation and farming decisions and for assigning bespoke management recommendations at a landscape scale.

Highlights

  • World-­wide declines in pollinators, including bumblebees, are attributed to the chronic exposure of populations to a multitude of stressors such as habitat loss and resource availability, emerging viruses and parasites, exposure to pesticides, and climate change operating at various spatial and temporal scales (Baude et al, 2016; Goulson, 2015; IPBES, 2016; Kerr et al, 2015; Williams & Osborne, 2009)

  • The Bumble-­BEEHAVE model represents a significant step towards predicting bumblebee population dynamics in a spatially explicit way

  • We present sensitivity analyses and compare simulations with empirical data to illustrate the potential of Bumble-­BEEHAVE in predicting (a) individual foraging behaviour, (b) colony growth and reproduction and (c) population nest density, in realistic landscape settings

Read more

Summary

| INTRODUCTION

World-­wide declines in pollinators, including bumblebees, are attributed to the chronic exposure of populations to a multitude of stressors such as habitat loss and resource availability, emerging viruses and parasites, exposure to pesticides, and climate change operating at various spatial and temporal scales (Baude et al, 2016; Goulson, 2015; IPBES, 2016; Kerr et al, 2015; Williams & Osborne, 2009). We propose that a mechanistic multilevel systems model (individual-­colony-­population-­community) is required to explore the resilience mechanisms of bumblebee populations and communities under stress, and inform management decisions We present such a model, Bumble-­BEEHAVE, and explain how it is radically different to other published bumblebee models. While useful in exploring the impact of individual stressors, such as food availability (Crone & Williams, 2016) or pesticides (Bryden et al, 2013; Cresswell, 2017), none as yet have the structural realism to incorporate multiple stressors or competition, operating at different organisational levels (individual or colony or population) They have limited flexibility to incorporate feedback mechanisms that may buffer the colony against environmental stress, or lead to spiralling collapse. We present sensitivity analyses and compare simulations with empirical data to illustrate the potential of Bumble-­BEEHAVE in predicting (a) individual foraging behaviour, (b) colony growth and reproduction and (c) population nest density, in realistic landscape settings

| MATERIALS AND METHODS
Findings
| DISCUSSION
| CONCLUSIONS
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call