Functional redundancy of Amazonian dung beetles confers community‐level resistance to primary forest disturbance

Cássio Alencar Nunes,Filipe França,Emma J Sayer,Fernando Z Vaz‐De‐Mello,Victor H F Oliveira,Laís F Maia,Jos Barlow,Rafael P Leitão,Julio Louzada,Ricardo R C Solar,Rodrigo Fagundes Braga,Erika Berenguer

doi:10.1111/btp.12998

Abstract

AbstractTropical forest biodiversity is being threatened by human activities, and species losses during forest disturbance can compromise important ecosystem functions and services. We assessed how species losses due to tropical forest disturbance affect community functional structure, using Amazonian dung beetles as a model group. We collected empirical data from 106 forest transects and used simulated extinction scenarios to determine how species loss influences community structure at regional and local scales. Although functional and taxonomic community metrics were largely unaffected by primary forest disturbance, they differed markedly between primary and secondary forests. However, our extinction scenarios demonstrated scale‐dependence of species losses, whereby functional structure only eroded with species extinction at the local scale. Hence, we extend the spatial insurance hypothesis by demonstrating that landscape‐scale functional redundancy offsets the impact of local species losses and confers community‐level resistance to primary forest disturbance.Abstract in portuguese is available with online material.

Highlights

Human activities cause changes in most terrestrial (Newbold et al, 2015) and aquatic ecosystems (Castello et al, 2013; Halpern et al, 2008), leading to a loss of biodiversity and ecosystem functions (Mitchell et al, 2015; Newbold et al, 2020)
Dung beetle functional richness was unaffected by primary forest disturbance, and largely mirrored the pattern of taxonomic richness, with similar values in the four primary forest classes, but lower values in secondary forests (χ2 = 11.06, p = 0.025, n = 101; Figure 3a), the Functional Richness (FRic) of burned and logged-and-burned primary forests were similar to those in secondary forests
None of the three indices was influenced by time since last disturbance in primary forests, and only FRic increased with regeneration time in secondary forests (Appendix S2: Figure S2 and Table SA1 and SA2)

Summary

| INTRODUCTION

Human activities cause changes in most terrestrial (Newbold et al, 2015) and aquatic ecosystems (Castello et al, 2013; Halpern et al, 2008), leading to a loss of biodiversity and ecosystem functions (Mitchell et al, 2015; Newbold et al, 2020). The “spatial insurance hypothesis” proposes that the spatial variability of local community composition insures the ecosystem functioning at larger scales, by allowing compensations between species (Loreau et al, 2003; Wang & Loreau, 2014) In this context, it is crucial to establish whether species that are more sensitive to human activities contribute more or less to the functional structure of communities. Dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae) are one such focal taxon: they play critical roles in detritivorous pathways (França et al, 2018), are abundant and diverse, and their sampling is highly cost- effective (Gardner et al, 2008; Halffter & Favila, 1993) Due to their feeding and nesting habits, they perform key ecological functions such as dung removal, soil fertilization and aeration, and secondary seed dispersal (Nichols et al, 2008). We tested our second hypothesis by simulating species loss at local and regional scales to assess the effects of distinct extinction scenarios on community functional structure

| METHODS

| RESULTS

| DISCUSSION