Quantifying the impacts of defaunation on natural forest regeneration in a global meta-analysis

Charlie J Gardner,Zoe G Davies,William Baldwin-Cantello,Jake E Bicknell,Matthew J Struebig

doi:10.1038/s41467-019-12539-1

Charlie J Gardner, Zoe G Davies + Show 3 more

Open Access

https://doi.org/10.1038/s41467-019-12539-1

Copy DOI

Abstract

Intact forests provide diverse and irreplaceable ecosystem services that are critical to human well-being, such as carbon storage to mitigate climate change. However, the ecosystem functions that underpin these services are highly dependent on the woody vegetation-animal interactions occurring within forests. While vertebrate defaunation is of growing policy concern, the effects of vertebrate loss on natural forest regeneration have yet to be quantified globally. Here we conduct a meta-analysis to assess the direction and magnitude of defaunation impacts on forests. We demonstrate that real-world defaunation caused by hunting and habitat fragmentation leads to reduced forest regeneration, although manipulation experiments provide contrasting findings. The extirpation of primates and birds cause the greatest declines in forest regeneration, emphasising their key role in maintaining carbon stores, and the need for national and international climate change and conservation strategies to protect forests from defaunation fronts as well as deforestation fronts.

Highlights

Intact forests provide diverse and irreplaceable ecosystem services that are critical to human well-being, such as carbon storage to mitigate climate change
Intact forests provide irreplaceable ecosystem services, including regulation of weather regimes and carbon storage, but their functioning depends on the maintenance of ecological communities[1]
We carried out four analyses, grouping the data according to the (i) category of defaunated taxonomic group, (ii) type of woody vegetation-animal interaction disrupted by defaunation, (iii) geographic region and (iv) seed dispersal syndrome of regenerating trees

Summary

Introduction

Intact forests provide diverse and irreplaceable ecosystem services that are critical to human well-being, such as carbon storage to mitigate climate change. 1234567890():,; Intact forests provide irreplaceable ecosystem services, including regulation of weather regimes and carbon storage, but their functioning depends on the maintenance of ecological communities[1] Human activities such as habitat conversion, degradation and hunting are causing vertebrate range contractions, population declines and extinctions at local and global scales, and altering faunal communities and their interactions with forest flora. 41% of monitored tropical forest vertebrate species populations (n = 369) declined between 1970 and 20122, and unsustainable hunting is thought to occur in a greater proportion of remaining forests than all other degradation drivers[1] This vertebrate defaunation[3,4] affects larger-bodied species because they are readily targeted for food and are both ecologically and demographically vulnerable[5,6]. We carried out four analyses, grouping the data according to the (i) category of defaunated taxonomic group, (ii) type of woody vegetation-animal interaction disrupted by defaunation, (iii) geographic region and (iv) seed dispersal syndrome of regenerating trees

Methods

Results

Conclusion