Warfare-induced mammal population declines in Southwestern Africa are mediated by species life history, habitat type and hunter preferences

Franciany Braga-Pereira,Carmen Van-Dúnem Santos,João Vitor Campos-Silva,Rômulo Romeu Nóbrega Alves,Carlos A Peres

doi:10.1038/s41598-020-71501-0

Abstract

Civil wars often coincide with global biodiversity hotspots and have plagued the everyday reality of many countries throughout human history. However, how do civil wars affect wildlife populations? Are these impacts the same in savannah and forest environments? How persistent are the post-war consequences on wildlife populations within and outside conflict zones? Long-term monitoring programs in war zones, which could answer these questions, are virtually nonexistent, not least due to the risks researchers are exposed to. In this context, only a few methodologies can provide data on wild populations during war conflicts. We used local ecological knowledge to assess the main consequences of a prolonged civil war (1975–2002) in Southwestern Africa on forest and savannah mammals. The post-war abundance in 20 of 26 (77%) mammal species considered in this study was lower in open savannah compared to the closed-canopy forest environments, with some species experiencing a decline of up to 80% of their pre-war baseline abundance. Large-bodied mammals were preferred targets and had been overhunted, but as their populations became increasingly depleted, the size structure of prey species gradually shifted towards smaller-bodied species. Finally, we present a general flow diagram of how civil wars in low-governance countries can have both positive and negative impacts on native wildlife populations at different scales of space and time.

Highlights

Civil wars often coincide with global biodiversity hotspots and have plagued the everyday reality of many countries throughout human history
Consistent with local perception, we found that the main impacts of the Angolan civil war on wildlife populations of the Quiçama region were indirect, arising from institutional and socio-economic changes, rather than from direct military tactics
Compared to the pre-war baseline, our results show an overall numerical population depletion of 77% across all mammal species during the war period, with some species experiencing a decline of up to 80% of their prewar baseline abundance

Summary

Introduction

Civil wars often coincide with global biodiversity hotspots and have plagued the everyday reality of many countries throughout human history. Long-term monitoring programs in war zones, which could answer these questions, are virtually nonexistent, not least due to the risks researchers are exposed to In this context, only a few methodologies can provide data on wild populations during war conflicts. The rehabilitation or recovery of mammal populations ideally requires an understanding of pre-disturbance baselines and broad assessments of the environmental effects of civil wars This information is imperative to facilitate mitigation plans in conflict-prone regions, so there is enormous value in characterizing multi-decadal wild population mass-mortality events. We conduct the first chronological-scale analysis (pre-, during, and post-war periods) of the effects of the prolonged Angolan civil war (1975–2002) on the abundance status of terrestrial non-volant mammal populations larger than 1 kg in two major West African protected areas in both forest and savannah environments (Fig. 1). We present a model of how civil wars in lowgovernance countries can have both positive and negative impacts on native wildlife, through socio-political changes, in detriment of national economies and their natural resource capital

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Results

Conclusion