Conservation and monitoring of wildlife in logged tropical forests: A study in Western Equatorial Africa

Abstract

Tropical forests harbor the largest share of all terrestrial biodiversity, including 62% of all terrestrial vertebrate species. Of the remaining tropical forests, more than one-quarter are designated as logging concessions, potentially putting wildlife at risk. Forest certification systems like the Forest Stewardship Council (FSC) claim that they address threats to biodiversity, but studies have to date not resulted in robust verification of impacts of certified logging on wildlife communities due to limitations in research design and scale. Measuring impact is important for informed decision-making and data-driven policies. For this, reliable population monitoring is a prerequisite. In this thesis the general aims are to assess whether wildlife is more effectively conserved in FSC-certified logging concessions than in non-FSC concessions, and to explore how wildlife populations can best be monitored in tropical forests. I start this thesis by reviewing the applications of the three main monitoring methods to provide guidance on wildlife monitoring in tropical forests. Then, I examine the knowledge gap concerning the impacts of FSC-certified forestry, by assessing whether wildlife is more effectively conserved in FSC-certified logging concessions than in non-FSC concessions. The data were gathered by using camera traps in fourteen forestry concessions in Western Equatorial Africa. I found that FSC-certified forestry benefits mammals when compared to non-FSC forestry, with the most pronounced positive impacts for mammals weighing 10 kg and more. Next, I develop and test two wildlife monitoring methods: the use of sound for primate monitoring, and the use of soundscapes as a proxy for the overall biodiversity in a forest. Species-specific monitoring using sound covers a different species range than camera traps. However, sound monitoring requires automated classification for it to be useful. For soundscapes, interpretation of changes in the soundscape and quantification of individual species’ contributions are the main challenges, as well as interpreting the relationship between the structure of the soundscape and local landscape heterogeneity. Further development and enhancement of wildlife monitoring methods is essential for impact verification and improvement of forest certification. Improved wildlife monitoring methods may also aid the development of biodiversity credit systems, potentially yielding new revenue streams for conservation.