Impact of Forest Fragmentation and Associated Edge Effects on Tropical Forest Biodiversity in North West Madagascar, Assessed via Ecoacoustics

ABSTRACT Tropical forests harbour up to 50% of the world's terrestrial biodiversity, making them vital refuges for many species. However, tropical forests are one of the world's most threatened habitats; 10 million km 2 of tropical forest has been cleared since 1800, and what remains is now highly fragmented. This poses a major threat to forest‐specialist organisms, many of which are already threatened with extinction. It is therefore imperative that we are able to rapidly assess the impact of forest loss on local biodiversity throughout the tropics. Here, we assessed how forest fragmentation and its associated edge effects impact animal biodiversity in the Sahamalaza‐Iles Radama National Park, North West Madagascar. We used passive acoustic monitoring to collect 6006 h of audio data, from which we calculated six acoustic indices for comparison between (1) continuous and fragmented forest and (2) core and edge forest. We found significant differences in the soundscape (acoustic indices) among forest areas. Some indices associated with overall biodiversity were significantly higher in continuous and core forest in comparison to fragmented and edge forest. Although significantly different among sites, indices associated with specific frequency bands did not show a clear relationship with fragmentation and edge effects. As our results broadly match biodiversity data collected via traditional methods at our study site, this study provides further support for ecoacoustics as a potentially efficient and reliable tool for remote assessment of biodiversity in the tropics. Our results also emphasise the detrimental effects of fragmentation and edge effects on forest animal biodiversity and our need to protect this important habitat.