Ecotones Shape Ground-Dwelling Mammal and Bird Diversity Along a Habitat Gradient in the Southern Coastal Dry Forests of Vietnam

Abstract

Understanding biodiversity patterns is essential for ecology and conservation. Globally, conservation efforts often prioritize tropical rainforests due to their high species richness. At the regional scale, the same is true in the Greater Annamites ecoregion of Vietnam and Laos, where conservation efforts have largely focused on broadleaf wet evergreen forest, despite the fact that other habitats remain threatened. One such habitat is the coastal dry forest landscape in southern Vietnam, which has received little conservation focus despite the fact that its forested areas have been severely reduced. Nui Chua National Park (NP) in southern Vietnam harbors one of the few remaining sizable areas of dry coastal forest. In this study, we used camera-trap data and a community Royle-Nichols model to explore community structure of ground-dwelling mammal and birds along a complex habitat gradient in Nui Chua NP. We first investigated species associations among three habitat types: dry forest, semi-dry forest, and broadleaf wet evergreen forest. We then used occupancy-based diversity profiles to assess diversity in these three habitats. Overall species diversity tended to be highest in the transitional semi-dry forest ecotone, which supported species from both dry and evergreen forests. Notably, the semi-dry forest also had the highest occupancies for several endemic and threatened species. Our findings highlight the importance of the semi-dry forest for conservation in the broader coastal dry forest landscape. We emphasize the need for fine-scale biodiversity assessments to inform conservation strategies, especially in habitats that may be overlooked by broader-scale conservation strategies.