Measuring the Impact of Forest Edges on the Highly Arboreal Sahamalaza Sportive Lemur, Lepilemur Sahamalaza, in North-Western Madagascar

The progressive fragmentation of forest habitat is causing an increase in edge areas that may differ structurally and in quality from forest interiors. We investigated the impact of edge effects on habitat structure, behaviour, and ecology of the small, nocturnal, and highly arboreal Sahamalaza sportive lemur, Lepilemur sahamalaza. To understand edge effects, we established edge-to-interior gradients using temperature, humidity, and light intensity measurements along transects. From 773 h of behavioural observations on 14 individual sportive lemurs between 2015 and 2016, we compared home range sizes, activity budgets, and habitat use of animals inhabiting the edge area and those in the core forest. We found that microclimatic edge effects penetrated the forest up to 165 m, but that there was no significant edge effect on vegetation; forest vegetation was structurally variable throughout. Individual sportive lemurs living in the edge area used more trees with a diameter at breast height of less than 5 cm but showed no other behavioural differences to individuals inhabiting the core forest. The study shows that this species may not be impacted by edge effects, at least in situations in which vegetation structure is not affected, despite microclimatic differences.