New Research on Lemur Distribution Following Cyclone Disturbance in Masoala National Park
Wildlife Madagascar is proud to share the publication of a new scientific study authored by members of our community, including current staff Dr Tim Eppley, Wildlife Madagascar’s Chief Conservation Officer, and Delaïd Claudin Rasamisoa, ASSR Conservation Program Manager, alongside former Wildlife Madagascar board member Dean Gibson.
The study, Lemur Distribution in Relation to Treefall Canopy Gaps in Masoala National Park, Northeast Madagascar, investigates how cyclone-driven forest disturbance influenced lemur distribution and habitat use over time within one of Madagascar’s most biodiverse rainforest landscapes.
This publication reflects the long-term commitment of researchers and conservation practitioners working across northeast Madagascar to better understand how rainforest ecosystems and lemur populations respond to environmental change.
Investigating Lemur Responses to Cyclone Disturbance
Madagascar is a global biodiversity hotspot facing increasing anthropogenic pressures, with 95% of lemur species threatened with extinction.
This research examined the effects of Cyclone Eliakim, which struck Masoala National Park in March 2018 with sustained wind speeds reaching 151 km/h. The study assessed whether lemur densities and microhabitat niches changed following the cyclone and whether species distributions were related to treefall canopy gaps created by fallen trees.
Researchers conducted 110 km of transect surveys for diurnal lemurs and 87 km for nocturnal lemurs between 2017 and 2022 in Andranobe, Masoala National Park, a region that experiences regular cyclone impacts.
Microhabitat data were recorded for each observation, and distance to the nearest canopy gap was used as a measure of association with treefall gaps.
Key Findings
The study found that densities of Varecia rubra, Eulemur albifrons, Avahi mooreorum, Lepilemur scottorum, and Microcebus sp. did not decline following Cyclone Eliakim.
Researchers also found that species niche separation was strongest immediately after the cyclone, suggesting intensified competition over limited resources. This pattern relaxed progressively as the forest recovered.
Gap size increased after the cyclone and then decreased by nearly 60% over the following 4.5 years, indicating progressive canopy closure.
Patterns of habitat use differed between species groups. Large diurnal lemurs were positively associated with canopy gaps larger than 150 m², which the authors suggest may reflect increased food availability in sun-exposed areas.
In contrast, small nocturnal lemurs were positively associated with smaller canopy gaps under 150 m² and avoided larger gaps, which the authors propose may be linked to increased aerial predator risk.
Expanding Understanding of Madagascar’s Rainforest Ecology
According to the authors, these findings contribute to understanding species interactions and ecosystem dynamics under climate-driven habitat change and provide new insight into how arboreal species respond to natural forest disturbance.