A long-term ecological study reveals that protected forest fragments in southeastern Madagascar (Mandena) significantly improve the survival of endangered mouse lemurs, while translocation strategies may fall short of expectations.
The study led by researcher Andrea Vallejo-Vargas (NMBU - Norwegian University of Life Sciences) analysed 21 years of capture-mark-recapture data from the littoral forests of Mandena. This research aimed at evaluating the effectiveness of the different strategies put in place in this region, including habitat protection and animal translocation, for the conservation of the grey mouse lemur (Microcebus murinus), a small nocturnal primate endemic to Madagascar.
Key findings:
Mouse lemurs in protected forest fragments had significantly higher average annual survival probabilities than those in degraded habitats.
Female consistently outlived males, with annual survival probabilities of 39% in protected areas versus 27% in degraded ones.
- Translocated individuals had drastically lower annual survival - just 4% for females and nearly zero for males.
- Temperature positively influenced female survival in protected areas, suggesting a link between climate and resource availability.
Conservation wins and warnings
"These findings underscore the critical role of protected areas in safeguarding biodiversity," said Vallejo-Vargas.
"However, they also highlight the need for more strategic planning around translocation efforts, which may not always yield the intended conservation benefits."
The study also found limited evidence of long-term trends in survival, suggesting that the most severe impacts of habitat degradation may have occurred before monitoring began. The study contrasts with recent findings from western Madagascar, where climate change has been shown to reduce lemur survival.
Despite the challenges, the authors noted that translocations could still contribute to genetic diversity if relocated individuals successfully reproduce before dying, as genetic data revealed that translocated lemurs carried more unique immune-related alleles than resident populations. But more research is needed to confirm the potential genetic contribution of translocated individuals.
The research emphasizes the importance of long-term ecological monitoring and data-driven conservation planning, especially in biodiversity hotspots like Madagascar, where habitat loss and fragmentation continue to threaten endemic species.
About the study:
This study is a collaboration between the researchers Andrea F. Vallejo-Vargas, and Pierre Dupont from the Norwegian University of Life Sciences, B. Karina Montero, from the Animal Ecology and Conservation group, Universität Hamburg, Hamburg, Germany, the Biodiversity Research Institute, University of Oviedo, Mieres, Spain, S. Jacques Rakotondranary from the Faculté des Sciences, Université d' Antananarivo, Madagascar, Ernest Refaly, Jean-Baptiste Ramanamanjato, Faly Randriatafika, and Cedric Tsagnangara from the Tropical Biodiversity and Social Enterprise, Fort Dauphin, Madagascar.
