Updated Lemur Species Ranges in Madagascar’s Corridor Forestier d’Ambositra Vondrozo (COFAV)

Slideshow

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Participants

  • Carly Batist; PhD Candidate, City University of New York, USA
  • Michael Bliss; Master’s Student, Kent State University, USA
  • David Weisenbeck; PhD Candidate, University of Kentucky, USA
  • Rija Rafamantanantsoa; University of Antananarivo, Madagascar
  • Georges Razafindrakoto; Centre ValBio Research Technician, Madagascar
  • Jerison Ranaivosolo; Centre ValBio Research Technician, Madagascar
  • Velo Jean Baptiste; Centre ValBio Research Technician, Madagascar
  • Patricia Wright; Distinguished Service Professor, Stony Brook University, USA
  • Mariah Donohue; PhD Candidate, University of Kentucky, USA

Summary

Madagascar’s exceptionally high endemism, combined with escalating deforestation, makes it one of the world’s most urgent conservation priorities. In southeastern Madagascar, the Corridor Forestier d’Ambositra Vondrozo (COFAV) is an unprotected rainforest corridor that contains roughly 15 species of lemurs, most of which are endangered. The COFAV connects multiple protected areas and plays a vital role in maintaining gene flow, dispersal, and long-term population viability. However, the corridor has not been systematically surveyed since the 1990s. We conducted an eight-month survey of the COFAV between Ranomafana National Park and the Mananara River to update lemur occurrence records and geographic ranges. Using transect surveys, opportunistic encounters, and community interviews, we covered approximately 227 km² and documented 11 lemur species and one putative hybrid species. We observed range expansions for Hapalemur aureus, H. griseus, and Propithecus edwardsi, but found the range of Varecia variegata contracted, with the species absent south of the Ambohimahamasina/Ikongo region. These results highlight both persistence and decline among lemur populations in this critical biodiversity corridor.

Techniques

Opportunistic lemur sighting and vocalization detection, GPS-based occurrence mapping, diurnal and nocturnal line-transect surveys, demographic assessments of group size and age-class composition, community interviews with local VOIs (forest management groups), ArcGIS Pro mapping of species distributions, comparative analysis with historical range records.

Future Directions

Future work will implement systematic, year-round transect surveys across diurnal and nocturnal periods to capture seasonal and life-history variation. Expanding coverage to less-sampled regions of the COFAV will refine southern range limits and clarify hybrid zone boundaries. Integrating ecological data such as forest phenology and floristic diversity will help link species presence to habitat quality. Planned genetic analyses will confirm hybridization zones and assess population connectivity. Collectively, these approaches will produce a more comprehensive understanding of lemur conservation needs across the COFAV.

Why This Matters

Lemurs are the most endangered group of mammals on Earth, with more than 90% of species threatened with extinction. Updated distribution data are essential for accurate IUCN Red List assessments, conservation planning, and prioritizing protection of habitats outside Madagascar’s formal national park network. The COFAV, though unprotected, remains a lifeline for gene flow among fragmented lemur populations and supports extraordinary biodiversity. Without timely action, deforestation, slash-and-burn agriculture, illegal mining, and intensified cyclone activity threaten to sever this critical corridor. By providing updated occurrence and range data, this study supports the urgent inclusion of forest corridors like the COFAV into Madagascar’s conservation framework, helping to safeguard endangered lemurs and the ecosystems they inhabit.

Figure 1. Map of the COFAV corridor (white outline) and connected protected areas (green outline). In the inset map (top left corner), the white box outlines the total study area. Numbered points indicate the location of each study site. 1) Namahoaka; 2) Maharira; 3) Ambalavero; 4) Mandriandry; 5) Malazamasina; 6) Antanivelona; 7) Sahafoza; 8) Andranomiditra; 9) Vinanitelo Sud; 10) Sandranata; 11) Itoalana/Lovasoa; 12) Lomaka; 13) Ankarimbelo; 14) Vohembe; 15) Ankona; 16) Ambarongy; 17) Ampasy; 18) Marandrano; 19) Emma; 20) Manasara; 21) Vevembe; 22) Bemahala. Basemap data from UNEP-WCMC & IUCN (2023) and Esri et al. (2023).

Figure 2. Map of lemur records from previous studies (blue) and this study (orange) for each species encountered in this study. A) Daubentonia madagascariensis; B) Brown lemurs; C) Eulemur rubriventer; D) Hapalemur aureus; E) H. griseus; F) Propithecus edwardsi; G) Varecia variegata. Basemap data from UNEP-WCMC & IUCN (2023) and Esri et al. (2023).

Poster

Click here to view the published paper.