Losing lemurs: Declining populations and land cover changes over space and time
Pamela R Narváez-Torres1, Nicola K Guthrie1, Typhenn A Brichieri-Colombi2
1Department of Anthropology and Archaeology, University of Calgary, Calgary, Alberta, Canada.
American Journal of Primatology
|March 11, 2024
Summary
Land cover changes in Madagascar severely impact lemur populations, with some species declining by 80%. Degraded habitats negatively affect primate density, highlighting urgent conservation needs for these unique species.
Area of Science:
- Ecology
- Conservation Biology
- Remote Sensing
Background:
- Global deforestation and habitat degradation threaten biodiversity, particularly in tropical and subtropical ecosystems.
- Madagascar's endemic lemurs are at high risk of population decline and extinction due to high deforestation rates.
- Understanding the impact of land cover changes on primate populations is crucial for effective conservation.
Purpose of the Study:
- To examine the effects of short-term land cover changes on lemur species density in a fragmented landscape in southeastern Madagascar.
- To assess the relationship between land use/land cover (LULC) changes and lemur population dynamics.
- To identify specific land cover types that negatively impact lemur species.
Main Methods:
- Line transect surveys were conducted monthly from 2015 to 2019 to assess lemur densities across five forest fragments.
- Land use/land cover (LULC) maps were generated annually using Sentinel-2 imagery and supervised classification.
- Species-specific buffers were overlaid on LULC maps to quantify land cover proportions within surveyed areas.
Main Results:
- Annual densities of four diurnal and cathemeral lemur species declined significantly, with one species (Varecia variegata) experiencing an 80% decrease.
- Two nocturnal lemur species showed decreased density, while one (Cheirogaleus major) increased fivefold between 2015 and 2016.
- Grassland became the dominant land cover by 2019 (50%), while mature agricultural land increased significantly. Degraded land cover types negatively impacted three lemur species, though higher forest cover did not correlate with higher lemur density.
Conclusions:
- Land cover changes, particularly the increase in degraded habitats, have significant negative repercussions for lemur populations in Madagascar.
- The varied responses of different lemur species to habitat modification underscore the complexity of conservation challenges.
- Urgent interventions addressing land-use changes and targeted conservation strategies are essential to mitigate lemur population declines.
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