Post-fire recolonization of dry deciduous forests by lemurs in northwestern Madagascar

Abstract

Wildfires significantly threaten biodiversity, especially in tropical regions like Madagascar, where unique ecosystems face ongoing habitat loss and degradation. This study investigated the effects of forest fires on lemur encounter rates, species richness, and their ability to recolonize burnt areas in Ankarafantsika National Park (ANP), the largest protected dry deciduous forest in northwestern Madagascar. ANP hosts eight lemur species with one diurnal ( Propithecus coquereli ), two cathemeral ( Eulemur mongoz , E. fulvus ), and five nocturnal species ( Avahi occidentalis , Lepilemur edwardsi , Cheirogaleus medius , Microcebus murinus , and M. ravelobensis ). Eighteen sites with varying fire histories (1 to > 35 years post-fire) and adjacent unburnt forest parts were surveyed using diurnal and nocturnal transect surveys. Transects included burnt (700 m) and unburnt (500 m) sections. We used Generalized linear mixed effect models (GLMMs) to assess the effect of fire variables such as time since the last fire, number of fires, intervals between fires, and fire severity on lemur encounter rate and species richness. A full lemur community was observed only in unburnt forests and areas with extended post-fire recovery (≥ 23 years). Frequent fires negatively impacted the encounter rates of E. fulvus and L. edwardsi , while they did not significantly affect the encounter rates of small nocturnal species ( C. medius , Microcebus spp.). Lemur species richness was higher in unburnt zones and decreased with an increasing number of fires. These findings reveal the need for long recovery periods for lemur communities post-fire, suggest species-specific fire vulnerabilities, and demonstrate significant faunal impacts of this destructive driver of landscape transformation.

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