Speaker
Description
Extreme climatic events are increasingly recognized as major drivers of biodiversity loss and ecosystem reorganization in tropical island ecosystems. Following Cyclone Chido, which struck Mayotte in December 2024 and caused extensive forest damage, we investigated the demographic responses, habitat selection, and spatial distribution of two key vertebrate seed dispersers: the Brown Lemur (Eulemur fulvus) and the Mayotte Flying Fox (Pteropus comorensis). For E. fulvus, population abundance and habitat suitability were assessed using line-transect-Density Surface Modelling, Ecological Niche Factor Analysis (ENFA), and Generalized Linear Models (GLMs). For P. comorensis, island-wide roosting characteristics surveys were conducted to assess population size, roost selection, and habitat use. Species Distribution Models based on Maximum Entropy (MaxEnt), multivariate analyses, and GLMs were used to identify the environmental determinants of occurrence and abundance. Both species experienced severe demographic declines following the cyclone. Brown lemur populations decreased by approximately 40% compared with pre-cyclone estimates. Habitat suitability was primarily associated with intermediate elevations, low anthropogenic disturbance, and structurally complex forest habitats. Spatial modelling provided the first island-wide assessment of the species’ distribution, identifying a potential distribution area of approximately 112 km² and a limited number of habitat cores supporting the highest predicted densities. The Mayotte Flying Fox experienced an even stronger decline, with populations reduced by nearly 56% relative to 2024 estimates. Species distribution models revealed a contraction of approximately one-third of the species’ ecological niche, while altitude emerged as the dominant predictor of occurrence. Colony abundance remained strongly associated with large trees and mature canopy structures. Despite these dramatic population collapses, both species exhibited signs of ecological resilience through persistence within a reduced network of habitat refugia. These findings identify priority areas for conservation and restoration and provide new insights into the resilience of tropical island ecosystems facing increasingly frequent extreme climatic events.
| Are you participating to the "AnaEE Environmental Rising Star Award "? | Yes |
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