Predicting the habitat suitability for endangered tree species Pterocarpus marsupium in Nepal, using ensemble species distribution models

Le résumé fourni par la source

Pterocarpus marsupium Roxb., locally known as Bijaysal, is a high-value tropical deciduous tree with a restricted and fragmented distribution in Nepal. We integrated 129 spatially occurring records with climatic, anthropogenic, edaphic, and topographic variables in an ensemble species distribution modelling framework (biomod2) to project current and future (2050s and 2090s) habitat suitability under four shared socioeconomic pathways (SSP) scenarios. Minimum temperature of the coldest month and precipitation seasonality were the dominant climatic drivers, followed by soil organic carbon, bulk density, and human footprint. The current suitable habitat is limited (11,154 km²; 7.6 % of Nepal) and confined to the western and central lowlands. Future projections indicate habitat expansion ranging from 40 % (SSP1-2.6 2090s) to 313 % (SSP2-4.5 2050s) with consistent southeastward centroid shifts (46–127 km), reflecting both northward expansion into the mid‑hills and eastward reorganization within the lowlands. However, these projections should be interpreted with caution, as actual migration may be limited by seed dispersal mechanisms and soil suitability in high-elevation zones. The unimodal response to human footprint challenges the conventional protected-area paradigm and indicates that well-managed community forests can serve as critical climate refugia. These findings suggest that well‑managed community forests can complement protected areas by maintaining intermediate disturbance and provide a spatially explicit roadmap for assisted colonization into the mid‑elevation zones.

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