Climate change impact on the distribution and priority areas for conservation of Sterculia setigera Delile in Benin, West Africa

Abstract

Climate change poses a major threat to species distribution and habitat loss, while also contributing to biodiversity decrease. Understanding these effects along climatic gradients is crucial for guiding conservation and mitigating declines. In this context, this study aims to assess the impact of climate change on the distribution of Sterculia setigera Delile, a widespread species with significant socio-economic value found in different climate zones of Benin. Given the heterogeneity of environmental conditions in Benin, a crucial question remains: how does climate change affect each S. setigera population group? And what are the priority areas for S. setigera conservation? To address these questions, we subjected each subgroup to species distribution modeling (SDM) using the maximum entropy algorithm (MaxEnt). This approach was applied under Shared Socioeconomic Pathways (SSP 2–4.5) and SSP 5–8.5 climate scenarios. A test of niche similarity between the groups was performed to assess their level of conservatism. Habitat prioritization was performed using Zonation software. Our results showed three distinct homogeneous subgroups (north-SN, center-SC and south-SS) with differentiated climatic conditions. SN was affected mainly by mean temperature of the warmest quarter, SS by precipitation of driest month, isothermality and minimum temperature of coldest month, while SC by elevation, temperature Seasonality and mean temperature of coldest quarter. Current climatic conditions were suitable for S. setigera in all climate zones. Under future climate scenarios SSP 2–4.5 and SSP 5–8.5, SN increased, while SC decreased. The SS subgroups, showed a decrease in suitable conditions under the SSP 2–4.5 scenario but an increase under the SSP 5–8.5 scenario. However, among the subgroups there was niche differentiation, leading to the emergence of ecotypes. The protected area was prioritized for the conservation of S. setigera in Benin. Therefore, future research should investigate further genetic and trait variation aspects within subgroups to confirm the existence of ecotypes.