Conservation of forest genetic resources in eastern India amidst climate change and abiotic stress
Eastern India’s tropical deciduous forest ecosystems, dominated by Shorea robusta C.F.Gaertn., are increasingly threatened by abiotic stressors and climate change, posing significant risks to species survival, regeneration dynamics, and forest genetic resources. This study assessed the current status and future distributional dynamics of S. robusta and its five major associates, Terminalia alata B.Heyne ex Roth, Pterocarpus marsupium Roxb., Lagerstroemia parviflora Roxb., Diospyros melanoxylon Blume, and Madhuca longifolia (J.Koenig ex L.) J.F.Macbr., under changing climatic conditions in eastern India. Field surveys were conducted across 870 quadrats distributed throughout the tropical deciduous forests of Jharkhand, Bihar, and West Bengal during 2020–2023 to collect species occurrence, population structure, and regeneration data. Species distributions under current and future climate scenarios were modelled using the Maximum Entropy (MaxEnt) software under different CMIP6 climate models (INM-CM5-0, IPSL-CM6A-LR and MIROC6) proxied through four shared socioeconomic pathways (SSPs). Under current climatic conditions, S. robusta occupied highest coverage (~ 12.13%) across the study area as suitable habitat, proving its dominance. Future projections indicated a northward shift and contraction of suitable habitat for S. robusta, P. marsupium, and L. parviflora, with S. robusta projected to lose approximately 14–67% of its suitable habitat by 2050. Under a business-as-usual scenario, all studied species were predicted to experience habitat decline, with the greatest reduction (~ 84%) observed for L. parviflora. Population assessments revealed good regeneration status for S. robusta, M. longifolia, P. marsupium, T. alata, and D. melanoxylon, whereas L. parviflora exhibited comparatively poorer regeneration. Notably, P. marsupium and M. longifolia exhibit resilience to climate stress, supported by favorable regeneration status. These findings provide a scientific basis for location- and species-specific conservation and restoration strategies to enhance the long-term resilience of eastern India’s tropical deciduous forest ecosystems under climate change. Current suitable habitats for S. robusta and its major associates are concentrated in the southern and western parts of eastern India, with promising regeneration status for most species except L. parviflora. Future climate projections indicate a potential northward shift and contraction in the suitable habitat of S. robusta, reflecting broader ecological transitions in the region. Among associated species, M. longifolia and P. marsupium show the highest resilience to climate change. Current suitable habitats for S. robusta and its major associates are concentrated in the southern and western parts of eastern India, with promising regeneration status for most species except L. parviflora. Future climate projections indicate a potential northward shift and contraction in the suitable habitat of S. robusta, reflecting broader ecological transitions in the region. Among associated species, M. longifolia and P. marsupium show the highest resilience to climate change.