Unveiling Plant Species Richness Patterns and Climate Influences in Indian Biogeographic Zones

Introduction: Conservation efforts have traditionally focused on biodiversity hotspots, overlooking the essential ecological roles and ecosystem services provided by cold spots. Cold spots are areas outside biodiversity hotspots, characterized by low species diversity and harboring rare species living in threatened habitats. Aim: This study aims to predict the present and future plant species distribution in cold spots across India, considering various environmental and non-environmental variables. Location India Methods: The Indian national-level plant species database generated through the project ‘ Biodiversity Characterization at Landscape Level’ was used . The species modelling (70% randomly selected training data) was carried out for four major biogeographic zones of India namely Arid and semi-arid zone, Deccan peninsula, and Gangetic plain. Generalized Linear Model (GLM), Generalized Boosted Model (GBM), Random Forest (RF), Support Vector Machine (SVM), and ensemble modeling were compared to predict species distribution. Future representative concentration pathways (RCP4.5 & RCP8.6) were used to forecast species distribution. Results: The study demonstrated good predictive ability with water and energy variables dominating in all zones, showing a strong agreement with the observed data (30% subset of the original data). Temperature annual range, annual precipitation, and precipitation of the driest month (bio7, bio12, and bio14) significantly influenced (r > 0.4) plant species patterns in the arid and semi-arid zone. Ensemble modeling showed improved results when validated with observed data, exhibiting a significant reduction in the RMSE and an improved correlation (r=0.8). Non-environmental variables (elevation and human influence index) showed significant influence in combination with water and energy variables in the Deccan peninsula zone. We observed continuous species loss in both future climate scenarios. Among biogeographic zones, the semi-arid and arid zones showed the maximum probable increase in species, with 69% and 52.5% of grids gaining species in 2050 (RCP4.5) and 69% and 84.7% of grids gaining species in 2070 (RCP8.6) respectively. Conclusion: The study provides insights into the species richness distribution of cold spots in major Indian biogeographic zones, supporting their climate-derived patterns at a macro-scale. Ensemble modeling proves to be more accurate than individual models, emphasizing its potential for conservation efforts. The study calls for a performance-based conservation approach, prioritizing criteria to safeguard valuable ecosystems and prevent species loss.