Ecological niche modelling to project past, current and future distributional shift of black ebony tree Diospyros melanoxylon Roxb. in India

Abstract

The present study utilized an ensemble modelling approach to predict the distribution of Diospyros melanoxylon under present, past (last glacial maximum (LGM), ~ 22 000 years BP, middle Holocene (MH) ~ 6000 years BP) and future climate change scenarios (RCP 2.6 and 8.5 for 2050s and 2070s). The annual mean temperature, mean temperature of the wettest quarter and annual precipitations were the most critical parameters that chiefly influence the distribution of D. melanoxylon. The ensemble model rendered high accuracy with AUC = 0.93, TSS = 0.74 and Kappa = 0.71. Past projections of D. melanoxylon indicated a widespread distribution during LGM and MH suggesting its adaptability to semi-dry as well as warm and humid climate, respectively. Presence of fossil pollen evidence of D. melanoxylon in the suitable habitats derived through past projections in this study complements the model results and marks occurrences of the species during LGM and MH. By 2050s and 2070s (RCP 8.5), there would be a decline in the distribution by only 0.4% (13 622 km²) and 0.2% (6842 km²) of the extremely suitable habitats, respectively. The main factor leading to reduced habitat suitability is the anticipated rise in temperature and variations in seasonal precipitation patterns. Our findings, help in identifying the parts of the country which would be severely affected by future climate change scenarios and plan conservation strategies for this commercially important species to facilitate its growth in suitable habitats which are likely to sustain under future climatic conditions.