Ecological niche modelling in identifying habitats for effective species conservation: A study on Endemic aquatic plant Crinum malabaricum

Abstract

Ecological niche modelling (ENM) aids in identifying new species populations and suitable habitats for species translocation, addressing the conservation challenge of endemic species with limited distribution. The current study aims to develop a habitat suitability map of Crinum malabaricum Lekhak & S. R. Yadav, an endemic species with a very limited geographical range, using Maxent-based ecological niche modelling to identify suitable receptor sites for conservation translocation. Out of 23 species occurrence records, 11 were used for this study. Seven predictive variables are selected based on Pearson’s correlation coefficient (r = ±0.8) and permutation importance (>3%) from a group of nineteen bioclimatic and two topographic variables. The study area encompasses the Malabar Plains of the Western Ghats. The accuracy of the model was assessed using the ROC curve method, and the contribution of variables was estimated using a Jackknife analysis. The results show that precipitation of the driest quarter and mean temperature of the driest quarter were the leading predictors of habitat suitability. The model shows high accuracy with a value of 1.6 for AUC ratios and values > 8 for AUC, partial AUC, Kappa, and TSS metrics. The model predicted a fundamental niche for this species with 2393 KM2 (3.6% of the study area) as a highly suitable area for C. malabaricum (where habitat suitability index ≥ 0.85), which is much higher than the calculated extend of occurrence (EOO = 283 KM2) of this species. The realized niche of this species was identified using field explorations, and ten suitable areas were selected for species translocation. These selected habitats are distributed across various regions of the southern Western Ghats. As a species with limited distribution and a lack of proper dispersal mechanisms, a successful species translocation to these sites will overcome the endemism in this species. For selecting appropriate sites for conservation translocations, this methodology will be reliable and effective, and it could be useful for other endemic species.