Modeling the climate suitability of tea [Camellia sinensis(L.) O. Kuntze] in Sri Lanka in response to current and future climate change scenarios

Abstract

Knowledge of potential distributions and habitat preferences of tea (Camellia sinensis) under current and future climate conditions are vital for policy makers and stakeholders to develop suitable adaptation measures to mitigate against any detrimental effects of climate change. Without broad awareness of climate suitability and potential changes in distributions of tea growing areas, efforts of expanding the productivity of tea would remain ineffective. This study aimed to model the climate suitability of tea in Sri Lanka in response to the current and future climate change scenarios using the correlative habitat suitability model MaxEnt. Three representative concentration pathways were used under MIROC5 and CCSM4 global climate models for the year 2050 and 2070. The MaxEnt model projected current habitat suitability for tea based on existing datasets with a mean AUC of 0.92. The TSS value with a mean 0.847 ± 0.007 signifies high accuracy of predicting suitability habitats while the maximum kappa value (k) of the current and future models was around 0.454, indicating the overall performance of the model was good. In relation to the current time, areas of 6090 km² (9.3%), 5769 km²(8.8%), and 5086 km² were projected as potential areas of having optimal, medium, and marginal climate suitability for tea, respectively. Results show that most of the optimal and medium suitability areas in the low elevation areas would be lost to a greater extent in comparison to the high elevation areas for all tested RCPs by 2050 and 2070 under both GCMs of MIROC5 and CCSM4. The comparison of the current and future distributions of suitable tea growing areas revealed a decline of approximately 10.5%, 17% and 8% in total 'optimal', 'medium', and 'marginal' suitability areas respectively, implying that climate would have a negative effect on the habitat suitability of tea in Sri Lanka by 2050 and 2070.