A performance based consensus approach for predicting spatial extent of the Chinese windmill palm (Trachycarpus fortunei) in New Zealand under climate change

摘要

The predicted distribution of the Chinese Windmill Palm (Trachycarpus fortunes) was modelled using several algorithms with inputs consisting of occurrence information and bioclimatic datasets. A global species distribution model was developed and projected into New Zealand to provide a visualization of suitability for the species in current and future conditions. To ensure model robustness, occurrence data was checked for redundancy, spatial auto-correlation and the environmental variables checked for cross-correlation and collinearity. The final maps predicting suitability resulted from ensembling the predictions of all the algorithms. The resulting ensembled maps were weighted based on the evaluation parameters AUC, Kappa and TSS. When reclassified into low, medium and high suitability categories, results show an expansion of high suitability areas accompanied by a reduction of low suitability areas for the species. The centroids of the high suitability areas also exhibit a general movement towards the Southwest under future climate conditions. The range expansion was proportional with the representative values of emission trajectories RCPs (2.5, 4.5, 6.0 and 8.5) used in projecting into future conditions. The movement magnitude and direction of predicted high suitability area centroids for the palm supports the use of the plant as an indicator of climate change.