Analysing the environmental niches for Caribbean Pine and Palmetto Palm in the lowland savannas of Southern Belize

Abstract

The lowland Belizean savannas consist of a mosaic landscape of varying ecosystems which provide valuable natural resources that largely derive from the heterogeneous vegetation species. In Belize, these provide socio-economic and conservation resources; requiring careful management to ensure sustainable use. This study is concerned with Caribbean Pine (Pinus caribaea) and Palmetto Palm (Acoelorrphe wrightii). Using Geographical Information Systems (GIS), this study identified the key determining and constraining environmental factors, which depending on geographic variance, combine to form the respective environmental niches for pine and palm. Deductive analysis identified the environmental niches for both species and these were tested using the historical datasets, which confirmed that they had been successfully identified.

Consequently, a maximum-entropy model (Maxent) was built to predict the potential environmental niches (suitable habitats) for pine and palm across the study area, which were then validated using contemporary pine/ palm distribution data. The results indicate Maxent performed well on a broad scale and slightly poorer at a more local scale, where it incorrectly predicted suitability in a relatively small number of locations. Poor soil fertility and poor drainage were the key determining and constraining variables for both niches, while topography was a key variable in the occurrence of palm in particular. The results suggest that the niches for pine and palm occupy slightly differing ecological thresholds on the savanna gradient, the significant difference being drainage as a result of topography. Further investigation is recommended before management recommendations could be proposed, however, these results contain valuable information could support management decisions.