Stan, K; Sanchez-Azofeifa, A; Calvo-Rodriguez, S; Castro-Magnani, M; Chen, J; Ludwig, R; Zou, LD (2020). Climate change scenarios and projected impacts for forest productivity in Guanacaste Province (Costa Rica): lessons for tropical forest regions. REGIONAL ENVIRONMENTAL CHANGE, 20(1), 14.

The Guanacaste Province of Costa Rica is home to highly diverse forests which are under threat of degradation due to ongoing climatic changes. There is concern that increasing temperatures and changes in precipitation will force these forests outside of their optimal growth ranges leading to widespread degradation of forest productivity. The objectives of this study are, therefore, to project and assess climatic changes in Guanacaste and to build a relationship between these climatic changes and forest productivity with the goal of projecting productivity trends into the future. The ClimateSA model was used to project RCP4.5 and 8.5 scenarios from 2018 to 2080 and then assess these projections for the mean and extreme future conditions. Furthermore, the MODIS gross primary productivity (GPP) algorithm was used to build a relationship between forest productivity and the vapour pressure deficit scalar (VPD scalar) and project GPP alteration under future climatic scenarios both seasonally and annually. Results indicate that Guanacaste's mean annual precipitation will stay within the historic levels for both the RCP4.5 and 8.5 scenarios. The monthly and annual temperatures increase in all projections. Results also indicate that the productivity-climate relationship follows a quadratic relationship between GPP and the VPD scalar. This quadratic relationship leads to areas with higher precipitation (high VPD scalar) experiencing an increase in GPP as they dry in the future. In drier areas (low VPD scalar), reduced precipitation will stabilize or decrease GPP.