Predicted regional impacts of climate change on the geographical distribution and diversity of tropical forests in Costa Rica

Aim Spatial models generated in a geographical information system (GIS) are utilized to predict shifts in the distribution and diversity of tropical forests in Costa Rica in response to climate change. Location Analyses were conducted using the Holdridge life zone classification system for the Central American country of Costa Rica. Methods Mean annual precipitation and temperature ranges were varied to reflect different magnitudes of climate change and then used to predict the distributions of nineteen forest types (life zones). Holdridge et al.'s (1971) field survey data of species richness and endemism for ten Costa Rican life zones were also analysed and considered in view of the climate change scenarios. Results The scenarios indicated that shifts in the distribution of tropical forest life zones are likely to occur as a result of climatic changes. High elevation life zones were shown to be more sensitive to changes in temperature, while lower elevation life zones tended to be more sensitive to changes in precipitation. Regional life zone diversity was greatly reduced in an extreme wet and warm climate scenario. Three elevation-associated life zones (lower montane rain forest, montane rain forest, and premontane rain forest) ranked in the top four in percentage number of endemic species. The lowland seasonally dry forest life zone ranked second in this group, suggesting that this life zone has a unique species composition in comparison with other lowland Holdridge life zones. Of the nineteen life zones, these four life zones displayed particular sensitivity to the climate changes modelled here. Main conclusions Elevation-associated life zones may be particularly vulnerable to future climatic changes. This is also true of lowland seasonally dry forest. Geographical regions in Costa Rica that contain these life zones are likely to warrant special management and conservation attention in the event of predicted climate change.