With more than 2,900 native plant species and high biodiversity, Central America’s tropical forests are important ecosystems. Forest scientists fear that climate change will affect the composition of the forests and cause irreversible losses of habitat and biodiversity. A team led by Prof. Dr. Marc Hanewinkel and Lukas Baumbach from the Institute of Forest Sciences at the University of Freiburg would like to be able to better assess these changes. Therefore, the researchers simulated how future climatic conditions will affect key tree types in Central America. The team published their results in the journal Communications Biology. The German Research Foundation funded the project.
Development toward drier vegetation
The models show the projected situation for the years 2061 to 2080. Large parts of the region studied will thus experience a change from forests adapted to moisture to dry forests, or those that can cope with a variety of environmental conditions. The Freiburg researchers have thereby confirmed previous studies that also forecast a trend toward drier vegetation. Areas with tree species adapted to moisture will separate and lose connectivity with each other. Fragmentation will be particularly noticeable in the biological corridor along the Caribbean coast, which is an important north-south migration and dispersal route for trees. At the same time, there is an increased risk that trees will die out along mountains and mountaintops, a phenomenon known to experts as “mountaintop extinction.”
Protected areas for tree species will be necessary
“Our findings underscore the urgent need to ensure habitat connectivity through biological corridors and expand protected areas,” Hanewinkel says. “At the current rate of environmental change, many species may not be able to adapt to new conditions, eventually leading to habitat shifts or extinction.”
For their analysis, the scientists looked at the physiological, morphological and life history characteristics of the plants and divided the regionally widespread tree species into seven groups for their simulations. The study region included the Central American subcontinent between longitudes 68° to 100° and latitudes 4° to 24°; the Caribbean islands were excluded because no data were available for them.
Tropical biodiversity is sensitive to climate change
The Central American landscape is characterized by many different forest types that are closely adapted to local environmental conditions. “Due to this high degree of specialization and the scarcity of alternative habitats, tropical biodiversity is expected to be particularly sensitive to climate change,” says Hanewinkel. This development would have a dramatic impact on biodiversity in Central America, emphasizes the Freiburg researcher: “Wet forests and montane forests are home to the largest number of amphibians, birds, mammals and reptiles, many of which are already threatened with extinction or suffering from habitat fragmentation.”
Baumbach, L., Warren, D.L., Yousefpour, R. & Hanewinkel, M. (2021): Climate change may induce connectivity loss and mountaintop extinction in Central American forests. In: Communications Biology. 4:869. DOI: 10.1038/s42003-021-02359-9