Ever-wet tropical forests, which have high annual rainfall and are aseasonal, harbor exceptional species diversity. These ever-wet zones currently cover 30% of the tropical forest biome, half of which remains as intact forest, but with only 6% protected.
Research by Emma Underwood, Allan Hollander, and Jim Quinn at the Information Center for the Environment together with colleague David Olson at Conservation Earth, used downscaled climate data projections for 2050 to estimate that these ever-wet zones are likely to decrease by at least 20% under future climates. The research also indicated that this would result in a loss of one-fifth of extant intact ever-wet tropical forest and one-quarter of the protected ever-wet tropical forests by 2050. The researchers found that a shift towards increasing variability in rainfall, rather than decreases in areas that receive high amounts of annual precipitation, was the main driver of this change.
The tropical forests which are currently ever-wet and will remain ever-wet in the future provide important refuges for biodiversity. Their protection, as part of a global conservation strategy, offers the best chance for thousands of wet-forest species to persist.
The full study, Ever-wet tropical forests as biodiversity refuges, appears in the September issue of Nature Climate Change.