Liverworts in a changing world: vulnerability and extinction risk of specialist species under climate change in a tropical country (Colombia)

The various effects of climate change pose major threats to biodiversity, increasing the risk of local and regional extinction of species. This study evaluates the effect of climate change on the risk of extinction and vulnerability of 18 species of epiphyllous (leaf-inhabiting) liverworts, a guild sensitive to environmental changes. The area of environmental suitability for typical Neotropical epiphyllous liverworts was evaluated under optimistic (SSP126) and pessimistic (SSP585) future climate scenarios (2080–2100) using bioclimatic variables and the MaxEnt algorithm, with a focus on Colombia. The vulnerability analysis was performed by integrating spatial and climate niche metrics, while the risk of extinction was based on the potential and projected distribution in future scenarios using the values of relative loss of extent of suitability area and area of occupancy (AOO), according to the IUCN Criterion A3(c). Climate change will have significant impacts on the community because the area of environmental suitability of most of the species evaluated (89%) will have declined in future scenarios. An extreme example is Bromeliophila helenae, which will lose 97.12% of its total area of suitability, and the proportion of suitable area protected within Protected Areas (PAs) will be reduced by ca. 80%. Although only five species are currently found within PAs, these PAs play an important role because the area of environmental suitability will increase in future scenarios, particularly in the Caribbean and Orinoco regions. The risk of extinction of almost all species (95%) evaluated will increase in future scenarios, especially in the Andes, a region with potential to act as a refuge for specialist liverwort species. The results of this study highlight the urgent need to develop conservation strategies that include the expansion of the number of PAs and greater efficiency in the management of the existing PAs.