Distribution and conservation of Mexican tepezmaite cycads

Abstract

The increasing threats to global biodiversity notably impact cycads, one of the most endangered organisms. Despite the importance of nature reserves, they only sometimes provide sufficient protection from habitat destruction and illegal harvesting. Identifying and prioritizing suitable Mexican tepezmaite (Ceratozamia) habitats is imperative for restoration and protection. This study uses distribution models to map habitats for C. brevifrons, C. delucana, C. morettii, and C. tenuis to highlight optimal conservation zones. The study area lies in the Sierra de Chiconquiaco, Veracruz, Mexico. All species occurrences were collected, and four sets of environmental predictors were selected as input variables for the model. An ensemble species distribution model was constructed for each species. When contrasting the habitat areas within established nature reserves, gaps in conservation coverage were discerned. We assessed its conservation status following the IUCN and Mexican legislation criteria. A further 4 km² of highly suitable habitat is desired for a nature reserves expansion strategy. C. brevifrons and C. tenuis are deemed vulnerable per IUCN criteria, while C. delucana and C. morettii are considered Endangered. However, Mexican laws categorize C. brevifrons, C. morettii, and C. tenuis as Endangered and C. delucana as threatened. Models suggest that the distribution of the species is constrained primarily by soil composition and topographical features. Based on the results of the models, it is essential to implement the restoration of the species’ natural habitat. The tepezmaite cycads are a group of endangered species that may soon become extinct unless formal habitat protection is conducted.