Mapeamento da distribuição e modelagem de nicho potencial de Holoregmia Viscida Nees, uma planta endêmica da Caatinga, em cenários paleoclimáticos e cenários futuros de aquecimento global.

Abstract

The Caatinga is a phytogeographic domain that occurs exclusively in northeastern Brazil. It has several endemic species typical of the region with a semi-arid climate. However, its entire biodiversity may be threatened due to the impacts generated by rapid changes in the climate and habitats' fragmentation. Thus, this work aimed to map the global distribution, model the potential niche, and assess the degree of threat to conservation of Holoregmia viscida Nees (Martyniaceae), a monotypic genus of plant endemic to the south of the Caatinga domain. The modelling covered the current climate scenario; three paleoclimatic scenarios: Last Interglacial, Last Glacial Maximum and Average Holocene; three global warming scenarios. The degree of threat of the species was classified according to IUCN criteria. In addition to the degree of fragmentation of vegetation in the region where the species occurs. As a result of its distribution, it was observed that the species is restricted to south of the Caatinga. For the current period modelling, a more significant potential for the occurrence of the species was observed in some regions of the Caatinga, with no potential for natural occurrence in other biomes in Brazil. The climatic models for the Pleistocene showed that the potential niche of the species varied according to precipitation, where the most significant expansion occurred in the Last Maximum Glacier and the lowest in the Middle Holocene. Global warming models indicated a considerable decrease in a potential niche with increasing temperature and reduced rainfall. In addition, displacement of the potential niche of the species to areas further south was observed. The evaluation based on the IUCN criteria indicated that the species has its Range of Occurrence arranged in more than 61,653 km², thus classified as Least Concern. The evaluation of the degree of fragmentation indicated that the species is located in areas with a high degree of fragmentation and in part with no remaining vegetation. Thus, stressing the importance of UC's in this biome. With the results presented here, the importance of ecological niche modelling tools is notorious, as they are supporting biodiversity conservation plans and categorical status analysis as a form of monitoring to prevent the extinction of distinct species.