Modelagem de nicho ecológico da espécie Encephalartos manikensis (Gilliland) na província de Manica

Abstract

Anthropogenic environmental changes are the main cause of species extinction in the Holocene. Species have been exposed to different sources of threats. However, the importance of these threats to the conservation status of species in a given region depends on the type of threats to which the species are exposed and the susceptibility of the species to these impacts. Encephalartos manikensis is a species belonging to the Zamiaceae family native to Mozambique and Zimbabwe, generally developing in inhospitable areas such as steep granite hills or montane forest areas in eastern Zimbabwe and western Mozambique, especially in the Manica district. It is classified as vulnerable (VU) on the International Union for Conservation of Nature's Red List. This category reflects the significant threats to the species, which have been driven by agricultural expansion and its collection for commercial purposes. The natural habitat of this plant tends to decrease, fragmenting populations and reducing its genetic diversity. The central objective of this work was to develop a predictive model of the ecological niche distribution of Encephalartos manikensis in the province of Manica. The results showed that the environmental variables that had the greatest influence on the species' distribution were: slope, soil organic carbon content, annual precipitation, cation exchange capacity, and elevation. Mountainous areas such as Mount Nhaumbwé (Garuso), Mount Chuala, and Mount Dengalenga showed greater environmental suitability and viability of individuals of the species (1000, 100, and 80, respectively), while the other mountains had few (less than 50 individuals), reflecting low viability. Mount Vista Alegre and Serra Choa were the areas with confirmed presence of E. manikensis, but with isolated records (only one individual), which may indicate small and isolated populations, and less favorable environments for the species in these areas. These results will serve as a key resource to support species conservation actions (TIPAs, KBAs, Hotspots) and in guiding fieldwork(TRADUÇÃO NOSSA)