Diversidade de espécies como métrica de referência para florestas de dunas costeiras no extremo Sul de Moçambique - uma contribuição para os contrabalanços da biodiversidade

Abstract

Decision-making on ecosystem/habitat reference areas for implementation of biodiversity offset projects requires scientifically valid data and metrics. Shortage of time, skilled human resources and poor logistics may limit the collection of reliable biological data for determination of such reference areas based on appropriate metrics in underdeveloped countries such as Mozambique. The present study aims to assess diversity as a reference metric for coastal dune forests in the extreme south of Mozambique from KaNyaka (Maputo City) to Matutuíne District (Maputo Province), including the localities of Machangulo, Mucombo, Milibangalala and Malongane. Data collection took place between March and June 2018. A total of 70 randomly selected and georeferenced grids were used to identify, count, and measure the height and diameter at breast height (DBH) of all plant individuals that rooted within the grid. Hierarchical cluster analysis was used to determine plant communities considering the calculation of Hill diversity and rarefaction, density, and average height of individuals. Linear regression models were constructed to select the best species diversity model based on the lowest Akaike coefficient (AIC). A total of 16,396 individuals belonging to 201 species, distributed in 112 genera of 42 families, were identified throughout the study area. Three plant communities were identified: community I (Inhaca), community II (Machangulo, Ponta Mucombo, Ponta Milibangalala) and community III (Ponta Malongane). Community II presented the highest Hill diversity values ​​(𝑞 = 125 and 𝑞 = 3.81) and the highest diversity value estimated by rarefaction was for community III (228.49). Community I presented high values ​​of densities (1718 ± 106.7 ind/ha) and average plant heights (8.2 ± 3.9). The average annual temperature, distance from the population, altitude and annual precipitation determined the species diversity in the plant communities. The results of the study suggest that Hill diversity is the best metric to quantify diversity and Community II (specifically, Ponta Milibangalala) is the best reference area for possible biodiversity offsets in the coastal forests of southern Mozambique(TRADUÇÃO NOSSA)