Beta diversity as an indicator of priority areas for Myrtaceae assemblage conservation in Subtropical Araucaria Forest

Abstract

We can say that studies on diversity provide knowledgeable insights into which areas with different compositions will be initially preserved or those which require more attention for government supervision. Thus, we aim to evaluate the alpha, beta and gamma diversity of the Myrtaceae assemblages as a tool for indicating priority conservation areas. Herein we explore the different levels of diversity resulting from fragments distributed along an altitudinal gradient in the Subtropical Araucaria Forest in the Santa Catarina Plateau of the Brazilian Atlantic Forest. In sequence, the Jaccard index and ordination by Detrended Correspondence Analysis were used for the β-diversity analysis and floristic substitution. Finally, the spatial dependence was analyzed by the Mantel Test based on floristic and geographical distances. Our results show that Myrtaceae assemblages along the altitude gradient are characterized by heterogeneous floristic compositions (β-diversity 0.55–0.95 variation), in which fragments above 1300 m are physiognomically marked by a predominance of the Myrceugenia and Myrcia genera. Higher altitudinal amplitude was characterized as an indicator for selecting complementary fragments due to dependence on β-diversity (r = 0.6961; p-value = 0.001), aiming at greater conservation effectiveness. In this sense, the LGS and URI complementary fragments are strategic because they comprise high beta diversity, high richness, the presence of exclusive and endemic species, and are located in different river basins. Our results show beta diversity as an effective tool for indicating priority areas for the conservation of Myrtaceae assemblages in AF, however it is essential to consider the exclusive and endemic species together.