LOCAL AND SPATIAL FACTORS INFLUENCE THE BETA DIVERSITY OF MACROPHYTES IN CAXIUANA BAY (AMAZON)

Aquatic plants. Nesting. Turnover. Aquatic biodiversity

Understanding the patterns that determine the diversity of species among different locations arouses scientific interest, as it is known that human actions can cause the loss of species and alter the functioning of this ecosystem, even more so in the Amazon region. Diversity patterns varied according to the spatial scale, allowing its decomposition into three components: alpha (local), beta (between communities in different locations) and gamma (regional) diversity. Thus, the objective of this work was to analyze the beta diversity of macrophytes and their components in an Amazonian river and to investigate which are the environmental factors that determine the change in species composition on a spatial scale. Our hypothesis is that spatial factors such as geographical distance and local factors such as (temperature, turbidity, conductivity, dissolved oxygen, depth and pH) influenced the diversity of macrophytes in the Anapu River, altering the total beta diversity and its components. For this, we collected macrophytes at 45 points on the Anapu River. Species composition was determined through observation and recording of species. With the use of a multiparameter probe, limnological variables of the water were collected, in addition we also measured the transparency of the water column. The results showed that aquatic macrophyte species are indicators of environmental conditions, responding well to physicochemical variations through changes in species composition between sites, which leads to greater beta diversity. This change can be due to the replacement of species (turnover) or the loss and gain of species (nesting). In our work, median values of beta diversity were observed with greater contribution from species replacement. In addition, the geographical distance between the points, electrical conductivity, turbidity and pH were responsible  for structuring the macrophyte community, corroborating our hypothesis. Our work brings new