Application of a Bayesian model based on probability of occurrence to evaluate the effect of an environmental gradient on the turnover of aquatic insect genera in Cerrado streams

In ecology, understanding and quantifying the species turnover rates among different locations is essential for a more concise and predictive science. However, little is known about how the turnover occurs among environmentally similar locations and how it may be related to habitat integrity. Using the communities of Ephemoptera, Plecoptera, and Trichoptera sampled from streams in the Brazilian Cerrado, we tested the following hypotheses: a) genus turnover between similar streams will higher in more preserved streams; b) the relationship between proportional genus turnover and the environment is influenced by the taxonomic group. We estimated parameters related to the number of potentials, observed, and alternation of these genera across a habitat integrity gradient in 101 observed streams using a model with Bayesian inference. Genera turnover among environmentally similar sites was directly related to the environmental integrity of the stream. Only the genera Plecoptera showed a pattern similar to the hypothesis we elaborated, showing an increased turnover among well-preserved streams. For the other orders, the turnover presented two peaks in the environmental gradient, one in impacted sites and the other in preserved ones.