Changes in the structure of bird communities over 10 years in the Ecological Corridor of Paraguay River, Pantanal wetland

Abstract

Studies with bird communities related to the hydrogeomorphological characteristics of climatic rivers associated with flood areas are important to identify short and long term temporal space changes. In this perspective, this research aims to evaluate the structure of the bird community of the Paraguay River, through the richness of descriptors, the quantity and the diversity and equability index over an interval of 10 years, 2008 / 9-2018 / 19 , considering the economies of the hydrological cycle, floods, floods, emptiness and drought and sampled macrohabitats. The study was developed addressing a connected hydrology of the Paraguay River, in the longitudinal and lateral dimensions. A study area comprised of three functional sectors of the Paraguay River, meandering, rectilinear and transitional, beginning in the urban period of the municipality of Cáceres-MT, up to a Descalvada Farm, with a 134 km course of the river, with 13 points in total. Each functional sector of the river, had a sampling point and 10 parental bays, with different degrees of lateral connectivity, were sampled. A survey analyzed and compared two hydrological sampling cycles, the first between June 2008 and March 2009, and the second between August 2018 and April 2019. The protocol for the sampling consisted of four campaigns corresponding to the hydrological drought studies, flood, full and ebb. The results pointed to a distinction in the community structure between the two cycles 2008/2009 - 2018/2019 show a difference in the relative scope and in the composition of the species in the sampled locations. The main change registered between the two cycles (2008/2009 and 2018/2019) was the disappearance of three nests - habitat for feeding and reproduction of colonial birds, identified in the first and without registration in the second cycle. The dominance of Mycteria americana is highlighted, a species sensitive to environmental changes, not observed in the first cycle of studies. The absence of nests in 2018/2019, coupled with the dominance of Pitangus sulphuratus, a generalist species, may indicate anthropic changes that occurred along the Paraguay River in this time interval. It is hoped that the results of this comparison will be able to subsidize or influence the effective decision-making for the conservation of the biodiversity of birds and the Paraguay and Pantanal river itself.