A comunidade zooplanctônica da região limnética dedezoito lagoas do Médio Rio Doce e as implicaçõespara a conservação ambiental: um olhar macroecológico

Abstract

Among the zooplankton communities structuring factors, the most studied are the physical and chemical variables of the lakes and the role of competition and predation. These are factors that act locally excluding species and shaping communities according to individual characteristics of each lake. Increasing attention is being given to regional factors, mostly related to dispersion, as an important communities structuring factor. Contrary to local factors, regional factors tend to homogenize communities, promoting an increase on local richness. In this study eighteen lakes were selected within the boundaries of Rio Doce State Park and its surrounding region. The zooplankton communities were sampled, as well the physical and chemical characteristics of lakes ponds and their geographical coordinates. The sampling periods were in August and November 2007 and February and May 2008. We attempted to verify the influence of local and regional factors in explaining the different zooplankton communities structures found. According to the physical and chemical characteristics, the lakes were divided into two groups: small/shallow-meso/eutrophic and large/deep-oligotrophic. The importance of local and regional factors differed according to the life histories of the groups. Cyclopoida copepods were not restricted neither to environmental variables nor to space. Calanoida showed only spatially restricted. Rotifers were related only to environmental variables and Cladocerans were related both to environmental variables and space. The introduction of exotic fish species seems to be the main human impact suffered by the communities. The presence of a well-developed macrophyte community was seen as mitigating that impact. Conservation Biogeography strategies are proposed based both on local and regional factors.