Rotifera from reservoirs under different environmental conditions in a protected fragment of atlantic rain forest

Abstract

Rotifers are generally planktonic organisms used as indicators of environmental quality in water bodies because they can quickly respond to environmental variations. The present research aimed to investigate whether in the same protected area (Dois Irmaos State Park, state of Pernambuco, Brazil) aquatic environments submitted to different levels of anthropic exposure present different attributes of the community of littoral rotifers. Four reservoirs were evaluated and grouped into two categories according to antropic exposure conditions: (i) Exposed and (ii) Not Exposed, according to the environmental characteristics of the surroundings of the reservoirs. Forty-one species were recorded, of which 11 occurred in the four reservoirs, and the genus Lecane was the richest in species (S = 14). The rotifer community differed between both exposure conditions, with a greater richness and density found for the group of Exposed reservoirs. The analysis of functional groups, through the Guild Ratio index (GR), resulted in a higher dominance of microphages for the Exposed group (GR = -0.93), than for the Not Exposed group (GR = -0.69). Even though both exposure conditions were dominated by microphage rotifers, which are indicators of aquatic ecosystem degradation, a lower representation of this functional group was observed in the Not Exposed group of reservoirs. Our results indicate that coastal planktonic rotifers present reliable answers for the environmental evaluation of shallow reservoirs, and that different management conditions can influence the environmental status of aquatic ecosystems of the same protected area.