Influence of environmental factors on aquatic macrophytes composition in oxbow lakes in the Southern Peruvian Amazon.

Abstract

Species richness and composition of aquatic macrophytes are influenced by morphometry and physical and chemical conditions of the aquatic body. However, the influence of these variables has not been confirmed for oxbow lakes or commonly called “cochas” in the Peruvian Amazon. 10 cochas disconnected from the main course of the river were investigated in the Southern Amazon of Peru to know 1) the species richness of aquatic macrophytes, 2) their life form, and 3) the influence of area and depth of the water body and, transparency, pH, dissolved oxygen, total dissolved solids, and temperature of the water on species richness and composition changes of aquatic macrophytes. 68 taxa were reported, where Cyperaceae and Poaceae were the most diverse families. Moreover, he predominant life forms were emergent (47,1 %) and amphibian (36,8 %). Finally, cochas with greater area, pH, and dissolved oxygen, at the same time, with lower temperature, shelter a higher species richness and favour strictly aquatic species establishment, indicating that exists a species turnover along the conformed gradient by the association of these variables. These results demonstrate that southern Amazon of Peru has an important aquatic macrophytes richness that is associated with area, pH, dissolved oxygen, and temperature of the aquatic body.