Variabilidad estructural de la comunidad de macrófitas en un gradiente pluviométrico en la provincia de Chubut

Mallines are Patagonian wetlands characterized by permanent waterlogging on its soils, sustaining small shallow lakes that hosts a vast biodiversity. In these ecosystems, aquatic plants (i.e. macrophytes) develop different life forms adapted to humid conditions, allowing them to regulate the physical and chemical conditions of the mallín. A distinctive characteristic of Patagonia is the exponential west-east decrease in rainfall, which generates three biozones: forest, ecotone and steppe. These biozones have been typified using landform plants, but whether macrophytes assemblages are related to each biozone or not has not been evaluated yet. The aim of this work is to compare the attributes of the macrophyte and wetlands landform plants community in each biozone. During the 2013-2014 austral Summer, 20 shallow lakes were sampled in the west province of Chubut, assessing macrophyte richness and physical and chemical water variables. Macrophytes were classified according to their life forms, origin, and its diversity was calculated. A total of 62 taxa were determined, most of them corresponding to the Cyperaceae, Poaceae and Ranunculaceae families. The steppe exhibited alkaline pH values, and higher conductivity and soluble reactive phosphorus (SRP) than the ecotone and the forest. High SRP values favored the abundance of macrophytes and macroalgae. However, three sites were eutrophic, exhibiting high chlorophyll a and total phosphorus values. Those sites showed higher abundances of macroalgae and emerging macrophytes. The sampled shallow lakes would act as reservoirs of macrophyte diversity at both local and regional scales. Thus, understanding the relationships among macrophytes and environmental variables could be useful for the mallines biodiversity conservation plans.