Diatom and desmid relationships with the environment in mountain lakes and mires of NW Spain

The mountain ranges in NW Spain have a large number of little known wetlands. We report the results of a study carried out on a group of 77 small lakes and mires in the Sierra Segundera and Cordillera Cantábrica. The main physical and chemical variables, and phytoplankton communities from littoral samples were studied. Cantabrian wetlands showed greater variability in all environmental variables measured as well as higher values in those related to mineralisation than the Segundera ones. Many of these ecosystems were oligotrophic and showed a high species richness. Desmids and diatoms were the two most abundant groups, both in the species number and in biovolume. Desmids were the most numerous group in taxa in Sierra Segundera, whereas diatoms were in Cordillera Cantábrica. Differences in species composition of algae communities between both mountain ecosystems were studied. Canonical Correspondence Analysis (CCA) was carried out on diatom and desmid flora composition. This analysis showed that alkalinity was the most important parameter in diatom distribution and pH the most important one in that of desmids.[PUBLICATION ABSTRACT]