Patagonian wetlands subjected to different intensities of cattle grazing pressure. Does it modify aquatic invertebrate and macrophytes community assemblages?

EPELE LUIS BELTRAN; MISERENDINO MARÍA LAURA; KUTSCHKER ADRIANA

Duluth

Congreso; SWS Annual Meeting 2013; 2013

Society of Wetland Scientists

Wetlands are important as water suppliers and sustain most of the livestock in semiarid and arid areas in the Patagonian steppe (Argentina). However, the consequences that these activities are having on such valuable ecosystems are not explicitly known. In order to assess if cattle produced a significant impact in water quality and biota we conducted a study at 30 wetlands from Middle West Patagonia. We analyzed the spatial changes in environmental features and also investigated variation in invertebrate and macrophytes assemblages. A considerable number of physical, chemical and environmental changes associated with different disturbance levels were documented. Invertebrate assemblages were dominated by Diptera, Coleoptera, Amphipoda and Hemiptera. Gamma diversity was 123 taxa. Among macrophytes (50 taxa), Cyperaceae, Juncaceae and Poaceae were the best represented groups. A Canonical Correspondence Analysis (CCA) based on invertebrates allowed us to distinguish specifics assemblages associated to different levels of disturbance. Pristina osborni, Boeckella spp., Berosus alternans, Syrphidae sp., Haliplus subseriatus, and Pentaneura sp., appeared on wetlands showing high levels of anthropogenic deterioration. Similar patterns were highlighted in another analysis (CCA) based in plant composition. The information obtained in this work will help to recognize how cattle management is affecting Patagonian wetlands conditions. Some specific actions for conservation of these environments should include controlled grazing areas, alternative sources of water supply and in some cases cattle exclusion. In this scenario it is crucial a financial support to ensure a sustained maintenance of the wetlands.