Disentangling natural and anthropogenic influences on Patagonian pond water quality.
Epele, L. B., Manzo, L. M., Grech, M. G., Macchi, P., Claverie, A. N., Lagomarsino, L. and Miserendino, M. L.
Centro de Investigacion Esquel de Montana y Estepa Patagonica (CONICET-UNPSJB), Roca 780, Esquel, Chubut, Argentina. Electronic address: luisbepele@comahue-conicet.gob.ar.
Centro de Investigacion Esquel de Montana y Estepa Patagonica (CONICET-UNPSJB), Roca 780, Esquel, Chubut, Argentina.
Instituto de Investigacion en Paleobiologia y Geologia (CONICET-UNRN), General Roca, Rio Negro, Argentina.
Facultad de Ciencias Naturales, Universidad Nacional de la Patagonia San Juan Bosco, Ruta 259, km 16.4, Esquel, Chubut, Argentina.
Laboratorio de Ecologia y Fotobiologia Acuatica, Instituto Tecnologico de Chascomus (INTECH), CC 164 (B7130IWA), Chascomus, Buenos Aires, Argentina.
The water quality of wetlands is governed not only by natural variability in hydrology and other factors, but also by anthropogenic activities. Patagonia is a vast sparsely-populated in which ponds are a key component of rural and urban landscapes because they provide several ecosystem services such as habitat for wildlife and watering for livestock. Integrating field-based and geospatial data of 109 ponds sampled across the region, we identified spatial trends and assessed the effects of anthropogenic and natural factors in pond water quality. The studied ponds were generally shallow, well oxygenated, with maximum nutrient values reported in sites used for livestock breeding. TN:TP ratio values were lower than 14 in >90% of the ponds, indicating nitrogen limitation. Water conductivity decreased from de east to the west, meanwhile pH and dissolved oxygen varied associated with the latitude. To assess Patagonian ponds water status we recommend the measure of total suspended solids and total nitrogen in the water, and evaluate the mallin (wetland vegetation) coverage in a 100m radius from the pond, since those features were significantly influenced by livestock land use. To evaluate the relative importance of natural variability and anthropogenic influences as driving factors of water quality we performed three generalized linear models (GLM) that encompassed the hydrology, hydroperiod and biome (to represent natural influences), and land use (to represent anthropogenic influences) as fixed effects. Our results revealed that at the Patagonian scale, ponds water quality would be strongly dependent on natural gradients. We synthetized spatial patterns of Patagonian pond water quality, and disentangled natural and anthropic factors finding that the dominant environmental influence is rainfall gradient.
Science of the Total Environment 613-614: 866-876 (2017)