Landuse effects on aquatic and wetland ecosystems: an overview of environmental impacts and tools for ecological assessment

Abstract

Unlike in many other territories, the colonization process in Patagonia is relatively recent; however, important human-induced changes have occurred since the arrival of the first settlers. With regard to aquatic resources, there has been frequent irresponsible management driven by the idea that the supply of water is unlimited. Despite their low population density, some areas in Patagonia are seeing an important increase in population, at a higher rate than many other regions in Argentina. This expansion is promoting an intensifcation of the land use and is having signifcant environmental impacts on the region’s aquatic resources.According to Morello et al. (2018), three different ecoregions can be distinguished in the vast Patagonian territory. A narrow strip of forests over and along the Andes and at the headwaters of all Patagonian basins forms the Patagonian Forest ecoregion. It is extended on the occidental part of Neuquén, Río Negro, Chubut, Santa Cruz province, and the austral strip of Tierra del Fuego, Antarctic, and South Atlantic Islands. The ecoregion also exhibits a wide proportion of shrubs, rocks, and continental ices. The temperate semi-deciduous rainforest dominates, with species changing with elevation, location (exposure), and latitude. The Patagonian Steppe ecoregion is a vast area that comprises Southwestern of Mendoza, west of Neuquén and Río Negro, most of Chubut and Santa Cruz and north of Tierra del Fuego. The main vegetation forms are shrub-grass species mostly adapted to extreme aridity conditions, low temperature, strong winds, and frequent frosts. It is composed of short shrubs, with cushion forms, prickly, with reduced leaf or even leafless. The herbaceous steppe with xerophytic grasses appears in a lower proportion. Wetlands are conspicuous in the continental sector and include meadows, marshes, bogs, forests, and shrubs (see Chap. 10). The Plains and Plateaus Monte ecoregion spreads from the Andes Cordillera to the Atlantic Ocean and includes great part of Mendoza, Neuquén, La Pampa, and a little portion of Río Negro and Chubut provinces. The landscape is dominated by plains and staggered plateaus wherein aridity is a prevailing feature. The main land-use practices in Patagonia include extensive livestock breeding, pasture conversion, forestry, pine plantations, mining and oil extraction, and to a lesser extent urbanization and industrial development. These practices have led to major ecosystem stressors, defned as any physical or chemical change promoted by anthropogenic action that causes signifcant modifcations in biological components, patterns, and relationships in natural systems. According to Dudgeon et al. (2006), five major threats or stressor categories have the potential to impact on freshwater biodiversity: overexploitation, water pollution, fow modifcation, habitat degradation, and species invasion. However, new threats emerged during the last few decades, with some of them disproportionately impacting freshwater systems. The consequences or impacts of these stressors are quantifable through the assessment of the attributes of biological components. Among organisms that respond consistently to different stressors are periphyton, macrophytes, and macroinvertebrates.Biodiversity in Patagonia is globally signifcant due to the region’s pronounced endemism, habitat heterogeneity, and biogeographic location. There is strong concern from a conservation standpoint, since both ongoing and emerging land-use practices are rapidly changing the ecological status of freshwater resources in the region.