Assessing Land-use Effects on Water Quality, In-stream Habitat, Riparian Ecosystems and Biodiversity in Patagonian Northwest Streams

CONICET Laboratorio de Investigaciones en Ecología y Sistemática Animal-Universidad Nacional de la Patagonia San Juan Bosco, Argentina.
Science of The Total Environment (Impact Factor: 4.1). 01/2011; 409(3):612-24. DOI: 10.1016/j.scitotenv.2010.10.034
Source: PubMed


Changes in land-use practices have affected the integrity and quality of water resources worldwide. In Patagonia there is a strong concern about the ecological status of surface waters because these changes are rapidly occurring in the region. To test the hypothesis that greater intensity of land-use will have negative effects on water quality, stream habitat and biodiversity we assessed benthic macroinvertebrates, riparian/littoral invertebrates, fish and birds from the riparian corridor and environmental variables of 15 rivers (Patagonia) subjected to a gradient of land-use practices (non-managed native forest, managed native forest, pine plantations, pasture, urbanization). A total of 158 macroinvertebrate taxa, 105 riparian/littoral invertebrate taxa, 5 fish species, 34 bird species, and 15 aquatic plant species, were recorded considering all sites. Urban land-use produced the most significant changes in streams including physical features, conductivity, nutrients, habitat condition, riparian quality and invertebrate metrics. Pasture and managed native forest sites appeared in an intermediate situation. The highest values of fish and bird abundance and diversity were observed at disturbed sites; this might be explained by the opportunistic behavior displayed by these communities which let them take advantage of increased trophic resources in these environments. As expected, non-managed native forest sites showed the highest integrity of ecological conditions and also great biodiversity of benthic communities. Macroinvertebrate metrics that reflected good water quality were positively related to forest land cover and negatively related to urban and pasture land cover. However, by offering stream edge areas, pasture sites still supported rich communities of riparian/littoral invertebrates, increasing overall biodiversity. Macroinvertebrates were good indicators of land-use impact and water quality conditions and resulted useful tools to early alert of disturbances in streams. Fish and birds having a greater ability of dispersion and capacity to move quickly from disturbances would reflect changes at a higher scale.

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Available from: Cecilia Brand, May 05, 2014
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    • "During the recent decades, the loss of freshwater biodiversity has been accentuated mainly due to changes in land use from humanrelated activities (e.g., forestry and livestock or arable farming) that have resulted in habitat destruction, fragmentation and eutrophication (e.g., Encalada et al., 2010; Miserendino et al., 2011; Lunde and Resh, 2012). In particular, because of the economic benefit from the cellulose industry (Valdovinos, 2006), the replacement of native forest by plantations of exotic species (i.e., monocultures of conifers and eucalyptus) has been a widespread forestry practice all over the world (Hartley, 2002). "
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    • "Por outro lado, indicadores biológicos das comunidades aquáticas têm sido usados na avaliação da qualidade da água há mais tempo. Por exemplo, comunidades de macroinvertebrados são consideradas bons indicadores por incluírem alta diversidade de espécies, com diferentes grupos que respondem a tipos distintos de perturbações, terem ciclos de vida suficientemente longos, serem relativamente sedentários para representar as condições locais e ocorrerem na maioria dos habitats aquáticos em grande abundância, sendo sua coleta de baixo custo (Friberg et al., 2011). Estas características possibilitam sua aplicação em diversos sistemas e com diversas abordagens de avaliação, incluindo o uso de índices multimétricos (Buss et al., 2015). "

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