Assessing land-use effects on water quality, in-stream habitat, riparian ecosystems and biodiversity in Patagonian northwest streams

MARÍA LAURA MISERENDINO, RICARDO CASAUX, MIGUEL ARCHANGELSKY, CECILIA YANINA DI PRINZIO, CECILIA BRAND, ADRIANA MABEL KUTSCHKER

SCIENCE OF THE TOTAL ENVIRONMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2011 vol. 409 p. 612 - 624

0048-9697

Changes in land-use practices have affected the integrity and quality of water resources worldwide. InPatagonia there is a strong concern about the ecological status of surface waters because these changes arerapidly occurring in the region. To test the hypothesis that greater intensity of land-use will have negativeeffects 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/littoralinvertebrate taxa, 5 fish species, 34 bird species, and 15 aquatic plant species, were recorded consideringall 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 managednative forest sites appeared in an intermediate situation. The highest values of fish and bird abundance anddiversity were observed at disturbed sites; this might be explained by the opportunistic behavior displayed bythese communities which let them take advantage of increased trophic resources in these environments. Asexpected, non-managed native forest sites showed the highest integrity of ecological conditions and also greatbiodiversity of benthic communities. Macroinvertebrate metrics that reflected good water quality werepositively related to forest land cover and negatively related to urban and pasture land cover. However, byoffering 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 qualityconditions and resulted useful tools to early alert of disturbances in streams. Fish and birds having a greaterability of dispersion and capacity to move quickly from disturbances would reflect changes at a higher scale.