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: 3.16). 01/2011; 409(3):612-24. DOI: 10.1016/j.scitotenv.2010.10.034
Source: PubMed

ABSTRACT 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.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Biological assessment of aquatic ecosystems is widely employed as an alternative or complement to chemical and toxicity testing due to numerous advantages of using biota to determine ecosystem condition. These advantages, especially to developing countries, include the relatively low cost and technical requirements. This study was carried out to establish relationship between water quality and macrozoobenthos assemblages along the Lukaya stream and to analyze fauna structure assemblages. Seven sites were selected along a 50-km stretch of the stream, which drained land under agricultural, residential and industrial uses. Water physico-chemical data was explored using multivariate analysis of Canonical Component Analysis to detect environmental trends. Water physico-chemical characteristics (temperature, pH, turbidity, conductivity, calcium, magnesium, nitrate, nitrite, sulphate and phosphate) and biodiversity indices (species richness, diversity, redundancy, evenness, abundance) did not show significant difference (P = 1) between sites along the stream but some correlation between variables and biodiversity indices were detected by spearman’s correlation analysis. Sixty-two taxonomic groups identified are dominated by odonata, diptera, shelfish and molluscs but three taxa: Lymnaeidae, Chironomyidae and Atyidae presented the highest abundance in all assemblages. The model of DIMO made it possible to split the various sites in two groups in function of H’, Hmax and J’. Moreover, rank-frequency diagrams of Frontier characterized stage 1 and middle between stages 1 and 2 structured curves. Keywords: Macro-invertebrates, water quality, biodiversity indices, Lukaya stream, physico-chemical parameters.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Understanding the primary effects of anthropogenic activities and natural factors on river water quality is important in the study and efficient management of water resources. In this study, analysis of Variance (ANOVA), Principal component analysis (PCA), Pearson correlations, Multiple regression analysis (MRA) and Redundancy analysis (RDA) were applied as an integrated approach in a GIS environment to explore the temporal and spatial variations in river water quality and to estimate the influence of watershed land use, topography and socio-economic factors on river water quality based on 3 years of water quality monitoring data for the Cao-E River system. The statistical analysis revealed that TN, pH and temperature were generally higher in the rainy season, whereas BOD5, DO and turbidity were higher in the dry season. Spatial variations in river water quality were related to numerous anthropogenic and natural factors. Urban land use was found to be the most important explanatory variable for BOD5, CODMn, TN, DN, NH4+-N, NO3--N, DO, pH and TP. The animal husbandry output per capita was an important predictor of TP and turbidity, and the gross domestic product per capita largely determined spatial variations in EC. The remaining unexplained variance was related to other factors, such as topography. Our results suggested that pollution control of animal waste discharge in rural settlements, agricultural runoff in cropland, industrial production pollution and domestic pollution in urban and industrial areas were important within the Cao-E River basin. Moreover, the percentage of the total overall river water quality variance explained by an individual variable and/or all environmental variables (according to RDA) can assist in quantitatively identifying the primary factors that control pollution at the watershed scale.
    PLoS ONE 08/2014; 9(8):e102714. · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Deforestation in the tropical Andes is affecting ecological conditions of streams, and determination of how much forest should be retained is a pressing task for conservation, restoration and management strategies. We calculated and analyzed eight benthic metrics (structural, compositional and water quality indices) and a physical-chemical composite index with gradients of vegetation cover to assess the effects of deforestation on macroinvertebrate communities and water quality of 23 streams in southern Ecuadorian Andes. Using a geographical information system (GIS), we quantified vegetation cover at three spatial scales: the entire catchment, the riparian buffer of 30 m width extending the entire stream length, and the local scale defined for a stream reach of 100 m in length and similar buffer width. Macroinvertebrate and water quality metrics had the strongest relationships with vegetation cover at catchment and riparian scales, while vegetation cover did not show any association with the macroinvertebrate metrics at local scale. At catchment scale, the water quality metrics indicate that ecological condition of Andean streams is good when vegetation cover is over 70%. Further, macroinvertebrate community assemblages were more diverse and related in catchments largely covered by native vegetation (.70%). Our results suggest that retaining an important quantity of native vegetation cover within the catchments and a linkage between headwater and riparian forests help to maintain and improve stream biodiversity and water quality in Andean streams affected by deforestation. This research proposes that a strong regulation focused to the management of riparian buffers can be successful when decision making is addressed to conservation/restoration of Andean catchments. Copyright: ß 2014 Iñ iguez–Armijos et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This research was funded through a scholarship of the Secretaria Nacional de Educació n Superior, Ciencia, Tecnología e Innovació n of Ecuador (SENACYT), a DFG (Deutsche Forschungsgemeinschaft) grant (FR615/28-1/-2) and by the Universidad Técnica Partucular de Loja (UTPL). The support from Henrietta Hampel was thanks to the PROMETEO Program of SENESCYT. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist.
    PLoS ONE 08/2014; 9(8):e105869. · 3.53 Impact Factor


Available from
May 20, 2014