부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.limno.2007.06.001 Byline: Romina E. Principe, Graciela B. Raffaini, Cristina M. Gualdoni, Ana M. Oberto, Maria C. Corigliano Keywords: Macroinvertebrate assemblages; Benthos; Hydraulic units; Habitat; Stream; Diversity and abundance patterns Abstract: Methods to assess the physical habitat provide important tools for many aspects of river management. Hydraulic units (defined as a homogeneous patch of flow type and substrate) were described in mountain streams of Central Argentina and the distribution of macrozoobenthos in these habitat units was analyzed. Four streams from the upper CarcaraA[+ or -]a River Basin (Cordoba, Argentina) were sampled in two hydrological periods. Hydraulic units (as substrate and flow type), current velocity, depth, macrophytes and macroalgae were assessed. Three benthic samples were taken in each hydraulic unit. A total of 12 hydraulic units were registered, which varied seasonally in their proportional abundance. The highest values of taxonomic richness, total abundance, diversity and evenness were found in the low-water period. The most heterogeneous hydraulic units (characterized by substrate of diverse grain size) presented the highest richness, diversity and evenness, whereas the highest total abundance was observed in hydraulic units with homogeneous substrate, such as bedrock or gravel sand. Canonical correspondence analysis grouped samples and taxa mainly in relation to the hydraulic units, and temporal variation in macroinvertebrate assemblages was observed. We found that the interaction between hydrological and geomorphological conditions affected benthic assemblages and that their organization is important at a mesoscale. Therefore, hydraulic units may be considered important tools in assessing stream integrity in lotic systems of central Argentina. Author Affiliation: Departamento de Ciencias Naturales, Universidad Nacional de Rio Cuarto, A.P. No. 3 (X5804 BYA) Rio Cuarto, Cordoba, Argentina Article History: Received 8 December 2006; Revised 14 June 2007; Accepted 15 June 2007