An index to evaluate the fluvial habitat degradation in lowland urbanstreams

COCHERO J; GOMEZ NORA; CORTELEZZI, A.; TARDA S.A.

ECOLOGICAL INDICATORS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 71 p. 134 - 144

1470-160X

tThe objective of the present article is to propose an index that allows the assessment of the fluvialhabitat quality in lowland streams that run through urbanized areas, by the use of metrics related tothe quality of the watercourse, the river banks, the riparian zone and the fluvial geomorphology. Themetrics retained in the index (USHI, Urban Stream Habitat Index) include the cover percentage andquality of the aquatic vegetation; the main features of the river banks; the presence of exotic trees, oflitter, of permanent structures (such as buildings) in the riparian zone and other major geomorphologicalalterations, such as dredging or channelization. The index is related to physical-chemical parametersthat are linked to water quality, the imperviousness of the watershed and to other biotic descriptors,particularly the macroinvertebrate and diatom assemblages. The values of the index for the sites inthe studied area revealed that 41.2% have a bad or very bad habitat quality, 27.8% a moderate habitatquality, while 31% have a good or very good habitat quality. The main issue detected in the studied sitesinvolved the dredging or partial channelization of the reaches. Unlike other indices that evaluate thequality of the physical habitat through the use of the diatoms or macroinvertebrate communities, theUSHI can be interpreted as a measure of the overall quality of the habitat, and uses indicators that do notrequire the identification of taxa, making it more accessible to non-specialists. Therefore it provides witha tool to evaluate the fluvial habitat quality of lowland streams that can be easily applied, particularlyby professionals that take part in the management and decision making process regarding urbanizedwatersheds.