An index to evaluate the fluvial habitat degradation in lowland urban streams

COCHERO, JOAQUÍN; CORTELEZZI, AGUSTINA; TARDA, SANTIAGO; GÓMEZ, NORA

ECOLOGICAL INDICATORS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 71 p. 133 - 134

1470-160X

The objective of the present article is to propose an index that allows the assessment of the fluvial habitat quality in lowlandstreams that run through urbanized areas, by the use of metrics relatedto the quality of the watercourse, the river banks, the riparian zone andthe fluvial geomorphology. The metrics retained in the index (USHI, UrbanStream Habitat Index) include the cover percentage and quality of theaquatic vegetation; the main features of the river banks; the presence ofexotic trees, of litter, of permanent structures (such as buildings) inthe riparian zone and other major geomorphological alterations, such asdredging or channelization. The index is related to physical-chemicalparameters that are linked to water quality, the imperviousness of thewatershed and to other biotic descriptors, particularly themacroinvertebrate and diatom assemblages. The values of the index for thesites in the studied area revealed that 41.2% have a bad or very badhabitat quality, 27.8% a moderate habitat quality, while 31% have a goodor very good habitat quality. The main issue detected in the studiedsites involved the dredging or partial channelization of the reaches.Unlike other indices that evaluate the quality of the physical habitatthrough the use of the diatoms or macroinvertebrate communities, the USHIcan be interpreted as a measure of the overall quality of the habitat,and uses indicators that do not require 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 thatcan be easily applied, particularly by professionals that take part inthe management and decision making process regarding urbanizedwatersheds.