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

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

ECOLOGICAL INDICATORS

ELSEVIER SCIENCE BV

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

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 related to the quality of the watercourse, the riverbanks, the riparian zone and the fluvial geomorphology. The metrics retained in the index (USHI, Urban Stream HabitatIndex) include the cover percentage and quality of the aquatic vegetation; the main features of the river banks; thepresence of exotic trees, of litter, 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 parameters that arelinked to water quality, the imperviousness of the watershed and to other biotic descriptors, particularly the macroinvertebrateand diatom assemblages. The values of the index for the sites in the studied area revealed that 41.2% have a bad orvery bad habitat quality, 27.8% a moderate habitat quality, while 31% have a good or very good habitat quality. The mainissue detected in the studied sites involved the dredging or partial channelization of the reaches. Unlike other indices thatevaluate the quality of the physical habitat through 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 identificationof taxa, making it more accessible to non-specialists. Therefore it provides with a tool to evaluate the fluvial habitatquality of lowland streams that can be easily applied, particularly by professionals that take part in the management anddecision making process regarding urbanized watersheds.