Summary
16 stations comprising a wide variety of running water in Kabylia, from streams to rivers
were sampled. These stations are located at altitudes ranging from 60 m to 1115 m. 112 taxa
of benthic invertebrates in 14 zoological groups were counted.
The abundance, richness, diversity and fairness were studied. The taxonomic diversity
of the different stations shows an altitudinal gradient with maximum diversity in the areas of
altitude.
The sites affected by a slight organic pollution have plenty important owing to the
proliferation of Oligochaeta, Ephemeroptera and Diptera of chironomids and Simuliides.
Upstream sites (stations TR, AA, AI, W1, A1, D1) have a fairly balanced structure with
abundances ranging from 4638 individuals (station IA) and 9509 individuals (station A1).
As for the low-lying sites (stations BH, FR, TA, BK) most affected by organic pollution and
or industrial, have a distorted structure with a lower abundance.
The study area, because of its terrain and topography, provides a wide variety of aquatic
habitats. The number of taxa varies from one station to another; it fluctuates between a
minimum of 30 taxa collected at station BK and a maximum of 64 taxa collected at station
D1. Stations upstream of rivers contain over 80% of the total taxonomic richness. Piedmont
stations and a record low level taxonomic richness between 38 and 48 taxa (areas
intermediate disturbance). In potamal stations (stations TA, BK), the number of taxa
collected is relatively small: between 30 and 34 taxa.
The benthic community structure (EPTC) was visualized by multivariate statistical
methods (APC, AFC) to show the affinities of species to environmental variables selected.
The ascending hierarchical classification (AHC) was used to individualize 4 cores affinity
between stations on the one hand and species TCPS other, determined by a longitudinal
gradient. Specific associations and the stations that host allowed to fragment the river
system studied in four areas. For each area so defined, a list of key species and accessories is
available.
As for the results of laboratory tests (IBGN), they show a clear deterioration of the
stations downstream sectors: from one class of excellent quality (1A) to a class of poor
quality (2). This is partly due to the standardization of the medium with a smaller number of
microhabitats downstream resulting in a decrease in the number of taxa and on the other
hand, the alteration of water quality inducing the disappearance of most taxa polluo-
sensitive: a shift from GI = 9 a GI = 3.
Keywords: River, benthic invertebrate, diversity, community structure, bioindication,
Kabylia.