The main objective of the ECOSTRIMED index (ECOlogical STatus
Rivers MEDiterranean) is to provide an integrated quality value for fluvial
ecosystems, including as main parameters the riparian habitat and the biological
quality of the water. it has been designed as an RBP (Rapid Bioassessment
Protocol) in order to be performed directly in the field with a short sampling
time schedule.
The Ecostrimed value is calculated by combining the values of
two other quality indices:
1. A biotic index based on macroinvertebrates (FBILL or BMWP’)
2. The riparian habitat quality index (QBR)
The Ecostrimed value is simple to calculate using the following
table, which gives the ecological status of the studied reach:
QBR
FBILL
BMWP’
> 75
45-75
<45
8-10
> 100
High
Good
Fair
6-7
61-100
Good
Fair
Poor
4-5
36-60
Fair
Poor
Poor
0-3
< 36
Poor
Bad
Bad
The main value in determining the ecological status is the
biotic index, because we consider that, even when the riparian habitat has an
excellent conservation status, very polluted waters make the functioning of the
freshwater ecosystem impossible. However, the riparian habitat is also a key
factor and in the case of very good biological conditions in the river but low
riparian quality, the highest value of the ecological status will be only fair.
The five classes of the ecological status are those put forward in the European
Union Water Framework Directive.
In this RBP version, the ECOSTRIMED index does not consider the
status of the fish community, the bird community, amphibians, reptiles or the
physicochemical characteristics of the water (which we consider to be already
included in the value of the biological index). Most of these parameters are
reflected totally or partially in the values of either the biotic indices (e.g.
physicochemical characteristic of the water or the fish community) or the QBR
(birds). Non-native fishes and other introduced species (such as the American
freshwater crayfish, Procambarus clarki,) should be considered in the
future, and if they are present and abundant, the ECOSTRIMED value should be
corrected. In many of our rivers the status of fishes and the importance of
non-native species is not known at present, and methods of studying these
animals are complicated and time consuming. For this reason they are not
considered in the first version of the protocol for the calculation of
ECOSTRIMED but should be included in future studies when information about them
becomes available.
Source: Diputació de Barcelona 2000 (Copyright)
Developed by the Department of Ecology, University of
Barcelona, with the collaboration of the Department of Environment of the
Barcelona Council
