Assessment methodology for southern siliceous basins in Portugal

Abstract

A sampling programme was developed in three stream types, of siliceous geology, from the south of Portugal (small and mid-sized lowland streams and small-sized median altitude streams). The samples were taken according to the AQEM site protocol procedure, keeping transport and depositional habitats samples separated. In each stream type, at least 13 sites were studied over a gradient of organic pollution (pre-classification). The benthic macroinvertebrates were identified to the lowest possible taxonomic level. A Detrended Correspondence Analysis of macroinvertebrate communities identified a gradient of organic pollution strongly related to the first axis. This ordination allowed the establishment of classes of organic pollution using the Kmeans software (post-classification). Metrics based on the macroinvertebrate communities (tolerance, richness, composition and trophic structure) were computed and tested for correlation with the gradient of organic pollution (first axis of DCA). Most of the selected metrics were able to discriminate the four quality classes (high, good, moderate and poor) of ecological status. A multimetric index, integrating ASPT index, Trichoptera families and percentage of Gasteropoda, Oligochaeta and Diptera, is proposed to assess the ecological status of Portuguese southern siliceous basins.

Effect of fixed-fraction subsampling on macroinvertebrate bioassessment of rivers

“…Metrics are defined as the "measurable parts or processes of a biological system empirically shown to change along a gradient of human influence" (Karr and Chu 1999). Since single metrics usually cover only one community characteristic, many multimetric indices have been developed (Karr and Chu 1999;Barbour et al 1999;Lorenz et al 2004a;Ofenböck et al 2004;Pinto et al 2004). A multimetric index combines several individual metric scores, the results of which are combined into the multimetric result.…”

The STAR common metrics approach to the WFD intercalibration process: Full application for small, lowland rivers in three European countries

“…A second option for comparing -and later harmonizing -boundaries, also based on the ICMi approach, is to contrast indirectly the national Based on 1-GOLD 1 -(relative abundance of Gastropoda, Oligochaeta and Diptera) Pinto et al (2004) Total number of families Sum of all Families present at the site e.g. Thorne & Williams, (1997) Number of EPT families Sum of Ephemeroptera, Plecoptera and Trichoptera taxa e.g.…”

“…Also, they were chosen on the basis of recent metric selection experiences (e.g. AQEM Consortium, 2002;Hering et al, 2004a;Pinto et al, 2004). The potential application of the metrics over a wide geographical scale was taken into account in order that they can be applied to most datasets in Europe (i.e.…”

Effects of sampling and sub-sampling variation using the STAR-AQEM sampling protocol on the precision of macroinvertebrate metrics

“…Two new metrics, 'Log(Sel_EPTD+1)' based on the logarithm of the total abundance of selected Ephemeroptera, Plecoptera, Tricoptera and Diptera, and '1-GOLD' based on the proportion of all individuals which are not Gasteropoda, Oligochaeta or Diptera (Pinto et al, 2004), were included because they are two of the six proposed Inter-calibration Common Metrics (ICMs) for use throughout Europe . Their values were calculated separately, but replicate sub-samples values were only available for sites in the Czech Republic.…”