Supplementary material

Fig. S1. Annual number of sites surveyed, with a distinction between belonging exclusively to REFNET (green bars), exclusively to REPNET (brown bars) and to both networks.

Fig. S2. Map of the Fish-based index trends for the REFNET sites, with the hydrographic basins limits.

Fig. S3. Description of taxa temporal trends using six indicators. Each point represents the annual median value of the indicator. Solid regression lines indicate that the Mann-Kendall trend test is statistically significant. The first two indicators “Density” and “Occupancy_rate” are fully described in the Methods section. The four other indicators are derived from the logistic models developed in Oberdorff et al. (2001) and giving the probability of occurrence of each of the 34 taxa as a function of a set of environmental characteristics. These models were originally fitted exclusively on reference (i.e., least-impacted) sites. We then considered a probability value over 50% as a predicted taxon presence and a probability below this threshold as a predicted taxon absence. These indicators are: (1) the percentage of sites where the taxon is predicted present and observed present (hereafter Confirmed_Presence), (2) the percentage of sites where the taxon taxon is predicted absent but observed present (hereafter Unexpected_Presence), (3) the percentage of sites where the taxon is predicted absent and observed absent (hereafter Confirmed_Absence) and (4) the percentage of sites where the taxon is predicted present but observed absent (hereafter Unexpected_Absence). When analyzed separately, these four indicators reflect temporal trends in the sites habitat suitability (or un-suitability) for a given taxon, according to the models.

Table S1. List of taxa contributing to each metric making up the FBI.

Table S2. Mann-Kendall test of monotonic temporal trend for the 25, 50 and 75^th percentiles of annual FBI score for REPNET and REFNET, 2013-2013, excluding the sites that are shared between these networks. The rows in bold indicate a significant trend (mk_pvalue < 0.05).

Table S3. Count and proportion of the REPNET and REFNET sites according to the Fish-based index trends.

© P. Irz et al., Published by EDP Sciences 2024