| 1. Total number of native species (S): As in other adaptations of multimetric indexes, the number of native species is expected to decrease with anthropic degradation following pollution, loss of habitat diversity or introduction of non-native species. |
Decrease |
| ii - Abundance |
|
| 2. W statistic from ABC curve (W)*: This method was proposed by Warwick (1986) and Clarke (1990) as a tool to infer about the effect of anthropic stress on the biota. The assumption is that less disturbed assemblages have larger and long live species, which in general are less abundant, but have higher dominance in weight. In this case, the dominance in weight is higher than in number of individuals and W has positive values. In disturbed environments, it is expected a predominance of small and opportunistic species that have high abundance but low biomass, resulting in negative values of W (Magurran, 2004). The metric was calculated by: , were Bi = the species weight in score i, Ai = the species numeric abundance in score i and S = species richness. The response of ABC curve to damming was analyzed by Penczak & Agostinho (1997) in Segredo reservoir, and by Gonçalves & Braga (2008) in the SHP Mogi-Guaçu. The pattern followed the expected behavior in all examples. |
Decrease |
| 3. Percent of dominance (PDOM): The percent of dominance of the most abundant species is an indicative of habitat simplification (McDonough & Hickman, 1999) and was used in Brazilian reservoirs by Petesse et al. (2007a) and by Terra & Araújo (2010). |
Increase |
| 4. Total number of individuals (N): This metric assumes that the total abundance decreases with disturbance. As different fish groups can vary in their response to environmental disturbance, the metric is complemented by the next three metrics (number 5 to 7) referent to different fish Orders and Families. |
Decrease |
| 5. Percent abundance of Characiformes (CHAR)*: This metric was used to evaluate fishes that use the water column, have visual orientation and are capable to colonize a wide variety of habitats. It was used in substitution to Characiformes richness (Araújo et al., 2003; Petesse et al., 2007a; Terra & Araújo, 2010), with justify in situation such as the present study were there is a small number of species (Magalhães et al., 2008). |
Decrease |
| 6. Percent abundance of Siluriformes (SIL)*: This metric intends to evaluate the benthic habitats as a substitution for the number of sucker species proposed by Karr (1981). The number of Siluriformes was first used in African rivers by Hugueny et al. (1996), and in Brazilian rivers and reservoirs by Araújo et al. (2003), Bozzetti & Schulz (2004), Petesse et al. (2007a) and Terra & Araújo (2010). It is assumed that the abundance of Siluriformes is reduced by the degradation of benthic habitat, which in reservoir can occur as result of siltation or oxygen depletion. |
Decrease |
| 7. Percent abundance of Cichlidae (CICH)*: This metric was considered in substitution for Cichlidae species richness used by Petesse et al. (2007a) as an indicator of degradation of the littoral zones used to nest construction. |
Decrease |
| 8. Percent abundance of introduced species (INTR)*: Used in substitution for the metric number of introduced species (Araújo et al., 2003; Petesse et al., 2007a). In reservoirs where these species are established, there are in general negative effects on native assemblage structure. |
Increase |
| 9. Percent abundance of individuals larger than 30 cm (L30): This metric was proposed by Petesse et al. (2007a) to evaluate the decrease of k-strategists species in favor of r-strategists. The dominance of r-strategists was verified by Gonçalves & Braga (2008) in the SHP Mogi-Guaçu. |
Decrease |
| iii - Trophic structure |
|
| 10. Weight percent of piscivorous (PIS): Piscivorous species are in the top of aquatic foodwebs and their abundance indicates an assemblage well diversified and structured (Karr, 1981). For all metric related to trophic structure it was use the weight percent because it is a better indicator of energy assimilation and transfer in foodwebs. |
Decrease |
| 11. Weight percent of insectivorous (INS): Insectivorous species, especially those feeding on allochthonous items are dependent on riparian vegetation well structured (Casatti, 2002; Esteves & Aranha, 1999; Menezes et al., 2007; Sabino & Castro, 1990). |
Decrease |
| 12. Weight percent of omnivorous (OMNI): A metric related to omnivory was proposed by Karr (1981) as evidence of disruption of the foodweb base. These species are in general opportunistic and predominate when the foodweb is simplified. |
Increase |
| 13. Weight percent of detritivorous (DET)*: It is proposed to evaluate the increase in detritus sedimentation favoring the species that use this alimentary resource. |
Increase |
| 14. Weight percent of herbivorous (HER)*: The number of herbivorous species was used by Araújo et al. (2003) and Petesse et al. (2007a). This metric intent to evaluate the contribution of species with high-specialized diet, which should be sensible to habitat disruption (Ganasan & Hughes, 1998; Petesse et al., 2007a). In Neotropical reservoirs this group is naturally rare (Agostinho et al., 2007). |
Decrease |
| iv - Reproduction |
|
| 15. Weight percent of species with parental care (PC)*: This metric was used to evaluate the effect of disruption of littoral zones resulted from siltation or hydrological stress (Petesse et al., 2007b). The species with parental care (Geophagus brasiliensis, Hoplias malabaricus, Hoplosternum littorale, Oreochromis niloticus and the genera Hypostomus) were based on Suzuki et al. (2005). |
Decrease |
Presence of riparian vegetation increases biotic condition of fish assemblages in two Brazilian reservoirs
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