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)Warwick, R.M. A new method for detecting pollution effects on marine macrobenthic communities. Marine Biology, 1986, 92(4), 557-562. http://dx.doi.org/10.1007/BF00392515. http://dx.doi.org/10.1007/BF00392515...
and Clarke (1990)Clarke, K.R. Comparison of dominance curves. Journal of Experimental Marine Biology and Ecology, 1990, 138(1-2), 143-157. http://dx.doi.org/10.1016/0022-0981(90)90181-B. http://dx.doi.org/10.1016/0022-0981(90)9...
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, 2004MAGURRAN, A.E. Measuring biological diversity. Oxford: Blackwell Science, 2004, 248 p.). 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)Penczak, T. and AGOSTINHO, A.A. Aplicação do método de comparação de abundância/biomassa (ABC) na comunidade de peixes do reservatório do Segredo. In A.A. AGOSTINHO and L.C. GOMES, eds. Reservatório de Segredo: bases ecológicas para o manejo. Maringá: Eduem, 1997, pp. 203-241. in Segredo reservoir, and by Gonçalves & Braga (2008)Gonçalves, C.S. and Braga, F.M.S. Diversidade e ocorrência de peixes na área de influência da UHE Mogi-Guaçu e lagoas marginais, bacia do alto Rio Paraná, São Paulo, Brasil. Biota Neotropica, 2008, 8(2), 103-114. http://dx.doi.org/10.1590/S1676-06032008000200012. http://dx.doi.org/10.1590/S1676-06032008...
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, 1999Mcdonough, T.A. and HICKMAN, G.D. Reservoir Fish Assemblage Index development: a tool for assessing ecological health in Tennessee Valley Authority impoundments. In T.P. SIMON, ed. Assessing the sustainability and Biological Integrity of water resources using fish communities. Boca Raton: CRC Press, 1999, pp. 523-540.) and was used in Brazilian reservoirs by Petesse et al. (2007a)Petesse, M.L., Petrere Junior, M. and Spigolon, R.J. Adaptation of the Reservoir Fish Assemblage Index (RFAI) for assessing the Barra Bonita Reservoir (São Paulo, Brazil). River Research and Applications, 2007a, 23(6), 595-612. http://dx.doi.org/10.1002/rra.1001. http://dx.doi.org/10.1002/rra.1001...
and by Terra & Araújo (2010)Terra, B.F. and Araújo, F.G. A preliminary fish assemblage index for a transitional river-reservoir system in southeastern Brazil. Ecological Indicators, 2010, 11(3), 874-881. http://dx.doi.org/10.1016/j.ecolind.2010.11.006. http://dx.doi.org/10.1016/j.ecolind.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., 2003Araújo, F.G., Fichberg, I., Pinto, B.C. and Peixoto, M.G. Preliminary index of biotic integrity for monitoring the condition of the Rio Paraiba do Sul, Southeast, Brazil. Environmental Management, 2003, 32(4), 516-526. http://dx.doi.org/10.1007/s00267-003-3003-9. PMid:14986900. http://dx.doi.org/10.1007/s00267-003-300...
; Petesse et al., 2007aPetesse, M.L., Petrere Junior, M. and Spigolon, R.J. Adaptation of the Reservoir Fish Assemblage Index (RFAI) for assessing the Barra Bonita Reservoir (São Paulo, Brazil). River Research and Applications, 2007a, 23(6), 595-612. http://dx.doi.org/10.1002/rra.1001. http://dx.doi.org/10.1002/rra.1001...
; Terra & Araújo, 2010Terra, B.F. and Araújo, F.G. A preliminary fish assemblage index for a transitional river-reservoir system in southeastern Brazil. Ecological Indicators, 2010, 11(3), 874-881. http://dx.doi.org/10.1016/j.ecolind.2010.11.006. http://dx.doi.org/10.1016/j.ecolind.2010...
), with justify in situation such as the present study were there is a small number of species (Magalhães et al., 2008Magalhães, M.F., Ramalho, C.E. and Collares-Pereira, M.J. Assessing biotic integrity in a Mediterranean watershed: development and evaluation of a fish-based index. Fisheries Management and Ecology, 2008, 15(4), 273-289. http://dx.doi.org/10.1111/j.1365-2400.2008.00612.x. http://dx.doi.org/10.1111/j.1365-2400.20...
). |
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)Karr, J.R. Assessment of biotic integrity using fish communities. Fisheries, 1981, 6(6), 21-27. http://dx.doi.org/10.1577/1548-8446(1981)006<0021:AOBIUF>2.0.CO;2. http://dx.doi.org/10.1577/1548-8446(1981...
. The number of Siluriformes was first used in African rivers by Hugueny et al. (1996)Hugueny, B., Camara, S., Samoura, B. and Magassouba, M. Applying an index of biotic integrity based on fish assemblages in a West African river. Hydrobiologia, 1996, 331(1-3), 71-78. http://dx.doi.org/10.1007/BF00025409. http://dx.doi.org/10.1007/BF00025409...
, and in Brazilian rivers and reservoirs by Araújo et al. (2003)Araújo, F.G., Fichberg, I., Pinto, B.C. and Peixoto, M.G. Preliminary index of biotic integrity for monitoring the condition of the Rio Paraiba do Sul, Southeast, Brazil. Environmental Management, 2003, 32(4), 516-526. http://dx.doi.org/10.1007/s00267-003-3003-9. PMid:14986900. http://dx.doi.org/10.1007/s00267-003-300...
, Bozzetti & Schulz (2004)Bozzetti, M. and Schulz, U.H. An index of biotic integrity based on fish assemblages for subtropical streams in southern Brazil. Hydrobiologia, 2004, 529(1-3), 133-144. http://dx.doi.org/10.1007/s10750-004-5738-6. http://dx.doi.org/10.1007/s10750-004-573...
, Petesse et al. (2007a)Petesse, M.L., Petrere Junior, M. and Spigolon, R.J. Adaptation of the Reservoir Fish Assemblage Index (RFAI) for assessing the Barra Bonita Reservoir (São Paulo, Brazil). River Research and Applications, 2007a, 23(6), 595-612. http://dx.doi.org/10.1002/rra.1001. http://dx.doi.org/10.1002/rra.1001...
and Terra & Araújo (2010)Terra, B.F. and Araújo, F.G. A preliminary fish assemblage index for a transitional river-reservoir system in southeastern Brazil. Ecological Indicators, 2010, 11(3), 874-881. http://dx.doi.org/10.1016/j.ecolind.2010.11.006. http://dx.doi.org/10.1016/j.ecolind.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)Petesse, M.L., Petrere Junior, M. and Spigolon, R.J. Adaptation of the Reservoir Fish Assemblage Index (RFAI) for assessing the Barra Bonita Reservoir (São Paulo, Brazil). River Research and Applications, 2007a, 23(6), 595-612. http://dx.doi.org/10.1002/rra.1001. http://dx.doi.org/10.1002/rra.1001...
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., 2003Araújo, F.G., Fichberg, I., Pinto, B.C. and Peixoto, M.G. Preliminary index of biotic integrity for monitoring the condition of the Rio Paraiba do Sul, Southeast, Brazil. Environmental Management, 2003, 32(4), 516-526. http://dx.doi.org/10.1007/s00267-003-3003-9. PMid:14986900. http://dx.doi.org/10.1007/s00267-003-300...
; Petesse et al., 2007aPetesse, M.L., Petrere Junior, M. and Spigolon, R.J. Adaptation of the Reservoir Fish Assemblage Index (RFAI) for assessing the Barra Bonita Reservoir (São Paulo, Brazil). River Research and Applications, 2007a, 23(6), 595-612. http://dx.doi.org/10.1002/rra.1001. http://dx.doi.org/10.1002/rra.1001...
). 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)Petesse, M.L., Petrere Junior, M. and Spigolon, R.J. Adaptation of the Reservoir Fish Assemblage Index (RFAI) for assessing the Barra Bonita Reservoir (São Paulo, Brazil). River Research and Applications, 2007a, 23(6), 595-612. http://dx.doi.org/10.1002/rra.1001. http://dx.doi.org/10.1002/rra.1001...
to evaluate the decrease of k-strategists species in favor of r-strategists. The dominance of r-strategists was verified by Gonçalves & Braga (2008)Gonçalves, C.S. and Braga, F.M.S. Diversidade e ocorrência de peixes na área de influência da UHE Mogi-Guaçu e lagoas marginais, bacia do alto Rio Paraná, São Paulo, Brasil. Biota Neotropica, 2008, 8(2), 103-114. http://dx.doi.org/10.1590/S1676-06032008000200012. http://dx.doi.org/10.1590/S1676-06032008...
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, 1981Karr, J.R. Assessment of biotic integrity using fish communities. Fisheries, 1981, 6(6), 21-27. http://dx.doi.org/10.1577/1548-8446(1981)006<0021:AOBIUF>2.0.CO;2. http://dx.doi.org/10.1577/1548-8446(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, 2002Casatti, L. Alimentação dos peixes em um riacho do Parque Estadual do Morro do Diabo, Bacia do Alto Paraná, sudeste do Brasil. Biota Neotropica, 2002, 2(2), 1-14. http://dx.doi.org/10.1590/S1676-06032002000200012. http://dx.doi.org/10.1590/S1676-06032002...
; Esteves & Aranha, 1999Esteves, K.E. and ARANHA, J.M.R. Ecologia trófica de peixes de riachos. In E.P. CARAMASCHI, R. MAZZONI and P.R. PERES-NETO, eds. Ecologia de peixes de riachos. Rio de Janeiro: PPGE-UFRJ, 1999, pp. 157-182.; Menezes et al., 2007Menezes, N.A., Weitzman, S.H., Oyakawa, O.T., Lima, F.C.T., CASTRO, R.M.C. and WEITZMAN, M.J. Peixes de água doce da Mata Atlântica. São Paulo: Museu de Zoologia da USP, 2007, 407 p.; Sabino & Castro, 1990Sabino, J. and CASTRO, R.M.C. Alimentação, período de atividade e distribuição espacial dos peixes de um riacho de floresta atlântica (sudeste do Brasil). Brazilian Journal of Biology = Revista Brasileira de Biologia, 1990, 50(1), 23-26.). |
Decrease |
12. Weight percent of omnivorous (OMNI): A metric related to omnivory was proposed by Karr (1981)Karr, J.R. Assessment of biotic integrity using fish communities. Fisheries, 1981, 6(6), 21-27. http://dx.doi.org/10.1577/1548-8446(1981)006<0021:AOBIUF>2.0.CO;2. http://dx.doi.org/10.1577/1548-8446(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)Araújo, F.G., Fichberg, I., Pinto, B.C. and Peixoto, M.G. Preliminary index of biotic integrity for monitoring the condition of the Rio Paraiba do Sul, Southeast, Brazil. Environmental Management, 2003, 32(4), 516-526. http://dx.doi.org/10.1007/s00267-003-3003-9. PMid:14986900. http://dx.doi.org/10.1007/s00267-003-300...
and Petesse et al. (2007a)Petesse, M.L., Petrere Junior, M. and Spigolon, R.J. Adaptation of the Reservoir Fish Assemblage Index (RFAI) for assessing the Barra Bonita Reservoir (São Paulo, Brazil). River Research and Applications, 2007a, 23(6), 595-612. http://dx.doi.org/10.1002/rra.1001. http://dx.doi.org/10.1002/rra.1001...
. This metric intent to evaluate the contribution of species with high-specialized diet, which should be sensible to habitat disruption (Ganasan & Hughes, 1998Ganasan, V. and Hughes, R.M. Application of an index of biological integrity (IBI) to fish assemblages of rivers Khan and Kshipra (Madhya Pradesh), India. Freshwater Biology, 1998, 40(2), 367-383. http://dx.doi.org/10.1046/j.1365-2427.1998.00347.x. http://dx.doi.org/10.1046/j.1365-2427.19...
; Petesse et al., 2007aPetesse, M.L., Petrere Junior, M. and Spigolon, R.J. Adaptation of the Reservoir Fish Assemblage Index (RFAI) for assessing the Barra Bonita Reservoir (São Paulo, Brazil). River Research and Applications, 2007a, 23(6), 595-612. http://dx.doi.org/10.1002/rra.1001. http://dx.doi.org/10.1002/rra.1001...
). In Neotropical reservoirs this group is naturally rare (Agostinho et al., 2007Agostinho, A.A., Gomes, L.C. and PELICICE, F.M. Ecologia e manejo de recursos pesqueiros em reservatórios do Brasil. Maringá: Eduem, 2007, 501 p.). |
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., 2007bPetesse, M.L., Petrere Junior, M. and Spigolon, R.J. The hydraulic management of the Barra Bonita reservoir (SP, Brasil) as a factor influencing the temporal succession of its fish community. Brazilian Journal of Biology = Revista Brasileira de Biologia, 2007b, 67(3), 433-445. http://dx.doi.org/10.1590/S1519-69842007000300008. PMid:18094826. http://dx.doi.org/10.1590/S1519-69842007...
). The species with parental care (Geophagus brasiliensis, Hoplias malabaricus, Hoplosternum littorale, Oreochromis niloticus and the genera Hypostomus) were based on Suzuki et al. (2005)Suzuki, H.I., Bulla, C.K., Agostinho, A.A. and GOMES, L.C. Estratégias reprodutivas de assembleias de peixes em reservatórios. In L. RODRIGUES, S.M. THOMAZ, A.A. AGOSTINHO and L.C. GOMES, eds. Biocenoses em reservatórios: padrões espaciais e temporais. São Carlos: Rima, 2005, pp. 223-242.. |
Decrease |