O impacto de pequenas centrais hidrelétricas na diversidade de anfíbios anuros
Data
2019-01
Autores
Pina, Ligia Ferracine de 
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
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Resumo
As alterações ambientais causadas por empreendimentos hidrelétricos, em constante
proliferação no Brasil, ameaçam tanto organismos aquáticos quanto terrestres. Grandes
hidrelétricas causam declínios na abundância e riqueza e alterações na composição de
espécies de anfíbios, tanto nas áreas afetadas pelo enchimento dos reservatórios, quanto nas
jusantes das barragens. Os impactos de instalação e funcionamento de Pequenas Centrais
Hidrelétricas (PCHs) são presumivelmente menores, porém ainda não há estudos que
avaliaram os impactos das mesmas na diversidade de anfíbios. Com o objetivo de investigar o
impacto de PCHs na diversidade da anurofauna no nordeste paulista, foram testadas as
seguintes hipóteses 1) a diversidade será maior em trechos não afetados por PCHs; 2) a
diversidade nas áreas a jusante das barragens será maior que no entorno dos reservatórios das
PCHs; e 3) a diversidade de anuros será menor após a instalação de PCHs. As PCHs
Anhanguera, Retiro e Palmeiras estão instaladas no médio rio Sapucaí-Mirim, entre os
municípios de Guará e São Joaquim da Barra, São Paulo. A composição, riqueza, dominância
e abundância relativa das espécies foram comparadas, tanto entre os períodos anteriores e
posteriores à instalação dos empreendimentos quanto entre áreas afetadas e não afetadas pelas
PCHs. Foram usados dados secundários de monitoramento da anurofauna nos períodos pré e
pós-enchimento dos reservatórios, fornecidos pelos empreendedores e órgãos ambientais,
além de dados primários obtidos em campo nas três PCHs, suas respectivas jusantes e em uma
área não afetada por PCHs. Em relação às comparações entre os períodos anteriores e
posteriores ao enchimento dos reservatórios, os resultados indicam maior riqueza de anuros
no período pré-enchimento das PCHs e alteração na composição com a variação na
abundancia de cada espécie. Consequentemente, a instalação das PCHs reduziu a diversidade
de anfíbios, corroborando a primeira hipótese. Quanto às comparações entre áreas afetadas e
não afetadas pelas PCHs, a maior riqueza e menor dominância indicaram a maior diversidade
de anuros no trecho não afetado por PCHs, seguido pelas áreas das jusantes e pelas áreas
diretamente afetadas pelas PCHs. Com isso, foram corroboradas tanto a hipótese de que a
diversidade de anuros é maior em trechos não afetados por PCHs quanto a hipótese de que a
diversidade nas áreas a jusante das barragens é maior que nas áreas das PCHs. A instalação
dos empreendimentos alterou a composição e reduziu a diversidade de anfíbios anuros na
região da bacia do Sapucaí-Mirim no nordeste paulista. Porém, estudos em outras bacias com
instalações de PCHs são necessários para o estabelecimento dos padrões referentes a este tipo
2
de empreendimento. Os impactos negativos da instalação de PCHs podem ser mais relevantes
no trecho médio-alto rio Sapucaí-Mirim. Portanto, caso a instalação de novas PCHs neste rio
seja imprescindível, sugere-se que o trecho médio-alto seja poupado. Sugere-se, ainda, o
investimento contínuo em recuperação efetiva das áreas de preservação permanente e em
monitoramento das populações da fauna, de modo a garantir a funcionalidade do corredor
ecológico representado pela vegetação ciliar do rio Sapucaí-Mirim.
The environmental changes caused by hydroelectric power plants, in constant proliferation in Brazil, threaten both aquatic and terrestrial organisms. Large hydroelectric power plants cause declines in abundance and richness and changes in the composition of amphibian species, both in the areas affected by reservoir filling and downstream of dams. The impacts of installation and operation of Small Hydroelectric Power Plants (SHPs) are presumably smaller, but there are still no studies that have evaluated their impacts on amphibian diversity. With the objective of investigating the impact of SHPs on the diversity of anurofauna in the northeast of São Paulo, the following hypotheses were tested: 1) diversity will be greater in areas not affected by SHPs; 2) diversity in the downstream areas of dams will be greater than in the vicinity of SHP reservoirs; and 3) the diversity of anurans will be smaller after the installation of SHPs. The Anhanguera, Retiro and Palmeiras SHPs are installed in the middle Sapucaí-Mirim river, between the municipalities of Guará and São Joaquim da Barra, São Paulo. The composition, richness, dominance and relative abundance of the species were compared, both between the periods before and after the installation of the projects, as well as between areas affected and not affected by SHPs. Were used secondary data from anurofauna monitoring in the pre and post filling periods of reservoirs, provided by the entrepreneurs and environmental agencies, as well as primary data obtained in the field by visual and auditory search methods in the three SHPs, their respective downstream and in an area not affected by SHPs. Regarding the comparisons between the periods before and after the filling of the reservoirs, the results indicated higher anuran species richness in the prefilling phase of the SHPs and alteration in the composition with the variation in the abundance of each species. Consequently, the installation of SHPs reduced the diversity of amphibians, corroborating the first hypothesis. As for the comparisons between areas affected and not affected by SHPs, greater richness and lower dominance indicated the greater diversity of 3 anurans in the area not affected by SHPs, followed by downstream areas and areas directly affected by SHPs. Thus, were corroborated both the hypothesis that the diversity of anurans is greater in areas not affected by SHPs and the hypothesis that the diversity in the downstream areas of the dams is greater than in the vicinity of the reservoirs. The establishment of the developments altered the composition and reduced the diversity of anuran amphibians in the region of the Sapucaí-Mirim basin in the northeast of São Paulo. However, studies in other basins with SHP facilities are necessary to establish the standards for this type of enterprise. The negative impacts of the installation of SHPs may be more relevant in the middle-upper Sapucaí-Mirim river. Therefore, if the installation of new SHPs in this river is essential, it is suggested that the medium-high section be spared. It is also suggested the continuous investment in effective recovery of the areas of permanent preservation and monitoring of fauna populations, in order to guarantee the functionality of the ecological corridor represented by the riparian vegetation of the Sapucaí-Mirim river.
The environmental changes caused by hydroelectric power plants, in constant proliferation in Brazil, threaten both aquatic and terrestrial organisms. Large hydroelectric power plants cause declines in abundance and richness and changes in the composition of amphibian species, both in the areas affected by reservoir filling and downstream of dams. The impacts of installation and operation of Small Hydroelectric Power Plants (SHPs) are presumably smaller, but there are still no studies that have evaluated their impacts on amphibian diversity. With the objective of investigating the impact of SHPs on the diversity of anurofauna in the northeast of São Paulo, the following hypotheses were tested: 1) diversity will be greater in areas not affected by SHPs; 2) diversity in the downstream areas of dams will be greater than in the vicinity of SHP reservoirs; and 3) the diversity of anurans will be smaller after the installation of SHPs. The Anhanguera, Retiro and Palmeiras SHPs are installed in the middle Sapucaí-Mirim river, between the municipalities of Guará and São Joaquim da Barra, São Paulo. The composition, richness, dominance and relative abundance of the species were compared, both between the periods before and after the installation of the projects, as well as between areas affected and not affected by SHPs. Were used secondary data from anurofauna monitoring in the pre and post filling periods of reservoirs, provided by the entrepreneurs and environmental agencies, as well as primary data obtained in the field by visual and auditory search methods in the three SHPs, their respective downstream and in an area not affected by SHPs. Regarding the comparisons between the periods before and after the filling of the reservoirs, the results indicated higher anuran species richness in the prefilling phase of the SHPs and alteration in the composition with the variation in the abundance of each species. Consequently, the installation of SHPs reduced the diversity of amphibians, corroborating the first hypothesis. As for the comparisons between areas affected and not affected by SHPs, greater richness and lower dominance indicated the greater diversity of 3 anurans in the area not affected by SHPs, followed by downstream areas and areas directly affected by SHPs. Thus, were corroborated both the hypothesis that the diversity of anurans is greater in areas not affected by SHPs and the hypothesis that the diversity in the downstream areas of the dams is greater than in the vicinity of the reservoirs. The establishment of the developments altered the composition and reduced the diversity of anuran amphibians in the region of the Sapucaí-Mirim basin in the northeast of São Paulo. However, studies in other basins with SHP facilities are necessary to establish the standards for this type of enterprise. The negative impacts of the installation of SHPs may be more relevant in the middle-upper Sapucaí-Mirim river. Therefore, if the installation of new SHPs in this river is essential, it is suggested that the medium-high section be spared. It is also suggested the continuous investment in effective recovery of the areas of permanent preservation and monitoring of fauna populations, in order to guarantee the functionality of the ecological corridor represented by the riparian vegetation of the Sapucaí-Mirim river.