Estrutura e dinâmica da comunidade de morcegos em mosaico vegetacional composto por reflorestamento de eucalipto e remanescentes de vegetação nativa no interior do estado de São Paulo
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Data
2019-01-21
Autores
Guimarães, Moisés
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Atualmente no Brasil milhares de hectares estão sendo utilizados para o plantio de eucalipto e consequentemente essas áreas sofrem corte raso de tempos em tempos para alimentar a produção fabril. De modo geral como medida mitigatória o setor florestal conserva, em meio a monocultura, fragmentos de vegetação nativa, respeitando a legislação ambiental nacional e seguindo os preceitos das certificadoras florestais, formando extensas áreas cobertas por um mosaico vegetacional de eucalipto e vegetação nativa. O conhecimento da fauna presente nesses mosaicos e o que ocorre com ela após o corte raso de parte do plantio é de extrema importância para a conservação da biodiversidade e os morcegos são uma ótima ferramenta em estudos que abordam esse tema, visto serem a segunda maior ordem de mamíferos em número de espécies e podem representar até 50% da fauna de mamíferos em florestais tropicais. O presente estudo foi realizado na Fazenda Rio Claro, interior do estado de São Paulo, na cidade de Lençóis Paulista, em mosaico vegetacional formado por fragmentos de Floresta Estacional Semidecidual e em plantio de eucalipto, objetivando caracterizar a fauna de morcegos presente nessa paisagem e analisar o que ocorre com essa comunidade após o corte raso de parte do plantio. O trabalho de campo ocorreu entre outubro de 2007 e julho de 2010, com sessões de capturas em vegetação nativa e em plantio de eucalipto. O esforço amostral foi de 42 noites de captura utilizando 40 redes de 12 metros de comprimento por 2,5 metros de altura, sendo 24 delas instaladas no subdossel e 16 no dossel, ficando essas expostas por 12 horas em cada noite. Após 21 noites de captura, parte das áreas de plantio de eucalipto que estavam sendo amostradas sofreu corte raso, sendo realizadas outras 21 noites de captura logo após esse corte. Foram capturados 217 morcegos pertencentes a 20 espécies e três famílias: Phyllostomidae (13 spp.), Vespertilionidae (5) e Molossidae (2), sendo listadas quatro novas ocorrências para a região da área estudada: Artibeus planirostris, Eptesicus diminutus, Myotis ruber e Molossops neglectus. A curva de rarefação não atingiu a assíntota e o estimador Jackknife de primeira ordem ficou acima da riqueza observada (n= 22,93). A diversidade encontrada na Fazenda Rio Claro alcançou um índice de Shannon-Wiener de 2,204, sendo as espécies Carollia perspicillata e Sturnira lilium as mais capturadas e as únicas consideradas comuns, o restante foram espécies raras durante o presente estudo. Houve diferença entre a diversidade observada nas estações seca e chuvosa (p= 0,0098), as espécies Eptesicus brasiliensis, E. diminutus, Glossophaga soricina, Lasiurus blossevillii, Molossops neglectus e Molossus rufus foram capturados com exclusividade na estação chuvosa, sendo esse período o mais diverso. Após o corte raso de parte de plantio houve diminuição na diversidade (p= 0,029), as espécies G. soricina, E. diminutus, L. blossevillii e Myotis ruber foram capturadas apenas antes do corte, tendo a última espécie uma diminuição expressiva em sua população (p= 0,0095). Platyrrhinus lineatus e M. rufus foram capturados apenas depois do corte e Sturnira lilium teve aumento significativo em sua população após o mesmo (p= 0,0134). O índice de diversidade encontrado na área de estudo pode ser equiparado com áreas consideradas conservadas, foram listadas quatro novas espécies para a região e a utilização de redes de espera no dossel foram responsáveis pelo registro de duas espécies: Chiroderma doriae e Eptesicus diminutus, aumentando a diversidade local. O corte raso provocou uma mudança esperada na comunidade de morcegos: diminuição da diversidade, modificação na composição de espécies e o aumento/diminuição na população delas.
Presently in Brazil thousands of hectares are occupied by eucalyptus plantations and those areas are completely deforested in a timely manner in order to supply the production chain. Generally as mitigation measure the forestry industry preserves native forest fragments among monoculture patches respecting the national environmental laws and the sustainable forestry certification guidelines, which creates large areas covered by a vegetation mosaic of eucalyptus and native forest. Assessing the fauna in these mosaic areas and consequences after partial harvest is extremely important for biodiversity conservation. Bats are a great tool for studying this topic since they represent the second largest mammalian order regarding number of species and up to 50% of mammalian fauna in tropical forests. The present study was developed at Fazenda Rio Claro, São Paulo state countryside, in Lençóis Paulista city, in a vegetation mosaic of Seasonal Semideciduous Forest and Eucalyptus sp plantation, and its aim was to assess bat fauna in the landscape and analyze changes within this community after partial harvest. Fieldwork was carried out between October 2007 and July 2010 with capture sessions in native vegetation and eucalyptus plantation. Sampling effort comprised 42 capture nights using 40 12m-length by 2.5m-height mist nets exposed for 12 hours each night, being 24 nets set along the subcanopy and 16 set on the canopy. After 21 capture nights part of the eucalyptus plantation areas that were being sampled was harvested and other 21 capture nights were carried after harvest. 217 individuals were captured, comprising 20 species and three families: Phyllostomidae (13 spp.), Vespertilionidae (5) and Molossidae (2), with four newly reported species for the region of Lençóis Paulista Artibeus planirostris, Eptesicus diminutus, Myotis ruber and Molossops neglectus. The rarefaction curve did not reach asymptote and the first-order Jackknife estimator remained above the observed richness (n= 22.93). Diversity found at Fazenda Rio Claro reached a Shannon-Wiener index of 2.204, of which Carollia perspicillata and Sturnira lilium were the most abundant species and the only ones considered common (the remaining species were considered rare throughout the study). There was a difference in diversity between dry and wet season (p= 0.0098) and Eptesicus brasiliensis, E. diminutus, Glossophaga soricina, Lasiurus blossevillii, Molossops neglectus and Molossus rufus were captured only during the rainy season, which was found to be the most diverse season. After partial harvest of the eucalyptus there was a decrease in diversity (p= 0.029), G. soricina, E. diminutus, L. blossevillii and Myotis ruber were captured only before the harvest and the latter species showed a sharp decrease in its population (p= 0.0095). Platyrrhinus lineatus and M. rufus were captured only after harvest and Sturnira lilium showed a significant increase in its population after harvest (p= 0.0134). The diversity index found in the study might be as high as those of areas classified as preserved, four new species were reported for the region and the use of mist nets on the canopy was responsible for finding two species: Chiroderma doriae and E. diminutus, increasing the reported local diversity. The partial harvest caused expected changes in the bat community: decrease in diversity, change in species composition and increase/decrease in their populations after harvest.
Presently in Brazil thousands of hectares are occupied by eucalyptus plantations and those areas are completely deforested in a timely manner in order to supply the production chain. Generally as mitigation measure the forestry industry preserves native forest fragments among monoculture patches respecting the national environmental laws and the sustainable forestry certification guidelines, which creates large areas covered by a vegetation mosaic of eucalyptus and native forest. Assessing the fauna in these mosaic areas and consequences after partial harvest is extremely important for biodiversity conservation. Bats are a great tool for studying this topic since they represent the second largest mammalian order regarding number of species and up to 50% of mammalian fauna in tropical forests. The present study was developed at Fazenda Rio Claro, São Paulo state countryside, in Lençóis Paulista city, in a vegetation mosaic of Seasonal Semideciduous Forest and Eucalyptus sp plantation, and its aim was to assess bat fauna in the landscape and analyze changes within this community after partial harvest. Fieldwork was carried out between October 2007 and July 2010 with capture sessions in native vegetation and eucalyptus plantation. Sampling effort comprised 42 capture nights using 40 12m-length by 2.5m-height mist nets exposed for 12 hours each night, being 24 nets set along the subcanopy and 16 set on the canopy. After 21 capture nights part of the eucalyptus plantation areas that were being sampled was harvested and other 21 capture nights were carried after harvest. 217 individuals were captured, comprising 20 species and three families: Phyllostomidae (13 spp.), Vespertilionidae (5) and Molossidae (2), with four newly reported species for the region of Lençóis Paulista Artibeus planirostris, Eptesicus diminutus, Myotis ruber and Molossops neglectus. The rarefaction curve did not reach asymptote and the first-order Jackknife estimator remained above the observed richness (n= 22.93). Diversity found at Fazenda Rio Claro reached a Shannon-Wiener index of 2.204, of which Carollia perspicillata and Sturnira lilium were the most abundant species and the only ones considered common (the remaining species were considered rare throughout the study). There was a difference in diversity between dry and wet season (p= 0.0098) and Eptesicus brasiliensis, E. diminutus, Glossophaga soricina, Lasiurus blossevillii, Molossops neglectus and Molossus rufus were captured only during the rainy season, which was found to be the most diverse season. After partial harvest of the eucalyptus there was a decrease in diversity (p= 0.029), G. soricina, E. diminutus, L. blossevillii and Myotis ruber were captured only before the harvest and the latter species showed a sharp decrease in its population (p= 0.0095). Platyrrhinus lineatus and M. rufus were captured only after harvest and Sturnira lilium showed a significant increase in its population after harvest (p= 0.0134). The diversity index found in the study might be as high as those of areas classified as preserved, four new species were reported for the region and the use of mist nets on the canopy was responsible for finding two species: Chiroderma doriae and E. diminutus, increasing the reported local diversity. The partial harvest caused expected changes in the bat community: decrease in diversity, change in species composition and increase/decrease in their populations after harvest.
Descrição
Palavras-chave
Remanescente florestal, Restauração florestal, Resiliência, Diversidade de espécies, Forest remnants, Forest restoration, Resilience, Species diversity