Colonização por macroinvertebrados bentônicos em substrato artificial e natural em um riacho da serra de Itatinga, São Paulo, Brasil

Abstract

Substratos artificial e natural foram comparados quanto ao processo de colonização por macroinvertebrados. No 1º, 3º, 7º, 13º, 21º, 31º e 42º dias de amostragem a riqueza e a abundância dos macroinvertebrados foi analisada. Larvas de Chironomidae foi o grupo mais abundante nos dois substratos durante todo o período amostral (53% em cada substrato), seguido por Oligochaeta (17 no artificial e 18 % no natural), formas imaturas de Ephemeroptera (16 e 11%) e Trichoptera (10 e 11%). O processo de sucessão ecológica foi similar nos dois substratos, sendo Oligochaeta um importante colonizador nos estágios iniciais do processo sucessional. Outra semelhança entre os substratos foi o aparecimento de Ephemeroptera-Leptohyphidae no sétimo dia de amostragem, após o que outros grupos apresentaram flutuações na sua abundância. Em conclusão, o substrato artificial foi apropriado para a colonização por macroinvertebrados, mostrando similaridade na estrutura da comunidade e nos processos de sucessão ecológica quando comparado ao substrato natural. Um período de estabilização na composição da comunidade ocorreu, para os dois substratos, entre e sétimo e 13º dias de amostragem.

Diet of invertebrates sampled in leaf-bags incubated in a tropical headwater stream

“…It is important to recognize that leaves can protect and influence the availability of trophic resources for benthic macroinvertebrates (CALLISTO et al 2001, CRISCI-BISPO et al 2007. A benthic community similar to that of the present work was also found by CARVALHO & UIEDA (2004, CARVALHO et al (2008) and RIBEIRO & UIEDA (2005) that analyzed the benthic macroinvertebrates associated to the rocky substratum of the Ribeirão da Quinta stream. In this sense, it may be over-simplistic to assume that all invertebrates collected from litter are feeding specifically on the leaves (BOULTON & BOON 1991).…”

“…Several recent papers have demonstrated that invertebrates associated to leaves may use them as food resource and/ or shelter (CARVALHO & UIEDA 2004, RIBEIRO & UIEDA 2005, CRISCI-BISPO et al 2007. It is important to recognize that leaves can protect and influence the availability of trophic resources for benthic macroinvertebrates (CALLISTO et al 2001, CRISCI-BISPO et al 2007.…”

“…The macroinvertebrates were sampled using leaf-bags incubated on the stream bottom for 13 days. This short colonization period was chosen because we learned from this study and from other studies developed in the same stream (unpublished data) that the invertebrate colonization in this stream is fast, although other data of experimental works about macroinvertebrate communities in tropical streams showed that peaks of invertebrate abundance and biomass occur around 21 days of incubation (CARVALHO & UIEDA 2004, CARVALHO et al 2008. Leaf-bags incubated for 21 days were completely decomposed, not remaining macroinvertebrates or leafs after this incubation period.…”

Distribution of oligochaetes in a stream in the Atlantic Forest in southeastern Brazil

“…The increased rainfall and consequent faster flow in the wet season is one of the main factors causing variation in the structure of benthic communities in tropical streams (Ribeiro and Uieda, 2005;Carvalho and Uieda, 2004;Battistoni et al, 2010). Our results, however, indicate that only the rich taxa (Enchytraeidae) were vulnerable to increased precipitation.…”

Colonization of formulated substrates of different composition by benthic macroinvertebrate community in an estuarine ecosystem: a case study of response of benthic invertebrates to substrate alteration

“…This is because, litter from riparian vegetation is a primary source of coarse particulate organic matter (CPOM) to aquatic systems (Carvalho and Uieda, 2004). However, in low-gradient Coastal Plain streams much of the CPOM becomes buried within the sandy stream beds following floods (Smith and Brumsickle, 1989).…”