Oligochaeta (Annelida, Clitellata) of lotic environments at Parque Estadual Intervales (São Paulo, Brazil)

Abstract

Studies on benthic macroinvertebrates of lotic environments usually focus on the occurrence, distribution, and richness of aquatic insects and decapod crustaceans. Only rarely these studies include the Oligochaeta. The aim of the present study was to examine the occurrence and species richness of Oligochaeta in different substrata patches of lotic environments. The studied included seven stream sites at Parque Estadual Intervales (São Paulo, Brazil). Stream sites differed in size and ranged from first to fourth order. In each stream, qualitative collections were made using a D-type net sampler with 0.21 mm mesh. Measures of pH, electrical conductivity, dissolved oxygen, temperature and water turbidity were taken in the studied sites during collections of Oligochaeta. Specimens of the Tubificidae (including Naidinae) and Enchytraeidae families were collected. The Tubificidae Aulodrilus limnobius, Limnodrilus neotropicus and Limnodrilus hoffmeisteri were associated with low-flow habitats containing fine organic material. The most representative species among the Naidinae, Nais communis, was predominantly associated with rocky substrates present in fast current locations. The two other Naidinae species, Pristina osborni and Amphichaeta leydigi, presented low frequency in the studied streams. The Enchytraeidae family was present in only one of the sampled habitats. Keywords: Atlantic Forest, Enchytraeidae, Tubificidae, Naidinae. Resumo: Estudos sobre macroinvertebrados bentônicos de ambientes lóticos geralmente focam na ocorrência, distribuição e riqueza de insetos aquáticos e de crustáceos decápodos. Tais estudos apenas raramente incluem Oligochaeta. O objetivo do presente estudo foi examinar a ocorrência e riqueza de espécies de Oligochaeta de diferentes substratos em ambientes lóticos. O estudo incluiu sete riachos do Parque Estadual Intervales (São Paulo, Brasil). Os riachos estudados variaram em tamanho desde primeira até quarta ordem. Em cada ambiente, foram realizadas coletas qualitativas utilizando amostrador do tipo rede em D com malha 0,21 mm. Simultaneamente às coletas de Oligochaeta foram tomadas medidas do pH, condutividade elétrica, oxigênio dissolvido, temperatura e turbidez da água dos ambientes. Foram coletados exemplares das famílias Tubificidae (incluindo Naidinae) e Enchytraeidae. Os Tubificidae Aulodrilus limnobius, Limnodrilus neotropicus e Limnodrilus hoffmeisteri estiveram associados à habitats com pouca correnteza e substrato contendo material orgânico fino. Nais communis espécie mais representativa entre os Naidinae, esteve predominantemente associada a substratos rochosos presentes em locais de correntes rápidas. As duas outras espécies de Naidinae, Pristina osborni e Amphichaeta leydigi apresentaram baixa freqüência nos córregos analisados. A família Enchytraeidae esteve presente somente em um dos ambientes amostrados.

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

“…These orders were found in this steam by Rosa et al (2009) during the same period and with the same substrate types. Alves et al (2008) also found low abundance of oligochaetes (n = 259 individuals) in forest streams with cold and well oxygenated water, the beds being made up mainly by pebbles and accumulation of fine and coarse organic matter. In organically polluted environments, unlike in the stream studied here, it is common to find a great abundance of worms, possibly favored by the absence of more sensitive organisms and elimination of competition and predation (Myslinski and Ginsburg, 1977;Martins et al, 2008).…”

Aquatic Oligochaeta (Annelida: Clitellata) from State of São Paulo, Brazil: Diversity and Occurrence review

“…However, the publication of books in the eightiesspecifically focused on the identification of oligochaetes in Brazil and South America (Righi 1984, Brinkhurst & Marchese 1989, respectively) --encouraged researches as Takeda (1999, Montanholi-Martins & Takeda (1999, , Alves & Strixino (2000), Pamplin et al (2005), Alves et al (2006Alves et al ( , 2008, Gorni & Alves (2008a, Martins & Alves (2010) and Rodrigues et al (2013aRodrigues et al ( , 2013b, which have broadened the knowledge on taxonomic and ecological aspects of these worms in Brazil.…”

Diversity and distribution of oligochaetes in tropical forested streams, southeastern Brazil

“…Species with high dispersal ability may be present in all places and greater similarity in community composition is expected (Thompson and Townsend, 2006). Although many species of aquatic oligochaetes present a wide geographic distribution (Martin et al, 2008), they do not have a good ability of disperse, (compared to aquatic insects, for example), so differences in their richness and composition can be related to the distance between sites, besides smaller scale environmental characteristics such as substrate types and water flow variations (Verdonschot, 1999(Verdonschot, , 2001Alves et al, 2008). Because of the lack of studies about the ecological processes responsible for the diversity and distribution of aquatic oligochaetes considering different habitat spatial scales, our objective in this study was to verify how different mesohabitats (litter in riffles and in pools), geographic distance between streams and type of phytophysognomy (seasonal semideciduous forest and rocky field), as well as their interaction, can influence variations in the composition (beta diversity) and structure of the assemblage of oligochaetes in low-order streams.…”