Global panorama of studies about freshwater oligochaetes: main trends and gaps

Abstract

Freshwater oligochaetes have been studied over the years in a wide range of habitats around the world. To analyse the data published about freshwater oligochaetes in the 31 year period between 1985 and 2015, we searched for documents in the ISI Web of Science, Scopus and SciELO databases. A total of 979 works were evaluated from 184 periodicals. The United States is the country with the most publications about aquatic oligochaetes, followed by France, Germany and Italy. Works related to the ecology and ecotoxicology of these organisms are most abundant. Studies carried out in the laboratory are most frequent, consisting of investigations involving bioassays, morphology, genetics and molecular biology. The results also show that spring, cave water bodies and swamps have been studied less than any other aquatic habitat and that countries of the Southern Hemisphere are under-represented in the studies of aquatic oligochaetes. Hence, there is a need for increased efforts to fill in gaps in the knowledge about these oligochaetes.

Aquatic oligochaetes (Annelida: Clitellata) in reservoirs in São Paulo State: list of occurrence and ecological observations on the species

“…In relation to South America, Christoffersen (2010) claims that the cataloged Oligochaeta represent only a fraction of their true diversity, which emphasizes the need for more studies that contemplate the species inventory in the Neotropical regions. However, it is noteworthy that over the past few years the number of surveys with freshwater Oligochaeta has been growing, especially in Brazil, and there are more than 2,300 surveys between the years 1985 and 2015 Alves, 2018).…”

“…Generally, these species are found in sediments with abundant organic matter (Marchese, 1987;Montanholi-Martins;Takeda, 1999;Behrend et al, 2009;Lafont et al, 2012). Other studies (Rosenberg; In this context, inventories of oligochaete fauna and ecological relationships between species and the environment are very important for the formulation of biodiversity conservation policies, especially in tropical environments (Christoffersen, 2010;Alves, 2018). Studies of oligochaete assemblage patterns can be useful to predict changes along environmental gradients, as well for standardized methods for testing organisms in ecotoxicological studies (Castro et al, 2020;Suriani et al, 2007;Behrend et al, 2012).…”

“…Species surveying is essential for understanding the biota of a given environment, specifically in Brazilian aquatic ecosystems where species diversity is poorly known due to the small number of taxonomists (ROCHA, 2003;AGOSTINHO et al, 2005). Although oligochaetes are among the most abundant species in sediments of Neotropical lakes and reservoirs, there is relatively poor ecological information, especially in comparison to the knowledge generated in temperate-zone habitats where these species are used to monitor water quality GELDER 1991, MARTIN et al, 2008, CHRISTOFFERSEN, 2010MARTIN 2015, RODRIGUES;ALVES 2018). The community composition and structure of the Class Oligochaeta provides important information for the assessment of water and sediment quality, and has therefore proved to be a great tool for aquatic biomonitoring (LAFONT, 1989;ROSSO, 1995;PRYGIEL et al, 2000;VIVIEN et al, 2014).…”

Record of Haplotaxis aedeochaeta Brinkhurst & Marchese, 1987 (Oligochaeta: Haplotaxidae) in a conservation unity in the state of São Paulo

“…However, despite the growing number of research projects focused on oligofauna in Brazil (Rosa et al, 2015;Sanches et al, 2016;Takeda et al, 2017), few regions have an inventory, thus explaining the need to intensify research throughout the country. In this scenario, the Southeast and South regions, represented mainly by the states of São Paulo, Minas Gerais and Paraná, are among those with the greatest amount of research performed (Rodrigues and Alves, 2018).…”