Zooplankton in littoral waters of a tropical lake: a revisited biodiversity

Abstract

The present study was carried out in Lake Dom Helvécio, in the state of Minas Gerais, with two main objectives: to demonstrate the contribution of the littoral zone, in order to better characterize zooplankton fauna; and to assess the distribution of zooplankton species in different habitats, i.e., the littoral zone with and without aquatic vegetation. The samples were collected in February and July 2006, throughout the littoral zone of the lake, in areas with and without aquatic vegetation. We identified a total of 188 species, of which 130 are new records for Lake Dom Helvécio. One hundred and eighty-four species were identified in the littoral zone with aquatic vegetation, and 117 in the zone with no vegetation. The higher zooplankton richness in areas of the littoral zone with aquatic vegetation can be related to the greater environmental heterogeneity. Compared to previous studies on the littoral zones of lakes along the middle River Doce, the present study expended greater sampling effort, and identified many more species. In relation to biological conservation, this study demonstrated the importance of the littoral zone for better characterization and conservation of the zooplankton fauna, especially when it is colonized by aquatic vegetation. Underestimating the richness of species may provide inaccurate data on the biota, as well as on the ecological conditions in an environment.Keywords: zooplankton, littoral zone, Lake Dom Helvécio, species richness. Zooplâncton da região litorânea de um lago tropical: a biodiversidade revisitadaResumo O presente estudo foi realizado no lago Dom Helvécio (MG) tendo como principais objetivos: demonstrar a contribuição da região litorânea para uma melhor caracterização da fauna zooplanctônica, avaliar a distribuição destas espécies em diferentes habitats (região litorânea com e sem vegetação aquática). As amostras foram coletadas nos meses de fevereiro e julho de 2006, ao longo da região litorânea, em pontos amostrais com e sem vegetação aquática. Um total de 188 espécies foi identificado. Desses organismos, 130 representaram novos registros para o lago Dom Helvécio. Foram identificadas 184 espécies na região litorânea com vegetação aquática e 117 na região litorânea sem vegetação. A maior riqueza em espécies zooplanctônicas na região litorânea com vegetação aquática está relacionada com a maior heterogeneidade ambiental. Quando comparado aos estudos realizados anteriormente na região litorânea de lagos do médio rio Doce, este estudo destaca-se pelo maior esforço amostral e número de espécies identificadas. No tocante à conservação biológica, o presente estudo mostrou a importância da região litorânea, especialmente quando colonizada por vegetação aquática para uma melhor caracterização e conservação da fauna zooplanctônica. A riqueza em espécies subestimada pode fornecer dados irreais sobre a biota, bem como das condições ecológicas de um ambiente.Palavras-chave: zooplâncton, região litorânea, lago Dom Helvécio, riqueza em espécies.

Pelagic and littoral cladocerans (Crustacea, Anomopoda and Ctenopoda) from reservoirs of the Northwest of São Paulo State, Brazil

“…Samplings from the littoral plus the pelagic zones in the present work resulted in a cladoceran species list where these three families were 67% of all the richness observed. Maia-Barbosa et al (2008), studying the Lake D. Helvécio, found a great number of new records of microcrustaceans species and they attribute this fact to sampling in littoral zone and not only in the pelagic one, as previous works in the same lake.…”

“…Macrophytes presence in the littoral is probably a controlling factor, since cladocerans richness and diversity were higher in zones with elevated macrophytes diversity than that with a scarce macrophytes community. Other studies already linked high zooplankton diversity with high macrophytes diversity (Matsumura-Tundisi et al 1990, Nunes et al 1996, Maia-Barbosa et al 2008 or a reduction in the number of invertebrates and vertebrates species with the disappearance of macrophytes banks (Timms & Moss 1984). Eutrophication can also favor zooplankton diversity increase in the littoral zones (Lemly & Dimmick 1982).…”

“…However, even though high diversity in these zones is frequently reported, the biology and the ecology of the littoral zooplankton are not well-known (Nogueira et al 2003, Maia-Barbosa et al 2008 what, according to Lemly & Dimmick (1982), can be attributed to the lack of efficient and standardized sampling methods.…”

Estimating cyclopoid copepod species richness and geographical distribution (Crustacea) across a large hydrographical basin: comparing between samples from water column (plankton) and macrophyte stands

“…ZOOLOGIA 31 (3): 239-244, June, 2014 There are no comparative studies of copepod richness between habitats in large geographical scales, only in lotic stretches or in lakes (LANSAC-TÔHA et al 2002, MAIA-BARBOSA et al 2008. This study is the first to compare copepod species richness in a large hydrographic basin, the fourth largest in the world.…”

“…For example, two studies sampling the two types of habitats, open water and macrophyte stands have documented this trend for lakes in Brazil (LANSAC-TÔHA et al 2002, MAIA-BARBOSA et al 2008. The habitat complexity provided by aquatic macrophytes (GENKAI-KATO 2007, LUCENA-MOYA & DUGGAN 2011 also allow several species to be more abundant in them (GERALDES & BOAVIDA 2004).…”