Gilmar Perbiche-Neves

Limnology of Two Contrasting Hydroelectric Reservoirs (Storage and Run-of-River) in Southeast Brazil

Artificial reservoirs created by the construction of dams along fluvial systems tend to exhibit intermediate limnological characteristics, as compared to rivers and lakes. The tendency of a reservoir to be more similar either to a lotic or to a lentic environment is basically related to the water retention time. As shorter is the retention time the similarity with a river is higher. Conversely, the structure and functioning of a reservoir will be comparable to a lake in case of high water retention time. In both cases it is generally observed conspicuous spatial gradients, represented by riverine, intermediate and lentic zones, in the main water body of the reservoir as well as in the lateral arms, in case of dendritic systems (Thornton, 1990; Tundisi, 1990).

Multi-dimensional effects on Cladoceran (Crustacea, Anomopoda) assemblages in two cascade reservoirs in Southeast Brazil

Instituto de Biociencias UNESP Univ Estadual Paulista, Rubiao Junior s/n, Botucatu, Sao Paulo

Historical biogeography of the neotropical Diaptomidae (Crustacea: Copepoda)

IntroductionDiaptomid copepods are prevalent throughout continental waters of the Neotropics, yet little is known about their biogeography. In this study we investigate the main biogeographical patterns among the neotropical freshwater diaptomid copepods using Parsimony Analysis of Endemicity (PAE) based on species records within ecoregions. In addition, we assess potential environmental correlates and limits for species richness.ResultsPAE was efficient in identifying general areas of endemism. Moreover, only ecoregion area showed a significant correlation with diaptomid species richness, although climatic factors were shown to provide possible upper limits to the species richness in a given ecoregion.ConclusionThe main patterns of endemism in neotropical freshwater diaptomid copepods are highly congruent with other freshwater taxa, suggesting a strong historical signal in determining the distribution of the family in the Neotropics.

New Diaptomidae records (Crustacea: Copepoda: Calanoida: Diaptomidae) in the Neotropical region

TIn this study we present 208 new diaptomids records, including 36 species from 10 genera. They are the result of new samplings as well as of the revision of samples from previous surveys from various localities in the Neotropical Region. In an attempt to clear elucidate about the species ranges we gathered all biogeographically important data and present them here, with comments about the relevance of each record to the understanding of the distribution of the group.

Trends in planktonic copepod diversity in reservoirs and lotic stretches in a large river basin in South America

Copepod assemblages were analysed across La Plata River basin, the second largest in South America. High values of species richness and Shannon-Wiener diversity were found in the lower ParanaRiver, the main and largest river of the basin, and in eutrophic reservoirs located in the upper basin. The species richness was negatively correlated with turbidity,probablybecauseofthenegative impactonfiltrationratesincalanoids. Therewasatrendofdecreasingrichness correlated with high water flow in reservoirs with short water-retention time (,40 days) and simple morphometric shape, and also in deeper oligo-mesotrophic reservoirs with very long water-retention time and dendritic shape (variables that occurredincombinationinthe presentstudy).The numberofcopepodspecies (46) foundinourstudyisonlyabouthalf of thegammadiversityestimatedusingJack1non-parametricanalysisforthebasin(86species).Therearegroupsofcopepod speciestypicalofreservoirsandrivers,andothersthatcanoccurinbothofthesehabitattypes.Reservoirandlenticspecies are favoured by a deeper water column, higher temperatures and higher transparency, whereas the opposite is the case of typical riverine species. There is also a group of species that occur in both sets of conditions. Additional keywords: crustaceans, diversity, ecology, freshwater, lentic, limnology, running water.

Two new species of Diaptomidae (Crustacea: Copepoda: Calanoida) from the Neotropical Region (Paraná River)

Two new species of Diaptomidae were found in the Middle Paraná River. The new species are referred to as “Diaptomus” curvatus sp. nov. and “Diaptomus” frutosae sp. nov. Important character states in “Diaptomus” curvatus include: right fifth leg with a well-developed endopod and with the lateral spine of the second exopod segment curved and longer than the segment on which it is inserted, plus the presence of a large dorsal process on urosomite 4 of the male. For “Diaptomus” frutosae they include: a differentiated hook-like process on segment 20 with chitinous protuberances at base of male right antennule; the last segment of the right leg 5 of male is triangular, and the lateral spine inserted distal to mid-level of this segment. Both species are placed in “Diaptomus” sensu lato as a temporary placement. http://www.zoobank.org/urn:lsid:zoobank.org:pub:FECDD6C4-C0AC-4043-ADDD-F29539B451F0

Identification guide to some Diaptomid species (Crustacea, Copepoda, Calanoida, Diaptomidae) of “de la Plata” River Basin (South America)

Abstract An identification guide is presented for species of calanoid copepod family Diaptomidae from “de la Plata” River Basin (Argentina, Brazil, Bolivia, Paraguay and Uruguay). It was based on material collected during the summer and winter of 2010 from 43 sites across the eastern part and the lower stretches of this basin, the second largest in South America and the fourth in the world. The guide contains identification keys and species diagnoses for males and females, richly supported by scanning electronic micrographs and/or line drawings of 19 species. It also includes some general remarks on the taxonomy and phylogenetic relationships of these species. The key was adjusted to be useful for these species only, with separate keys for each sex, and is the first for females of South America. One species classified herein as incertae sedis was not included in the analysis. At least ten other species have previously been recorded in the basin but were not present in our samples. This is the first attempt to compile comprehensive taxonomic information on this group of copepods in this region, and it is expected to become a useful tool for biologists and young taxonomists interested in the crustacean biota of the Neotropical region.

Changes in the phytoplankton structure downstream a large reservoir: effects of tributaries on the assemblages attributes

Abstract Changes in richness, diversity, evenness and abundance of phytoplankton in relation to environmental variables and tributary entrances were studied along 30 km of the Paraná River downstream Itaipu Reservoir. A high number of taxa was found, 315. The Paraná River differed from the tributaries Iguaçu River and Monday River. The phytoplankton and limnological characteristics of the Paraná River changed after the entrance of these tributaries. Higher values of richness and alpha diversity of phytoplankton were found in the two tributary rivers, which also produced an increase in the corresponding mean values in the Paraná River. Higher values of total abundance and lower values of evenness were found at the dam site with typical lentic conditions. The assemblages of the two tributary rivers were homogeneous. Bellow dam the phytoplankton exhibited a decrease in abundance and an increase in evenness. Water transparency, water flow, nutrients and turbidity were the main indicators of the system spatial heterogeneity. Several species were correlated with silicate, redox potential and/or water temperature. Reservoir conditions promote conspicuous differences in the phytoplankton of the Paraná River. The downstream reorganization of the community, with a sharp decrease in abundance, is positively influenced by tributary rivers in terms of richness and diversity.

A new trap for collecting aquatic and semi-aquatic insects from madicolous habitats

A new trap is described for capturing adult insects (especially Chironomidae) from madicolous habitats in mountainous environments. The trap is light enough to be carried and is easy and inexpensive to build, being constructed of mosquito netting fabric (no‐see‐um mesh size), galvanised wire, a plastic bottle, a plastic conduit and nylon clamps. Seventy‐one traps deployed along an altitudinal gradient on three different mountains (altitude 0–2700 m above sea level) captured c. 1400 adult insects, representing 20 higher taxa (i.e. families or orders) of insects.

Range extension of Boeckella bergi Richard, 1897 (Crustacea: Copepoda: Centropagidae), with comments on the taxonomy of the species

We present new records of Boeckella bergi at several water bodies in Argentina and Brazil. Within these records the northernmost and southernmost limits of occurrence of B. bergi in South America are included. The ample range of distribution is consistent with former studies, but it is more extensive than previously known. Observations on habitat preferences are also made. This species is tolerant to temperate climate conditions in this region of South America, with wide amplitude of temperature between summer and winter seasons, and irregular patterns of precipitation.