Invertebrate Richness and Hatching Decrease with Sediment Depth in Neotropical Intermittent Ponds.

Unlabelled: Some groups of invertebrates from intermittent wetlands produce dormant stages in response to environmental fluctuations. Dormancy is a strategy to survive such fluctuations and to persist in extreme aquatic habitats, such as temporary habitats. We investigated the hatching responses of invertebrate dormant stages across different depths of sediment in intermittent ponds.

Bet-hedgers commit to the hedge: Zooplankton in ephemeral semiarid wetlands of tropical Brazil that widely spread risk.

Bet-hedging is an ecological risk-aversion strategy in which a population does not commit all its effort toward a single reproductive event or specific environmental condition, and instead spreads the risk to include multiple reproductive events or conditions. For aquatic invertebrates in dry wetlands, this often takes the form of some propagules hatching in the first available flood, while remaining propagules hatch in subsequent floods (the "hedge"); this better ensures that a subset of propagules will hatch in a flood of sufficient duration to successfully complete development. Harsh environmental conditions are believed to promote an increased reliance on bet-hedging.

Ground-dwelling Spider Communities Respond to Changes in Riparian Vegetation Widths.

Spiders play a key role in the ecological dynamics in riparian habitats. However, most studies on the effects of changes in riparian habitats on spider communities have focused on the conversion of riparian forest to other land uses rather than on a gradient of forest widths. We assessed the community structure of ground-dwelling spiders in riparian vegetation fragments with varying widths in Southern Brazil.

Development stage-dependent oxidative stress responses to the exposure to roundup original© in a neotropical annual killifish.

Herbicides are the most commonly applied pesticides in Brazil, specifically those based on glyphosate, and are used for different crops, near the habitats of annual killifish. Annual killifish presents a short life cycle with generally restricted geographic distribution. In this context, we evaluated the effect of the Roundup Original© (65, 130 and 260 µg.

Biomarkers of oxidative stress in the post-embryonic characterization of the neotropical annual killifish.

Annual killifish are among the most remarkable extremophile species with the shortest vertebrate life span. Few studies have reported on the oxidative balance throughout their life cycle and its association to the natural aging process of these neotropical animals in a natural environment. We standardized and analyzed physiological markers related to the redox balance of the annual killifish (Cynopoecilus fulgens) throughout the post-embryonic life cycle (enzyme activity of Superoxide Dismutase, Catalase, Glutathione Peroxidase, and Glutathione S-transferase, as well as the determination of the levels of Lipoperoxidation, Carbonylated Proteins, and Total Proteins).

Recognizing the enemy: do predator cues influence hatching in Neotropical annual killifish?

Annual fish species have evolved complex adaptations to survive in temporary wetlands. The main adaptation of these fish is the ability to produce embryos that survive dry periods. Embryo development of this fish can show variation at multiple levels influenced by many environmental factors, such as photoperiod and temperature.

Three new species of Hyalella (Crustacea: Amphipoda: Hyalellidae) from the Southern Brazilian Coastal Plain.

In this study, three new species of Hyalella (Crustacea: Amphipoda: Hyalellidae) are described based on specimens collected in wetlands located in three freshwater ecoregions (Southeastern Mata Atlântica, Tramandaí-Mampituba and Laguna dos Patos) of the southern Brazilian Coastal Plain (states of Rio Grande do Sul and Santa Catarina). Hyalella minuana n. sp.

Two new annual fishes (Cyprinodontiformes: Rivulidae) unexpectedly discovered in the highlands of southern Brazil.

Two new species of Austrolebias are described based on specimens collected from temporary pools located in natural grassland landscape within the Araucaria Forest domain at exceptionally high altitudes (~1000 meters a.s.l.

Does taxonomic and numerical resolution affect the assessment of invertebrate community structure in New World freshwater wetlands?

The efficiency of biodiversity assessments and biomonitoring studies is commonly challenged by limitations in taxonomic identification and quantification approaches. In this study, we assessed the effects of different taxonomic and numerical resolutions on a range of community structure metrics in invertebrate compositional data sets from six regions distributed across North and South America. We specifically assessed the degree of similarity in the metrics (richness, equitability, beta diversity, heterogeneity in community composition and congruence) for data sets identified to a coarse resolution (usually family level) and the finest taxonomic resolution practical (usually genus level, sometimes species or morphospecies) and by presence-absence and relative abundance numerical resolutions.

Climate- versus geographic-dependent patterns in the spatial distribution of macroinvertebrate assemblages in New World depressional wetlands.

Analyses of biota at lower latitudes may presage impacts of climate change on biota at higher latitudes. Macroinvertebrate assemblages in depressional wetlands may be especially sensitive to climate change because weather-related precipitation and evapotranspiration are dominant ecological controls on habitats, and organisms of depressional wetlands are temperature-sensitive ectotherms. We aimed to better understand how wetland macroinvertebrate assemblages were structured according to geography and climate.

Oxidative stress resistance in a short-lived Neotropical annual killifish.

Oxidative stress plays an important role in the evolution of aging and life history. High investments in life-history traits and environmental conditions can be associated with increased oxidative stress and aging process. However, to date, most studies that investigated variations in oxidative status were performed with long-lived vertebrates.

Coevolution between male and female genitalia in Belostoma angustum Lauck, 1964 (Insecta, Heteroptera, Belostomatidae): disentangling size and shape.

Sexual and natural selection mechanisms might drive variation in the genitalia of male animals. All aforementioned mechanisms are known to predict the coevolution of male and female genital morphology. Belostoma angustum is known to have subtle variation in the male and female genitalia of its members.

Age-associated liver alterations in wild populations of Austrolebias minuano, a short-lived Neotropical annual killifish.

Aging processes have become an attractive field for researchers and annual fish have been used as biological models. However, the study on the changes in age-associated markers during the normal aging in wild populations of annual fish remains open. Austrolebias is a genus of Neotropical annual killifishes, distributed mainly in ephemeral pools across grassland floodplains of temperate South America and represent an emerging biological model for aging research, but studies investigating rapid aging and senescence in this genus of annual fish are almost non-existent.

Responses of macroinvertebrate communities to pesticide application in irrigated rice fields.

The ability to recover to original states after disturbances makes macroinvertebrates useful tools for assessing the impacts of pesticides. Many studies showed that direct exposure to pesticides decreases macroinvertebrate richness and alters their composition. The main objective of this study was to assess recovery patterns in macroinvertebrate communities after pesticide application in irrigated rice fields.

Reduced riparian zone width compromises aquatic macroinvertebrate communities in streams of southern Brazil.

Recent changes in Brazilian legislation reduced the width of riparian forest buffer needed to be preserved in private properties from 30 to 15 m or less. The consequences of these modifications can be dramatic, mainly because riparian buffer width is an important parameter for riparian forest structure and functioning. Our study assessed whether (1) macroinvertebrate family richness and Ephemeroptera, Plecoptera, and Trichoptera (EPT) family richness decrease with reduced riparian buffer width; (2) taxonomic composition and functional feeding group (FFG) composition of macroinvertebrates vary with a reduced riparian buffer width; and (3) reduced riparian buffer width similarly influence the macroinvertebrate community in different stream substrates.

Does the Lagoa do peixe sandbar opening influence the macrophyte richness and composition in Southern Brazil wetlands?

The Lagoa do Peixe has its connection with the sea artificially opened every year at the end of winter. However, this management has been carried out without the evaluation of the impact of this opening in the aquatic biodiversity. This information is crucial for the management of the natural resources of the Lagoa do Peixe National Park, the unique Ramsar site in Southern Brazil.

Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region.

The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (approximately 280 000km2), and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil.

Can rice field channels contribute to biodiversity conservation in Southern Brazilian wetlands?

Conservation of species in agroecosystems has attracted attention. Irrigation channels can improve habitats and offer conditions for freshwater species conservation. Two questions from biodiversity conservation point of view are: 1) Can the irrigated channels maintain a rich diversity of macrophytes, macroinvertebrates and amphibians over the cultivation cycle? 2) Do richness, abundance and composition of aquatic species change over the rice cultivation cycle? For this, a set of four rice field channels was randomly selected in Southern Brazilian wetlands.