Snake diversity in floodplains of central South America: Is flood pulse the principal driver?

Seasonal changes in taxonomic and functional diversity of lizard communities in southern Brazilian Pantanal

Seasonal changes play a key ecological role, structuring biotic processes and communities. Yet we generally lack an understanding of how seasonal flood regimes affect communities in floodplains. Herein, we investigated the effects of seasonal changes in taxonomic and functional diversity of lizard communities in southern Pantanal ecoregion. Lizards were sampled in seven sites encompassing seasonally flooded grasslands and dense arboreal savannas, across rainy and dry seasons (2005-2006). Functional diversity metrics were based on three morphological traits and included intraspecific variability. We collected a total of 810 lizards from 13 species. Species richness did not differ across seasons or months. Lizard abundance varied among sampling months, but did not differ between rainy and dry season. Low values of abundance were recorded at drawdown period. Community composition did not vary between seasons. Functional diversity metrics exhibited random distributions, and both functional richness and evenness were not influenced by seasons. Although communities seem to be resilient to seasonal variations, our findings highlighted that transition from rainy to dry season may represent an important constraint on lizard abundance. Including traits related to food acquisition and predator avoidance could provide new insights into the effects of seasonal floods on floodplains' lizard communities.

Favourable climatic niche in low elevations outside the flood zone characterises the distribution pattern of venomous snakes in Bangladesh

Snakes are sensitive to both environmental and climate gradients. To design conservation plans, a scientific understanding of snake habitats in light of environmental and climatic variables is an essential prerequisite. For venomous snakes, denoting favourable habitats should also be relevant for snakebite management. We have considered 18 spatial variables to portray the range of terrestrial venomous snake distribution in Bangladesh. Our results indicate that the distribution of 29 studied venomous snakes in this country is primarily driven by climatic and environmental variables. We found that especially low elevation and flood risk constrain the distribution of those terrestrial snakes, i.e. regular floods in central Bangladesh push venomous snakes towards the edges of the country. Moreover, none of these species occupies the whole of its anticipated climatically favourable area. Projections into the future indicated that 11 studied species, Amphiesma platyceps, Boiga siamensis, Chrysopelea ornata, Pseudoxenodon macrops, Rhabdophis himalayanus, Rhabdophis subminiatus, Bungarus lividus, Ophiophagus hannah, Daboia russelii, Ovophis monticola and Trimeresurus popeiorum will lose their entire climatically suitable area within the country. Therefore, we suggest establishing more protected areas in the hilly ecosystems in the eastern part and in the mangrove forests in the south-western corner of Bangladesh to mitigate future extinction risks, such as climate change, sea-level rise and increase in flood severity. Conserving village forests and croplands, which are subject to rapid change, will also need to be addressed equally, as these are inhabited by almost one-third of the studied species. The occurrence of the cobras and kraits in village forests and cropland dominant habitats demands more attention to minimise snakebite related mortality and morbidity.

Composition and natural history of a snake community from the southern Cerrado, southeastern Brazil

The natural history of a cerrado snake community in a protected area in southeastern Brazil (Santa Bárbara Ecological Station; SBES) is described. A visual guide and an identification key are also provided to assist researchers and local people in identifying snakes in that region.

Sampling was performed through pitfall traps, time-constrained search, accidental encounters, and observations by local people for two years, which corresponded to 240 days of sampling. Among the 388 individuals found in the field, 33 snake species belonging to 21 genera of seven families were recorded. Most species were restricted or found at least once in non-forest vegetation types (campo sujo, campo cerrado, and cerrado sensu stricto) and a few were restricted to forest habitats (cerradão). Our results show that most species (1) occupy open areas; (2) present both diurnal and nocturnal activity; (3) are primarily terrestrial; (4) include lizards, mammals and/or anurans in the diet; (5) present seasonal reproductive activity; and (6) use mainly visually oriented defensive tactics. Despite its small size (3,154 ha), the SBES harbours preserved habitats and a rich and typical Cerrado snake fauna, including threatened species. Furthermore, most of the SBES snakes occur in non-forest environments (54%) and some species are sensitive to habitat disturbance.

Dataset of occurrences and ecological traits of amphibians from Upper Paraguay River Basin, central South America

There are many gaps in our biodiversity knowledge, especially in highly diverse regions such as the Neotropics. Basic information on species occurrence and traits are scattered throughout different literature sources, which makes it difficult to access data and ultimately delays advances in ecology, evolution, and conservation biology. We provide species occurrence and trait data for amphibian species in the Upper Paraguay River Basin, central South America. The compiled information is made available through two different datasets that hold (i) 17K species occurrence records and (ii) 30 species-level traits for 113 amphibian species. The first dataset includes the species occurrence records and informs specimen id, collection of housing, locality, geographical coordinates, geographic accuracy, collection date, and collector name. The second dataset covers species-level attributes on morphometry, diet, activity, habitat, and breeding strategy. These datasets improve accessibility to spatial and trait data for amphibian species in the Pantanal ecoregion, one of the largest wetlands on Earth.