Sonia Zanini Cechin

Eficiência de armadilhas de queda (pitfall traps) em amostragens de anfíbios e répteis no Brasil

The effectiveness of pitfall traps associated with drift fences to capture amphibians and reptiles in three field studies, in Rio Grande do Sul (extreme southern Brazil), Sao Paulo (Sao Paulo, southeastern Brazil), and Amazonas (Amazonas, northern Brazil) is described. At Santa Maria, a total of 2040 amphibians and reptiles were caught in 30 pitfalls (200 L, with drift fence) during 18 months of study (capture efficiencies of 3.78 amphibians and reptiles/pitfall/month and 0.14 snake/pitfall/month). At Itirapina, Sao Paulo, 1262 amphibians and reptiles were obtained in 72 pitfalls (100 L, with drift fence) during six months (capture efficiencies of 11,9 amphibians and reptiles/pitfall/month and 0,38 snake/pitfall/month). At Rio Pitinga, Amazonas, over 600 amphibians and reptiles were caught in 50 pitfalls (100-150 L, with drift fence) during three months (capture efficiencies of ca. 4.00 amphibians and reptiles/pitfall/month and 0.87 snake/pitfall/month). Capture efficiencies of 1.25 to ~3.92 amphibians and reptiles/pitfall/month were obtained in four other unpublished studies made by other authors in Brazil, all of them using 20-35 L traps, either with or without drift fences. Higher capture efficiencies for snakes were obtained in those studies in which larger containers (100-200 L) were used. The results presented here indicate that pitfall traps are extremely useful to sample amphibians and reptiles in Brazil, especially anurans and lizards. From these results, it is possible to preview the capture of 125 to 1200 amphibians and reptiles with 100 pitfalls during one month, regardless of the size of the pitfalls and sampling design of the trap arrays. The main advantages and disadvantages of the method and detailed guidelines on how to design, install, and use the traps is discussed.

An austral anuran assemblage in the Neotropics: seasonal occurrence correlated with photoperiod

The study describes habitat use and temporal occurrence of calling males for an austral anuran assemblage in the Neotropics, southern Brazil. Three study sites (S1 – a permanent river and a stream, S2 – a dam and backwater, S3 – two permanent ponds periodically connected) were sampled between August 2005 and July 2006. The site S3 presented the richest and most diverse assemblage and habitat use within studied sites, and was partitioned by species groups. Richness and abundance of calling males for overall assemblage were seasonal, concentrated in spring and summer and correlated with photoperiod. Temperature, rainfall and air humidity were not correlated with the richness and abundance of calling males. Photoperiod also explained the calling seasons when species were analyzed individually. Habitat use and temporal occurrence were complementary in the partitioning of breeding resources, explaining species coexistence.

The role of spatial and temporal descriptors for neotropical tadpole communities in southern Brazil

We evaluated tadpole communities of temporary and permanent ponds, in order to understand how community richness varies monthly in a subtropical humid climate, to interpret the community structure in relation to biotic and abiotic environmental variables related to the temporary and permanent ponds. The study site was the Pró-Mata Research and Nature Conservation Center, a private reserve in southern Brazil. The climate is classified as Temperate Superhumid, with no dry season. We sampled three temporary and three permanent ponds. We compared the richness of tadpole assemblages of permanent and temporary ponds through individual-based rarefaction curves, and tested for possible differences using a MANOVA test. Tadpole richness was related to temporal environmental descriptors through General Regression Model. Relationships between the tadpole assemblages and possible predictors of their spatial variation were measured using a partial Canonical Correspondence Analysis. Analysis of rarefaction curves indicated higher expected richness for the temporary ponds. The mean values of richness were significantly different between the two hydroperiods across all months. Monthly richness showed the same tendency of variation for both pond types. Only temperature was related to tadpole richness. The pCCA analysis was significant. The most important predictors on the first pCCA axis were vegetation cover, conductivity, depth, and predator diversity. In this study, vegetation cover, conductivity, predator diversity, and water depth explained the spatial variation of tadpoles between ponds, with tadpole richness and diversity being higher in temporary than in permanent ponds. Our results suggest that different spatial-seasonal patterns operating in temporary and permanent ponds are related to maintaining the species diversity of pond-breeding anurans.

Mamíferos do campus da Universidade Federal de Santa Maria, Rio Grande do Sul, Brasil

Universidade Estadual Paulista Instituto de Biociencias Programa de Pos-Graduacao em Ciencias Biologicas (Zoologia)

Hibernation and emergence pattern of Tupinambis merianae (Squamata: Teiidae) in the Taim Ecological Station, southern Brazil

The emergence period and winter aggregations of a population of Tupinambis merianae from southern Brazil as well as some behavioural aspects from its post‐emergence period are examined. Fifty‐six individuals were captured and marked in 64 days (640 h) of field study. Most of the hibernacula identified were beneath human constructions. The first individuals emerged in August and the last active ones were observed in April. The populations emergence shows a protandric pattern, where males emerge before females, both in adults and juveniles. After emerging, males basked in aggregations of up to 13 individuals, in which individuals changed positions following audible resonant signals emitted by the lizards. Sibilated sounds were emitted in stress situations or in agonistic interactions. Future studies are necessary to elucidate behaviour patterns of the species in the natural environment, mainly related to the utilization of sound communication.

Identification of influential events concerning the Antarctic ozone hole over southern Brazil and the biological effects induced by UVB and UVA radiation in an endemic treefrog species

The increased incidence of solar ultraviolet radiation (UV) due to ozone depletion has been affecting both terrestrial and aquatic ecosystems and it may help to explain the enigmatic decline of amphibian populations in specific localities. In this work, influential events concerning the Antarctic ozone hole were identified in a dataset containing 35 years of ozone measurements over southern Brazil. The effects of environmental doses of UVB and UVA radiation were addressed on the morphology and development of Hypsiboas pulchellus tadpole (Anura: Hylidae), as well as on the induction of malformation after the conclusion of metamorphosis. These analyzes were complemented by the detection of micronucleus formation in blood cells. 72 ozone depletion events were identified from 1979 to 2013. Surprisingly, their yearly frequency increased three-fold during the last 17 years. The results clearly show that H. pulchellus tadpole are much more sensitive to UVB than UVA light, which reduces their survival and developmental rates. Additionally, the rates of micronucleus formation by UVB were considerably higher compared to UVA even after the activation of photolyases enzymes by a further photoreactivation treatment. Consequently, a higher occurrence of malformation was observed in UVB-irradiated individuals. These results demonstrate the severe genotoxic impact of UVB radiation on this treefrog species and its importance for further studies aimed to assess the impact of the increased levels of solar UVB radiation on declining species of the Hylidae family.

Anurans of Turvo State Park: testing the validity of Seasonal Forest as a new biome in Brazil

The composition of the anuran community of Turvo State Park was compared with that of other localities of Mesophytic semideciduous Forest, aiming to test the hypothesis that localities situated nearest the Misiones nucleus support the new phytogeographic unit, known as Tropical Seasonal Forests Region. In total 32 amphibian species were recorded in the park area and surroundings: Anura, 30 native species and one exotic; Gymnophiona, one species. The ordination among the 20 localities of Seasonal Forest showed the formation of three groups with 45% similarity: group 1, composed of localities of south-eastern and central western regions; group 2, composed of the localities of the transitional portion with the Atlantic Forest sensu stricto and group 3, composed of the southern localities. The consolidation of the second group, which includes the occurrence of endemic species, supports the proposal of a new phytogeographic unit.

Population ecology of Tupinambis merianae (Squamata, Teiidae): home-range, activity and space use

The activity and space parameters (home range and use of space) for a population of Tupinambis merianae was recorded through 640 h of observation during nine months, and by monitoring 56 marked individuals. There was a significant difference in activity in the periods stipulated in this study throughout the months. Active lizards were not registered before 7:30 a.m., nor after 6:00 p.m. The greatest level of activity by the individuals occurred during November and December. Fluctuations in the population size and in the activity of the different age classes were recorded throughout the studied months. We recorded the minimum home-range of three males and two females, which varied from 0.05 to 26.44 ha. We also observed agonistic interactions. The utilization area of the animals did not vary during the studied months, but it was possible to observe gregarious behavior in spatial use. The highest daily activity occurred at the hours of higher temperatures. The positive correlation between seasonal activity and the maximum temperature (air and substrate) showed a unimodal distribution and was identical to the records from a tropical area (southeastern Brazil). It is possible that temperature is not the only environmental variable/factor that influences the seasonal activity cycle of the species. Although teiids are not considered territorial, some of our results could suggest territoriality in the studied population.

Reproductive biology of the swamp racer Mastigodryas bifossatus (Serpentes: Colubridae) in subtropical Brazil

The swamp racer Mastigodryas bifossatus (Raddi, 1820) is a large snake of Colubrinae. It is widely distributed in open areas throughout South America. Dissection of 224 specimens of this species housed in herpetological collections of the southern Brazilian states of Rio Grande do Sul, Santa Catarina and Parana provided information on its sexual dimorphism, reproductive cycle and fecundity in subtropical Brazil. Adult specimens of M. bifossatus average approximately 1190 mm in snout-vent length and females are larger than males. The reproductive cycle of females is seasonal, with secondary vitellogenesis occurring from July to December. However, examination of male gonads did not reveal signs of reproductive seasonality in this sex. Egg laying was recorded from November to January. The estimated recruitment period extends from February to April. The mean number of individuals per clutch is 15, and there is a positive correlation between female length and clutch size.

Extension of the geographical distribution of two anuran species for Rio Grande do Sul State, Brazil, with comments on natural history

We record for the first time Crossodactylus schmidti (Anura: Hylodidae) and Proceratophrys avelinoi (Anura: Cycloramphidae) from Rio Grande do Sul State, Brazil, based on individuals captured in an area of Mesophytic Semideciduous Forest, the Parque Estadual do Turvo, located in the northwest region of the state. These records extend the geographical range for both species in about 60 km from the nearest known locality, the Municipality of San Vicente, Misiones, Argentina. We provide a characterization of the calling site used by males of Crossodactylus schmidti, and we also determined the niche breadth of P. avelinoi regarding to the use of water bodies.