Structure of a Population of Hydromedusa maximiliani (Testudines, Chelidae) from Parque Estadual da Serra do Mar, an Atlantic Rainforest Preserve in Southeastern Brazil (original) (raw)
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Bar. Brazilian Administration Review, 2009
Studies on population structure of freshwater turtles belonging to the family Chelidae are scarce in Brazil. Herein we describe the structure of a population of the chelid Mesoclemmys vanderhaegei in a Cerrado area in the municipality of Chapada dos Guimarães, Mato Grosso, Brazil. A total of 80 individuals were captured in five collecting sites, from January to March 2007: 42 adult females, 27 adult males, and 11 juveniles with undetermined sex. Among 80 individuals, 24% were recaptured, at least once. This is the first attempt to estimate the size of a population of Mesoclemmys vanderhaegei. Our results suggest that additional sampling efforts are needed for more accurate estimates of population structure. Nevertheless, they surely provide minimum values of the number of individuals of M. vanderhaegei living in the locality sampled.
2018
We present new records of Phrynops williamsi in southern Brazil and field observations that point to at least three threats to the species in the Upper Uruguay River Basin. Our report provides for the first time direct observation of death and injuries as a consequence of falls from dams and walls of hydroelectric plants shortly after the reservoir formation, apparently as an attempt to abandon the artificial lakes and corroborates the species’ dependence on lotic environments, justifying the increasing concern with its conservation in southern Brazil.
Herpetology Notes
Hydromedusa maximiliani is endemic to mountainous regions, with distribution in the Atlantic Forest region along mountain ranges in Southeastern and part of northeastern Brazil. This work aimed at studying the feeding habits of a H. maximiliani population from Minas Gerais state, Southeastern Brazil. Specimens were captured, marked, measured and submitted to stomach washing. Pitfall traps were used to capture prey in terrestrial environments, and nets were used to collect macroinvertebrates in the aquatic environmental. We captured and recaptured a total of 33 individuals. From 16 samples of stomach content, we recorded aquatic insect larvae, crabs, and terrestrial invertebrates. In total, 16 categories of prey items were identified. These belonged to 16 orders and 70 families of Insecta, 3 families of Diplopoda, 2 families of Crustacea, and 13 families of Arachnida. Lepidoptera, Baetidae and Diplopoda reached maximum electivity. The most representative group in the diet was Insecta, especially those with aquatic larval phase. The information obtained in this study about the diet of H. maximiliani indicates this vertebrate as a potential predator for regulating the density of benthic macroinvertebrates, and our data corroborate other studies which also showed the importance of H. maximiliani as a predator essential to aquatic food web dynamics. These data will be useful in future studies dealing with the biomonitoring of H. maximiliani, and contributing to its preservation as well as to the preservation of habitats where this species lives.
Amphibia-Reptilia, 2008
The Snake-necked Turtle (Hydromedusa tectifera) is mainly distributed in the northeastern provinces of Argentina; however, some isolated populations occur in central Córdoba. This is the first report on some ecological aspects of one of these populations. Population density and annual activity pattern were characterized at Toro Muerto Stream in the Sierras region of the Córdoba province, central Argentina. Turtles were hand-captured and sex and carapace length were determined for each individual. Mark-recapture data were used to estimate population density, variation in monthly capture rates, and sex ratios throughout the sampling months. A total of 96 turtles were captured and density was estimated at 218 individuals ha −1 . Individuals were captured all year round, but showed activity peaks in spring and summer. This seasonal pattern has also been observed in other freshwater turtles. During the mating season a higher number of males were captured, which suggested a seasonal difference in activity patterns between sexes.
Demography of Acanthochelys spixii (Testudines, Chelidae) in the Brazilian Cerrado
We estimated demographic parameters for Acanthochelys spixii in Parque Nacional de Brası´lia, Distrito Federal, Brazil, based on 4 years of data collection, and also analyzed the effects of sex, temporal variation, and climatic factors on population dynamics. The adult sex ratio did not vary significantly from 1:1. By using the Akaike’s information criterion, selection of candidate models constrained for climatic variables indicated that the interaction between total rainfall and average air temperature from the previous month as well as recapture probability (p) on a monthly basis explained most variation in demographic parameters, with a constant annual apparent survival (W) value of 0.82. Recapture rates during the study period varied from 0.01 to 0.23 and, during the dry season, from 0.01 to 0.04. The monthly average population size was 30 adult turtles, with values between 10 and 35 adults over 4 years. The annual population growth rates were 1.37 for 2005–2006 and 0.59 for 2006–2007. The small population size of Acanthochelys spixii seems characteristic of chelids in the area, and maintaining it depends on preserving natural ecosystems inside Parque Nacional de Brası´lia.
We present the 1st estimates of density of the Solitary Tinamou (Tinamus solitarius (Vieillot, 1819)) in the Reserva Natural Vale (RNV), one of the two largest remnants of the Atlantic Rainforest in the State of Espírito Santo, Brazil. We also modeled the spatial distribution and habitat use of the species using occupancy and detectability modeling. We used a line-transect survey to estimate density and abundance, and camera-traps to estimate habitat use and activity pattern. We conducted the survey within a 13-month period (April 2013 to May 2014). Estimated density was 9 ± 2 individuals / km 2 and estimated population size for the entire RNV was 2115 ± 470 individuals. Occupancy was best described by the: distance to forest edge; distance between trees; poaching intensity; and understorey cover. Detectability was affected by the: distance between trees and poaching intensity. We conclude that in the RNV, the near-threatened T. solitarius is a diurnal species preferring intact closed-canopy forest but tending to avoid areas near to forest edges or areas under comparatively high intensity of poaching. These results reinforce the importance of RNV as a source of resource to T. solitarius reproduction at Brazilian Atlantic forest remnants.