Esse estudo teve como objetivo atualizar a lista de serpentes do estado de Rondônia a partir de l... more Esse estudo teve como objetivo atualizar a lista de serpentes do estado de Rondônia a partir de levantamento bibliográfico, e fornecer algumas informações sobre a distribuição das espécies. São registradas para o estado de Rondônia 118 espécies de serpentes, pertencentes a oito famílias: Leptotyphlopidae (4 espécies), Typhlopidae (1), Aniliidae (1), Boidae (6), Colubridae (21), Dipsadidae (67), Elapidae (9) e Viperidae (9). Dessas, 109 foram registradas para áreas de floresta amazônica e 27 em cerrado. A menor riqueza encontrada em cerrado (27 espécies) provavelmente deve estar associada aos poucos trabalhos desenvolvidos nessas áreas e pelo fato dessa formação vegetal ocupar uma área de cerca de apenas 5% do estado. Nove espécies (Epicrates crassus, Chironius flavolineatus, Drymoluber brazili, Apostolepis striata, Oxyrhopus rhombifer, Pseudoboa nigra, Xenodon merremii, Bothrops mattogrossensis e Crotalus durissus) foram registradas exclusivamente em áreas de cerrado, sendo formas a...
BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting... more BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research.
We estimated demographic parameters for Acanthochelys spixii in Parque Nacional de
Brası´lia, Dis... more 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 studied the diet of Acanthochelys spixii in a wild population in the Cerrado of central Brazil... more We studied the diet of Acanthochelys spixii in a wild population in the Cerrado of central Brazil for 19 months, investigating ontogenetic, sexual, and interindividual variation. The diet consisted mainly of nymphs of Odonata, although other insects, amphibians, and plant material were also present. We observed no ontogenetic shifts in diet composition (e.g., no shift from carnivorous juveniles to herbivorous adults), which can be related to the high abundance of prey at the study site. There was no association between prey size and turtle carapace length, with larger animals still taking small prey. Dietary niche overlap was high, and there was no difference in niche breadth between sexes. However, differences in diet composition suggested differential habitat use, with males using more the periphery and females using more the center of ponds. Diet composition varied more among males than among females, which can result from higher diversity of prey at the pond margins, higher movement rates, or larger home range of males. The high frequency of empty stomachs (41%) reflected life-history characteristics of turtles (e.g., low metabolism, ectothermy, late sexual maturity, and great longevity). The importance of prey categories sensitive to pollution in the diet of A. spixii highlights the integrity of the study sites and the vulnerability of these populations to the rapid degradation of Cerrado biome.
Esse estudo teve como objetivo atualizar a lista de serpentes do estado de Rondônia a partir de l... more Esse estudo teve como objetivo atualizar a lista de serpentes do estado de Rondônia a partir de levantamento bibliográfico, e fornecer algumas informações sobre a distribuição das espécies. São registradas para o estado de Rondônia 118 espécies de serpentes, pertencentes a oito famílias: Leptotyphlopidae (4 espécies), Typhlopidae (1), Aniliidae (1), Boidae (6), Colubridae (21), Dipsadidae (67), Elapidae (9) e Viperidae (9). Dessas, 109 foram registradas para áreas de floresta amazônica e 27 em cerrado. A menor riqueza encontrada em cerrado (27 espécies) provavelmente deve estar associada aos poucos trabalhos desenvolvidos nessas áreas e pelo fato dessa formação vegetal ocupar uma área de cerca de apenas 5% do estado. Nove espécies (Epicrates crassus, Chironius flavolineatus, Drymoluber brazili, Apostolepis striata, Oxyrhopus rhombifer, Pseudoboa nigra, Xenodon merremii, Bothrops mattogrossensis e Crotalus durissus) foram registradas exclusivamente em áreas de cerrado, sendo formas a...
BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting... more BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research.
We estimated demographic parameters for Acanthochelys spixii in Parque Nacional de
Brası´lia, Dis... more 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 studied the diet of Acanthochelys spixii in a wild population in the Cerrado of central Brazil... more We studied the diet of Acanthochelys spixii in a wild population in the Cerrado of central Brazil for 19 months, investigating ontogenetic, sexual, and interindividual variation. The diet consisted mainly of nymphs of Odonata, although other insects, amphibians, and plant material were also present. We observed no ontogenetic shifts in diet composition (e.g., no shift from carnivorous juveniles to herbivorous adults), which can be related to the high abundance of prey at the study site. There was no association between prey size and turtle carapace length, with larger animals still taking small prey. Dietary niche overlap was high, and there was no difference in niche breadth between sexes. However, differences in diet composition suggested differential habitat use, with males using more the periphery and females using more the center of ponds. Diet composition varied more among males than among females, which can result from higher diversity of prey at the pond margins, higher movement rates, or larger home range of males. The high frequency of empty stomachs (41%) reflected life-history characteristics of turtles (e.g., low metabolism, ectothermy, late sexual maturity, and great longevity). The importance of prey categories sensitive to pollution in the diet of A. spixii highlights the integrity of the study sites and the vulnerability of these populations to the rapid degradation of Cerrado biome.
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Papers by Thiago Barros
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.
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.