Socio-economic and spatial determinants of anthropogenic predation on Yellow-spotted River Turtle, Podocnemis unifilis (Testudines: Pelomedusidae), nests in the Brazilian Amazon: Implications for sustainable conservation and management

Human expansion has drastically affected wildlife species across Amazonian waterways and the continued increase in rural populations across Amazonia is likely to increase pressure on widely exploited chelonian species. The lack of information evaluating determinants of human consumption patterns limits the effective implementation of conservation strategies. Our objective was to determine the relative importance of social, economic, and spatial variables on human exploitation of Podocnemis unifilis Troschel, 1848 around a sustainable-use protected area in the eastern Brazilian Amazon. We conducted interviews with 51 riverine residents to evaluate attitudes towards and exploitation of P. unifilis. We used multimodel inference to evaluate 12 working hypothesis predicting social, economic, and spatial influences on the occurrence and intensity of P. unifilis egg consumption. None of the respondents reported catching and/or eating adult P. unifilis and none sold adults or eggs during the previous year. Although the majority (58.8%) of respondents had eaten P. unifilis eggs during the previous year and the species was occasionally caught in fishing nets, P. unifilis was rarely cited as a liked or disliked species. Our information theoretic analysis showed that spatial hypotheses were the most strongly supported whereas social and economic hypotheses were only weakly supported in explaining if and how many P. unifilis eggs had been consumed by riverine residents during the previous year. Our findings suggest that current Amazonian development patterns may be associated with reduced consumption of adult P. unifilis, but consumption of eggs together with other indirect anthropogenic perturbations continue to threaten remaining P. unifilis populations.

Socio-economic and spatial determinants of anthropogenic predation on Yellow-spotted River Turtle, Podocnemis unifilis (Testudines: Pelomedusidae), nests in the Brazilian Amazon: Implications for sustainable conservation and management

Human expansion has drastically affected wildlife species across Amazonian waterways and the continued increase in rural populations across Amazonia is likely to increase pressure on widely exploited chelonian species. The lack of information evaluating determinants of human consumption patterns limits the effective implementation of conservation strategies. Our objective was to determine the relative importance of social, economic, and spatial variables on human exploitation of Podocnemis unifilis Troschel, 1848 around a sustainable-use protected area in the eastern Brazilian Amazon. We conducted interviews with 51 riverine residents to evaluate attitudes towards and exploitation of P. unifilis. We used multimodel inference to evaluate 12 working hypothesis predicting social, economic, and spatial influences on the occurrence and intensity of P. unifilis egg consumption. None of the respondents reported catching and/or eating adult P. unifilis and none sold adults or eggs during the previous year. Although the majority (58.8%) of respondents had eaten P. unifilis eggs during the previous year and the species was occasionally caught in fishing nets, P. unifilis was rarely cited as a liked or disliked species. Our information theoretic analysis showed that spatial hypotheses were the most strongly supported whereas social and economic hypotheses were only weakly supported in explaining if and how many P. unifilis eggs had been consumed by riverine residents during the previous year. Our findings suggest that current Amazonian development patterns may be associated with reduced consumption of adult P. unifilis, but consumption of eggs together with other indirect anthropogenic perturbations continue to threaten remaining P. unifilis populations.

Socio-economic and spatial determinants of anthropogenic predation on Yellow-spotted River Turtle, Podocnemis unifilis (Testudines: Pelomedusidae), nests in the Brazilian Amazon: Implications for sustainable conservation and management

Human expansion has drastically affected wildlife species across Amazonian waterways and the continued increase in rural populations across Amazonia is likely to increase pressure on widely exploited chelonian species. The lack of information evaluating determinants of human consumption patterns limits the effective implementation of conservation strategies. Our objective was to determine the relative importance of social, economic, and spatial variables on human exploitation of Podocnemis unifilis Troschel, 1848 around a sustainable-use protected area in the eastern Brazilian Amazon. We conducted interviews with 51 riverine residents to evaluate attitudes towards and exploitation of P. unifilis. We used multimodel inference to evaluate 12 working hypothesis predicting social, economic, and spatial influences on the occurrence and intensity of P. unifilis egg consumption. None of the respondents reported catching and/or eating adult P. unifilis and none sold adults or eggs during the previous year. Although the majority (58.8%) of respondents had eaten P. unifilis eggs during the previous year and the species was occasionally caught in fishing nets, P. unifilis was rarely cited as a liked or disliked species. Our information theoretic analysis showed that spatial hypotheses were the most strongly supported whereas social and economic hypotheses were only weakly supported in explaining if and how many P. unifilis eggs had been consumed by riverine residents during the previous year. Our findings suggest that current Amazonian development patterns may be associated with reduced consumption of adult P. unifilis, but consumption of eggs together with other indirect anthropogenic perturbations continue to threaten remaining P. unifilis populations.

Breeding biology and reproductive success of Polystictus superciliaris (Aves: Tyrannidae), an uncommon tyrant-flycatcher endemic to the highlands of eastern Brazil

Polystictus superciliaris (Wied, 1831) is a small tyrant-flycatcher endemic to mountaintops in the highlands of eastern Brazil. In this paper we present the first description of the breeding biology of P. superciliaris and estimate its reproductive success from a population inhabiting rocky outcrops. This study was conducted during 2005 in the Parque Estadual da Serra do Rola Moça, municipality of Nova Lima (20°03'S, 44°00'W), state of Minas Gerais, southeastern Brazil. Fourteen pairs of P. superciliaris were banded and monitored. The onset of the breeding season in 2005 was assumed to have been sometime before the 26th of July, while it was assumed to have ended on the 23rd of November based on the last observation of a successful brood. Clutch size was invariably two eggs (N = 21), the incubation period averaged 17.7 ± 1.3 days (N = 9), and the nestling period averaged 16.4 ± 1.3 days (N = 8). We estimated the probability of reproductive success for P. superciliaris to be 41.3%, during this particular breeding season. Of the 12 (57.1%) unsuccessful nests, eight (66.7%) had eggs and four (33.3%) had nestlings when they failed. In nine (42.8%) of these cases, the nests were lost to predation, two to parasitism by botflies, and one due to abandonment. This study suggests that the reproductive success of P. superciliaris is intermediate compared to the other species of Tyrannidae that have been studied and closer to the lower limit of the 40%-80% range which is characteristic of tyrant _ flycatcher species that breed in temperate regions.

Breeding biology and reproductive success of Polystictus superciliaris (Aves: Tyrannidae), an uncommon tyrant-flycatcher endemic to the highlands of eastern Brazil

Polystictus superciliaris (Wied, 1831) is a small tyrant-flycatcher endemic to mountaintops in the highlands of eastern Brazil. In this paper we present the first description of the breeding biology of P. superciliaris and estimate its reproductive success from a population inhabiting rocky outcrops. This study was conducted during 2005 in the Parque Estadual da Serra do Rola Moça, municipality of Nova Lima (20°03'S, 44°00'W), state of Minas Gerais, southeastern Brazil. Fourteen pairs of P. superciliaris were banded and monitored. The onset of the breeding season in 2005 was assumed to have been sometime before the 26th of July, while it was assumed to have ended on the 23rd of November based on the last observation of a successful brood. Clutch size was invariably two eggs (N = 21), the incubation period averaged 17.7 ± 1.3 days (N = 9), and the nestling period averaged 16.4 ± 1.3 days (N = 8). We estimated the probability of reproductive success for P. superciliaris to be 41.3%, during this particular breeding season. Of the 12 (57.1%) unsuccessful nests, eight (66.7%) had eggs and four (33.3%) had nestlings when they failed. In nine (42.8%) of these cases, the nests were lost to predation, two to parasitism by botflies, and one due to abandonment. This study suggests that the reproductive success of P. superciliaris is intermediate compared to the other species of Tyrannidae that have been studied and closer to the lower limit of the 40%-80% range which is characteristic of tyrant _ flycatcher species that breed in temperate regions.

Breeding biology and reproductive success of Polystictus superciliaris (Aves: Tyrannidae), an uncommon tyrant-flycatcher endemic to the highlands of eastern Brazil

Polystictus superciliaris (Wied, 1831) is a small tyrant-flycatcher endemic to mountaintops in the highlands of eastern Brazil. In this paper we present the first description of the breeding biology of P. superciliaris and estimate its reproductive success from a population inhabiting rocky outcrops. This study was conducted during 2005 in the Parque Estadual da Serra do Rola Moça, municipality of Nova Lima (20°03'S, 44°00'W), state of Minas Gerais, southeastern Brazil. Fourteen pairs of P. superciliaris were banded and monitored. The onset of the breeding season in 2005 was assumed to have been sometime before the 26th of July, while it was assumed to have ended on the 23rd of November based on the last observation of a successful brood. Clutch size was invariably two eggs (N = 21), the incubation period averaged 17.7 ± 1.3 days (N = 9), and the nestling period averaged 16.4 ± 1.3 days (N = 8). We estimated the probability of reproductive success for P. superciliaris to be 41.3%, during this particular breeding season. Of the 12 (57.1%) unsuccessful nests, eight (66.7%) had eggs and four (33.3%) had nestlings when they failed. In nine (42.8%) of these cases, the nests were lost to predation, two to parasitism by botflies, and one due to abandonment. This study suggests that the reproductive success of P. superciliaris is intermediate compared to the other species of Tyrannidae that have been studied and closer to the lower limit of the 40%-80% range which is characteristic of tyrant _ flycatcher species that breed in temperate regions.

Nesting of Phrynops geoffroanus (Testudines: Chelidae) on sandy beaches along the Upper Xingu River, Brazil

This work presents the first data on incubation temperature of Phrynops geoffroanus (Schweigger, 1812) in a natural environment, and provides information on nest predation, hatching success and size of offspring born in the nests on sandy beaches along the Upper Xingu River. Thirty-one P. geoffroanus nests were found, of which eleven were completely predated, mainly by Cerdocyon thous (Linnaeus, 1766). Incubation was completed in nine out of the 17 nests protected by netting. The nests presented an average of 13.1 eggs and were distributed over the various geomorphological sectors of the nine sampled beaches. The size and weight of the hatchlings varied significantly between nests, and the incubation period in protected nests lasted for 76.5 days, less than reported for controlled incubation in the laboratory. Daily variation in incubation temperature in the three nests monitored for temperature was lower in those situated in fine sand sediments. Incubation temperature varied from 22 to 39 C and may have affected hatching success, which reached 60.8% in protected nests. Nest distribution in different geomorphological sectors indicated the plasticity of P. geoffroanus in terms of variation in nesting environment, which partly explains the species' broad geographical distribution.

Nesting of Phrynops geoffroanus (Testudines: Chelidae) on sandy beaches along the Upper Xingu River, Brazil

This work presents the first data on incubation temperature of Phrynops geoffroanus (Schweigger, 1812) in a natural environment, and provides information on nest predation, hatching success and size of offspring born in the nests on sandy beaches along the Upper Xingu River. Thirty-one P. geoffroanus nests were found, of which eleven were completely predated, mainly by Cerdocyon thous (Linnaeus, 1766). Incubation was completed in nine out of the 17 nests protected by netting. The nests presented an average of 13.1 eggs and were distributed over the various geomorphological sectors of the nine sampled beaches. The size and weight of the hatchlings varied significantly between nests, and the incubation period in protected nests lasted for 76.5 days, less than reported for controlled incubation in the laboratory. Daily variation in incubation temperature in the three nests monitored for temperature was lower in those situated in fine sand sediments. Incubation temperature varied from 22 to 39 C and may have affected hatching success, which reached 60.8% in protected nests. Nest distribution in different geomorphological sectors indicated the plasticity of P. geoffroanus in terms of variation in nesting environment, which partly explains the species' broad geographical distribution.

Nesting of Phrynops geoffroanus (Testudines: Chelidae) on sandy beaches along the Upper Xingu River, Brazil

This work presents the first data on incubation temperature of Phrynops geoffroanus (Schweigger, 1812) in a natural environment, and provides information on nest predation, hatching success and size of offspring born in the nests on sandy beaches along the Upper Xingu River. Thirty-one P. geoffroanus nests were found, of which eleven were completely predated, mainly by Cerdocyon thous (Linnaeus, 1766). Incubation was completed in nine out of the 17 nests protected by netting. The nests presented an average of 13.1 eggs and were distributed over the various geomorphological sectors of the nine sampled beaches. The size and weight of the hatchlings varied significantly between nests, and the incubation period in protected nests lasted for 76.5 days, less than reported for controlled incubation in the laboratory. Daily variation in incubation temperature in the three nests monitored for temperature was lower in those situated in fine sand sediments. Incubation temperature varied from 22 to 39 C and may have affected hatching success, which reached 60.8% in protected nests. Nest distribution in different geomorphological sectors indicated the plasticity of P. geoffroanus in terms of variation in nesting environment, which partly explains the species' broad geographical distribution.

Teste do efeito de borda na predação de ninhos naturais e artificiais no Cerrado

The Cerrado is still one of the most important ecosystems in Brazil, even though more than 50% of its area has been altered or converted to pastureland and plantations. Despite its intense degradation, few ecological processes that might affect its biodiversity have been evaluated. The goal of this study was to test the edge effect on the predation rates at natural and artificial nests, at the Ecological Station of Águas Emendadas, Federal District, Brazil. Natural nests were found and monitored every three to four days from September to December of 2004 in the interior and at the edge of the reserve. Artificial nests were placed at four distances from the edge (0, 500, 1000 and 2000 m) in three spatial replicates in September and again in December of 2004. Each nest received one Japanese Quail and one plasticine egg and was monitored every five days, for 15 days. There was no difference between the rates of predation either in the natural nests or in the artificial nests between treatments. For one bird species, Elaenia chiriquensis (Lawrence, 1865), Tyrannidae, daily survival rates in the incubation and in the hatchling period had opposite values between the edge and the interior. Marks on plasticine eggs suggest that birds are the main predators. Estimates of the abundance of two potential nest predators, Cyanocorax cristatellus (Temminck, 1823), Corvidae and Canis familiaris (Linnaeus, 1758), Canidae, revealed no relationship with distance to the edge, nor with predation rates. Brood parasitism of natural nests was similar between the interior (0%) and the edge (3.8% of the nests). The results described here do not support the edge effect hypothesis for nest predation rates on either natural or artificial nests, nor for brood parasitism rates.

Teste do efeito de borda na predação de ninhos naturais e artificiais no Cerrado

The Cerrado is still one of the most important ecosystems in Brazil, even though more than 50% of its area has been altered or converted to pastureland and plantations. Despite its intense degradation, few ecological processes that might affect its biodiversity have been evaluated. The goal of this study was to test the edge effect on the predation rates at natural and artificial nests, at the Ecological Station of Águas Emendadas, Federal District, Brazil. Natural nests were found and monitored every three to four days from September to December of 2004 in the interior and at the edge of the reserve. Artificial nests were placed at four distances from the edge (0, 500, 1000 and 2000 m) in three spatial replicates in September and again in December of 2004. Each nest received one Japanese Quail and one plasticine egg and was monitored every five days, for 15 days. There was no difference between the rates of predation either in the natural nests or in the artificial nests between treatments. For one bird species, Elaenia chiriquensis (Lawrence, 1865), Tyrannidae, daily survival rates in the incubation and in the hatchling period had opposite values between the edge and the interior. Marks on plasticine eggs suggest that birds are the main predators. Estimates of the abundance of two potential nest predators, Cyanocorax cristatellus (Temminck, 1823), Corvidae and Canis familiaris (Linnaeus, 1758), Canidae, revealed no relationship with distance to the edge, nor with predation rates. Brood parasitism of natural nests was similar between the interior (0%) and the edge (3.8% of the nests). The results described here do not support the edge effect hypothesis for nest predation rates on either natural or artificial nests, nor for brood parasitism rates.

Teste do efeito de borda na predação de ninhos naturais e artificiais no Cerrado

The Cerrado is still one of the most important ecosystems in Brazil, even though more than 50% of its area has been altered or converted to pastureland and plantations. Despite its intense degradation, few ecological processes that might affect its biodiversity have been evaluated. The goal of this study was to test the edge effect on the predation rates at natural and artificial nests, at the Ecological Station of Águas Emendadas, Federal District, Brazil. Natural nests were found and monitored every three to four days from September to December of 2004 in the interior and at the edge of the reserve. Artificial nests were placed at four distances from the edge (0, 500, 1000 and 2000 m) in three spatial replicates in September and again in December of 2004. Each nest received one Japanese Quail and one plasticine egg and was monitored every five days, for 15 days. There was no difference between the rates of predation either in the natural nests or in the artificial nests between treatments. For one bird species, Elaenia chiriquensis (Lawrence, 1865), Tyrannidae, daily survival rates in the incubation and in the hatchling period had opposite values between the edge and the interior. Marks on plasticine eggs suggest that birds are the main predators. Estimates of the abundance of two potential nest predators, Cyanocorax cristatellus (Temminck, 1823), Corvidae and Canis familiaris (Linnaeus, 1758), Canidae, revealed no relationship with distance to the edge, nor with predation rates. Brood parasitism of natural nests was similar between the interior (0%) and the edge (3.8% of the nests). The results described here do not support the edge effect hypothesis for nest predation rates on either natural or artificial nests, nor for brood parasitism rates.