Microhabitat selection of the poorly known lizard Tropidurus lagunablanca (Squamata: Tropiduridae) in the Pantanal, Brazil

Abstract Understanding how different environmental factors influence species occurrence is a key issue to address the study of natural populations. However, there is a lack of knowledge on how local traits influence the microhabitat use of tropical arboreal lizards. Here, we investigated the microhabitat selection of the poorly known lizard Tropidurus lagunablanca (Squamata: Tropiduridae) and evaluated how environmental microhabitat features influence animals presence. We used a Resource Selection Function approach, in a case/control design where we analyzed the effect of substrate temperature and trees diameter at breast height (DBH) in the probability of presence of lizards using mixed Conditional Logistic Regression. We found that T. lagunablanca uses trees with DBH from 0.40 m to 4 m and substrate temperatures ranging from 25.9°C to 42°C. Moreover, we showed that thickness of the trees and substrate temperatures significantly increased the probability of presence of T. lagunablanca individuals, being the probability of presence higher than 50% for trees up to 1.5 m DBH and temperature of substrate up to 37.5°C. Our study probed that T. lagunablanca individuals choose trees non-randomly, selecting thicker and warmer tree trunks. This information advances the knowledge of the spatial ecology of Neotropical arboreal lizards and is relevant for conservation, putting an emphasis on preserving native vegetation in the Pantanal.

Microhabitat selection of the poorly known lizard Tropidurus lagunablanca (Squamata: Tropiduridae) in the Pantanal, Brazil

Abstract Understanding how different environmental factors influence species occurrence is a key issue to address the study of natural populations. However, there is a lack of knowledge on how local traits influence the microhabitat use of tropical arboreal lizards. Here, we investigated the microhabitat selection of the poorly known lizard Tropidurus lagunablanca (Squamata: Tropiduridae) and evaluated how environmental microhabitat features influence animal's presence. We used a Resource Selection Function approach, in a case/control design where we analyzed the effect of substrate temperature and tree's diameter at breast height (DBH) in the probability of presence of lizards using mixed Conditional Logistic Regression. We found that T. lagunablanca uses trees with DBH from 0.40 m to 4 m and substrate temperatures ranging from 25.9°C to 42°C. Moreover, we showed that thickness of the trees and substrate temperatures significantly increased the probability of presence of T. lagunablanca individuals, being the probability of presence higher than 50% for trees up to 1.5 m DBH and temperature of substrate up to 37.5°C. Our study probed that T. lagunablanca individuals choose trees non-randomly, selecting thicker and warmer tree trunks. This information advances the knowledge of the spatial ecology of Neotropical arboreal lizards and is relevant for conservation, putting an emphasis on preserving native vegetation in the Pantanal.

Microhabitat selection of the poorly known lizard Tropidurus lagunablanca(Squamata: Tropiduridae) in the Pantanal, Brazil

Understanding how different environmental factors influence species occurrence is a key issue to address the study of natural populations. However, there is a lack of knowledge on how local traits influence the microhabitat use of tropical arboreal lizards. Here, we investigated the microhabitat selection of the poorly known lizard Tropidurus lagunablanca(Squamata: Tropiduridae) and evaluated how environmental microhabitat features influence animals presence. We used a Resource Selection Function approach, in a case/control design where we analyzed the effect of substrate temperature and trees diameter at breast height (DBH) in the probability of presence of lizards using mixed Conditional Logistic Regression. We found that T. lagunablanca uses trees with DBH from 0.40 m to 4 m and substrate temperatures ranging from 25.9°C to 42°C. Moreover, we showed that thickness of the trees and substrate temperatures significantly increased the probability of presence of T. lagunablanca individuals, being the probability of presence higher than 50% for trees up to 1.5 m DBH and temperature of substrate up to 37.5°C. Our study probed that T. lagunablanca individuals choose trees non-randomly, selecting thicker and warmer tree trunks. This information advances the knowledge of the spatial ecology of Neotropical arboreal lizards and is relevant for conservation, putting an emphasis on preserving native vegetation in the Pantanal.(AU)

Spatiotemporal ecology of two Neotropical herbivorous mammals

On this study, we used camera traps in a Semi deciduous Seasonal Forest, northeast of Brazil, to estimate the frequencies of occurrence of two Neotropical herbivorous mammals: the spotted paca (Cuniculus paca) and the tapeti (Sylvilagus brasiliensis), analyzing their seasonal variations of spatial distribution. We also characterized the activity pattern of the species and their seasonal variation. The herbivorous frequencies of occurrence were constant during all the seasons. In general, both species were mostly active at night. However, between the rainy and dry season, we identified differences in spotted paca activity peaks. Here we present one of the first studies on the tapeti, whose ecology is understudied. Our results also show a general view of the spotted paca and tapeti behavior strategies to seasonal variations. Due to the scarce food resource in the dry season, possibly these herbivorous need to search for different kinds of food available IFS around.

Spatiotemporal ecology of two Neotropical herbivorous mammals

On this study, we used camera traps in a Semi deciduous Seasonal Forest, northeast of Brazil, to estimate the frequencies of occurrence of two Neotropical herbivorous mammals: the spotted paca (Cuniculus paca) and the tapeti (Sylvilagus brasiliensis), analyzing their seasonal variations of spatial distribution. We also characterized the activity pattern of the species and their seasonal variation. The herbivorous frequencies of occurrence were constant during all the seasons. In general, both species were mostly active at night. However, between the rainy and dry season, we identified differences in spotted paca activity peaks. Here we present one of the first studies on the tapeti, whose ecology is understudied. Our results also show a general view of the spotted paca and tapeti behavior strategies to seasonal variations. Due to the scarce food resource in the dry season, possibly these herbivorous need to search for different kinds of food available IFS around.(AU)

Ecology of the snake Atractus paraguayensis (Dipsadidae) in southern Brazil

Knowledge of snake ecology is important to support conservation strategies. Atractus paraguayensis Werner, 1924 is a dipsadidae with semi fossorial habits distributed throughout southern Brazil. We analyzed the morphology, seasonality and reproductive biology of this species in a subtropical area in southern Brazil by combining material from scientific collections and field data. We found that females have a larger body size than males and that the reproductive cycle of females is seasonal, with vitellogenesis occurring in the warmer months of the year. Males exhibited no differences in testicle volume throughout the year; however, mating likely occurs in the spring when males are more active. Recruitment of newborns occurs in late summer. The number of individuals collected during the hottest months (September through February) was significantly higher than the number of individuals collected during the colder months. Our results, which reveal sexual dimorphism in the species and seasonal breeding restricted to warm months, contribute important information about this species biology.

Ecology of the snake Atractus paraguayensis (Dipsadidae) in southern Brazil

Knowledge of snake ecology is important to support conservation strategies. Atractus paraguayensis Werner, 1924 is a dipsadidae with semi fossorial habits distributed throughout southern Brazil. We analyzed the morphology, seasonality and reproductive biology of this species in a subtropical area in southern Brazil by combining material from scientific collections and field data. We found that females have a larger body size than males and that the reproductive cycle of females is seasonal, with vitellogenesis occurring in the warmer months of the year. Males exhibited no differences in testicle volume throughout the year; however, mating likely occurs in the spring when males are more active. Recruitment of newborns occurs in late summer. The number of individuals collected during the hottest months (September through February) was significantly higher than the number of individuals collected during the colder months. Our results, which reveal sexual dimorphism in the species and seasonal breeding restricted to warm months, contribute important information about this species biology.(AU)

Activity patterns and use of microhabitat in lizards of the genus Tropidurus in a urbanized area of Natal, Brazil / Padrões de atividade e utilização de micro-habitat em lagartos do gênero Tropidurus em espaço urbanizado de Natal, Brasil

This study analyzed sun exposure, substrate type selected, and various behaviors exhibited by the lizard Tropidurus during thermoregulation. Observation entailed thirty days in an urbanized area of Centro de Biociências/ Universidade Federal do Rio Grande do Norte. Their behavior was recorded using a scan sampling route and an instantaneous record method at three different time intervals (9am to 10am, 12am to 1pm, and 3pm to 4pm). Significant differences were seen with sun exposure (p = 0.027), with most lizards remaining in shadowed areas, where the animals preferentially remained standing (p 0.001). We were also able to observe more lizards in the following substrates: tile, wall, rocks, and bricks (p 0.001). In addition, the animals were in these substrates more frequently from 12am to 1pm (p = 0.004). (AU)

Analisamos a exposição solar, o tipo de substrato e os comportamentos exibidos por lagartos Tropidurus durante a termorregulação. Foram realizados 30 dias de observações nos horários 9h-10h, 12h-13h e 15-16h, através de amostragem por escaneamento, com registro instantâneo a cada um minuto, em um espaço urbanizado do Centro de Biociências/Universidade Federal do Rio Grande do Norte. Observamos diferença significativa quanto à exposição solar (P = 0,027), com a maior ocorrência de lagartos em áreas sombreadas, onde os animais preferencialmente permaneceram parados (P < 0,001). Observou-se maior frequência de lagartos em substratos compostos por telhas, paredes, rochas e tijolos (P < 0,001). Os animais tiveram maior ocorrência nesses substratos no horário 12h-13h (P < 0,05).(AU)

Activity patterns and use of microhabitat in lizards of the genus Tropidurus in a urbanized area of Natal, Brazil / Padrões de atividade e utilização de micro-habitat em lagartos do gênero Tropidurus em espaço urbanizado de Natal, Brasil

This study analyzed sun exposure, substrate type selected, and various behaviors exhibited by the lizard Tropidurus during thermoregulation. Observation entailed thirty days in an urbanized area of Centro de Biociências/ Universidade Federal do Rio Grande do Norte. Their behavior was recorded using a scan sampling route and an instantaneous record method at three different time intervals (9am to 10am, 12am to 1pm, and 3pm to 4pm). Significant differences were seen with sun exposure (p = 0.027), with most lizards remaining in shadowed areas, where the animals preferentially remained standing (p 0.001). We were also able to observe more lizards in the following substrates: tile, wall, rocks, and bricks (p 0.001). In addition, the animals were in these substrates more frequently from 12am to 1pm (p = 0.004).

Analisamos a exposição solar, o tipo de substrato e os comportamentos exibidos por lagartos Tropidurus durante a termorregulação. Foram realizados 30 dias de observações nos horários 9h-10h, 12h-13h e 15-16h, através de amostragem por escaneamento, com registro instantâneo a cada um minuto, em um espaço urbanizado do Centro de Biociências/Universidade Federal do Rio Grande do Norte. Observamos diferença significativa quanto à exposição solar (P = 0,027), com a maior ocorrência de lagartos em áreas sombreadas, onde os animais preferencialmente permaneceram parados (P < 0,001). Observou-se maior frequência de lagartos em substratos compostos por telhas, paredes, rochas e tijolos (P < 0,001). Os animais tiveram maior ocorrência nesses substratos no horário 12h-13h (P < 0,05).

Habitat use and seasonal activity of insectivorous bats (Mammalia: Chiroptera) in the grasslands of southern Brazil

In temperate zones, insectivorous bats use some types of habitat more frequently than others, and are more active in the warmest periods of the year. We assessed the spatial and seasonal activity patterns of bats in open areas of the southernmost region of Brazil. We tested the hypothesis that bat activity differs among habitat types, among seasons, and is influenced by weather variables. We monitored four 1,500-m transects monthly, from April 2009 to March 2010. Transects corresponded to the five habitat types that predominate in the region. In each sampling session, we detected and counted bat passes with an ultrasound detector (Pettersson D230) and measured climatic variables at the transects. We recorded 1,183 bat passes, and observed the highest activity at the edge of a eucalyptus stand (0.64 bat passes/min) and along an irrigation channel (0.54 bat passes/min). The second highest activity values (0.31 and 0.20 bat passes/min, respectively) were obtained at the edge of a riparian forest and at the margin of a wetland. The grasslands were used significantly less (0.05 bat passes/min). Bat activity was significantly lower in the winter (0.21 bat passes/min) and showed similar values in the autumn (0.33 bat passes/min), spring (0.26 bat passes/min), and summer (0.29 bat passes/min). Bat activity was correlated with temperature, but it was not correlated with wind speed and relative humidity of the air. Our data suggest that, in the study area, insectivorous bats are active throughout the year, and use mostly forest and watercourses areas. These habitat types should be considered prioritary for the conservation of bats in the southernmost region of Brazil.

Habitat use and seasonal activity of insectivorous bats (Mammalia: Chiroptera) in the grasslands of southern Brazil

In temperate zones, insectivorous bats use some types of habitat more frequently than others, and are more active in the warmest periods of the year. We assessed the spatial and seasonal activity patterns of bats in open areas of the southernmost region of Brazil. We tested the hypothesis that bat activity differs among habitat types, among seasons, and is influenced by weather variables. We monitored four 1,500-m transects monthly, from April 2009 to March 2010. Transects corresponded to the five habitat types that predominate in the region. In each sampling session, we detected and counted bat passes with an ultrasound detector (Pettersson D230) and measured climatic variables at the transects. We recorded 1,183 bat passes, and observed the highest activity at the edge of a eucalyptus stand (0.64 bat passes/min) and along an irrigation channel (0.54 bat passes/min). The second highest activity values (0.31 and 0.20 bat passes/min, respectively) were obtained at the edge of a riparian forest and at the margin of a wetland. The grasslands were used significantly less (0.05 bat passes/min). Bat activity was significantly lower in the winter (0.21 bat passes/min) and showed similar values in the autumn (0.33 bat passes/min), spring (0.26 bat passes/min), and summer (0.29 bat passes/min). Bat activity was correlated with temperature, but it was not correlated with wind speed and relative humidity of the air. Our data suggest that, in the study area, insectivorous bats are active throughout the year, and use mostly forest and watercourses areas. These habitat types should be considered prioritary for the conservation of bats in the southernmost region of Brazil.(AU)

Daily activity and microhabitat use of sympatric lizards from Serra do Cipó, southeastern Brazil

We studied the influence of seasonality on the daily activity pattern and microhabitat use of three sympatric lizard species, Cnemidophorus ocellifer Spix, 1825 (Teiidae), Tropidurus montanus Rodrigues, 1987 and Eurolophosaurus nanuzae (Rodrigues, 1981) (Tropiduridae), in an area of campos rupestres (rocky fields) habitat in state of Minas Gerais, Brazil. Cnemidophorus ocellifer exhibited low density and activity concentrated within the hottest hours of the day, and was observed mainly on shaded rocks. Tropidurus montanus and E. nanuzae had similar activity patterns that did not vary between seasons. Activity of T. montanus was related to environmental temperatures. However, we did not find such relationships for E. nanuzae during the dry season. Both T. montanus and E. nanuzae were sighted mainly on exposed rocks. Extension of activity varied between seasons, shorter for C. ocellifer and longer for T. montanus and E. nanuzae during the rainy season.

Nós estudamos a influência da sazonalidade no padrão de atividade e uso de microhabitat ao longo do dia em três espécies simpátricas de lagartos Cnemidophorus ocellifer Spix, 1825 (Teiidae), Tropidurus montanus Rodrigues, 1987 e Eurolophosaurus nanuzae (Rodrigues, 1981) (Tropiduridae) em uma área de campos rupestres no estado de Minas Gerais, Brasil. Cnemidophorus ocellifer apresentou uma baixa densidade na área e sua atividade se concentrou nas horas mais quentes do dia, sendo visto principalmente em rochas sombreadas. Tropidurus montanus e E. nanuzae demonstraram padrão de atividade similar que não variou entre as estações. No entanto, a atividade em T. montanus esteve ligada às temperaturas do ambiente, enquanto esta condição não afetou o padrão de E. nanuzae durante a estação seca. Tanto T. montanus quanto E. nanuzae foram avistados principalmente em rochas expostas. A extensão da atividade variou entre as estações, sendo menor para C. ocellifer durante a estação chuvosa e maior para T. montanus e E. nanuzae durante o mesmo período.

Daily activity and microhabitat use of sympatric lizards from Serra do Cipó, southeastern Brazil

We studied the influence of seasonality on the daily activity pattern and microhabitat use of three sympatric lizard species, Cnemidophorus ocellifer Spix, 1825 (Teiidae), Tropidurus montanus Rodrigues, 1987 and Eurolophosaurus nanuzae (Rodrigues, 1981) (Tropiduridae), in an area of campos rupestres (rocky fields) habitat in state of Minas Gerais, Brazil. Cnemidophorus ocellifer exhibited low density and activity concentrated within the hottest hours of the day, and was observed mainly on shaded rocks. Tropidurus montanus and E. nanuzae had similar activity patterns that did not vary between seasons. Activity of T. montanus was related to environmental temperatures. However, we did not find such relationships for E. nanuzae during the dry season. Both T. montanus and E. nanuzae were sighted mainly on exposed rocks. Extension of activity varied between seasons, shorter for C. ocellifer and longer for T. montanus and E. nanuzae during the rainy season.

Nós estudamos a influência da sazonalidade no padrão de atividade e uso de microhabitat ao longo do dia em três espécies simpátricas de lagartos Cnemidophorus ocellifer Spix, 1825 (Teiidae), Tropidurus montanus Rodrigues, 1987 e Eurolophosaurus nanuzae (Rodrigues, 1981) (Tropiduridae) em uma área de campos rupestres no estado de Minas Gerais, Brasil. Cnemidophorus ocellifer apresentou uma baixa densidade na área e sua atividade se concentrou nas horas mais quentes do dia, sendo visto principalmente em rochas sombreadas. Tropidurus montanus e E. nanuzae demonstraram padrão de atividade similar que não variou entre as estações. No entanto, a atividade em T. montanus esteve ligada às temperaturas do ambiente, enquanto esta condição não afetou o padrão de E. nanuzae durante a estação seca. Tanto T. montanus quanto E. nanuzae foram avistados principalmente em rochas expostas. A extensão da atividade variou entre as estações, sendo menor para C. ocellifer durante a estação chuvosa e maior para T. montanus e E. nanuzae durante o mesmo período.

Daily activity of four tropical intertidal hermit crabs from Southeastern Brazil

This study describes the daily activity in a simulated high tide situation of four species of hermit crabs (Pagurus criniticornis, Clibanarius antillensis, C. sclopetarius, and C. vittatus) that coexist in an intertidal flat in southeastern Brazil. Observations were done in two-hour intervals during two subsequent days (48 h) in three replicate pools with thirty crabs each. Among species (between and within genera) there was an evident variation in activity patterns, of which three could be distinguished. The circadian activity patterns of C. antillensis and C. vittatus could be characterized as evening and nocturnal, with resting peaks during the morning and afternoon. The circadian activity pattern of C. sclopetarius was characterized by two marked peaks of inactivity, corresponding to dawn and evening, which could represent an intrinsic association with the semi-lunar tidal cycles of the study area. Pagurus criniticornis showed high activity not influenced by day/night conditions during the entire observed period. These activity pattern variations of the studied hermit crabs should be taken into account in designing further experiments. More precise and accurate interspecific behavioral comparisons among species could be achieved in nocturnal experiments, the high activity period of all species.

Este estudo descreve a atividade diária, sob condição simulada de maré alta, de quatro espécies de ermitões (Pagurus criniticornis, Clibanarius antillensis, C. sclopetarius and C. vittatus) que coexistem em uma planície lodosa entremarés na região Sudeste do Brasil. As observações foram efetuadas em intervalos de duas horas durante dois dias subseqüentes (48 h) em três piscinas contendo 30 indivíduos cada. Verificou-se evidente variação nos padrões de atividade entre as quatro espécies de ermitões estudadas (entre e dentro dos gêneros). Três padrões foram evidenciados. O padrão circadiano de atividade de C. antillensis e C. vittatus pode ser caracterizado como crepuscular e noturno, com períodos de inatividade durante a manhã e início da tarde. O padrão circadiano de atividade de C. sclopetarius apresentou dois picos marcantes de inatividade, correspondentes ao nascer e ao pôr-do-sol, o que pode representar associação intrínseca com os ciclos de marés semilunares da área de estudo. Pagurus criniticornis mostrou alta atividade durante todo o período de observação, não sendo influenciado pelas condições diúrnas-noturnas. A variação nos padrões de atividade observados para esses ermitões deverá ser utilizada no planejamento de experimentos futuros. Além disso, maior precisão em comparações comportamentais interespecíficas entre essas espécies poderá ser obtida no período noturno, quando todas as espécies estão ativas.