Habitat temperature is a major determinant of performance and activity in fish. I examined the relationships between thermal response metrics describing growth (optimal growth temperature [OGT] and final temperature preferendum [FTP]), survival (upper incipient lethal temperature [UILT] and critical thermal maximum [CTMax]), and reproduction (optimum spawning [OS] and optimum egg development temperature [OE]) for 173 North American freshwater fish species. All metrics were highly correlated and associated with thermal preference class, reproductive guild and spawning season. Controlling for phylogeny resulted in an overall decrease in correlation strength, varying with metric pair relationship. ANCOVA and Bayesian hierarchical models were utilized to assess the influence of phylogeny on metric pair relationships. For both methods, FTP based metric pairs were weakly correlated within taxonomic family. Strong within family associations were found for reproduction metrics OS-OE. These results suggest that evolutionary history plays an important role in determining species thermal response to their environment.

Habitat temperature is a major determinant of performance and activity in fish. I examined the relationships between thermal response metrics describing growth (optimal growth temperature [OGT] and final temperature preferendum [FTP]), survival (upper incipient lethal temperature [UILT] and critical thermal maximum [CTMax]), and reproduction (optimum spawning [OS] and optimum egg development temperature [OE]) for 173 North American freshwater fish species. All metrics were highly correlated and associated with thermal preference class, reproductive guild and spawning season. Controlling for phylogeny resulted in an overall decrease in correlation strength, varying with metric pair relationship. ANCOVA and Bayesian hierarchical models were utilized to assess the influence of phylogeny on metric pair relationships. For both methods, FTP based metric pairs were weakly correlated within taxonomic family. Strong within family associations were found for reproduction metrics OS-OE. These results suggest that evolutionary history plays an important role in determining species thermal response to their environment.

Orientador: Tânia Marcia Costa / Resumo: A temperatura é uma das principais restrições ambientais à distribuição dos organismos, afetando a fisiologia e sobrevivência. Organismos que habitam a zona do entremarés estão constantemente expostos à variação da temperatura e, com as mudanças climáticas, esses organismos devem enfrentar condições diferentes, que incluem temperaturas mais elevadas, levando a maiores taxas de perda de água por evaporação e, consequentemente, redução do desempenho ou mortalidade. Neste estudo, testamos os efeitos da dessecação em duas espécies de caranguejos violinistas (Leptuca thayeri e Minuca rapax) que ocupam habitats distintos em relação à cobertura da vegetação e posição no entremarés e, portanto, podem responder de forma diferente ao estresse por dessecação e ao aumento da temperatura. Leptuca thayeri, que é restrita à zona intermediária do entremarés, é mais sensível à dessecação do que M. rapax, uma espécie generalista, com maiores taxas de dessecação e mortalidade quando expostas à dessecação por 120 minutos. Além disso, em comparação com M. rapax, L. thayeri possui uma carapaça mais permeável. Também avaliamos se o aumento de temperatura pode causar alterações fisiológicas na espécie mais restrita L. thayeri, tendo acesso a alimento e à água. Uma elevação de temperatura de 10 ° C e 20 ° C durante 72 h não causou mortalidade em L. thayeri nem mudanças na concentração de glicose e proteína na hemolinfa. No entanto, as temperaturas mais altas aumentaram os níveis de lactato desidrogen... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Elucidating the factors that drive variation in the abundance and distribution of organisms is central to ecology. Variables that explain the spatial variation in the abundance of organisms primarily include environmental (e.g., temperature and precipitation) and biotic factors (e.g., competition, predation, and parasitism). An important mechanism influencing the spatial distribution of organisms, at least at small spatial scales, is habitat selection. Traditionally, habitat selection theory has assumed that animals select habitat based on their ability to acquire depletable resources within that habitat, especially food. Ectotherms, however, may instead select habitat based on their ability to process food within the habitat, given the strong dependence of body temperature (and performance) on environmental temperature in this group. The major objective of my thesis was to determine whether energy gain, habitat selection, and population density were driven primarily by food availability or by temperature in ectotherms. I used Sceloporus jarrovii lizards as a study species because these lizards occur at high densities and in similar habitat across a broad altitudinal range. In Chapter 1, I tested the prediction, central to the thermal coadaptation hypothesis, that juvenile lizards prefer body temperatures that maximize their net energy gain. I also tested whether lizards shifted their preferred body temperatures to correspond to the optimal temperature for different energetic states, as per Huey’s (1982) energetics model. In Chapter 2, I determined whether the home range size and density of lizards shifted in response to manipulations of food availability and/or thermal quality within a site. In Chapters 3 and 4, I determined whether mean body condition, individual growth rate, and population density were driven by food availability or thermal quality. In Chapter 3, I visited 32 study sites over a 1,550 m altitudinal range within a year; whereas in Chapter 4, I food-supplemented five out of 10 study sites where I performed mark-recapture over a period of three years. Overall, my thesis demonstrates that both food availability and thermal quality of the habitat drive energy gain, habitat selection, and population density. Juvenile S. jarrovii preferred body temperatures that maximized net energy gain, regardless of energetic state. Although they did not shift their preferred body temperature range depending on energetic state, the difference in the optimal temperature for net energy gain between states (0.4°C), may have been too small to warrant a change in behaviour. Within a site, S. jarrovii increased their home range size and occurred at higher densities as natural food availability increased, and decreased their home range size and occurred at lower densities as the thermal quality under the rocks increased. This suggests that S. jarrovii respond to food availability and thermal quality at different scales, selecting territories based on thermal quality and home ranges based on food availability. Over 32 sites, the abundance of S. jarrovii increased with food availability, whereas the mean body condition increased and the rate at which lizards attained their maximum body size decreased with elevation (at lower thermal quality). In the three-year study, mean body condition and individual growth rate decreased and population density increased with thermal quality, but the strength of the relationship depended on natural food availability. Overall, both food availability and thermal quality of the habitat drive energy gain, habitat selection, and population density; however, thermal quality is often the stronger driver. Thus, improvements to habitat selection models should incorporate habitat thermal quality to improve predictions on how ectotherms distribute themselves on a landscape.

Recognizing how climate change will impact populations can aid in making decisions about approaches for conservation of endangered species. The Blunt-nosed Leopard Lizard (Gambelia sila) is a federally endangered species that, despite protection, remains in extremely arid, hot areas and may be at risk of extirpation due to climate change. We collected data on the field-active body temperatures, preferred body temperatures, and upper thermal tolerance of G. sila. We then described available thermal habitat using biophysical models, which allowed us to (1) describe patterns in lizard body temperatures, microhabitat temperatures, and lizard microhabitat use, (2) quantify the lizards’ thermoregulatory accuracy, (3) calculate the number of hours they are currently thermally restricted in microhabitat use, (4) project how the number of restricted hours will change in the future as ambient temperatures rise, and (5) assess the importance of Giant Kangaroo Rat burrows and shade-providing shrubs in the current and projected future thermal ecology of G. sila. Lizards maintained fairly consistent daytime body temperatures over the course of the active season, and use of burrows and shrubs increased as the season progressed and ambient temperatures rose. During the hottest part of the year, lizards shuttled among kangaroo rat burrows, shrubs, and open habitat to maintain body temperatures below their upper thermal tolerance, but occasionally, higher than their preferred body temperature range. Lizards are restricted from staying in the open habitat for 75% of daylight hours and are forced to seek refuge under shrubs or burrows to avoid surpassing their upper thermal threshold. After applying climatic projections of 1 and 2˚C increases to 2018 ambient temperatures, G. sila will lose additional hours of activity time that could compound stressors faced by this population, potentially leading to extirpation. Finally, temperature-based activity estimation (TBAE) is an automated method for predicting surface activity and microhabitat use based on the temperature of an organism and its habitat. In an attempt to lessen impacts on sensitive species and costs, we assessed continuously logged field active body temperatures as a tool to predict the surface activity and microhabitat use of an endangered lizard (Blunt-nosed Leopard Lizard, Gambelia sila). We found that TBAE accurately predicts whether a lizard is above or below ground 75.7% of the time when calculated using air temperature, and 60.5% of the time when calculated using biophysical models. While surface activity was correctly predicted about 93% of the time using either method, accuracy in predicting below ground (burrow) occupancy was 62% for air temperature and 51% for biophysical models. Using biophysical model data, TBAE accurately predicts microhabitat use in 79% of observations in which lizards are in the sun, 47% in the shade, and 51% in burrows. Heliotherms bask in the sun, and thus body temperatures can shift rapidly when the animal moves to a new microhabitat. This sensitivity, makes TBAE a promising means of remotely monitoring animal activity, particularly for specific variables like emergence time and surface activity.

O lagarto Tropidurus torquatus (Wied, 1820) possui ampla distribuição geográfica e é encontrado em abundância nas áreas onde ocorre, sendo considerada uma espécie apropriada para estudos ecológicos. No presente estudo nós analisamos o período de atividade, o uso do microhabitat, a intensidade de forrageamento, a dieta e a ecologia térmica de uma população de T. torquatus do Costão de Itacoatiara, no Parque Estadual da Serra da Tiririca, situado nos municípios de Niterói e Maricá, RJ. Os dados foram coletados em dois períodos: entre julho de 2004 e janeiro de 2008 para estudo do período de atividade, uso do microhabitat e intensidade de forrageamento, e entre julho e agosto de 2010 para estudo da ecologia térmica e dieta. Todos os indivíduos coletados eram adultos, com comprimento rostro-cloacal médio de 66,2 12,0mm para machos (n = 11) e 64,1 8,0mm para fêmeas (n = 03). O período de atividade de T. torquatus no Costão de Itacoatiara durou de 12 a 14 horas. Teve um padrão unimodal na estação seca, com pico de atividade entre 09:00h e 13:00h, durante as horas mais quentes do dia. Na estação chuvosa o padrão de atividade foi bimodal, com um pico entre 8:00h e 9:00h e outro entre 16:00h e 17:00h, ambos associados aos horários de temperaturas ambientais mais amenas. O período de atividade não diferiu entre as estações, o que pode ser explicado pelo extenso pico de atividade dos lagartos na estação seca. Os microhabitats mais utilizados foram o substrato rochoso do Costão e a bromélia, refletindo a disponibilidade destes na área. A intensidade de forrageamento não diferiu sazonalmente e o tempo médio que os lagartos ficaram parados foi maior do que o tempo médio em deslocamento. A dieta foi onívora e esteve composta por artrópodes, principalmente insetos, e material vegetal, principalmente frutos. Os principais insetos consumidos foram Formicidae, Coleoptera e Hymenoptera não-Formicidae como pequenas vespas e abelhas. Os frutos, as sementes e as flores consumidos pertenciam às cactáceas Rhipsalis cereoides e Coleocephalocereus fluminensis, para as quais T. torquatus pode ser um potencial agente dispersor de sementes na área. Lagartos maiores consumiram itens maiores, mas em menor número, indicando um balanço energético positivo. O consumo de material vegetal variou de acordo com o tamanho dos lagartos, aumentando sua proporção nos indivíduos mais velhos. A temperatura média em atividade de T. torquatus foi de 34,3 2,5C, estando na faixa de temperatura corpórea média encontrada para outras populações e para outros Tropidurus. O substrato foi a fonte de calor ambiental com maior importância relativa para a termorregulação dos lagartos durante a estação seca, explicando cerca de 48% da variação na temperatura corpórea da população. Os lagartos termorregularam de forma passiva, principalmente em relação à temperatura do substrato. / The lizard Tropidurus torquatus (Wied, 1820) has a wide geographical distribution and is abundant within its area of occurrence, thus making it a suitable species for ecological studies. In the present study we analysed the activity period, microhabitat use, foraging intensity, diet and thermal ecology of a T. torquatus population in Costão de Itacoatiara, State Park of Serra da Tiririca, situated in the municipalities of Niterói and Maricá, RJ. Data were collected in two steps: between July 2004 and January 2008 for the activity period, microhabitat use and foraging intensity studies and between July and August 2010 for diet and thermal ecology studies. All specimens collected were adults, with snout-vent length = 66,2 12,0mm for males (n = 11) and 64,1 8,0mm for females (n = 3). The activity period of T. torquatus in Costão de Itacoatiara was between 12 and 14 hours. In the dry season it had a unimodal pattern, with a peak between 09:00 and 13:00h, during the hottest hours of the day. In the rainy season the pattern was bimodal, with a peak between 8:00 and 9:00h and another between 16:00 and 17:00h. Both periods were associated with lower temperatures. There was no significant difference in activity period between seasons, which can be explained by the intense lizard activity period in dry season. The most used microhabitats were rock and bromeliads, which reflects the wide availability of these microhabitats in the study area. Foraging intensity showed no seasonal differences and the mean time that lizards were stationary was higher than the mean time lizards were moving. Diet was omnivorous and composed of arthropods, mainly insects, and vegetable matter, mainly fruits. The most consumed insects were Formicidae, Coleoptera, and other Hymenoptera such as small wasps and bees. Fruits, seeds and flowers consumed belonged to the Cactaceae Rhipsalis cereoides and Coleocephalocereus fluminensis, for which T. torquatus seems to be a potential seed dispersor. Larger lizards consumed larger items, but in smaller numbers, indicating a positive energetic balance. The consumption of vegetable matter varied with lizard size, increasing its proportion in older individuals. The mean activity temperature was 34.3 2.5C, which was inside the range of mean temperature registered for other populations and Tropidurus species. Substrate was the most important environmental heat source for lizard thermoregulation along the dry season, explaining about 48% of the variation in lizard body temperature. The T. torquatus population was predominantly thermoconformer, mainly in relation to the substrate temperature.

O lagarto Tropidurus torquatus (Wied, 1820) possui ampla distribuição geográfica e é encontrado em abundância nas áreas onde ocorre, sendo considerada uma espécie apropriada para estudos ecológicos. No presente estudo nós analisamos o período de atividade, o uso do microhabitat, a intensidade de forrageamento, a dieta e a ecologia térmica de uma população de T. torquatus do Costão de Itacoatiara, no Parque Estadual da Serra da Tiririca, situado nos municípios de Niterói e Maricá, RJ. Os dados foram coletados em dois períodos: entre julho de 2004 e janeiro de 2008 para estudo do período de atividade, uso do microhabitat e intensidade de forrageamento, e entre julho e agosto de 2010 para estudo da ecologia térmica e dieta. Todos os indivíduos coletados eram adultos, com comprimento rostro-cloacal médio de 66,2 12,0mm para machos (n = 11) e 64,1 8,0mm para fêmeas (n = 03). O período de atividade de T. torquatus no Costão de Itacoatiara durou de 12 a 14 horas. Teve um padrão unimodal na estação seca, com pico de atividade entre 09:00h e 13:00h, durante as horas mais quentes do dia. Na estação chuvosa o padrão de atividade foi bimodal, com um pico entre 8:00h e 9:00h e outro entre 16:00h e 17:00h, ambos associados aos horários de temperaturas ambientais mais amenas. O período de atividade não diferiu entre as estações, o que pode ser explicado pelo extenso pico de atividade dos lagartos na estação seca. Os microhabitats mais utilizados foram o substrato rochoso do Costão e a bromélia, refletindo a disponibilidade destes na área. A intensidade de forrageamento não diferiu sazonalmente e o tempo médio que os lagartos ficaram parados foi maior do que o tempo médio em deslocamento. A dieta foi onívora e esteve composta por artrópodes, principalmente insetos, e material vegetal, principalmente frutos. Os principais insetos consumidos foram Formicidae, Coleoptera e Hymenoptera não-Formicidae como pequenas vespas e abelhas. Os frutos, as sementes e as flores consumidos pertenciam às cactáceas Rhipsalis cereoides e Coleocephalocereus fluminensis, para as quais T. torquatus pode ser um potencial agente dispersor de sementes na área. Lagartos maiores consumiram itens maiores, mas em menor número, indicando um balanço energético positivo. O consumo de material vegetal variou de acordo com o tamanho dos lagartos, aumentando sua proporção nos indivíduos mais velhos. A temperatura média em atividade de T. torquatus foi de 34,3 2,5C, estando na faixa de temperatura corpórea média encontrada para outras populações e para outros Tropidurus. O substrato foi a fonte de calor ambiental com maior importância relativa para a termorregulação dos lagartos durante a estação seca, explicando cerca de 48% da variação na temperatura corpórea da população. Os lagartos termorregularam de forma passiva, principalmente em relação à temperatura do substrato. / The lizard Tropidurus torquatus (Wied, 1820) has a wide geographical distribution and is abundant within its area of occurrence, thus making it a suitable species for ecological studies. In the present study we analysed the activity period, microhabitat use, foraging intensity, diet and thermal ecology of a T. torquatus population in Costão de Itacoatiara, State Park of Serra da Tiririca, situated in the municipalities of Niterói and Maricá, RJ. Data were collected in two steps: between July 2004 and January 2008 for the activity period, microhabitat use and foraging intensity studies and between July and August 2010 for diet and thermal ecology studies. All specimens collected were adults, with snout-vent length = 66,2 12,0mm for males (n = 11) and 64,1 8,0mm for females (n = 3). The activity period of T. torquatus in Costão de Itacoatiara was between 12 and 14 hours. In the dry season it had a unimodal pattern, with a peak between 09:00 and 13:00h, during the hottest hours of the day. In the rainy season the pattern was bimodal, with a peak between 8:00 and 9:00h and another between 16:00 and 17:00h. Both periods were associated with lower temperatures. There was no significant difference in activity period between seasons, which can be explained by the intense lizard activity period in dry season. The most used microhabitats were rock and bromeliads, which reflects the wide availability of these microhabitats in the study area. Foraging intensity showed no seasonal differences and the mean time that lizards were stationary was higher than the mean time lizards were moving. Diet was omnivorous and composed of arthropods, mainly insects, and vegetable matter, mainly fruits. The most consumed insects were Formicidae, Coleoptera, and other Hymenoptera such as small wasps and bees. Fruits, seeds and flowers consumed belonged to the Cactaceae Rhipsalis cereoides and Coleocephalocereus fluminensis, for which T. torquatus seems to be a potential seed dispersor. Larger lizards consumed larger items, but in smaller numbers, indicating a positive energetic balance. The consumption of vegetable matter varied with lizard size, increasing its proportion in older individuals. The mean activity temperature was 34.3 2.5C, which was inside the range of mean temperature registered for other populations and Tropidurus species. Substrate was the most important environmental heat source for lizard thermoregulation along the dry season, explaining about 48% of the variation in lizard body temperature. The T. torquatus population was predominantly thermoconformer, mainly in relation to the substrate temperature.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-05-09T15:56:51Z No. of bitstreams: 1 julianavazenunes.pdf: 1792666 bytes, checksum: 385a1cf5dc7d2ff7ac85dab538741ff1 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-17T14:27:52Z (GMT) No. of bitstreams: 1 julianavazenunes.pdf: 1792666 bytes, checksum: 385a1cf5dc7d2ff7ac85dab538741ff1 (MD5) / Made available in DSpace on 2017-05-17T14:27:52Z (GMT). No. of bitstreams: 1 julianavazenunes.pdf: 1792666 bytes, checksum: 385a1cf5dc7d2ff7ac85dab538741ff1 (MD5) Previous issue date: 2008-02-12 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este estudo teve como objetivo elaborar um etograma básico para indivíduos adultos de Tropidurus itambere, através de observações realizadas em ambiente natural e em ambientes artificiais e estudar a ecologia termal e o dimorfismo sexual dos indivíduos, em dezembro de 2006 e entre fevereiro e novembro de 2007. As observações dos comportamentos foram realizadas pelo método do animal focal e scan, totalizando 285 horas de registros. Nos ambientes artificiais os lagartos foram observados em cinco situações: (1) indivíduo sozinho; (2) 1 macho + 1 macho; (3) 1 macho + 1 fêmea (4) 2 machos + 1 fêmea (5) 1 fêmea + 1 fêmea. Os comportamentos exibidos pelos indivíduos cativos foram similares àqueles observados em campo. Foram registrados 78 atos comportamentais distribuídos em nove categorias funcionais. Os comportamentos movimentação vertical da cabeça (head bob) e lamber o substrato foram os atos comportamentais mais freqüentes exibidos pela espécie e parecem atuar juntos como sinais de reconhecimento, visual e químico, da área. A temperatura corpórea média de atividade de T. itambere foi de 32,08 ± 3,36ºC, com uma amplitude de 20,30 a 37,90ºC e apresentou variação sazonal. As temperaturas dos microhábitats (substrato e ar) influenciaram a temperatura corpórea dos lagartos sendo que na estação chuvosa a temperatura do ar explicou melhor a temperatura dos lagartos e, na estação seca, a temperatura do substrato explicou melhor a temperatura dos indivíduos. As análises mostraram uma diferença significativa no tamanho e forma do corpo e massa corpórea entre os sexos, com os machos sendo mais pesados e maiores, apresentando as medidas de todas as variáveis morfométricas significativamente maiores do que as medidas das fêmeas, com exceção da largura do abdômen cuja média das fêmeas foi maior do que a dos machos, porém essa diferença não foi significativa. A análise discriminante selecionou o tamanho da cabeça (RCT) como a variável que melhor explicou as diferenças entre os sexos, tendo classificado corretamente 89,5% dos indivíduos. / The aim of this study was to elaborate a basic ethogram for adult individuals of Tropidurus itambere, through observations accomplished in field and outdoor and indoor enclosures and to study the thermal ecology and the sexual dimorphism of the lizards, on December 2006 and between February and November 2007. The observations of the behaviors were accomplished by the method of the focal animal and scan, totalizing 285 hours of registrations. In the artificial enclosures the lizards were observed in five situations: (1) individual alone; (2) 1 male + 1 male; (3) 1 male + 1 female (4) 2 males + 1 female (5) 1 female + 1 female. The behaviors exhibited by the captive individuals were similar to those observed in the field. We registered 78 behavioral acts distributed in nine functional categories. The head bob was the act more frequently exhibited by the species, having been observed in all the treatments in the outdoor enclosure. The behaviors head bob and to lick the substratum seem to act together as signs of recognition of the area. The body temperature average of activity of T. itambere was 32,08 ± 3,36ºC and it presented seasonal variation accompanying the environmental temperatures. The temperatures of the microhabitats (substratum and air) influenced the body temperature of the lizards so that in the rainy season just the temperature of the air affected the temperature of the lizards and, in the dry season, just the temperature of the substratum affected the temperature of individuals. The analyses showed a significant difference in size and shape of the body and mass between the sexes, with the males being heavier and larger, presenting the measures of all the morphometrics variables significantly larger than the measures of the females, except for the width of the abdomen whose average of the females was larger than that of the males, even so that difference was not significant. The discriminant analysis selected the size of the head (RCT) as the variable that better explained the differences between the sexes, having classified correctly 89,5% of the individuals.

The coefficient of body temperature change (K) ranged from -0.53 to -0.072 for bass weighing 73-1440 g. The double log regression of K on weight was similar to that reported for other poikilotherms (slope = -0.57; R = 0.93). Fingerling bass were eurythermal, being capable of surviving instantaneous temperature changes over a 20 C range at acclimation temperatures of 15, 25 and 30 C and over a 15 C range at acclimation temperatures of 20 and 35 C. Preferred temperatures for adult bass measured in the laboratory ranged from 27-32 C with no relationship to day or night. The overall mean preferred temperature was 29 C. The laboratory determined preferred temperatures were supported by limited field determined body temperatures taken in a vertical temperature gradient near the discharge of a power plant effluent. Routine metabolic rates of bass from a heated reservoir and a nearby hatchery were similar from 10-30 C in summer and winter. The weight exponent (0.77) and Q^gS (1*6-2.9) were similar to those published for more northern bass populations; however, the Texas bass had lower metabolic rates than those published for the northern populations. Bass exposed to rapid temperature increase (0.2 C/min) from 25-30 C increased their metabolic rate by 53% but showed no detectable increase in opercular rate. Bass warmed from 30-35 C and 30-33 C increased their metabolic rate by 140%, and their opercular rates increased to over 100 beats per minute before death.

Made available in DSpace on 2014-12-17T15:36:57Z (GMT). No. of bitstreams: 1 PabloAGS.pdf: 2059832 bytes, checksum: 8f5ad8bf243bff28547c0104bc0b6e7c (MD5) Previous issue date: 2010-03-18 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / As part of a broader project, Diversity and Distribution Patterns of Floristic and Faunistic composition of remnants of Potiguar s Atlantic Forest, as subsidies to conservation , that subsidizes a group of institutional research, This study aimed to evaluate the structure of the assemblage of lizards a remnant of the of the northern Atlantic Forest, identifying ecological factor (s) that contribute to the coexistence of sympatric species. Additionally, we studied the thermal ecology and thermoregulatory behavior of umbrophily and heliophily species live the Parque Estadual Mata da Pipa (PEMP), a remnant of Atlantic forest located in the Tibau do Sul municipality of, Rio Grande do Norte State, Brazil. It is one of the largest remnants of the Atlantic Forest and has an area of approximately 290 ha. The study was performed by four excursions to the field for 20 days each, when active search and pitfalls traps were used to record and colleted specimens in different habitats of the area. We recorded the presence of 19 species of lizards, of which seven are typical of forest areas, three are endemic Atlantic Forest, these two northern and one are new record for the Rio Grande do Norte. The use of resources, the results showed that phylogenetically related species do not always use a similar way the resources available; the feeding niche was the segregated component of the species that overlapped extensively in the use of space and vice versa. To examine the thermal ecology and thermoregulatory behavior of Kentropyx calcarata and Coleodactylus natalensis, we recorded the clocal temperature (Tc), oh the substrate (Ts) and of the air (Ta) to investigate what of these are the source of heat more important to the temperature s body of these lizards. Behavioral observations were conducted to analyze strategies to optimize the acquisition of heat. The air temperature explained most strongly to variation in body temperature of K. calcarata, while the temperature of the substrate to C. natalensis. As for the behavioral observations, they confirmed that K. calcarata is an active thermoregulatory; C. natalensis is a passive thermoregulatory. / Como parte de um Projeto mais amplo, Diversidade e Padr?es de Distribui??o da Composi??o Flor?stica e Faun?stica de remanescentes da Mata Atl?ntica potiguar, como subs?dios ? Conserva??o , que subsidia um grupo de pesquisa institucional, este estudo objetivou avaliar a estrutura da assembl?ia de lagartos de um remanescente de Mata Atl?ntica setentrional, identificando fator (es) ecol?gicos que contribuem para a coexist?ncia das esp?cies simp?tricas. Adcionalmente, foram estudados a ecologia termal e o comportamento de termorregula??o de esp?cies umbr?filas e heli?filas habitantes do Parque Estadual Mata da Pipa (PEMP), um remanescente de Mata Atl?ntica localizado no munic?pio de Tibau do Sul, Estado do Rio Grando do Norte, Brasil. ? um dos maiores remanescente de Mata Atl?ntica do Estado e possui uma ?rea de aproximadamente 290 ha. O trabalho foi efetuado por meio de quatro excurs?es ? campo, com dura??o de 20 dias cada, quando buscas ativas e armadilhas de queda foram utilizadas para registrar e coletar os esp?cimes nos diversos h?bitats da ?rea. Registraram-se 19 esp?cies de lagartos, das quais sete s?o de ?reas florestadas, tr?s end?micas de Mata Atl?ntica duas destas setentrionais e uma ? um novo registro para o Rio Grande do Norte. Quanto ? utiliza??o dos recursos, as esp?cies filogeneticamente pr?ximas nem sempre utilizaram de maneira semelhante os recursos dispon?veis; o nicho alimentar foi o componente segregativo das esp?cies que se sobrepuseram amplamente no uso do espa?o e vice-versa. Para analisar a ecologia t?rmica e o comportamento termoregulat?rio de Kentropyx calcarata e Coleodactylus natalensis registrou-se a temperatura cloacal (Tc), a do substrato (Ts) e a do ar (Ta) para averiguar qual (is) destas constitui a fonte de calor mais importante para a regula??o de temperatura corp?rea desses lagartos. Observa??es comportamentais foram efetuadas para analisar estrat?gias para otimizar a obten??o de calor. A temperatura do ar explicou mais fortemente a varia??o na temperatura corporal de K. calcarata, enquanto a temperatura do substrato a de C. natalensis. Quanto ?s observa??es comportamentais, foi confirmado para K. calcarata que este ? um termorregulador heli?filo ativo; C. natalensis ? umbr?filo ou termorregulador passivo.