Com o objetivo de obter dados relacionados às estratégias reprodutivas de Hydromedusa maximiliani no Parque Estadual Carlos Botelho, SP, fêmeas e jovens foram radiografados entre setembro de 2007 e dezembro de 2008. A estação reprodutiva estendeu-se de setembro a dezembro, com a ocorrência de desovas entre novembro e dezembro, tanto em 2007 como em 2008. Das 33 fêmeas radiografadas, 19 (58%) apresentaram ovos, e, dessas, apenas três (16%) reproduziram-se nos dois anos. O tamanho da ninhada variou entre 1 e 3 ovos, mas a maioria das fêmeas (90%) apresentou dois ovos. O volume da ninhada foi de 22128,01 ± 4939,8 mm³ (10493,422136,12 mm³; N = 44). Houve fortes relações positivas entre o tamanho corpóreo das fêmeas com o tamanho dos ovos e volume da ninhada. Os dados reprodutivos obtidos no presente estudo, em conjunto com os dados populacionais estabelecidos para H. maximiliani na mesma área de estudo por outros autores, permitiram a realização de uma análise de viabilidade da população. As simulações geradas no programa VORTEX (versão 9.92) foram baseadas em dois cenários principais, denominados População Real (PR) e População Hipotética Isolada (PHI). O primeiro foi criado com base nas informações existentes para H. maximiliani, coletadas ao longo de mais de 10 anos, a partir do qual foram feitas alterações de algumas variáveis (aumento de 10% na taxa de mortalidade; aumento em duas vezes no valor de frequência de catástrofes; inclusão de depressão por endogamia com aumento de 10% no valor default do programa e diminuição da capacidade de suporte), gerando o cenário PHI, com o objetivo de avaliar as diferenças entre uma população protegida em uma unidade de conservação e uma população isolada e sujeita a maiores influências negativas. Os resultados das simulações demonstraram existir diferença significativa (p = 0,0005) entre os dois cenários com probabilidade de extinção equivalente a 31% para o cenário real e 90% para o cenário hipotético. Testes de sensibilidade foram realizados com a finalidade de verificar a influência de variações na taxa de mortalidade, catástrofes e depressão por endogamia, e forneceram indicações de que variações em todos os parâmetros testados possuem forte influência na sobrevivência da população. Estudos de longaduração e informações a respeito das espécies de áreas sujeitas a fortes pressões antrópicas, como a Mata Atlântica, são de grande importância para a conservação, já que podem auxiliar na elaboração de análises de viabilidade populacional e no delineamento de estratégias de manejo focadas nos fatores reais que ameaçam as populações. / The reproductive strategies of Hydromedusa maximiliani at the Carlos Botelho State Park, SP, was verified by X-ray in females and juveniles between September 2007 and December 2008. Throughout the study two reproductive seasons were detected, both beginning in September. From a total of 33 X-rayed females, only 19 showed eggs, and three of them showed eggs in the two reproductive seasons. Clutch size varied from 1 to 3 eggs, but only one female presented one egg and another female presented three eggs. Clutch volume was 22128.01 ± 4939.8 mm³ (10493.422136.12 mm³; N = 44). Female body size was positively correlated to clutch volume, a pattern usually detected in chelonians. Reproductive information acquired in the present study together with population data available for H. maximiliani in the study site makes it possible a population viability analysis using the software VORTEX (version 9.92). A principal scenario (Real Population) was created based on life-history data collected throughout 10 years. In order to compare the protected area with an unprotected hypothetical area regarding the persistence of the population, this scenario was modified by altering some variables (10% increasing of mortality rate, 10% increasing of inbreeding depression, decreasing of carrying capacity), which generates a scenario named Hypothetical Isolated Population. Results were compared and sensitivity tests were carried out to verify the influence of variation in mortality ratio, catastrophes and inbreeding depression. There was a significant difference between the two scenarios (p = 0.0005). The extinction risk was 31% for Real Population and 90% for Hypothetical Isolated Population. The sensitivity analysis indicated that mortality ratio, deforestation, forest fires and inbreeding depression strongly influence the population survival. Long-term studies and biological information on species inhabiting areas subjected to anthropogenic impacts, like the Atlantic Rainforest, are vital to conservation actions, since they make it possible population viability analyses and the design of management strategies to threatened populations.

Most studies of wetlands tend to focus on the biotic and abiotic interactions within the aquatic habitat. Though wetlands and associated biota may appear to be somewhat isolated from the influence of the wider landscape, wetland habitats are critically linked with adjacent terrestrial habitats and other wetlands through the two-way flows of energy and nutrients and provision of structure. While an understanding of these inter-habitat linkages is breaking down the perceived boundaries between &quotaquatic" and &quotterrestrial" ecosystems, there is more limited knowledge on the ecology of wetland animals that must meet critical needs in both aquatic and terrestrial habitats at some time during their life or seasonal cycles. Here, I examine the terrestrial ecology of a freshwater turtle, the eastern long-necked turtle (Chelodina longicollis) in the temporally dynamic and heterogeneous landscape of Booderee national park in south-east Australia by 1) providing a description of terrestrial behaviours, 2) identifying the factors driving terrestrial behaviour and its functional significance, 3) examining factors that may limit or constrain terrestrial behaviour and 4) demonstrating how various terrestrial behaviours can factor prominently in the overall biology of a nominally aquatic animal. Chelodina longicollis used terrestrial habitats for reasons other than nesting, including aestivation and movements between wetlands. Radio-telemetry of 60 turtles revealed that nearly 25 % of all locations were in terrestrial habitats up to 505 m from the wetland, where turtles remained for extended periods (up to 480 consecutive days) buried under sand and leaf litter in the forest. Individuals also maintained an association with a permanent lake and at least one temporary wetland within 1470 m, though some inter-wetland dispersal movements were much longer (5248 m). As a result of their associations with several wetlands and terrestrial aestivation sites, C. longicollis traversed large areas and long distances (13.8 +/- 2.8 ha home range, 2608 +/- 305 m moved), indicating that this species is highly vagile. In fact, a three-year capture-mark-recapture study conducted in 25 wetlands revealed that 33% of the population moved overland between wetlands. After scaling this rate to the number of generations elapsed during the study, C. longicollis moved between discrete water bodies at a rate of 88-132% per generation. This rate is not only high for freshwater turtles, but is among the highest rates of inter-patch movement for any vertebrate or invertebrate. Chelodina longicollis demonstrated an impressive capacity for individual variation in nearly every aspect of its behaviour examined. Most of the variation in space use, movements, terrestrial aestivation and activity could be attributed to extrinsic local and landscape factors, seasonal influences and rainfall, whereas intrinsic attributes of the individual such as sex, body size, body condition and maturity status were less important. Turtles increased movement distance and home range size in regions where inter-wetland distances were farther and with increasing wetland size. Individuals spent more time in terrestrial habitats with decreasing wetland hydroperiod and increasing distance to the nearest permanent lake. Overland movements between wetlands were correlated with rainfall, but the directionality of these movements and the frequency with which they occurred varied according to the prevalent rainfall patterns; movements were to permanent lakes during drought, but turtles returned to temporary wetlands en masse upon the return of heavy rainfall. However, deteriorating conditions in drying wetlands forced turtles to move even in the absence of rainfall. Captures at a terrestrial drift fence revealed that immature turtles as small as 72.3 mm plastron length may move overland between wetlands with similar frequency as larger adults. Taken together, these results suggest that C. longicollis behaviour is in part conditional or state-dependent (i.e., plastic) and shaped by the spatiotemporal variation and heterogeneity of the landscape. Perhaps the most surprising aspect of individual variation was the alternate responses to wetland drying. Turtles either aestivated in terrestrial habitats (for variable lengths of time), or moved to other wetlands. Movement to other wetlands was the near universal strategy when only a short distance from permanent lakes, but the proportion of individuals that aestivated terrestrially increased with distance to the nearest permanent lake. When long distances must be travelled, both behaviours were employed by turtles in the same wetland, suggesting that individuals differentially weigh the costs and benefits of residing terrestrially versus those of long-distance movement. I propose that diversity in response to wetland drying in the population is maintained by stochastic fluctuations in resource quality. The quality of temporary wetlands relative to permanent wetlands at our study site varies considerably and unpredictably with annual rainfall and with it the cost-benefit ratio of each strategy or tactic. Residency in or near temporary wetlands is more successful during wet periods due to production benefits (high growth, reproduction and increased body condition), but movement to permanent wetlands is more successful, or least costly, during dry periods due to the fitness benefits of increased survival and body condition. I used the doubly-labelled water (DLW) method to provide the first estimates of water and energy costs of aestivation and overland movement for any freshwater turtle behaving naturally in the field. Chelodina longicollis remained hydrated while terrestrial with water flux rates (14.3-19.3 ml kg-1 d-1) on par with those of strictly terrestrial turtles, but field metabolic rate during aestivation (20.0-24.6 kJ kg-1 d-1) did not indicate substantial physiological specializations in metabolism during aestivation. Energy reserves, but not water, are predicted to limit survival in aestivation to an estimated 49-261 days, which is in close agreement with the durations of natural aestivation. The energy costs of overland movement were 46-99 kJ (kg d)-1, or 1.6-1.7 times more expensive than aestivation. When a wetland dries, a turtle that foregoes movement to other wetlands can free sufficient energy to fuel up to 134 days in aestivation. The increasing value of this energy &quottrade-off" with travel distance fits our behavioural observations of variance in response to wetland drying. Taken together, this evidence indicates that terrestrial habitats provide more than just organic and structural inputs and filtering services and that nearby wetlands are important for reasons other than potential sources of occasional colonists to a population. Terrestrial habitats are used for aestivation in response to wetland drying and different wetlands are diverse in their functions of meeting the annual or life-cycle requirements of C. longicollis in temporally dynamic wetland systems. As overland movements between these various habitat types are in response to spatiotemporal variation in habitat quality and associated shifts in the fitness gradient between them, I suggest that terrestrial and different aquatic habitats in Booderee offer complementary resources contributing to regional carrying capacity and population persistence of the turtle population. Thus, important ecological processes regulating C. longicollis in a focal wetland should not be viewed as operating independently of other nearby wetlands and their adjacent terrestrial habitats. Collectively, these findings highlight the complex and dynamic associations between a population of freshwater turtles and the wider terrestrial and aquatic landscape, demonstrating that turtle populations and the factors that impact them can extend well beyond the boundaries of a focal wetland.

I studied aspects of the ecology of the Murray River turtle, Emydura macquarii, to determine the impact of the introduced red fox, Vulpes vulpes. The fox is one of Australia's worst vertebrate pests through its predation on livestock and native mammals, but their impact on reptilian communities is not known. I conducted a large-scale mark-recapture study to evaluate population growth of E. macquarii in the Albury region of the upper Murray River by determining growth, reproduction and survival. The study was conducted downstream of the first, and largest, impoundment on the Murray River, Lake Hume. Emydura macquarii predominantly inhabit the lagoons in the upper Murray River, as the mainstream and Lake are possibly too cool to maintain metabolic processes. They are easily captured in hoop traps and the use of live decoys maximises trap success. Over 2000 hatchling turtles were marked and released into two lagoons between January 1997 and January 1998. Growth of these individuals is rapid over the first few years but declines towards maturity, and is indeterminate after maturity. Although growth annuli are not well defined, even on young individuals, the von Bertalanffy model describes the growth of both male and female E. macquarii. Male turtles mature at 5-6 years and females mature at 10-12 years. Female turtles may maximise reproductive potential by delaying maturity and producing one relatively large clutch (mean = 21 eggs) per year, which is positively correlated with body size (PL). Although primarily related to body size, clutch size varies annually because of environmental conditions. If winter and summer rainfalls are below average and temperatures are above average, E. macquarii may reduce clutch size to increase the chance of the eggs surviving. Nesting predominantly occurs during the first major rain-bearing depression in November. Habitat variables, including distance from water, nearest nest, and tree, and soil type were measured for each nest to determine characteristics that attract predators. Nests close to the shoreline and trees are heavily preyed on, and nests constructed in sand are less likely to be destroyed by predators. Foxes detect nests through a combination of chemical cues from eggs and slight soil disturbances, whereas birds only destroy nests observed being constructed during the day. Female turtles alter nesting behaviour and construct nests much further away from water when foxes were removed and as a result, nests are less dense and away from trees. Thus in high predation risk areas, turtles minimise emergence and search times to reduce the risk of direct predation by foxes. Predation is reduced when nests are in lower densities and away from trees, because predators increase search efforts when nests are in higher densities and birds are more likely to destroy nests close to trees. Reproductive success is further reduced in high predation risk areas because more nests are constructed in sandy substrates where clutch success is reduced compared to incubation in more dense substrates. Where predators are a significant source of mortality, prey may use indirect methods, such as chemical recognition, to avoid encounters. Nesting turtles did not avoid areas where fox odour was present, suggesting that they assess predation pressure from foxes by other mechanisms, such as visual recognition. However, an innate response occurs to the odour of a once common predator on the Murray River, the eastern quoll (Dasyurus viverrinus), whereby turtles recognise and avoid nesting in areas where quoll odour is present. Therefore nesting turtles show a similar avoidance response to two different predators, using different mechanisms of detection. Similarly, predation risk may influence hatching times and nest emergence. The rate of embryonic development of E. macquarii may increase or eggs may hatch early so that the clutch hatches synchronously, thereby reducing the risk of predation through group emergence from the nest. Emydura macquarii reach densities of over 100 turtles.ha-1, with the majority of the population consisting of sexually mature individuals. Emydura macquarii has a Type III survival curve where mortality is extremely high in the egg stage (93% nest predation), remaining high over the hatchling stage (minimum survival rate- 10%), but decreasing rapidly throughout the juvenile stage (~70% juvenile survival). Adult survival is extremely high, with greater than 95% of adults surviving each year. Foxes through nest predation cause most mortality but a small proportion (~3%) of nesting adult females are killed by foxes each year. A removal program evaluated the impact of foxes. In 1996, fox numbers were monitored around four lagoons by spotlighting and non-toxic bait uptake. Foxes were removed from around two of the lagoons throughout 1997 and 1998, using spotlight shooting and 1080 bait poisoning. Fox numbers were continually monitored around all four lagoons during the study. Nest predation rates remained around 90% in all sites where foxes were present, but fell to less than 50% when foxes were removed. At the same time, predation on nesting female turtles was eliminated where foxes were removed. Demographic models using staged based survival schedules, together with growth and fecundity values for E. macquarii show a decline of 4% per year in these populations. Elasticity analyses shows that survival of adult female E. macquarii has the major influence on population stability and a reduction of nest predation alone is unlikely to address the population decline. Management options, such as reducing foxes prior to nesting around key lagoons, will stabilise the population decline, and eliminating foxes completely from certain areas with high dispersal potential, will promote recruitment of juvenile E. macquarii.

I studied aspects of the ecology of the Murray River turtle, Emydura macquarii, to determine the impact of the introduced red fox, Vulpes vulpes. The fox is one of Australia's worst vertebrate pests through its predation on livestock and native mammals, but their impact on reptilian communities is not known. I conducted a large-scale mark-recapture study to evaluate population growth of E. macquarii in the Albury region of the upper Murray River by determining growth, reproduction and survival. The study was conducted downstream of the first, and largest, impoundment on the Murray River, Lake Hume. Emydura macquarii predominantly inhabit the lagoons in the upper Murray River, as the mainstream and Lake are possibly too cool to maintain metabolic processes. They are easily captured in hoop traps and the use of live decoys maximises trap success. Over 2000 hatchling turtles were marked and released into two lagoons between January 1997 and January 1998. Growth of these individuals is rapid over the first few years but declines towards maturity, and is indeterminate after maturity. Although growth annuli are not well defined, even on young individuals, the von Bertalanffy model describes the growth of both male and female E. macquarii. Male turtles mature at 5-6 years and females mature at 10-12 years. Female turtles may maximise reproductive potential by delaying maturity and producing one relatively large clutch (mean = 21 eggs) per year, which is positively correlated with body size (PL). Although primarily related to body size, clutch size varies annually because of environmental conditions. If winter and summer rainfalls are below average and temperatures are above average, E. macquarii may reduce clutch size to increase the chance of the eggs surviving. Nesting predominantly occurs during the first major rain-bearing depression in November. Habitat variables, including distance from water, nearest nest, and tree, and soil type were measured for each nest to determine characteristics that attract predators. Nests close to the shoreline and trees are heavily preyed on, and nests constructed in sand are less likely to be destroyed by predators. Foxes detect nests through a combination of chemical cues from eggs and slight soil disturbances, whereas birds only destroy nests observed being constructed during the day. Female turtles alter nesting behaviour and construct nests much further away from water when foxes were removed and as a result, nests are less dense and away from trees. Thus in high predation risk areas, turtles minimise emergence and search times to reduce the risk of direct predation by foxes. Predation is reduced when nests are in lower densities and away from trees, because predators increase search efforts when nests are in higher densities and birds are more likely to destroy nests close to trees. Reproductive success is further reduced in high predation risk areas because more nests are constructed in sandy substrates where clutch success is reduced compared to incubation in more dense substrates. Where predators are a significant source of mortality, prey may use indirect methods, such as chemical recognition, to avoid encounters. Nesting turtles did not avoid areas where fox odour was present, suggesting that they assess predation pressure from foxes by other mechanisms, such as visual recognition. However, an innate response occurs to the odour of a once common predator on the Murray River, the eastern quoll (Dasyurus viverrinus), whereby turtles recognise and avoid nesting in areas where quoll odour is present. Therefore nesting turtles show a similar avoidance response to two different predators, using different mechanisms of detection. Similarly, predation risk may influence hatching times and nest emergence. The rate of embryonic development of E. macquarii may increase or eggs may hatch early so that the clutch hatches synchronously, thereby reducing the risk of predation through group emergence from the nest. Emydura macquarii reach densities of over 100 turtles.ha-1, with the majority of the population consisting of sexually mature individuals. Emydura macquarii has a Type III survival curve where mortality is extremely high in the egg stage (93% nest predation), remaining high over the hatchling stage (minimum survival rate- 10%), but decreasing rapidly throughout the juvenile stage (~70% juvenile survival). Adult survival is extremely high, with greater than 95% of adults surviving each year. Foxes through nest predation cause most mortality but a small proportion (~3%) of nesting adult females are killed by foxes each year. A removal program evaluated the impact of foxes. In 1996, fox numbers were monitored around four lagoons by spotlighting and non-toxic bait uptake. Foxes were removed from around two of the lagoons throughout 1997 and 1998, using spotlight shooting and 1080 bait poisoning. Fox numbers were continually monitored around all four lagoons during the study. Nest predation rates remained around 90% in all sites where foxes were present, but fell to less than 50% when foxes were removed. At the same time, predation on nesting female turtles was eliminated where foxes were removed. Demographic models using staged based survival schedules, together with growth and fecundity values for E. macquarii show a decline of 4% per year in these populations. Elasticity analyses shows that survival of adult female E. macquarii has the major influence on population stability and a reduction of nest predation alone is unlikely to address the population decline. Management options, such as reducing foxes prior to nesting around key lagoons, will stabilise the population decline, and eliminating foxes completely from certain areas with high dispersal potential, will promote recruitment of juvenile E. macquarii.

Com o objetivo de obter dados relacionados às estratégias reprodutivas de Hydromedusa maximiliani no Parque Estadual Carlos Botelho, SP, fêmeas e jovens foram radiografados entre setembro de 2007 e dezembro de 2008. A estação reprodutiva estendeu-se de setembro a dezembro, com a ocorrência de desovas entre novembro e dezembro, tanto em 2007 como em 2008. Das 33 fêmeas radiografadas, 19 (58%) apresentaram ovos, e, dessas, apenas três (16%) reproduziram-se nos dois anos. O tamanho da ninhada variou entre 1 e 3 ovos, mas a maioria das fêmeas (90%) apresentou dois ovos. O volume da ninhada foi de 22128,01 ± 4939,8 mm³ (10493,422136,12 mm³; N = 44). Houve fortes relações positivas entre o tamanho corpóreo das fêmeas com o tamanho dos ovos e volume da ninhada. Os dados reprodutivos obtidos no presente estudo, em conjunto com os dados populacionais estabelecidos para H. maximiliani na mesma área de estudo por outros autores, permitiram a realização de uma análise de viabilidade da população. As simulações geradas no programa VORTEX (versão 9.92) foram baseadas em dois cenários principais, denominados População Real (PR) e População Hipotética Isolada (PHI). O primeiro foi criado com base nas informações existentes para H. maximiliani, coletadas ao longo de mais de 10 anos, a partir do qual foram feitas alterações de algumas variáveis (aumento de 10% na taxa de mortalidade; aumento em duas vezes no valor de frequência de catástrofes; inclusão de depressão por endogamia com aumento de 10% no valor default do programa e diminuição da capacidade de suporte), gerando o cenário PHI, com o objetivo de avaliar as diferenças entre uma população protegida em uma unidade de conservação e uma população isolada e sujeita a maiores influências negativas. Os resultados das simulações demonstraram existir diferença significativa (p = 0,0005) entre os dois cenários com probabilidade de extinção equivalente a 31% para o cenário real e 90% para o cenário hipotético. Testes de sensibilidade foram realizados com a finalidade de verificar a influência de variações na taxa de mortalidade, catástrofes e depressão por endogamia, e forneceram indicações de que variações em todos os parâmetros testados possuem forte influência na sobrevivência da população. Estudos de longaduração e informações a respeito das espécies de áreas sujeitas a fortes pressões antrópicas, como a Mata Atlântica, são de grande importância para a conservação, já que podem auxiliar na elaboração de análises de viabilidade populacional e no delineamento de estratégias de manejo focadas nos fatores reais que ameaçam as populações. / The reproductive strategies of Hydromedusa maximiliani at the Carlos Botelho State Park, SP, was verified by X-ray in females and juveniles between September 2007 and December 2008. Throughout the study two reproductive seasons were detected, both beginning in September. From a total of 33 X-rayed females, only 19 showed eggs, and three of them showed eggs in the two reproductive seasons. Clutch size varied from 1 to 3 eggs, but only one female presented one egg and another female presented three eggs. Clutch volume was 22128.01 ± 4939.8 mm³ (10493.422136.12 mm³; N = 44). Female body size was positively correlated to clutch volume, a pattern usually detected in chelonians. Reproductive information acquired in the present study together with population data available for H. maximiliani in the study site makes it possible a population viability analysis using the software VORTEX (version 9.92). A principal scenario (Real Population) was created based on life-history data collected throughout 10 years. In order to compare the protected area with an unprotected hypothetical area regarding the persistence of the population, this scenario was modified by altering some variables (10% increasing of mortality rate, 10% increasing of inbreeding depression, decreasing of carrying capacity), which generates a scenario named Hypothetical Isolated Population. Results were compared and sensitivity tests were carried out to verify the influence of variation in mortality ratio, catastrophes and inbreeding depression. There was a significant difference between the two scenarios (p = 0.0005). The extinction risk was 31% for Real Population and 90% for Hypothetical Isolated Population. The sensitivity analysis indicated that mortality ratio, deforestation, forest fires and inbreeding depression strongly influence the population survival. Long-term studies and biological information on species inhabiting areas subjected to anthropogenic impacts, like the Atlantic Rainforest, are vital to conservation actions, since they make it possible population viability analyses and the design of management strategies to threatened populations.