First satellite tracks of South Atlantic sea turtle 'lost years': seasonal variation in trans-equatorial movement.

In the South Atlantic Ocean, few data exist regarding the dispersal of young oceanic sea turtles. We characterized the movements of laboratory-reared yearling loggerhead turtles from Brazilian rookeries using novel telemetry techniques, testing for differences in dispersal during different periods of the sea turtle hatching season that correspond to seasonal changes in ocean currents. Oceanographic drifters deployed alongside satellite-tagged turtles allowed us to explore the mechanisms of dispersal (passive drift or active swimming). Early in the hatching season turtles transited south with strong southward currents. Late in the hatching season, when currents flowed in the opposite direction, turtles uniformly moved northwards across the Equator. However, the movement of individuals differed from what was predicted by surface currents alone. Swimming velocity inferred from track data and an ocean circulation model strongly suggest that turtles' swimming plays a role in maintaining their position within frontal zones seaward of the continental shelf. The long nesting season of adults and behaviour of post-hatchlings exposes young turtles to seasonally varying ocean conditions that lead some individuals further into the South Atlantic and others into the Northern Hemisphere. Such migratory route diversity may ultimately buffer the population against environmental changes or anthropologic threats, fostering population resiliency.

Spatio-temporal variation in the incubation duration and sex ratio of hawksbill hatchlings: implication for future management.

Climate change poses a unique threat to species with temperature dependent sex determination (TSD), such as marine turtles, where increases in temperature can result in extreme sex ratio biases. Knowledge of the primary sex ratio of populations with TSD is key for providing a baseline to inform management strategies and to accurately predict how future climate changes may affect turtle populations. However, there is a lack of robust data on offspring sex ratio at appropriate temporal and spatial scales to inform management decisions. To address this, we estimate the primary sex ratio of hawksbill hatchlings, Eretmochelys imbricata, from incubation duration of 5514 in situ nests from 10 nesting beaches from two regions in Brazil over the last 27 years. A strong female bias was estimated in all beaches, with 96% and 89% average female sex ratios produced in Bahia (BA) and Rio Grande do Norte (RN). Both inter-annual (BA, 88 to 99%; RN, 75 to 96% female) and inter-beach (BA, 92% to 97%; RN, 81% to 92% female) variability in mean offspring sex ratio was observed. These findings will guide management decisions in Brazil and provide further evidence of highly female-skew sex ratios in hawksbill turtles.

Ghrelin and leptin modulate the feeding behaviour of the hawksbill turtle Eretmochelys imbricata during nesting season.

Female sea turtles have rarely been observed foraging during the nesting season. This suggests that prior to their migration to nesting beaches the females must store sufficient energy and nutrients at their foraging grounds and must be physiologically capable of undergoing months without feeding. Leptin (an appetite-suppressing protein) and ghrelin (a hunger-stimulating peptide) affect body weight by influencing energy intake in all vertebrates. We investigated the levels of these hormones and other physiological and nutritional parameters in nesting hawksbill sea turtles in Rio Grande do Norte State, Brazil, by collecting consecutive blood samples from 41 turtles during the 2010-2011 and 2011-2012 reproductive seasons. We found that levels of serum leptin decreased over the nesting season, which potentially relaxed suppression of food intake and stimulated females to begin foraging either during or after the post-nesting migration. Concurrently, we recorded an increasing trend in ghrelin, which may have stimulated food intake towards the end of the nesting season. Both findings are consistent with the prediction that post-nesting females will begin to forage, either during or immediately after their post-nesting migration. We observed no seasonal trend for other physiological parameters (values of packed cell volume and serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transferase, low-density lipoprotein, and high-density lipoprotein). The observed downward trends in general serum biochemistry levels were probably due to the physiological challenge of vitellogenesis and nesting in addition to limited energy resources and probable fasting.

Fragmentação de habitat e a estrutura de uma taxocenose de morcegos em São Paulo (Brasil) / Fragmentação de hábitat e a estrutura de uma taxocenose de morcegos em São Paulo (Brasil)

O Brasil, juntamente com a Colômbia, o México e a Indonésia, é considerado um país megadiverso (Mittermeier et al., 1992), devido a grande quantidade de espécies animais e vegetais que abriga. Atualmente,essa biodiversidade está ameaçada por uma conjunção de causas que pode levar à perda de várias dessas espécies. Dentre essas causas estão a incursão do homem nos ambientes naturais e a contínua fragmentação dos hábitats em subdivisões cada vez menores. O declínio da diversidade de espécies nesse processo é hoje um fato empírico bem estabelecido(Terborgh, 1992).

O Brasil, juntamente com a Colômbia, o México e a Indonésia, é considerado um país megadiverso (Mittermeier et al., 1992), devido a grande quantidade de espécies animais e vegetais que abriga. Atualmente,essa biodiversidade está ameaçada por uma conjunção de causas que pode levar à perda de várias dessas espécies. Dentre essas causas estão a incursão do homem nos ambientes naturais e a contínua fragmentação dos hábitats em subdivisões cada vez menores. O declínio da diversidade de espécies nesse processo é hoje um fato empírico bem estabelecido (Terborgh, 1992).

Fragmentação de habitat e a estrutura de uma taxocenose de morcegos em São Paulo (Brasil) / Fragmentação de hábitat e a estrutura de uma taxocenose de morcegos em São Paulo (Brasil)

O Brasil, juntamente com a Colômbia, o México e a Indonésia, é considerado um país megadiverso (Mittermeier et al., 1992), devido a grande quantidade de espécies animais e vegetais que abriga. Atualmente,essa biodiversidade está ameaçada por uma conjunção de causas que pode levar à perda de várias dessas espécies. Dentre essas causas estão a incursão do homem nos ambientes naturais e a contínua fragmentação dos hábitats em subdivisões cada vez menores. O declínio da diversidade de espécies nesse processo é hoje um fato empírico bem estabelecido(Terborgh, 1992).

O Brasil, juntamente com a Colômbia, o México e a Indonésia, é considerado um país megadiverso (Mittermeier et al., 1992), devido a grande quantidade de espécies animais e vegetais que abriga. Atualmente,essa biodiversidade está ameaçada por uma conjunção de causas que pode levar à perda de várias dessas espécies. Dentre essas causas estão a incursão do homem nos ambientes naturais e a contínua fragmentação dos hábitats em subdivisões cada vez menores. O declínio da diversidade de espécies nesse processo é hoje um fato empírico bem estabelecido (Terborgh, 1992).