Annual Plasticity of the Trophic Niche of the Bridled Tern Onychoprion anaethetus in Cuba

International audiencethe trophic ecology of the Bridled tern Onychoprion anaethetus is poorly understood despite its great abundance in tropical and subtropical regions. Important breeding colonies are located in the Caribbean, where significant human disturbances occur and where coverage by marine protected areas is still largely insufficient. Bridled tern populations are likely to experience considerable variation in trophic niche throughout their annual cycle, especially between the non-breeding and breeding phases as they change their feeding areas. In this study, we assessed the year-round variability of the Bridled tern isotopic niche (δ15N and δ13C) from two breeding areas in North Central Cuba, as a proxy of its trophic niche. Feathers, down and blood samples were taken from adults and chicks, representing four life cycle phases of this species (non-breeding, pre-laying, incubation and chick-rearing). Overall, Bridled terns occupied a narrow and relatively plastic isotopic niche, along the studied life cycle phases. the largest variability occurred between the non-breeding and the pre-laying phases, showing a marked reduction of the niche breadth. Patterns of niche variability differed among breeding areas only during the incubation phase. Considering that adult females of Bridled tern rely on few prey species during the pre-laying, this life cycle phase is a period of high vulnerability for the Cuban colonies

Did the animal move? : a cross‑wavelet approach to geolocation data reveals year‑round whereabouts of a resident seabird

Considerable progress in our understanding of long-distance migration has been achieved thanks to the use of small geolocator devices (GLS). The tracking of resident or short-distance migrant animals remains however challenging because geolocation errors are substantial and difficult to estimate. This study aims to examine the sex-specific marine space uses of a resident tropical seabird, the masked booby (Sula dactylatra), during its full annual life cycle at the Fernando de Noronha archipelago (Brazil). Masked boobies (n = 31) tagged with GLS recording light intensity, seawater immersion, and water temperature showed a resident behaviour over their entire annual cycle. A wavelet analysis of GLS data revealed oscillatory patterns of inferred longitude correlated with changes in immersion frequency. This synchronicity demonstrated that birds traveled away and back from the colony on consecutive trips of short length ( ∼ 2–4 days) and short range ( ∼ 100–300 km) eastward of the colony. Duration and range of trips depended on the sex of the individual and on the time of the year. Trip duration increased gradually from the end of the breeding period to the post-breeding period, probably due to the release of the central-place breeding constraints. During the pre-breeding period, females had farther ranges eastward and spent more time in water than males. Despite inherent limits of light-based geolocation, this study demonstrates the relevance of synchronicity analysis of GLS data for investigating year-round movements of resident or short-distance migrants

Did the animal move? A cross-wavelet approach to geolocation data reveals year-round whereabouts of a resident seabird

Considerable progress in our understanding of long-distance migration has been achieved thanks to the use of small geolocator devices (GLS). The tracking of resident or short-distance migrant animals remains however challenging because geolocation errors are substantial and difficult to estimate. This study aims to examine the sex-specific marine space uses of a resident tropical seabird, the masked booby (Sula dactylatra), during its full annual life cycle at the Fernando de Noronha archipelago (Brazil). Masked boobies (n = 31) tagged with GLS recording light intensity, seawater immersion, and water temperature showed a resident behaviour over their entire annual cycle. A wavelet analysis of GLS data revealed oscillatory patterns of inferred longitude correlated with changes in immersion frequency. This synchronicity demonstrated that birds traveled away and back from the colony on consecutive trips of short length (∼ 2–4 days) and short range (∼ 100–300 km) eastward of the colony. Duration and range of trips depended on the sex of the individual and on the time of the year. Trip duration increased gradually from the end of the breeding period to the post-breeding period, probably due to the release of the central-place breeding constraints. During the pre-breeding period, females had farther ranges eastward and spent more time in water than males. Despite inherent limits of light-based geolocation, this study demonstrates the relevance of synchronicity analysis of GLS data for investigating year-round movements of resident or short-distance migrants

Machine and deep learning approaches to understand and predict habitat suitability for seabird breeding

The way animals select their breeding habitat may have great impacts on individual fitness. This complex process depends on the integration of information on various environmental factors, over a wide range of spatiotemporal scales. For seabirds, breeding habitat selection integrates both land and sea features over several spatial scales. Seabirds explore these features prior to breeding, assessing habitats' quality. However, the information-gathering and decision-making process by seabirds when choosing a breeding habitat remains poorly understood. We compiled 49 historical records of larids colonies in Cuba from 1980 to 2020. Then, we predicted potentially suitable breeding sites for larids and assessed their breeding macrohabitat selection, using deep and machine learning algorithms respectively. Using a convolutional neural network and Landsat satellite images we predicted the suitability for nesting of non-monitored sites of this archipelago. Furthermore, we assessed the relative contribution of 18 land- and marine-based environmental covariates describing macrohabitats at three spatial scales (i.e. 10, 50 and 100 km) using random forests. Convolutional neural network exhibited good performance at training, validation and test (F1-scores >85%). Sites with higher habitat suitability (p > .75) covered 20.3% of the predicting area. Larids breeding macrohabitats were sites relatively close to main islands, featuring sparse vegetation cover and high chlorophyll-a concentration at sea in 50 and 100 km around colonies. Lower sea surface temperature at larger spatial scales was determinant to distinguish the breeding from non-breeding sites. A more comprehensive understanding of the seabird breeding macrohabitats selection can be reached from the complementary use of convolutional neural networks and random forest models. Our analysis provides crucial knowledge in tropical regions that lack complete and regular monitoring of seabirds' breeding sites

A Novel Synthetic Inhibitor of CDC25 Phosphatases

International audienc

Marine spatial planning in the tropical Atlantic

The goal of marine spatial planning is to manage uses of marine space to reduce tensions between human activities and the health of marine ecosystems. This is a major and complex challenge, as oceans lie at the intersection of multiple and increasing interests: biodiversity conservation, climate change regulation, economic development, food security. This handbook takes an interdisciplinary, sustainability science approach to explore the potential and limitations of marine spatial planning, a tool developed in the Global North, and its current or possible future applications in the tropical South Atlantic – specifically in Brazil, Senegal and Cabo Verde. To protect our global ocean commons, communities of stakeholders need to transcend disciplinary boundaries and bring together diverse knowledge to move towards a shared goal of sustainability (part 1). The development of this collective intelligence in tropical marine ecosystem research must take into account local, national and international issues (part 2) and can be supported by innovative interdisciplinary tools (part 3). This handbook is aimed at decision-makers, researchers and, more generally, all users of marine areas, highlighting crucial points to consider when implementing marine spatial planning