Participatory research in the service of the
Biodiversity conservation of the National Marine Park of
João Vieira and Poilão
Project duration: 2013 - 2017
This project provided scientific instruments for the management and monitoring of the João Vieira - Poilão National Marine Park, strengthening the collective capacities of local communities, national researchers and the Park team.
1. Carry out the first inventory of the area's biodiversity
2. Document the use of space and resources and measure likely impacts and developments
3. Provide benchmarks and methodologies for participatory long-term follow-up
4. Contribute to assessing the impacts of climate change on biodiversity
5. Reduce the pressure by reinforcing the presence of actors on the ground, developing conservation actions and seeking alternatives together with grassroots communities
6. Produce scientific publications and materials for dissemination and education
Monitoring of sea turtles at Poilão island, Bijagós Archipelago
The island of Poilão is an extremely important nesting ground for the green turtle (Chelonia mydas), hosting the main African rookery for the species, the third largest of the Atlantic. For this reason, the Institute for Biodiversity and Protected Areas (IBAP) of Guinea-Bissau organizes an annual monitoring campaign in Poilão, with the main objectives of (1) ensuring the presence of conservation teams that protect the large concentration of breeding turtles during this sensitive period, and (2) monitor the abundance of the reproductive population over the years. During this project several training activities were carried out to improve the techniques of monitoring the local teams.
In addition, scientific studies have also been conducted to understand the impacts of climate change on green turtles.
Nest-site selection and reproductive success
Since sea turtles rely on sandy beaches to lay their eggs, they are particularly vulnerable to rising sea levels as this will cause nesting habitat loss. To understand how sea turtles will respond to these changes, it is necessary to assess the status of populations and habitats in the current climate scenario. During the monitoring campaigns of 2013 and 2014 in Poilão, a study analyzed the spatial distribution of 1559 nests and monitored 657 females during oviposition to assess the population and individual preferences at the nesting site. In general, individual preferences in nesting location led to trade-offs in the phenotype of offspring, but overall, most nesting females selected sites that increased offspring survival, suggesting that nesting site selection is an adaptive trait that has been under selection.
Estimating sex-ratios of green turtle hatchlings at Poilão, Guinea-Bissau
The sexual determination of sea turtles is closely linked to the incubation temperature of the eggs. Changes in average long-term temperatures can lead to an exaggerated gender bias of populations, which will have serious implications for their sustainability. In this context, a study analyzed the sex ratio of the green turtle hatchlings from Poilão, and found that it was marginally female-biased, and that both temporal and spatial variation in incubation conditions suggested resilience and potential adaptation to climate change if the present habitat settlement remains unchanged. These results underscore the importance of Poilão for the future conservation of green turtles.
Read the full study here.