How vulnerable are the nesting sites of loggerhead turtles in Cabo Verde?

Marine turtles’ nesting grounds face imminent threats from urbanisation, climate change, and pollution. In this study, we estimated the vulnerability of loggerhead turtles (Caretta caretta) nesting beaches in Cabo Verde, one of the largest rookeries globally. We surveyed 61 sandy beach segments (~ 100 m) with a drone and modelled nest density by incorporating topographical and oceanographic variables. Then, we digitised all beaches across the islands, divided them into smaller sections (digitised segments), and projected the model onto this layer. Each digitised beach segment was evaluated considering their exposure to five risk factors: (a) marine litter density, (b) inundation trends, (c) land surface temperature trends, (d) light pollution trends, and (e) tourism pressure. Our analysis revealed that 48% of digitised segments are exposed to at least one threat. São Vicente, Santiago, and Sal are the most affected islands, mainly from marine debris and light pollution, while Santo Antão and Maio are the least impacted. Sal showed the highest overlap between vulnerable areas and high-density sites, highlighting its priority for conservation, though less affected islands should also be protected. We found that marine debris correlates positively with nest density, while light pollution negatively affects it. Our study emphasises the need for conservation efforts to ensure the sustainability of nesting sites amid escalating global changes.

Open access funding provided by FCT|FCCN (b-on). A grant from Fundação para a Ciência e Tecnologia (FCT) supports the DSG’s work (https://doi.org/10.54499/2020.04775.BD), co-supported by the European Social Fund through NORTE 2020; fieldwork was partially supported by Centro de Investigação em Ciências Geo-Espaciais (UIDB/00190/2020), funded by COMPETE 2020 and FCT. JPM is supported by Pew Fellows Program in Marine Conservation. NS was supported by a CEEC2017 contract (CEECIND/02213/2017) from FCT.

Peer reviewed