Adaptation of sea turtles to climate warming: Will phenological responses be sufficient to counteract changes in reproductive output?
Mariana M. P. B. Fuentes, Armando J. B. Santos, F. Alberto Abreu‐Grobois, Raquel Briseño-Dueñas, Jassim A. Al‐Khayat, Sara Khalily Hamza, Sally Saliba, Dave W. Anderson, Kirt W. Rusenko, Nicola J. Mitchell, Malindi Gammon, Blair P. Bentley, Damla Beton, David T. Booth, Annette C. Broderick, Liliana P. Colman, Robin Snape, M.F. Calderón-Campuzano, Eduardo Cuevas, Melania C. López‐Castro, Cynthia D. Flores-Aguirre, F. Mendez de la Cruz, Y. Segura‐Garcia, A. Ruiz‐Garcia, Sabrina Fossette, Christopher R. Gatto, Richard D. Reina, Marc Girondot, Matthew Godfrey, Vicente Guzmán‐Hernández, Catherine E. Hart, Yakup Kaska, Paulo Lara, Maria Ângela Marcovaldi, Anne Marie LeBlanc, David C. Rostal, Michael J. Liles, Jeanette Wyneken, Alexandra Lolavar, Sean A. Williamson, Muralidharan Manoharakrishnan, Chandana Pusapati, Mark Chatting, S. Mohd Salleh, Ana R. Patrício, Aissa Regalla, Jaime Restrepo, Rosa D. García, Pilar Santidrián Tomillo, Çisem Sezgin, Kartik Shanker, F. Tapilatu, Oğuz Türkozan, Roldán A. Valverde, Kim Williams, Can Yılmaz, N. Tolen, Ronel Nel, Jiří Tuček, D. Legouvello, Marga L. Rivas, Clara Gaspar, Margaux Touron, Quentin Genet, Michael Salmon, Maria Araújo, Jordana Borini Freire, Vinícius Davel Castheloge, Paulo R. Jesus, Paulo Dias Ferreira, Frank V. Paladino, D. Montero‐Flores, Doğan Sözbilen, Jonathan R. Monsinjon
Abstract
Sea turtles are vulnerable to climate change since their reproductive output is influenced by incubating temperatures, with warmer temperatures causing lower hatching success and increased feminization of embryos. Their ability to cope with projected increases in ambient temperatures will depend on their capacity to adapt to shifts in climatic regimes. Here, we assessed the extent to which phenological shifts could mitigate impacts from increases in ambient temperatures (from 1.5 to 3°C in air temperatures and from 1.4 to 2.3°C in sea surface temperatures by 2100 at our sites) on four species of sea turtles, under a "middle of the road" scenario (SSP2-4.5). Sand temperatures at sea turtle nesting sites are projected to increase from 0.58 to 4.17°C by 2100 and expected shifts in nesting of 26-43 days earlier will not be sufficient to maintain current incubation temperatures at 7 (29%) of our sites, hatching success rates at 10 (42%) of our sites, with current trends in hatchling sex ratio being able to be maintained at half of the sites. We also calculated the phenological shifts that would be required (both backward for an earlier shift in nesting and forward for a later shift) to keep up with present-day incubation temperatures, hatching success rates, and sex ratios. The required shifts backward in nesting for incubation temperatures ranged from -20 to -191 days, whereas the required shifts forward ranged from +54 to +180 days. However, for half of the sites, no matter the shift the median incubation temperature will always be warmer than the 75th percentile of current ranges. Given that phenological shifts will not be able to ameliorate predicted changes in temperature, hatching success and sex ratio at most sites, turtles may need to use other adaptive responses and/or there is the need to enhance sea turtle resilience to climate warming.