Potential effects of future high tides on sea turtle nesting

Abstract

Sandy beaches are the preferred nesting habitat for sea turtles. Multiple climate change events may, however, impact on this habitat, since the projected increase in the intensity and frequency of high tides as a consequence of rises in sea level and storm events may cause a higher rate of flooding of nests. Knowledge regarding future scenarios of tidal inundation and nest-site selection is required to design action plans with which to protect suitable habitats. The objectives of this study were: i) to quantify the impact of high tides on the nesting of two endangered species of sea turtles, Eretmochelys imbricata and Chelonia mydas in Ecuador, ii) to identify relevant trends regarding tides that might impact on the hatching success of the nests and, iii) to project the hatching success of these sea turtles’ nests in next decade using changes in high tides events as a basis. We measured microhabitat characteristics along seven beaches on which sea turtles nest on the mainland coast of Ecuador. The tidal data and the hatching success of 210 nests were monitored from 2013 to 2020. We observed a positive trend as regards future high tide occurrences, which are a key factor in explaining nest hatching success. This increase in high tide might cause a reduction in the hatching success of these endangered species of sea turtles; with the E. imbricata being the species most affected by this threat. Considering that Eretmochelys imbricata is categorized as critically endangered and Chelonia mydas is listed as endangered, estimations of the potential risk of climate events on their reproductive success might contribute to management strategies, and in turn, to the conservation of their populations.