Nesting failure of sea turtles in Ecuador - causes of the loss of sea turtle nests: the role of the tide

Abstract

The nesting environment is known to significantly affect the breeding success of sea turtles. Sandy beach habitats, where sea turtles nest, are frequently affected by high tides and waves on Ecuadorian beaches during windy events. The objectives of this study were: i) to determine the variables that affect nest site selection by two sea turtle species, Eretmochelys imbricata and Chelonia mydas in Ecuador, ii) to compare features of the nesting places of successful vs. failed clutches and iii) to quantify the changes in the intensity and frequency of the tide and its relation to the loss of eggs for the last 10 years. We monitored 15 hawksbill and 26 green turtle nests for two years on five beaches on the mainland coast of Ecuador. The results show that the presence of a dune scarps negatively affected successful nesting, while the proportion of eggs lost was positively associated with road distance, sea distance and nest depth. In addition, the results showed that the loss of eggs was greater for the green turtle, the presence of dune scarps and tides. Finally, using the data available on hatching success over the last 10 years we found a significant relationship between the intensity of the tides and the loss of eggs during this period. We conclude that nest site selection and hatching success vary with beach microhabitats and therefore local information is needed to protect suitable habitats.