How changes in beach morphology affect hawksbill turtle (Eretmochelys imbricata) nesting distribution at Celestun, Yucatan, Mexico

Abstract The Yucatan Peninsula harbors important nesting beaches for the largest hawksbill turtle (Eretmochelys imbricata) populations in the Western Atlantic. Over the last decade, erosion has substantially modified segments of the nesting beach along the coastal zone of Celestun town, Mexico. The recent rise in sea level makes this area among the most vulnerable of the Yucatan coastal zone, potentially jeopardizing its suitability as a nesting site for hawksbill turtles. The objectives of this study were to: (1) identify spatiotemporal patterns of the hawksbill nesting season over 11 years (1997–2007); (2) characterize spatiotemporal dynamics in the morphology of the nesting beach; and (3) assess the relationship between beach morphology changes and hawksbill nesting activity. We observed a well-defined spatial pattern of hawksbill nesting activity along the beach, occupying steep and narrow beach zones where human presence and activity was low. The beach was under a strong erosional process, causing a retreat displacement that varied in magnitude along the littoral zone. Principal component analysis showed a strong correlation between beach morphology variables, separating segments of beach according to the effect of morphology. Variation in hawksbill nest densities was inversely correlated to the distance to town and to artificial light intensity. It is suggested that the influence of human activities and infrastructure on nesting females forces the use of beach segments where flooding and nest erosion from high tides and storm surges jeopardize their reproductive success and makes more relevant the identification of spatial priority zones for targeted management strategies that aim to preserve hawksbill nesting.