The Effects of Sea Level Rise and Nest Location on Reproductive Success in Leatherback (Dermochelys coriacea) and Green ( Chelonia mydas) Sea Turtles on Bioko Island, Equatorial Guinea

Callie Annette Veelenturf, Purdue University

Abstract

This study of the nesting ecology of leatherback (Dermochelys coriacea) and green (Chelonia mydas) sea turtles, investigated how several environmental factors and beach characteristics on Bioko Island, Equatorial Guinea are influencing sea turtle reproductive success and how these characteristics are subject to change with sea level rise. Results show that an average of 61.75% of Bioko’s current nesting habitat could be lost by 2046-2065 and 86.25% by the years 2081-2100. Clutch elevation relative to the high tide line (HTL) was found to be the most influential factor in determining hatching success, further compounding the gravity of these sea level rise predictions. Multiple linear regression analysis demonstrates that nest distance to vegetation and sand conductivity also played significant, formative roles in observed hatching success. On the other hand, 64% of green turtle experimental nests were affected by predation, making conclusions about the roles of environmental characteristics in this species’ hatching success difficult to make at this time. For leatherback turtles, 33% percent were affected by inundation and 17% by predation. Here, an optimum clutch elevation range for leatherback turtles is identified, where a distinct increase in hatching success was observed between -0.286 m to -0.0528 m clutch elevation. We propose further investigation into influential characteristics in green nests and confirmation of the observed optimum elevation range on Bioko Island in future years. Identified sensitivities of each species to sea level rise and beach characteristics will be used to encourage the government of Equatorial Guinea to consider the vulnerability of their resident turtle populations when planning for future development.^

Degree

M.S.

Advisors

Frank V. Paladino, Purdue University.

Subject Area

Biology|Ecology|Climate change

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