Nesting Ecology of the Green Turtle (Chelonia mydas ) and Nesting Success After a Tropical Storm Event at Playa Cabuyal, Guanacaste Province, Costa Rica

Kelcy J Tolliver, Purdue University

Abstract

The green turtle (Chelonia mydas) is listed as endangered by the International Union for Conservation of Nature (IUCN) due to a continuing decline in population trends. The objective of this study was to determine how hatching success of the green turtle is affected by various environmental pressures at Playa Cabuyal, Guanacaste Province, Costa Rica. A tropical storm event occurred at the beginning of the 2017–2018 nesting season, which caused rapid coastal erosion along the entire length of the beach. Measurements of moisture content, sand grain size, and canopy cover, as well as distance from the high tide line and estuary were taken at the site of each nest to determine how these variables correlated with hatching success. Hatching success was significantly influenced by canopy cover (p=0.04) and distance from the high tide line at the time of laying (p=0.049). The tropical storm did not appear to influence nest site selection in green turtles when compared to the previous seven nesting seasons at Playa Cabuyal. A southward shift in nest site selection observed in the past two nesting seasons were likely due to volcanic rock and changing currents. Height measurements of the berm measured with a clinometer and compared with elevation levels estimated by a UAV throughout the nesting season indicate that the beach is recovering due to accretion of sand at the berm sites. With increasing sea surface temperatures and sea level rise, the results of this study indicate the importance of relocation to suitable nesting areas when nests are at a risk of critically high temperatures or innundation from high tide.

Degree

M.S.

Advisors

Paladino, Purdue University.

Subject Area

Biology

COinS