Optimism for mitigation of climate warming impacts for sea turtles through nest shading and relocation

Abstract

Increasing incubation temperatures may threaten the viability of sea turtle populations. We explored opportunities for decreasing incubation temperatures at a Caribbean rookery with extreme female-biased hatchling production. To investigate the effect of artificial shading, temperatures were measured under simple materials (white sheet, white sand, palm leaves). To test natural drivers of incubation temperature, temperatures were measured at average nest depths with shading on two beaches. Results from a pilot experiment suggest the most effective material was palm leaves. Shading decreased temperatures by a mean of 0.60 °C (SE = 0.10 °C, N = 20). Variation between beaches averaged 1.88 °C (SE = 0.13 °C, N = 20). We used long-term rookery data combined with experimental data to estimate the effect on sex ratio: relocation and shading could shift ratios from current ranges (97–100% female) to 60–90% female. A conservation mitigation matrix summarises our evidence that artificial shading and nest relocation are effective, low-cost, low-technology conservation strategies to mitigate impacts of climate warming for sea turtles.

Leatherback Sea Turtle (Dermochelys coriacea) Embryo and Hatchling Pathology in Grenada, with Comparison to St. Kitts

“…An immunohistochemical approach to determine the sex of the embryos and hatchlings was considered, but that process was made unnecessary based on a study by Tezak et al (2017) showing that there was 100% agreement between histology and immunohistochemistry. Regardless, these findings support the potential need to identify and implement effective mitigations to alleviate high nest temperatures such as shading, relocation, and hatchery translocation (Sieg et al 2011;Esteban et al 2018).…”

Potential feminization of Red Sea turtle hatchlings as indicated by in situ sand temperature profiles

“…There are several management strategies that could be used to artificially lower the incubation temperature of turtle nests if it was determined that intervention was needed. At rookeries with extreme female‐biased hatchling production, artificial shading can be used to decrease temperatures (Esteban et al, 2018). Shade can be created with simple materials, such as white sheets or white sand, which make it a low‐cost and low‐technology conservation strategy to minimize the impacts of climate change (Esteban et al, 2018).…”

“…At rookeries with extreme female‐biased hatchling production, artificial shading can be used to decrease temperatures (Esteban et al, 2018). Shade can be created with simple materials, such as white sheets or white sand, which make it a low‐cost and low‐technology conservation strategy to minimize the impacts of climate change (Esteban et al, 2018). Another strategy used as a mitigation of climate warming impacts is the relocation of sea turtle eggs (Tuttle & Rostal, 2010).…”

A Review of the Effects of Climate Change on Chelonians

“…Increasing the number of males in a population with TSD can be as simple as creating a simple artificial screen in order to reduce nest temperatures [208]. The use of palm leaves for shade, for example, was successful in reducing temperatures by 0.6 • C at a sea turtle rookery in St Eustatius, in the northeastern Caribbean [209]. Watering nests was also suggested as a method to reduce nest temperatures, although the effects are believed to be most beneficial in dry areas with low rainfall [210].…”