Terrestrial basking sea turtles are responding to spatio-temporal sea surface temperature patterns

Area of Science:

• Marine Biology
• Climate Change Ecology
• Animal Behavior

Background:

• Terrestrial basking in green turtles (Chelonia mydas) has been observed since Darwin's era.
• The environmental drivers and global distribution of this behavior remain poorly understood.
• Understanding basking behavior is crucial for assessing climate change impacts on marine reptiles.

Purpose of the Study:

• To investigate the relationship between sea surface temperature (SST) and green turtle basking behavior.
• To assess the potential impact of projected ocean warming on the future of terrestrial basking.
• To provide data for predicting and managing climate change effects on green turtle populations.

Main Methods:

• Conducted 6 years of daily basking surveys in Hawaii.
• Compared basking data with local sea surface temperature (SST) phenology.
• Analyzed decadal SST profiles for 11 global green turtle populations (1990-2014).

Main Results:

• Green turtle basking peaks during cooler SST periods, consistent with bone stress marking timelines.
• Terrestrial basking generally occurs when winter SST drops below 23°C.
• Global green turtle populations experienced SST warming at an average of 0.04°C yr(-1), significantly exceeding the global average.

Conclusions:

• Projected ocean warming trends suggest terrestrial basking in green turtles may cease globally by 2100.
• Climate change poses a significant threat to this essential thermoregulatory and behavioral adaptation.
• Further research is needed to understand how climate influences organismal biology for effective conservation.