22.02.07
Tremough scientists warn of climate change risk to marine turtles

North American marine turtles are at risk if global warming occurs at predicted levels, according to scientists from the University of Exeter's Tremough Campus, Penryn. An increase in temperatures of just one degree Celsius could completely eliminate the birth of male turtles from some beaches. A rise of three degrees Celsius would lead to extreme levels of infant mortality and declines in nesting beaches across the USA.

Research published today in the journal Global Change Biology analyses 26 years of loggerhead turtle nesting and climate data and compares the findings with models for future temperatures. The study shows just how vulnerable marine turtle populations are to changes in temperature. The sex of marine turtle hatchlings is determined by the temperature of eggs during incubation, with warmer temperatures producing females and cooler conditions producing males. Temperatures during nesting also need to be at the right level for eggs to develop healthily and hatch successfully.

"We are stunned by these results and what they could mean for the species in the future," said Dr Brendan Godley of the University of Exeter's School of Biosciences. "In particular, we're concerned that populations that are already predominantly female could become 100% female if temperatures increase by just one degree. This is a major issue for nesting populations further south, in Florida, for example, where males are already in short supply."

The research team recommends that conservation efforts are focused on protecting northern breeding grounds. While in Florida 90% of hatchlings are female, in North Carolina 42% are male and scientists believe some of these males currently travel south, bolstering southern populations. A decline in male turtles in northern populations, as a result of global warming, could potentially impact marine turtles across the continent. "We take this as an important step in identifying essential thermal habitat for marine turtles," said study co-author Dr Matthew Godfrey, of the North Carolina Wildlife Resources Commission. "It highlights the need to establish measures to specifically protect male-producing beaches."

Dr Brendan Godley continued: "In the face of climate change, it's essential that we prioritise the protection of sites that produce males not only for local breeding success, but to help support potentially vulnerable populations further south."

This work was carried out by the University of Exeter's Centre for Ecology and Conservation, Tremough Campus, in partnership with the Bald Head Island Conservancy and the North Carolina Wildlife Resources Commission.

The £100 million Tremough campus is a Combined Universities in Cornwall initiative of which the University of Exeter and University College Falmouth are two of the founding partners. It is funded mainly by the European Union (Objective One), the South West Regional Development Agency, and the Higher Education Funding Council for England, with support from Cornwall County Council. Set in 70 acres of countryside, but close to the waterside towns of Penryn and Falmouth, the campus offers a lively student community. The University of Exeter is expanding its courses available to include Politics, Law and History to existing degrees in Mining Engineering, Geology, Biology, Geography, English and Renewable Energy.

For further information contact Sarah Hoyle of the University of Exeter on 01392 262062 or email S.Hoyle@exeter.ac.uk.

The Objective One Programme for Cornwall and the Isles of Scilly has invested in the Combined Universities in Cornwall (CUC) project, both Phase 1 and Phase 2, through the European Regional Development Fund (ERDF) and the European Social Fund (ESF). The University of Exeter is a partner of the CUC.

Editor's notes:

Clare Morgan
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