How can conservationists help sea turtles adapt to climate change?
Consider the challenge: sea turtles nest on island beaches, one of the habitats hit hardest by rising sea levels. But Conservancy senior scientist Rick Hamilton has a vision: use traditional knowledge and the latest science to “climate proof” sea turtles.
The recovery occurred on the largest rookery in the Solomon Islands. After 20 years, data show the number of hawskbill nests laid on the Arnavon Islands, part of the Solomons, increased by 200 percent.
This turnaround was due to a combination of local protection efforts and national policy. But Hamilton knows conservationists can’t just rest on this success. “Fifty to 60 years from now, beach erosion due to climate change could undo all this success,” he says. “Many of the beaches where we’ve seen the most recovery are going to be at risk from beach erosion.”
Hamilton’s vision: map the Arnavon rookeries – where sea turtles nest – and focus protection efforts on long, sloping beaches which are most resilient to the effects of climate change.
“If we can build a profile of all these nesting beaches,” says Hamilton, “we can build up a picture of where sea turtles have the best chances.”
The latest technology plus traditional knowledge can provide a more complete picture of the nesting beaches. Hamilton believes using Go Pro cameras on drones can provide good data on beach elevations; drones have been used for similar conservation mapping around the world (including in marine environments).
The extensive knowledge held by local people was essential for protecting the rookeries from harvest. This knowledge will be equally important in protecting sea turtle nesting beaches.
There is one additional obstacle, though: sea turtles return to the same nesting beaches year after year. What if long, sloping beaches are protected, but sea turtles keep returning to the eroded ones?
“Sea turtles do return, but they actually aren’t a 100 percent loyal,” says Hamilton. “This depends on the availability of nesting beaches. They can bounce around a bit locally to find the right spot.”
A sea turtle comes ashore and moseys around to find the perfect spot. If the conditions aren’t right, they’ll go back out to sea and try somewhere else. I’ve seen this behavior while reporting on sea turtle conservation in the Caribbean – it can take a turtle a long time to commit to a beach area.
Hamilton recalls a cyclone that hit the Arnavons in the 1970s that took out a lot of nesting beaches. The turtles found the nearest suitable location and nested there.
Unfortunately, some of these “alternate” locations were unprotected by conservation measures, so turtles were killed by subsistence fishers.
This underscores the need to protect not just beaches important to sea turtles now, but also those beaches that they may use in the future.
But some turtles may need a bit more direct intervention from people. They may find a good, dry nesting location that will end up underwater during high tide.
“When nests are laid below the high tide, we could very carefully move them to higher ground,” says Hamilton. “You can relocate all the eggs to an artificial nursery area.”
By using this combination of mapping the best habitat plus direct intervention, even highly susceptible animals like sea turtles could be much more resilient to climate change.
“I think it’s possible to almost entirely climate proof sea turtles on the Arnavons,” says Hamilton. “In the 1970s, it looked like sea turtles faced a tough future here, but working with local communities, we were able to increase populations significantly. Many people think climate change will pose even bigger threats to sea turtles. But by using data and local knowledge, we can ensure a hopeful future for these animals.”