GALAPAGOS, Ecuador (Reuters) - Climate change could endanger the unique wildlife of the Galapagos Islands, and scientists are trying to figure out how to protect vulnerable species such as blue-footed boobies and Galapagos Penguins.
Some 175 years after the wildlife of the Galapagos helped inspire Charles Darwin to develop his theory of evolution, scientists are measuring the impact of global warming on the rich but fragile biodiversity of the islands.
The volcanic archipelago, about 600 miles west of the Ecuadorean coast, is home to scores of endemic species that closely depend on one another for survival.
Scientists say abrupt and frequent changes in sea temperatures and the death of coral reefs near the islands show that global warming is taking its toll on local sea life.
"The coral reefs create a habitat; they are like a forest, like the Amazon. They are home to scores of species. ... If the corals die we lose thousands of species that are associated to the coral," said German marine biologist Judith Denkinger.
The Galapagos-based scientist said the harm that pollution and climate change are causing marine life could trigger a domino effect and hurt on-shore species as well.
"Everything is intertwined. You can't say this is land, this is sea, they are both one," Denkinger said, sitting on a rock by the sea and surrounded by growling sea lions.
According to the United Nations, global warming is to blame for the melting of ice caps, rising sea levels and wacky weather worldwide, including storms, droughts and floods.
The United Nations says that between 20 percent and 30 percent of plant and animal species worldwide are likely to face an increased risk of extinction due to warming caused by greenhouse gas emissions.
Islands are particularly vulnerable to climate change, experts say.
Gabriel Lopez, executive director of the Galapagos-based Charles Darwin Foundation, said the islands have a very fragile ecosystem. Lopez expressed concern that global warming "will have very strong impacts on sea lions -- due to the lack of food available to them -- on penguins, and on marine iguanas."
The foundation conducts scientific research aimed at preserving the Galapagos Islands, home to such creatures as giant tortoises, penguins, the blue-footed booby seabird, iguanas, albatrosses, finches and sea lions.
Scientists based in the Galapagos say the archipelago could become "a life-sized laboratory" in which researchers could gauge the threat of global warming, and develop strategies to mitigate its effects on wildlife.
"The Galapagos can be a barometer for the global community ... because in such fragile ecosystem the changes could be immediate," Lopez said.
The location of the islands also could help experts understand how a possible change in the strength or temperature of ocean currents could hurt sea life.
"The Galapagos are amid a unique, dynamic crossroad of currents. Here we can do controlled experiments to see how global warning could affect marine ecosystems in the long run," Denkinger said.
Among the currents that funnel their way between the islands is the oxygen-and-nutrient rich Cromwell current, on which sharks, sea lions and whales depend for food.
The Charles Darwin Foundation is concerned that it may soon need to help animals such as penguins better cope with higher temperatures or food shortages.
Lopez said Galapagos Penguins -- there are around 900 of them in the islands -- may need to live in man-made "condos" if the worst-case scenarios regarding global warming materialize.
"We are going to do all we can not to resort to such extreme measures, but ... if the (worst) climate-change models are accurate, I think that it's going to be a real challenge to save the penguins," he said.
Overfishing and a booming tourism industry also are hurting the archipelago's ecosystem.
Lured by exceptional wildlife and pristine beaches, some 173,000 tourists last year visited the islands, which belong to Ecuador. That was about double the number in 2003.
More tourists means more hotels, restaurants, shops and bars in the Galapagos, and more people from the mainland coming to the islands looking for jobs.
Environmentalists say that despite the Galapagos National Park's good job at caring for the islands, the tourism industry has some impact on the ecosystem.
"I was here in the early 1990s and especially here in Puerto Ayora (in the island of Santa Cruz) the changes have been quite dramatic. More vehicles, more construction, more population, the tourist influx ... it worries me," Lopez said.
Overfishing is also a concern. Park rangers often intercept ships fishing illegally and carrying slaughtered sharks and banned equipment, such as long-lines and shark nets.
A drop in the shark population could upset the delicate balance of life in the islands, according to experts.
"I love snorkeling, and the truth is that life under water has changed significantly. Before, it was easy to see enormous schools of fish, and sharks by the hundreds. I'm not exaggerating," said Jorge Fernandez, a yacht captain.
"If you see a shark now you should consider yourself lucky," said the seafarer, who has been working in cruise ships in the islands for 20 years.
Editing by Fiona Ortiz and Will Dunham