Climate Change Endangering Biodiversity
Cram 90,000 species into a country the size of the U.S. state of West Virginia, add global warming and mounting threats from development and urbanization, and you’re left with a ticking time bomb, according to the country’s leading experts on biodiversity and climate change.
“Costa Rica has more species, in a smaller area, than almost any other country in the world,” explained Jesús Ugalde, director of biodiversity at INBio, a shady, cool research station and park in Heredia, in the Central Valley. “No one is prepared to say exactly what effects global warming will have here. What is clear is that there will be a serious effect.”
Costa Rica ranks first in Central America when it comes to species density (species per 1,000 kilometers), according to INBio’s statistics – and far ahead of such biodiversity powerhouses as Brazil, Colombia, Indonesia and Australia.
The country harbors almost 5% of the world’s biodiversity in just 0.003% of its landmass – a figure that has long been a source of pride and advertising slogans for Costa Rica, which derives a big part of its livelihood from tourism.
But the figure is as scary as it is exciting, Ugalde said, because the country also has the most to lose.
It’s not just the number of species, he said, but “their density, and dependence on fragile microclimates and ecosystems” that makes them so vulnerable to mounting threats from so many different angles – development, deforestation, pollution and, of course, climate change.
“Species that are already threatened are going to suffer the most,” he said, though he’s quick to point out that climate change doesn’t discriminate.
Outside Ugalde’s office door, a flock of lime-green parakeets clamored and squawked among palms, geckos scrambled silently along the white walls and yigüirros, or clay-colored robins, Costa Rica’s national bird, yodeled their singsong anthem.
Even such everyday sightings and occurrences as these are subject to change, Ugalde explains.
Yigüirros, he said, renowned for their ability to predict the onset of summer rains, now seem confused, singing too early, or too late. Some species, including geckos, ants and birds, are moving up hillsides from the coastal lowlands into the cooler air of the mountains, where years ago they were rarely, if ever, sighted.
“Cycles of emergence, and the patterns of plants and wildlife are already changing.
These events were much more predictable in the past,” he said.
He worries that a “desychronization,” of such patterns could have serious potential effects on the country’s wildlife, and consequently on human populations.
“Not all organisms will respond the same. Some will adapt. Others won’t. This could change the function of the entire forest,” he said.
Ugalde’s desk is buried beneath stacks of research papers, some yellowing and old, others pasty white. All are part of an effort he has made to collect accumulated data from years of studies on global warming related subjects in Costa Rica’s jungles.
A welcoming government, a large percentage of protected areas and high-profile species such as the golden toad, a charismatic amphibian that hasn’t been seen for almost two decades, have converted Costa Rica into a hotbed of global warming research activity.
Taken alone, these studies are alarming. Together, they warn of a major tragedy. “People are already talking about the possibility of the sixth major wave of extinction,” he said, adding that the five prior waves – including the die-off of many species of dinosaurs – occurred over longer periods of time, and none so rapidly as the one that looms.
Ugalde holds up one study from 1999, by Alan Pounds, a U.S. biologist at the Monteverde Cloud Forest Preserve and TropicalScienceCenter, that reveals 20 of 50 species of frogs and toads in a 30 square kilometer study area have disappeared, including the infamous golden toad – a species unique to Costa Rica.
The study links the losses to the declining frequency of mist and cloud cover in the forest during the dry season – a requirement forspecies with porous skin like frogs and toads (TT, June 3, 2005).
He digs another study from the heaping pile – this one released in 2006 and conducted by a group of biologists at the La Selva Biological Research Station on the Caribbean slope.
“We use data collected over 35 years to show that the population density of all species of terrestrial amphibians has declined by about 75% since 1970,” states the report summary.
Though no one is fingering global warming as the sole culprit in either case, recent studies show that warmer temperatures means slower growing trees, and therefore less leaf litter on the forest floor, according to David Clark, a U.S. researcher at La Selva (TT May 25).
For shade- and moisture-seeking amphibians and reptiles, this translates to fewer places to hide – and a higher susceptibility to disease.
Even the larger, charismatic “megafauna” such as monkeys – which are more mobile than plants or smaller species – are threatened by rising temperatures and a thinning ozone layer that increases exposure to solar radiation.
A recent study revealed that monkeys here are suffering from increasing incidence of cataracts, an eye disease possibly prompted by increased exposure to solar radiation (TT, April 27).
Roberto Villalobos, a scientist with the National Meteorological Institute, hesitates to put any figures, timetables or numbers on the effects of global warming on Costa Rica. But like most meteorologists, Villalobos, who sports a neatly trimmed mustache and an equally rigid demeanor – admits something is changing.
“What we know is that temperatures are going up,” he said. According to the most recent statistics from the International Panel on Climate Change (IPCC), 11 of the past 12 years rank among the warmest 12 years since instrument recordkeeping began in 1850, and temperatures are projected to rise 3.1 to 7.2 degrees Fahrenheit (1.8 to 4 degrees Celsius) through the century.
Villalobos said he believes global patterns will lead to more precipitation on the country’s Caribbean slope, and less on the Pacific – though he cautions studies are still inconclusive.
“It will be good for tourists, who come to Guanacaste from the white north to escape the cold weather, but bad for our water supplies, and for our crops,” he said.
Slow-moving plants and animals, which have spent thousands of years evolving to specific habitats and microclimates in Costa Rica, will have far fewer choices, Ugalde explains.
“They will have two options: go north, or go up,” he said. Costa Rica’s most threatened species, he explains, are those that are already at the tops of high mountain peaks – including many species of lichens, fungi and specially-adapted insects, birds and animals.
“For certain species already isolated at the tops of mountains, surrounded by deforestation or development, the outlook is not good. They have nowhere to go,” he said.
Maarten Kappelle, science director for the Nature Conservancy in Central America, and an expert on páramos, highland habitats often including grasslands and stunted vegetation, explains that changes in precipitation patterns could cause more immediate, more serious damage.
“Often people think that climate change is just global warming. But rain distribution has more of an impact in the short-term,” said Kappelle, a researcher from Holland who has spent more than 15 years studying highland habitats in Costa Rica.
“Our clouds are disappearing. Fewer clouds, means less rain, means these forests are drying up,” he said, adding that fires have become more and more common in these areas – where once they were rare, or even unheard of.
Hundreds of unique species – including 70 bird species and 400-500 plant species, 10% of which are unique to Costa Rica – could be lost forever, Kappelle explained.
“There are very narrow elevation bands where many of these species can live. If these forests disappear, so does an entire host of species,” he said.
Biodiversity at a Glance
• Costa Rica has 90,000 of the world’s nearly 2 million known species of living organisms, and ranks among the top 20 countries in the world for total number of species. Scientists estimate that figure accounts for only 18% of the Costa Rica’s jungles – leaving roughly 418,000 to be discovered.
• Costa Rica ranks 13th in the world in total number of amphibians (183), 17th in plants (11,451), 20th in reptiles (226), 24th in birds (857), and 32nd in mammals (239).
• Costa Rica ranks 128 in terms of total landmass (0.003% of the earth’s surface), but harbors almost 5% of its biodiversity.
• Costa Rica ranks first in Central America for species density, thanks to its location between the North and South American continents and enormous variety of habitats – páramo (highland), mountain, wetland, mangrove, cloud forest and coastal plain.
• Approximately 160 new species are discovered in Costa Rica each year – most of them insects and invertebrates.
Source: Biodiversidad de Costa Rica en Cifras, Vilma Obando, 2007