The study reveals that every species lost causes a faster unraveling of the overall ecosystem. Conversely, every species recovered adds significantly to the overall productivity and stability of the ecosystem, as well as its ability to withstand stresses.

“Whether we looked at tide pools or studies over the entire world’s ocean, we saw the same picture emerging,” says lead author Boris Worm, PhD, of Dalhousie University in Nova Scotia, Canada. “In losing species, we lose the productivity and stability of entire ecosystems. I was shocked and disturbed by how consistent these trends are—beyond anything we suspected.”

The four-year analysis is the first to examine all existing data on ocean species and ecosystems, synthesizing historical, experimental, fisheries’ and observational data to understand the importance of biodiversity at the global scale. The results reveal global trends that mirror what scientists have observed on smaller scales, proving that progressive biodiversity loss not only impairs the ability of oceans to feed a growing human population, but also sabotages the stability of marine environments and their ability to recover from stresses.

While the data show that ocean ecosystems still hold a great ability to rebound, the current global trend projects the collapse of all species of wild seafood that are currently fished by the year 2050. (Collapse is defined as 90% depletion.) Collapses are also hastened by the decline in overall health of the ecosystem, as fish rely on clean water, prey populations and diverse habitats.

“Unless we fundamentally change the way we manage all the oceans’ species together, as working ecosystems, then this century is the last century of wild seafood,” says coauthor Stephen Palumbi, PhD, a Pew Fellow in Marine Conservation at Stanford University in California.

The impact of species loss goes beyond declines in seafood. Human health risks emerge as depleted coastal ecosystems become vulnerable to invasive species, disease outbreaks and harmful algal blooms.

“The ocean is a great recycler,” Dr. Palumbi says. “It takes sewage and recycles it into nutrients, it scrubs toxins out of the water, and it produces food and turns carbon dioxide into food and oxygen. But in order to provide these services, the ocean needs all its working parts: the millions of plant and animal species that inhabit the sea.”

“The data show us it’s not too late,” notes Dr. Worm. “We can turn this around. But less than 1% of the global ocean is effectively protected right now. We won’t see complete recovery in one year, but in many cases species come back more quickly than people anticipated—in three to five to 10 years. And where this has been done we see immediate economic benefits.”

The authors conclude that restoring marine biodiversity through an ecosystem-based management approach—including integrated fisheries management, pollution control, maintenance of essential habitats and creation of marine reserves—is essential to avoid serious threats to global food security, coastal water quality and ecosystem stability.

“This isn’t predicted to happen; this is happening now,” says coauthor Nicola Beaumont, an ecological economist with the Plymouth Marine Laboratory in England. “If biodiversity continues to decline, the marine environment will not be able to sustain our way of life. Indeed, it may not be able to sustain our lives at all.”

Earthwatch volunteers are traveling to Malaysia to study bats in the Krau Wildlife Reserve.

“This 30 million-year-old rainforest is a bat paradise,” says Dr. Tigga Kingston, an assistant professor of biology at Texas Tech University and principal investigator of Earthwatch’s Malaysian Bat Conservation project (pictured here holding a bat for measurement). “It is home to the greatest diversity of insect-eating bats in the world, with at least 60 species. When the fruit-eating bats are included, the species list tops 71 bats.”

For four years, Earthwatch teams have been helping Dr. Kingston monitor bats in Krau Wildlife Reserve, using “harp” traps to capture the flying mammals and banding them for further study. Volunteers gain a rare chance to explore parts of this ancient rainforest that are off-limits to tourists, and they gain a unique perspective on how important bats are.

“For me and the other volunteers on my expedition, this was an amazing opportunity to work with these animals up close,” says volunteer Ed Barker. “Bats are incredibly delicate, voracious insect eaters, with a highly sophisticated ability to move through the jungle. Helping to understand what role they play in forest ecosystems was really rewarding.”

Dr. Kingston recently summarized her four years of trapping at the 36th Annual North American Symposium on Bat Research, held Oct. 18–21. She reported nearly 16,000 bat captures at five sites—probably one the most intensive studies of bat “assemblages” in the world, including 38 species in six families.

Bat assemblages generally include all of the bats in a given area. Dr. Kingston reported that bat assemblages in Krau Wildlife Reserve vary drastically from one site to another, and from one time to another. This finding poses new challenges for scientists studying the evolution of bats, as well as those trying to conserve bat populations in the face of deforestation and other threats.

Bats are a key component of Malaysian biodiversity, also providing valuable pollination, seed dispersal and insect removal. Dr. Kingston’s continued efforts will help local resource managers better manage this ancient rainforest and the diversity of animals it supports.

“Earthwatch volunteers have been vital to the success of the project on so many levels,” she says. “Not only does their labor make a major contribution to the somewhat arduous art of bat-catching, but their enthusiasm, curiosity and appreciation buoys up the whole research team.”

Earthwatch teams will return to Malaysia to help Dr. Kingston next March, April and July. For more information about the Malaysian Bat Conservation project, click here.

And be sure to watch A Year on Earth, a two-part special that will debut on the Discovery Kids Channel on Dec.  3 and 10. It chronicles the adventures of three American teens who join Dr. Kingston in Malaysia, as well as Earthwatch research projects around the world.

Photo by Stephen Rossiter/Earthwatch