Wednesday, April 14, 2004
By David Suzuki

Recently, I wrote about a report from Birdlife International that described how birds around the world were in trouble. The authors noted that birds were an indicator species — canaries in the coal mine, you might say — and they argued that if birds were faring poorly, then other species and the environment in general probably weren't doing so hot either.

Just days after the report, results of a long-term study of bird, butterfly, and plant populations in Great Britain were published in the journal Science. The results confirmed that, in Great Britain at least, many bird species are indeed declining. But even more disturbing, the researchers found that birds and other vertebrates may not necessarily make good indicator species because lesser-known creatures, like insects, seem to be faring much worse.

For the Great Britain study, researchers looked through 15 million records of species amassed by some 20,000 volunteers. Over 40 years, these volunteers kept detailed records of more than 3,000 separate 10 square-kilometrer test areas across the country. Great Britain is the only place in the world where such detailed records have been maintained for so long.

After studying the data for a year, researchers concluded that 28 percent of plant species and 50 percent of bird species have disappeared from at least one study area. Butterflies fared the worst, with 71 percent of those species disappearing from at least one area over the past 20 years. In fact, two butterfly species went extinct from Britain during the study period, as did six native plants.

These findings are disturbing because insects account for more than half of the known species on the planet. According to the researchers, if insects are disappearing faster than birds, then biologists have actually been underestimating the loss of life on Earth, thus "strengthening the hypothesis that the natural world is experiencing the sixth major extinction event in its history."

While the last major extinction event occurred when an asteroid collided
with the planet some 60 million years ago, current extinction levels have a
much more mundane cause: human activities.

Sometimes the effects of these activities are obvious — like when we fill in a wetland to build a parking lot. Others are more subtle. For example, results of a study published in Science found that excess nitrogen from intensive agricultural production and air pollution in Great Britain is reducing plant biodiversity by creating conditions more favorable to plant species that are better adapted to high nutrient levels.

When most of us think of species extinction, we tend to think about the big, charismatic species that we feel an affinity towards, species like tigers, gorillas, and whales. But plants and insects form the backbone of biodiversity on the planet. To a certain extent, everyone else, including us, relies on them.

Humans evolved at a time of plenty on Earth. A stable climate, bountiful natural resources, high levels of life diversity and vibrant ecosystem services have all helped provide us with everything we needed to develop our modern society. By degrading these services and driving so many species to extinction, we put our own future in peril.

The good news is that if humans are causing the problem, we can still fix it. It won't be easy, but it's not impossible either.

Across Canada, municipalities are banning the cosmetic use of insecticides and herbicides. That will help. As we learned from the Great Britain plant study, reducing air pollution and developing more sustainable agricultural practices will help too. And Canada's new species at risk act will help, if it ever shows some teeth.

These are a start, but we have along way to go. If butterflies and plants are indeed canaries in the coalmine, we don't have any time to lose.

To discuss this topic with others, visit the discussion forum at the David Suzuki Foundation.

Source: David Suzuki Foundation