When Benoit Godin began trapping spiders last summer, he didn't expect to break scientific ground. But it happened.

The Environment Canada scientist was looking for an efficient way to monitor the health and status of forests. He thought insects and similar invertebrates might provide a useful tool.

One of the most common and effective ways of monitoring aquatic systems like lakes and streams, Godin explains, is to look at the tiny creatures, the invertebrates, who live in and near the bottoms of water bodies.

Their life cycles are short and they depend on the resources provided by the water in which they live. If something changes in the quality or quantity of that water, the impact tends to show up fairly quickly in the size and mix of local invertebrate populations.

Godin hoped the same technique might be used to monitor the status and health of forest ecosystems.

"We were looking for small species that will respond to environmental change clearly in a matter of a few years," he says. Insects and related animals might be the answer, but simply collecting all insects wouldn't work.

"There are so many insects all over the place, that it would be a daunting task," he explains.

Godin and his Environment Canada colleague, Doug Davidge, decided to narrow their quarry to beetles and spiders. Because there are fewer beetles and spiders in terms of sheer numbers than other insects like mosquitoes or flies, it should be easier to see population trends, they reasoned.

"We chose beetles because they are the most diverse type of organism in the world," says Godin. They live in a wide variety of environments and have developed a rich assortment of adaptations to deal with the specific conditions of those environments. If the conditions change, the impact should show up in the health and mix of beetle species.

They also decided to look at spiders. Spiders are the top predators in the invertebrate world, and the Yukon has a good variety of spiders, with about 300 recorded species. In addition, spiders move by walking, remaining in a relatively small area, which makes them a good indicator of local conditions. If the state of the forest changes enough to affect other invertebrate populations, explains Godin, the change should show up in the populations of the spiders that prey on them.

With their quarry chosen, Godin and Davidge set out their traps. In that first season, Godin says, they were simply experimenting with trapping techniques and locations, trying to see if the idea would work. To keep costs down, they did most of their trapping close to their Whitehorse base -- in the Wolf Creek area, along the Fish Lake and Long Lake roads, and right near Environment Canada's offices on the Alaska Highway.

Their trapping technique is low-cost and low-tech, requiring two beer cups per trap and a little water, soap and preservative.

"Basically, it's a hole in the ground," says Godin. "You put two beer cups in it, one inside another, so that you can take one out without collapsing the hole."

The inside beer cup contains water, liquid soap to break the surface tension, and a bit of preservative to keep the creatures that fall into it from deteriorating. The traps are checked every two weeks and the specimens collected. When time permits, they are sorted. When money permits, they are shipped off to experts for identification.

With only a small percentage of the samples identified so far, the results are already exciting. For example, one recently-analyzed sample has dramatically expanded our knowledge of Yukon spiders.

The sample contained nine species of spiders that had never before been recorded in the Yukon, bringing the total of spider species identified from the traps to 95 and counting. Even better, the sample contained one spider that is entirely new to science.

"It still needs to be described scientifically," says Godin. "It was found at the EMAN [Environmental Monitoring and Assessment Network] plot near the Wolf Creek cadet camp."

While the main purpose of the trapping is to develop a tool for assessing forests, finding new species is also important, he says.

"It's also a question of biodiversity, of looking at what we have here in the Yukon."

For more information about environmental monitoring, contact Benoit Godin at Environment Canada, Whitehorse, (867) 667-3402.