When they began doing research there in 1995, biologists suspected that the southeast Yukon would turn out to be an interesting corner of the territory. Their instincts about this relatively unknown area were proven to be right. During five years of research, they found a host of animals and plants that no one had seen before in the Yukon.

More than 20 species have been documented there that previously were not known to live in the Yukon, including Devil's Club, Philadelphia Vireo, and Chorus Frog. Large numbers of black bears roam the area, and healthy populations of bull trout swim in the streams.

Cameron Eckert, a conservation biologist with the Yukon Government, is helping to write a technical report on the vegetation and birds of the La Biche and Beaver River valleys. The information will be used to help with management decisions in the area, as industrial development is on the rise there.

Eckert says that he could tell that the La Biche area was going to be something special as soon as he arrived there. "We were simply blown away by the abundance and diversity that we found there. Just stepping off of the plane it was obvious," he says.

For Eckert, the richness of the bird life there is obvious even with your eyes closed. "To walk through a Yukon forest at dawn in June and be confronted with a wall of song is not something that you would experience in the Whitehorse area. You do not feel like you are in the boreal forest typical of the rest of the Yukon."

Many of the songbird species found there are at the extreme northwest end of their ranges on this continent, and some are considered threatened or declining in other parts of their range. Species like the Rose-breasted Grosbeak, Canada Warbler, and Bay-breasted Warbler were known to occur in northeastern British Columbia, but not in the Yukon.

While these songbirds are abundant in the extreme southeast Yukon, they do not make it much further west. "One of the curious things with some of these species is that they are abundant at the very edge of their range. In the La Biche there can be Red-eyed Vireos everywhere and they you go 50 kilometres to the west and there is not a one. They are extremely plentiful there, and then it is like they fall off a cliff," he says.

This sort of abundance at the edge of a species' range is unusual, and biologists assume that habitat has a lot to do with it. The mixed forest growing there is not typical for the Yukon. Large balsam poplar and trembling aspen are plentiful, even well away from the rivers, and the undergrowth is dense. About 500 of the 1176 known plant species in the Yukon are found in the La Biche and Beaver River Valleys.

Mike Gill, a Canadian Wildlife Service biologist, is also working on the technical report. He describes the woods in the lower La Biche valley as so wet and lush that it is easy to imagine that you are walking through a coastal forest. The trees are also big, largely due to the fact that there have been no major forest fires in these lowland forests for at least 250 years.

The region gets about the same amount of annual precipitation as does Watson Lake, but more of its rain falls in the summer when forest fires are a threat. Gill says that when flying into the area, he would often leave behind the typically clear summer skies as soon as the plane got close to the La Biche.

"When you drop into the La Biche it is frequently filled with low clouds, so this is not just a difference that you see on a chart. You actually see how much wetter it is there in the summer," he says.

Geography probably accounts for the area's astonishing diversity. It is located at the boundary of the western mountains and the lowland plains to the east, and species typical of both these zones are found in abundance in the southeast Yukon.

The big trees in the area are also of interest for the logging industry; as well, oil and gas exploration is increasing in the southeast Yukon. Ensuring that the region's unique ecology is protected will be a balancing act, but some initial efforts have been made.

Numerous parties -- including the federal and territorial governments and private stakeholders -- worked together on a forest ecosystem network for the area. It is designed to ensure that the long-term health of the region's biological communities is protected. This plan has not yet been implemented, as the Department of Indian Affairs and Northern Development wants more public consultation before it decides on specific boundaries for a network in the area.

The five years of research will be used to support future management decisions in the area, but the biologists do not think that they have come close to learning all there is to know about the southeast Yukon. "There was no end to the discoveries that we were making in the area, and there are still huge areas that have not been surveyed," says Eckert.

Cameron Eckert can be reached at cameron.eckert@gov.yk.ca. Mike Gill can be reached at mike.gill@ec.gc.ca.