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COSEWIC Assessment and Status Report on the Baikal Sedge in Canada

Limiting Factors and Threats

The greatest threat to the persistence of populations ofCarex sabulosa would be through natural changes to the dune systems. At the Kaskawulsh/Dezadeash river dunes, the Carex sabulosa plant community likely leads a precarious existence. Changes to the habitat could come through natural succession or climate change that might affect the glaciers, and subsequent changes in wind speeds, along the Alsek River.

Threats of disturbance from recreational use are of little concern at the Kaskawulsh/Dezadeash or Takhini River (north) dunes. The former is located in the Kluane National Park Reserve while the latter is accessible only by canoe and is not visible from the river. The remaining three systems may be threatened with increased recreation vehicle use. Carex sabulosa clones at these sites are not drastically impacted with light use since the root and rhizome system is relatively deep (Figure 10) and not disturbed by minimal surface disturbance. Heavy use, however, which packs the sand, can eliminate C. sabulosa clones. This compaction, and subsequent elimination of vegetation, is most evident at the Klondike Highway dunes (Figures 11 and 12).

Figure 11: Heavy Recreational Vehicle Use, Which Packs the Sand and Eliminates Carex sabulosa Clones, is Evident Here on the Klondike Highway Dunes, Near Carcross

Figure 11: Heavy recreational vehicle use, which packs the sand and eliminates Carex sabulosa clones, is evident here on the Klondike Highway dunes, near Carcross.

The vegetation on either side of the tracks, which has received lighter use, is able to persist (Photo by S.J. Smith, Douglas Ecological Consultants Ltd.).

Figure 12: Recreational Use by an All-terrain Vehicle on the Klondike Highway Dune System Near the Town of Carcross

Figure 12: Recreational use by an all-terrain vehicle on the Klondike Highway dune system near the town of Carcross.

Photo by S.J. Smith, Douglas Ecological Consultants Ltd.

At the Carcross Klondike Highway dunes, there is the imminent threat of development of a large hotel and resort complex to be completed in 2006. This development could change wind patterns or sand distribution and dune stabilization at this site and would almost certainly lead to vegetation invasion. Increased recreational use of the dunes would also result from the regular, scheduled, tourist stops of the White Pass Railroad at Carcross planned as part of the recent federal and territorial initiatives aimed at increasing economic growth and tourism in the area in 2006.

Another potential threat to the populations of C. sabulosa is their vulnerability to extirpation due to their small area occupied in Canada. Such geographically restricted populations are more vulnerable to demographic and environmental variation and loss of genetic variability (Primack 1998). Since suitable habitats for C. sabulosa are also extremely restricted, the opportunities for colonization and expansion are also limited.