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COSEWIC Assessment and Status Report on the Baikal Sedge in Canada

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COSEWIC
Executive Summary

Baikal Sedge
Carex sabulosa

Species Information

Baikal sedge, Carex sabulosa, is a tufted perennial plant with long rhizomes. The stems are 15-35 cm long, weak, arching, with mature fruiting heads often touching the ground. The 1-3.5 mm wide leaves are thick at the base, grayish-green, flat with margins curled inward. The leaves have purplish sheaths and are mostly shorter than the stems. The 2-5 cm long inflorescence consists of 3 to 5 spikes. The club-shaped terminal spike has female flowers positioned above the male flowers while the lateral spikes have female flowers only.

 

Distribution

In North America, Carex sabulosa occurs at four areas in southwestern Yukon and one in central Alaska. It is then disjunct to central Asia, over 3000 km away. In Canada, Carex sabulosa has recently been confirmed in the Yukon in Kluane National Park Reserve near the Kaskawulsh/Dezadeash Rivers, at two sites along the Takhini River, and at two sites near the town of Carcross. A fourth location, at Christmas Bay, Kluane Lake could not be reconfirmed and is considered historic.

 

Habitat

Carex sabulosa occurs on semi-stabilized and active sand dunes where it is often the only prominent species. Associates may include Elymus calderii, Artemisia alaskana, A. campestris, Aster sibiricus, Bromus pumpellianus, Calamagrostis purpurascens, Equisetum arvense, Festuca saximontana, Kobresia myosuroides, Lupinus kuschei, Oxytropis campestris, Pinus contorta, Populus balsamifera, Polemonium pulcherrimum, Silene acaulis and Solidago simplex.

 

Biology

The biology of Carex sabulosa has not been studied. It is evident, however, that this species can withstand high, desiccating winds. Reproduction of Carex sabulosa is by seed and rhizomes.

 

Population Sizes and Trends

Carex sabulosa has been recently recorded on five dune systems, at three areas, in the Yukon. A search was made for a historic site but it was not relocated during 2003.

The largest dune system in the southern Yukon, covering almost 40 ha, is found near the confluences of the Kaskawulsh/Dezadeash rivers in Kluane National Park. Estimates of ramet numbers range from three to four million at this site. The Carcross dune systems had ramet numbers ranging from 38 to 196 thousand covering areas of 4.8 to 13.1 ha while the Takhini River dune systems had ramet numbers ranging from 168 to 294 thousand covering areas of 8.4 to 9.6 ha.

Population trends at all but the two Carcross dune systems have probably remained stable in recent years since there has been little change at the dunes. Clones of Carex sabulosa have probably declined in recent years at the Carcross systems due both to reductions in dune system size and recreational vehicles.

 

Limiting Factors and Threats

The greatest threat to the persistence of populations of Carex sabulosa would be through natural changes to the dune systems, especially at the Kaskawulsh/Dezadeash rivers dunes. Climate changes that affect the glaciers, and subsequently wind speeds, could result in drastic alterations to the dune systems, such as successional changes.

Threats of disturbance from recreational vehicles are of concern at the Takhini River (south) and Carcross dune systems. Carex sabulosa clones at these sites are threatened by heavy use, which packs the sand and eliminates the clones.

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.

 

Special Significance of the Species

Carex sabulosa occurs in a sand dune ecosystem that is no longer common in the Yukon or Canada. The potential sites for the plant are restricted; thus the plant is rare. In addition, the populations are of possible genetic interest since they are at the eastern periphery of a range that extends from central Asia to the southwestern Yukon.This sedge occurs on lands under Aboriginal jurisdiction in the Yukon Territory. Although no information on this species was found in a major ethnobotany database, other species of Carex are used extensively by Aboriginal peoples in North America.

 

Existing Protection or Other Status Designations

In Canada, Carex sabulosa is protected in the Kluane National Park Reserve; the Takhini River dune system will be protected in the proposed Kusawa Territorial Park. Elsewhere it occurs on Crown land where only a special federal order can protect the species under the Species at Risk Act.