Recovery Strategy for the Baikal Sedge in Canada [Proposed] 2011: Species Information
Date of Assessment: May 2005
Common Name (population): Baikal Sedge
Scientific Name: Carex sabulosa
COSEWIC Status: Threatened
Reason for Designation: A geographically restricted species of three sand dune areas that serve as habitat for five populations. These consist of several million shoots produced mainly through asexual reproduction. The species has been impacted by declines in population numbers, size, area, quality of its habitat and on-going impacts from recreational use of all-terrain vehicles at Carcross and Bennett Lake. Such activity and much increased tourist visitations at the Carcross dune system may result in increased impacts on the habitat with the development of a major resort facility at this location. If the Alsek River is dammed again by the advance of the Lowell Glacier, as had occurred in recent past, the large population at the confluence of the Dezadeash and Kaskawulsh Rivers could be at risk.
Canadian Occurrence: Yukon Territory
COSEWIC Status History: Designated Threatened in 2005. Assessment based on a new status report.
In North America, Baikal Sedge populations have been identified in four separate large valleys in southwest Yukon and in one area in central Alaska. There are other populations more than 3000 km away in central Asia (COSEWIC 2005).
Baikal Sedge has a naturally restricted extent of occurrence and area of occupancy in Canada. At the time of initial assessment by COSEWIC, there were only 5 known populations. Baikal Sedge was assessed as threatened because of 1) a very small extent of occurrence (ca. 200 km²) and area of occupancy (<1 km²), combined with declines in area of occupancy, quality of habitat, and number of mature plants resulting especially from recreational use of the sand dune habitat, 2) the presence of only 5 populations and on-going and imminent threat from recreational activities, particularly at the Carcross dunes (affecting two of the original 5 populations), and 3) the possibility that the Lowell Glacier could advance and dam the Alsek River, thereby affecting the Alsek sedge population (representing 75% of the plants in Canada).
In the years since the initial COSEWIC assessment in 2005, 10 additional Baikal Sedge populations have been discovered.As well, the two Carcross populations and the two Takhini populations described in the COSEWIC report were re-evaluated and are now considered to be single populations (using NatureServe criteria). A total of 14 populations have now been reported in Canada. Population trend and area of occupancy were listed as declining (1-2% and 2-3% respectively) in the COSEWIC status report, however these metrics should be re-evaluated in light of the discovery of several new populations. In addition, the Lowell Glacier has receded substantially in recent years, significantly decreasing the risk of the glacier advancing enough to dam the Alsek River. Because of 1) the increased number of populations now known to occur in Yukon (only three of which are currently threatened by recreational use or development), 2) the increased population trend and area of occupancy due to the discovery of new populations, and 3) the decreased risk of glacial advance, Baikal Sedge no longer meets the COSEWIC criteria for Threatened status.
Baikal Sedge, (Carex sabulosa), is a perennial plant that grows in northern dune environments. The plant has a long, thin triangular stem that can be between 15 and 35 centimeters long. Small clusters of cream-coloured flowers grow on three to five spikes that emerge from the top few centimetres of the stem. The top or terminal spike is club-shaped and has female flowers positioned above the male flowers while the remaining lateral spikes have only female flowers (Ball & Reznicek 2003). As the flowers mature and go to seed, the stems get weighed down by the drooping fruiting heads and take on a characteristic “arched” appearance. The seeds are enclosed in a cream-coloured balloon-like structure called a perigynium.
The leaves of the sedge are thin and look almost like grass. Dried leaves become curly and may persist for several growing seasons. Baikal Sedge has long rhizomes, a horizontal root system that sends out shoots to create more plants. As a result, one plant can populate a large area.
Baikal Sedge can be found growing alongside another, more common sedge, Carex maritima. They can be difficult to distinguish from one another so care must be taken in identifying Baikal Sedge. For a more detailed taxonomic description, see "Flora of N. America".
Baikal Sedge is distributed across Russia, Kazakhstan, and Mongolia, but is only found at a few sites in North America (COSEWIC 2005). These include one population found in central Alaska and 14 in Yukon. Baikal Sedge was likely more common in Yukon and Alaska at the end of the last ice age when open sand dune habitat was more plentiful. Glacial lakes, glacial rivers and strong winds moved sand deposits across the landscape. Populations of this plant were probably equally dynamic, with seed and plant fragments being dispersed over long distances by these same mechanisms.
In Yukon, Baikal Sedge has been identified at 14 separate sites (Figure 1 and Table 2). These include two within Kluane National Park and Reserve: one at Alsek Dunes at the confluence of the Kaskawalsh, Dezadeash and Alsek Rivers (identified in the COSEWIC status report); and a smaller dune system about 18 kilometers south on the Alsek River (Line and Freese, 2006). Another two sites are located within Kusawa Territorial Park along the Takhini River. The Carcross Dunes near the community of Carcross and two sandy areas near Robinson are each home to Baikal Sedge populations. The Carcross population is split by a highway and was listed as two separate populations in the COSEWIC status report, however it is now considered to be a single population using the NatureServe criteria. Recent inventory work in the area revealed that the Robinson population was significantly larger than originally thought. In addition, populations have been identified at the following locations: Dezadeash Lake, Champagne (three separate populations), Taye Lakes (two populations), Rose Creek and Riverdale (Whitehorse) (Line 2010).
Two sites where Baikal Sedge had been collected in the past were also surveyed during the 2009-2010 inventory work to determine if the populations may have persisted undetected in recent years. These were Christmas Bay on Kluane Lake, originally located by V.C. Brink in 1974, and an unidentified location near Kusawa Lake originally located by C.A. Kennedy in 1985. Neither the Kusawa nor the Christmas Bay populations could be re-located during surveys, although at least one local resident thought they had recently seen the plant at Christmas Bay.
There are other small dune systems in southern and western Yukon, and inventory work is ongoing to find additional populations in the region. Traditional knowledge studies have been carried out by Yukon First Nations and several other potential sites have been identified for further surveys in 2011.
Figure 1: Locations of Baikal Sedge in Yukon
© Parks Canada
Sources: COSEWIC status report (2005), Line and Freese (2006), Line (2010), Line (2011)
Baikal Sedge is predominantly found in areas where there are active, shifting sand dunes. The sand is loose and deep, usually 0.5 to 4 meters (COSEWIC 2005). The Yukon populations are found in areas close to the coastal mountains and glaciers where strong cold winds consistently blow. These environments are remnants of ice age landscapes when large glaciers and lakes covered much of the region. The winds and cool microclimates are important for the persistence of these dune environments.
Blowing sand is a common element of Baikal Sedge habitat, and the plant has the ability to send out new clones if older ones get buried. It is possible that patches of ramets shift location within the dune over time, which may mean that the plant requires a large area in order to maintain its population. In Yukon, the largest population by far (75% of the estimated total current population in Yukon) is found at Alsek Dunes, near the confluence of the Alsek and Kaskawulsh Rivers in Kluane National Park and Reserve. This area was flooded by glacial Lake Alsek, which was created when the Lowell Glacier dammed the Alsek River. When the glacier retreated 150 years ago, the lake completely drained and only the river now remains. The Alsek river valley therefore contains relatively young populations of Baikal Sedge. Approximately 3 million Baikal Sedge plants are now growing at this site (Line and Freese 2006).
It appears that Yukon's Baikal Sedge populations are maintained predominantly by asexual reproduction (rhizomes or horizontal root systems produce clones) (Line and Freese 2006). Clones from one plant can cover a large area, which means there may not be many individual plants. Initial results from a population genetics study indicate that there is limited genetic variation, which points to cloning, but that there is some genetic variation within the population (Jeff Saarela pers. com). However, additional work must be done in order to verify these findings. It is also unclear whether sexual reproduction takes place (i.e. viable seed is produced) with any frequency. If sexual reproduction is low, the Yukon populations may have low genetic diversity, making them more vulnerable to environmental change (Line and Freese 2006). In addition, the compaction of sand, through development or recreational activities, could limit the sedge's ability to reproduce by reducing the area where rhizomes could take hold.
Baikal Sedge plays an important role in stabilizing sand dunes. These plants are usually some of the first to colonize loose sandy areas and, through their root systems, create an environment that allows for the establishment of other plants. The sedge may also be important to the overall dune ecosystem. At this time, it is unknown if it is significant in the life cycle of other dune insects, plants or soil microorganisms.
Research on eolian deposits in the territory suggests sand dunes were common in Yukon and other northern landscapes during the last ice age (Stephen Wolfe, pers. com.). Most of these dunes have since been covered by Boreal forest through natural succession. As Baikal Sedge roots stabilize the loose open sand, Boreal plants are able to establish and eventually out-compete the specialized sedge. This natural process may affect the long-term viability of some Baikal Sedge populations. Recent inventory work has focused on the remaining open eolian deposits, resulting in the discovery of several new sedge populations. As more of these dune environments disappear through natural succession, there are fewer sites where Baikal Sedge can flourish.