Recovery Strategy for the Baikal Sedge in Canada [Proposed] 2011: Threats

* The threat of invasive species is listed as ‘High’ to highlight the need for vigilance due to the potential for significant impacts to populations should invasive species be permitted to take hold. Continued monitoring and early action can keep this threat from ever truly becoming a concern.

The establishment of invasive plant species in Yukon sand habitats is perhaps the greatest potential threat to Canada's Baikal Sedge populations. At this time, invasive dune stabilizers such as Leymus angustus (Altai Wild Rye) are beginning to encroach upon Baikal Sedge habitat in the Carcross Dunes area. Melilotus officinalis (sweet clover) is also beginning to invade the Dezadeash River corridor and it could move toward the populations found along the Alsek River. Both of these invasive species could out-compete Baikal Sedge since they also thrive in loose sand. Based on our knowledge of the behavior of these invasive species in other jurisdictions, the effects of their establishment at the Baikal Sedge sites could be significant in a very short time period. This type of threat requires a rapid, proactive control program to prevent it from occurring.

Recreational use is not a threat for Baikal Sedge populations in Kluane National Park and Reserve. The dunes located in Taye Lakes, Dezadeash, Rose Creek and on the northeast side of the Takhini River are also fairly inaccessible and are not visited by humans very often. The Champagne sites are within reach of the highway and the community of Champagne, but currently do not experience much human use. Recreational use may pose a problem for the 4 populations that are easily accessed: the southwest side of the Takhini River, the Carcross Dunes, Whitehorse-Riverdale and Robinson. Use of motorized recreational vehicles in the dunes can compact the sand and directly kill ramets. This is of particular concern in the Carcross Dunes, where recreational vehicle use is prevalent. The Takhini River sites will soon be part of the new Kusawa Territorial Park, which may have specific management approaches laid out in the park's management plan, and municipal regulations prohibit vehicle use at the Riverdale site.

Since 2007, a local tour company has been offering summer ATV excursions through the ‘Carcross Desert' near the Klondike Highway. Most of these are packaged tours for Holland America cruise ship passengers, and it appears the tours generally follow the same route each time. In addition to this commercial venture, individual citizens also use the Carcross Dunes on a regular basis for ATV recreation in summer. The Whitehorse-Riverdale Dunes are a heavily used recreational area for biking, tobogganing, snowmobiles and ATVs, although municipal regulations prohibit vehicle use. The level of impact of recreational activities, especially vehicle use, on the Carcross and Whitehorse-Riverdale Dunes is unknown. Efforts must be made to determine what the impacts are to sedge populations of varying levels of recreational activity.

Snowmobiles are also used extensively in the Carcross Dunes. It is estimated that up to 30 snow machines can be using the dunes during a given winter weekend (Barrett pers. com.). While the snow machines are using the dunes primarily when they are covered with snow, they may have a compacting effect. Erosion of sand along the crest of dunes has been observed in Carcross. Again, the impacts of these activities on the sedge are unclear, and more monitoring would be required to develop a clearer understanding of the effects of snow machines.

Four of the 14 Baikal Sedge populations in Yukon are located in either national or territorial parks, so development in these areas is strictly controlled. There are a variety of landowners at the other sites, including private, First Nation, municipal and the crown. Two of the 14 populations occur right in town sites – Carcross and Whitehorse-Riverdale.

Community and economic development initiatives are important to the people of Carcross. Over the years, a few initiatives have been proposed that could impact the dunes and, subsequently, the sedge. As part of their Land Claims agreement, the Carcross Tagish First Nation owns as settlement land a waterfront portion of the Carcross Dunes; the First Nation may use this parcel for residential development. This land parcel is within Baikal Sedge habitat, and if development occurred at the site, it would destroy plants in the immediate vicinity and could impact habitat downwind of the site. As well, a hotel complex was proposed for the northwest corner of the Carcross dunes, but the project has not come to fruition. This development could also have impacts on the Baikal Sedge populations at this site.

One initiative that has occurred is the expansion of railway service between Carcross and the port of Skagway. This has meant larger numbers of tourists visiting the area during the summer months. The White Pass & Yukon Route Railway Company owns a significant portion of the Carcross dunes and it is not known whether the company plans to use these lands for future tourism opportunities. The Yukon Government Historic Sites Unit (Cultural Services Branch) has recently contacted the Carcross community to discuss future options for developing tourism, which may include ecotourism.

The Yukon government is working with Carcross Tagish First Nation and the community of Carcross to develop a local area plan and to update the existing zoning regulations for the area. New zoning regulations will implement the results of the local area planning process and could include recovery strategies (such as the Baikal Sedge recovery strategy).

The Whitehorse-Riverdale Baikal Sedge site is a recent discovery and we have yet to evaluate the full range of land uses at this site. This population is very small and requires a population and area of occupancy assessment.

One of the longer-term threats to Baikal Sedge in Yukon is habitat loss due to natural succession - encroachment by and competition from other plant species. This could be the result of a variety of factors, including the sedges themselves creating a stable environment for other species to take hold in the absence of sufficient natural disturbance. Vegetation encroachment is less likely to take place in areas where natural disturbance cycles provide a source of loose sand for early successional species like Baikal Sedge. The speed with which this process is taking place at the Baikal sedge dune sites in Yukon is unclear and requires further study.

Climate change is another threat that might affect some of the dune-forming influences such as wind speed, rainfall and temperature at a local scale. Climate change and subsequent glacial melt may pose a particular concern for the large populations located along the Alsek River. At this time, the full extent of climate change and its effects on Baikal Sedge habitat are unknown. Continued monitoring of sites and climate patterns will help provide a better understanding of these changes.

Planetella lironis is a smut fungus that infects the seeds of the sedge. The fungus has been documented in most Baikal Sedge populations. It is unclear how the fungus affects the overall survival of the plant. This species of smut fungus is very host-specific, suggesting a long-term evolutionary relationship. There are likely mechanisms in place such that the fungus parasitizes but doesn't kill its host outright. Further research is needed to determine what affects the fungus has on seed production and viability. The overall severity of the threat is probably low.

Baikal Sedge is naturally rare in Canada, occurring as isolated populations within a restricted geographic area. Inventory work since the COSEWIC assessment in 2005 has shown that there are nearly three times as many populations in Canada as originally thought. For this and other reasons described in this strategy, the species no longer meets COSEWIC's published criteria for an assessment of Threatened.

The population objective for Baikal Sedge is to maintain at least 11 of the known populations in Yukon. Species found at 10 or fewer locations may be assessed as Threatened under criterion B (small distribution range & decline or fluctuation) of COSEWIC's 2010 assessment criteria, and our goal is eventual down-listing of the species. To prevent declines in the total number of mature individuals and the current area of occupancy, the populations to be maintained should include those with plants in a vigorous state of health in dunes with sufficient natural processes (ie/ wind) required to maintain suitable habitat over the long term. The distribution objective is to prevent a decline in the extent of occurrence, by maintaining populations across the currently known range of the species in Yukon. Each dune ecosystem will be managed collaboratively to the extent possible to ensure the long-term persistence of healthy populations throughout the range.

The key threats to Baikal Sedge in Yukon are 1) the potential for invasion by exotic species that exclude native vegetation, 2) recreational use with motorized vehicles (ie/ ATVs etc), 3) development and 4) natural succession. Three of the 14 known populations are subject to significant recreational use by motor vehicles (Carcross, Whithorse-Riverdale and Kusawa West), however one (the Kusawa West population) will shortly be designated as a Territorial Park. Five other populations are within relatively close proximity to human habitation and could become subject to threats from motor vehicle use or development in the future. Several other populations are either protected or found in remote areas away from most of the threats. Natural succession is the only threat not caused by human uses.

• Complete inventory of the few remaining candidate dune systems and determine if new populations exist.
  
• Map Baikal Sedge distribution in Yukon and determine areas of occupancy at each location.
  
• Minimize or mitigate the threat of invasive species (including Leymus angustus, Melilotus officinalis (a.k.a. Melilotus alba)) before they take hold at any of the dune sites.
  
• Ensure that Baikal Sedge considerations are included in all relevant land and species management planning processes within the species' range in Yukon.
  
• Implement stewardship and public education/communications about Baikal Sedge to increase public support and stewardship activities for Baikal Sedge and sand dune ecosystems.
  
• Fill critical knowledge gaps regarding threats to Baikal Sedge, especially the impacts of recreational use as well as the long-term impacts of natural processes on the viability of sedge populations in Yukon.

The recovery team for Baikal Sedge includes federal, territorial and First Nation governments, conservation organizations and community groups. Over the past few years, as awareness of the sedge has increased, a series of actions have been taken by the different groups to learn more about the sedge and to raise awareness about its importance.

In 2006, Parks Canada in partnership with the Yukon government conducted an inventory of Baikal Sedge sites found within Kluane National Park and Reserve. This survey led to the discovery of a second small site within the park, 18 km south of the already identified Alsek dunes. Samples of smut fungus were gathered as part of this inventory and sent to Agriculture and Agri-Food Canada for analysis.

Further research was conducted by the Yukon government in 2007, including inventory at four known Baikal Sedge sites. Parks Canada, the Yukon government and the Canadian Museum of Nature also began a population genetics study that includes information from the initial six sites. The purpose of this study is to determine the levels of genetic diversity at each site and also to compare diversity among the sites. It is hoped that this study will shed some light on the amount of cloning within each population. Understanding how important asexual reproduction is to Baikal Sedge populations may also assist in estimating numbers of individuals within each population.

Also in 2007, the Yukon government, in partnership with the Carcross-Tagish First Nation and the Yukon Conservation Society, received funding from the federal Habitat Stewardship Program to begin community outreach and data collection for recovery planning. Interpretive hikes, which targeted locals and special interest groups, were held throughout the summer. Five local youth were trained to use GPS and conducted plant surveys of the sedge in the Carcross Dunes. This was primarily an educational exercise and did not establish defensible information on critical habitat for Baikal Sedge, but provided insight into the overall distribution of the sedge in the Carcross Dunes.

In 2008 and 2009, the population genetics study continued with the Canadian Museum of Nature. Parks Canada and the Yukon government also began work with the University of Alaska to gain a better understanding of Baikal Sedge seed viability. Further work on the smut fungus was carried out by Agriculture and Agri-Food Canada. Some initial work on invasive species removal was carried out in the Carcross Dunes area. Analyses of these data are ongoing.

Several First Nations in southern Yukon received funding from the Aboriginal Funds for Species at Risk in 2009 and 2010 to collect traditional knowledge on Baikal Sedge and sand dune ecosystems, to perform some inventory work, and to report back to the communities. This work was carried out successfully for the most part, and in addition to adding new sites to the known distribution, resulted in increased awareness of the sedge in many communities throughout the species' range.

Several additional new Baikal Sedge populations were discovered during Environment Canada surveys for the Dune Tachinid Fly (Germaria angustata (Zett.)) in 2009.

¹ Level of Concern: signifies that managing the threat is of (high, medium or low) concern for the recovery of the species, consistent with the population and distribution objectives. This criterion considers the assessment of all the information in the table).

² Severity: reflects the population-level effect (High: very large population-level effect, Moderate, Low, Unknown).

³ Causal certainty: reflects the degree of evidence that is known for the threat (High: available evidence strongly links the threat to stresses on population viability; Medium: there is a correlation between the threat and population viability e.g. expert opinion; Low: the threat is assumed or plausible).