Scientific Name: Symphyotrichum nahanniense
Taxonomy Group: Vascular Plants
Range: Northwest Territories
Last COSEWIC Assessment: May 2014
Last COSEWIC Designation: Special Concern
SARA Status: No schedule, No Status
Nahanni Aster is a perennial wildflower up to 35 cm tall with white to pale pink flower heads. It typically grows in clumps of about two to ten stems from short, woody rhizomes (horizontal underground stems). The stems are branched to form an open panicle typically with one to three flower heads, but some plants have 15 or more. The number of flower heads appears to vary between sites and may be determined by growing conditions. The stems are green to reddish, often with fine woolly hairs, especially towards the base. Each flower head consists of a yellow disc, surrounded by 15 to 41 white to pale pink rays. Nahanni Aster is endemic to Canada and found only in Nahanni National Park Reserve. It may have evolved here when this part of the Mackenzie Mountains remained unglaciated while the surrounding region was still covered by ice until about 11,000 years ago. (Updated 2017/07/28)
Nahanni Aster is confined to six known sites in the southern Mackenzie Mountains of the Northwest Territories, within about 110 km of each other. The hot springs are mostly arranged along two major faults. The southeast – northwest trending Broken Skull Fault follows the valley of the South Nahanni River and lies beneath the Rabbitkettle Hotsprings. Another fault extends down the valley of the Flat River. (Updated 2017/07/28)
Nahanni Aster is found at hot and warm spring habitats with tufa (calcium carbonate deposits). Nahanni Aster grows around the edge of the springs and along the streams and seepage discharging from the spring. It is rooted in moss, but also occurs in broken old tufa and dense turf with various rushes and sedges and is typically unshaded by trees or shrubs. (Updated 2017/07/28)
Very little is known of the biology of Nahanni Aster. It is a perennial species forming clumps of flowering stems with multiple shoots. It reproduces both by seed and asexually using short rhizomes. Flowering occurs in August to September. Nahanni Aster occurs exclusively at a limited number of springs in a small geographic area, suggesting that it tolerates a narrow range of habitat conditions. Dispersal presumably occurs by wind-borne seeds, as is the case with other aster species. Dispersal between springs is probably limited by the scarcity of suitable habitat. (Updated 2017/07/28)
Nahanni Aster habitat is protected from industrial development and roads by its isolated habitat and protected status in the Nahanni National Park Reserve. Climate change is the most likely threat to Nahanni Aster habitat. The climate in Nahanni National Park Reserve is warming and rainfall patterns are changing. Changes in groundwater discharge at hot springs due to climate change and seismic activity are potential threats. Its extremely limited range (six occurrences covering less than 10 ha in total) make it vulnerable to random environmental events. (Updated 2017/07/28)
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
Nahanni Aster is a perennial wildflower up to 35 cm tall with white to pale pink flower heads. It typically grows in clumps of about two to ten stems from short, woody rhizomes (horizontal underground stems). The stems are branched to form an open panicle typically with one to three flower heads, but some plants have 15 or more. The number of flower heads appears to vary between sites and may be determined by growing conditions. The stems are green to reddish, often with fine woolly hairs, especially towards the base. Each flower head consists of a yellow disc, surrounded by 15 to 41 white to pale pink rays. Nahanni Aster is endemic to Canada and found only in Nahanni National Park Reserve. It may have evolved here when this part of the Mackenzie Mountains remained unglaciated while the surrounding region was still covered by ice until about 11,000 years ago.
The global population of this species is restricted to hot springs in Nahanni National Park Reserve. A very small range and population size make this endemic species susceptible to losses through natural alterations due to geothermal processes or to landslide events that may become more frequent as climate warms and permafrost melts.
His Excellency the Governor General in Council, on the recommendation of the Minister of the Environment, acknowledges receipt, on the making of this Order, of the assessments done pursuant to subsection 23(1) of the Species at Risk Act by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) with respect to the species set out in the annexed schedule.
Biodiversity is rapidly declining worldwide as species become extinct. Today’s extinction rate is estimated to be between 1 000 and 10 000 times higher than the natural rate. Biodiversity is positively related to ecosystem productivity, health and resiliency (i.e. the ability of an ecosystem to respond to changes or disturbances). Given the interdependency of species, a loss of biodiversity can lead to decreases in ecosystem function and services (e.g. natural processes such as pest control, pollination, coastal wave attenuation, temperature regulation and carbon fixing). These services are important to the health of Canadians, and also have important ties to Canada’s economy. Small changes within an ecosystem resulting in the loss of individuals and species can therefore result in adverse, irreversible and broad-ranging effects.
Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to "assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species".
COSEWIC held two Wildlife Species Assessment Meetings in this reporting year (October, 2013 to September, 2014) from November 24 to November 29, 2013 and from April 27 to May 2, 2014. During the current reporting period, COSEWIC assessed the status or reviewed the classification of 56 wildlife species.
The wildlife species assessment results for the 2012-2013 reporting period include the following:
Special Concern: 20
Data Deficient: 0
Not at Risk: 1
Of the 56 wildlife species examined, COSEWIC reviewed the classification of 40 that had been previously assessed. The review of classification for 25 of those wildlife species resulted in a confirmation of the same status as the previous assessment.
The Government of Canada is committed to preventing the disappearance of wildlife species at risk from our lands. As part of its strategy for realizing that commitment, on June 5, 2003, the Government of Canada proclaimed the Species at Risk Act (SARA). Attached to the Act is Schedule 1, the list of the species provided for under SARA, also called the List of Wildlife Species at Risk. Extirpated, Endangered and Threatened species on Schedule 1 benefit from the protection of prohibitions and recovery planning requirements under SARA. Special Concern species benefit from its management planning requirements. Schedule 1 has grown from the original 233 to 521 wildlife species at risk.
Please submit your comments byApril 15, 2015, for terrestrial species undergoing normal consultationsand byOctober 15, 2015, for terrestrial species undergoing extended consultations.For a description of the consultation paths these species will undergo, please see:Species at Risk Public Registry website