Nahanni Aster | NWT Species at Risk

Nahanni Aster

Symphyotrichum nahanniense

NWT List of Species at Risk:

No status

NWT SARC Assessment:

Not assessed

Federal Species at Risk Act list:

Special Concern

COSEWIC Assessment:

Special Concern

NWT General Status Rank:

Sensitive

Description:

Nahanni Aster is a perennial wildflower. Its flowers have yellow centres and white to pale pink or purple petals. It typically grows in clumps of about two to ten stems which are green to reddish and often have fine woolly hairs towards the base. The stems are branched to form an open cluster of flowers. Nahanni Aster is similar in appearance to the Rush Aster (Symphyotrichum boreale) which also occurs in the Nahanni area.

Height: up to 35 cm (13.8 in)

Report Nahanni Aster sightings to WILDLIFEOBS@gov.nt.ca

Distribution

Nahanni Aster is a rare flowering plant found only in Nahanni National Park Reserve, in the southern Mackenzie Mountains of the NWT.

Range map information

Habitat and biology

Nahanni Aster is found at hot and warm springs with tufa (calcium carbonate deposits) within Nahanni National Park Reserve. It thrives around the edge of thermal springs and along the streams and seepage discharging from the springs. It is usually rooted in moss, but has also been found in broken old tufa and dense turf with rushes and sedges. Nahanni Aster grows in open areas, unshaded by shrubs or trees.

Nahanni Aster may have persisted through the last ice age in an ice-free refugium, or it may have evolved about 11,000 years ago when the Nahanni area was ice-free but the surrounding region was still covered by ice.

Population size and trends

Nahanni Aster is confined to seven known sites at thermal springs that are associated with two major geological faults. All Nahanni Aster sites are within about 150 km of each other.

In 2019, a survey was done to monitor and map the extent of previously known sites and explore other thermal springs in the area. A new Nahanni Aster population was discovered in 2019, bringing the total number to seven. Parks Canada will continue to learn more about this species and monitor typical Nahanni Aster habitat in search of potential new populations.

Threats

Nahanni Aster faces little direct threat from human activities because it occurs in remote locations within a national park reserve. Potential threats include climate change and seismic activity that could alter groundwater discharge and lead to changes in the habitat, trampling by Park visitors or researchers, or accidental introduction of invasive non-native plant species. Nahanni Aster is found at very few sites, so a random environmental event such as an earthquake, fire, or landslide could potentially have a large impact on the population.

Protection and recovery

Nahanni Aster is found only within Nahanni National Park Reserve.

In 2014, the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assessed Nahanni Aster as a species of Special Concern. Nahanni Aster was listed as Special Concern under the federal Species at Risk Act in 2018.

A national management plan for Nahanni Aster is available on the federal Species at Risk Public Registry.

Gallery:

Area:

Dehcho