Houghton's goldenrod (Solidago houghtonii) COSEWIC assessment and status report: chapter 2

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Executive Summary

Species information

Houghton’s goldenrod (Solidago houghtonii) is about 30-60 cm high with slender reddish hairless stems, basal rosettes, linear leaves, and a flat-topped inflorescence consisting of 5 to 30 yellow flowering heads. It is most likely to be mistaken for grass-leaved goldenrod (Euthamia graminifolia) or Ohio goldenrod (Solidago ohioensis). It is believed to have evolved from a hybrid of either S. ptarmicoides and S. ohioensis or S. riddellii and S. ohioensis.

Distribution

Houghton’s goldenrod is a Great Lakes endemic found only in Ontario, Michigan and New York. In Ontario, it is found on about 215 km² of Manitoulin Island and on 5 km² of Cabot Head on the Bruce Peninsula.

Habitat

Houghton’s goldenrod grows on seasonally wet limestone pavements (alvars), calcareous beach sands, or interdunal wetlands along the Great Lakes shoreline. The Ontario population is primarily found on alvars. There is little information regarding microclimate requirements.

Biology

Solidago houghtonii is similar to other species of Solidago in terms of its reproductive biology and floral morphology. Flowering occurs in approximately 6 to 31% of shoots. Flowers are insect pollinated and appear to be incapable of self-pollination. Fruit set and germinability are low. Solidago houghtonii can also reproduce vegetatively by means of underground rhizomes.

Population sizes and trends

There are an estimated number of 27,000 mature flowering individuals of Houghton’s goldenrod in Canada. Area of occupancy is approximately 7.4 ha. Populations appear to be stable.

Limiting factors and threats

Houghton’s goldenrod is restricted to alvars and interdunal wetlands. The main threats to the species are drought, heavy recreational use, and quarry operations. There may also be some threat from floods, invasive species, and residential development.

Special significance of the species

Houghton’s goldenrod is a Great Lakes endemic, with a limited distribution globally. There may be little existing public support for its preservation, since goldenrods, in general, are considered weeds.

Existing protection or other status designations

The species is designated threatened in the United States and in the state of Michigan. It has a global rank of G3, and subnational rank of S2 (imperiled) in Ontario. In Canada, only the Cabot’s Head population is on protected land.

COSEWIC History

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) was created in 1977 as a result of a recommendation at the Federal-Provincial Wildlife Conference held in 1976. It arose from the need for a single, official, scientifically sound, national listing of wildlife species at risk. In 1978, COSEWIC designated its first species and produced its first list of Canadian species at risk. Species designated at meetings of the full committee are added to the list. On June 5, 2003, the Species at Risk Act (SARA) was proclaimed. SARA establishes COSEWIC as an advisory body ensuring that species will continue to be assessed under a rigorous and independent scientific process.

COSEWIC Mandate

The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) assesses the national status of wild species, subspecies, varieties, or other designatable units that are considered to be at risk in Canada. Designations are made on native species for the following taxonomic groups: mammals, birds, reptiles, amphibians, fishes, arthropods, molluscs, vascular plants, mosses, and lichens.

COSEWIC Membership

COSEWIC comprises members from each provincial and territorial government wildlife agency, four federal agencies (Canadian Wildlife Service, Parks Canada Agency, Department of Fisheries and Oceans, and the Federal Biodiversity Information Partnership, chaired by the Canadian Museum of Nature), three non-government members and the co-chairs of the species specialist and the Aboriginal Traditional Knowledge subcommittees. The Committee meets to consider status reports on candidate species.

Definitions (November 2004)

Wildlife Species

A species, subspecies, variety, or geographically or genetically distinct population of animal, plant or other organism, other than a bacterium or virus, that is wild by nature and it is either native to Canada or has extended its range into Canada without human intervention and has been present in Canada for at least 50 years.

Extinct (X)

A wildlife species that no longer exists.

Extirpated (XT)

A wildlife species no longer existing in the wild in Canada, but occurring elsewhere.

Endangered (E)

A wildlife species facing imminent extirpation or extinction.

Threatened (T)

A wildlife species likely to become endangered if limiting factors are not reversed.

Special Concern (SC)^Footnotea

A wildlife species that may become a threatened or an endangered species because of a combination of biological characteristics and identified threats.

Not at Risk (NAR)^Footnoteb

A wildlife species that has been evaluated and found to be not at risk of extinction given the current circumstances.

Data Deficient (DD)^Footnotec

A wildlife species for which there is inadequate information to make a direct, or indirect, assessment of its risk of extinction.