Prototype quillwort (Isoetes prototypus) COSEWIC assessment and status report: chapter 2

Executive Summary

Prototype Quillwort
Isoetes prototypus

Species information

Prototype quillwort (Isoetes prototypus), a perennial aquatic fern ally, consists of a clump of straight, brittle quill-like leaves that arise from a bilobed (rarely trilobed) corm. The leaves are swollen at the base where the reproductive spores (megaspores and microspores) are formed. Plants are commonly dislodged from the substrate where they are rooted and float to the surface, often accumulating in shoreline wrack. Identification is principally by the size of the reproductive spores and their surface ornamentation and by chromosome number.

Distribution

Isoetes prototypus is known from thirteen lakes worldwide: nine in Nova Scotia, three in New Brunswick and one in Maine.

Habitat

Often forming dense mats in oligotrophic (nutrient-poor), spring-fed lakes, I. prototypus is usually found in 1.5 to 2.5 m of water, rooted in soft, flocculent oozy sediment over sand or gravel. Water colour in these lakes is usually clear but occasionally can be tannin-stained (tea-colored). It most often occurs with other species of rosette-forming aquatic plants, particularly Eriocaulon aquaticum and Isoetes lacustris.

Biology

Isoetes prototypus is believed to follow the typical life cycle of members of the genus Isoetes. The dark-green-quilled sporophytes (the adult stage of the life-cycle with paired chromosomes) produce megaspores (female) and microspores (male) that germinate to form separate gametophytes (plantlets that have a single set of chromosomes and produce the sex cells). Once the eggs within female gametophytes have been fertilized by the spermatozoids of the male gametophytes, a new sporophyte develops directly from the egg.

Little is known on the ecology of this species. Floating, uprooted mats are sometimes found along the shores of lakes where I. prototypus occurs. How these plants are dislodged is not known with certainty.

Population sizes and trends

This species was first recognized as a species new to science in 1988 at a single lake in New Brunswick (site 10). Knowledge of its distribution was expanded to five sites (sites 1, 4, 6 in Nova Scotia and site 13 in Maine) through examination of herbarium records by D.M. Britton from 1988-93. He discovered two new locations in Nova Scotia through field exploration between 1989 and 1998 (sites 3 and 7); Isoetes prototypus was independently found at one of these locations (site 7) by D.F. Brunton around the same time it was found there by D.M. Britton.

Fieldwork conducted in 2003 for the preparation of this report has added another four locations (sites 2, 5, 8 and 9) in Nova Scotia. Two new sites were identified in New Brunswick in 2004 (sites 11 and 12). None of the I. prototypus sites has been specifically monitored for changes in population size. Growing in dense mats with up to 392 plants per sq. metre, fieldwork for this report suggests a very conservative estimate for a total Canadian population of about 250,000 individuals, though the total surface area of lakes in which I. prototypus occurs is quite small (<961 ha).

Limiting factors and threats

Although no specific threats were noted at the precise in situ locations where I. prototypus occurs within the lakes at which it has been found, roadways and/or causeways border or encroach upon the shoreline at three of the lakes, and cottage development and associated shoreline deforestation were at least locally extensive at four of the lakes. The impacts of this development are unknown but such habitat modifications could potentially have a negative impact on I. prototypus. Dislodging of plants in the vicinity of underwater moose tracks and as a result of swimming with flippers was observed. Additional potential threats that may possibly impact this species have been documented or considered by other researchers and include direct damage to or uprooting of plants by boating, fishing, the use of anchors, raking swimming areas, the installation of water intake pipes, and the activities of wildlife; and habitat alterations such as changes in water levels by damming or draining, water pollution, eutrophication, siltation, changes in pH and competition by invasive and/or exotic aquatic plant species.

Special significance of the species

This species is an eastern endemic of thirteen small lakes found principally in Nova Scotia and New Brunswick. As one of two native diploid species in northeastern North America, it is likely the ancestor of several other North American species. D.F. Brunton, a specialist in these plants, believes it is ‘a living fossil’ of global significance.

Existing protection or other status designations

Isoetes prototypus is not listed under either the Canadian Species at Risk Act or The Endangered Species Act of 1973 in the United States.

In New Brunswick, I. prototypus and its habitat are protected under the provincial Endangered Species Act. It is not listed as an endangered species under legislation in Nova Scotia or Maine. None of the Canadian lakes where I. prototypus has been found is within a protected area. One site in New Brunswick is on Department of National Defence land. Two lakes (site 13 in Maine and site 1 in Nova Scotia) are protected as sources of public drinking water. The site in Maine is located within Acadia National Park and hence is within a protected area. 

Isoetes prototypus is ranked as an S1 species in New Brunswick and Maine, and as an S2 species in Nova Scotia. It is listed as N1? in Canada and N1 in USA and has been assigned a Global Heritage Status Rank of G1?.

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.

 

Canadian Wildlife Service

The Canadian Wildlife Service, Environment Canada, provides full administrative and financial support to the COSEWIC Secretariat.

 

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