Wood-poppy (Stylophorum diphyllum) COSEWIC assessment and status report: chapter 2

COSEWIC Executive Summary

Wood-Poppy
Stylophorum diphyllum

Species information

Wood-poppy (Stylophorum diphyllum) is a perennial herb that has yellow or orange sap, a stout rhizome and showy yellow flowers that bloom in early spring. A cluster of 1-4 flowers is produced at the end of an elongated shoot above two or three more-or-less opposite leaves. The flower has four yellow petals that are 2-5 cm in length, and numerous stamens. The woody poppy’s fruit is a greyish, oval, hairy capsule that splits by longitudinal clefts into three or four segments. The leaves are mostly basal, have long petioles and are pale underneath. They are deeply divided into five to seven irregular lobes or toothed segments.

Distribution

The distribution of wood-poppy is restricted to northeastern North America, centered in Kentucky and Missouri, but extending as far south as Georgia and Alabama. At the western part of its range, wood-poppy is found in Arkansas, eastern Missouri and Michigan. In Ontario, four historic collections are known from the 1880s, all along the Thames River near London, Ontario. The three extant populations occur near London where they occupy a total area of habitat comprising < 1 ha. The extent of occurrence is 150 km² and the area of occupancy, based on a 1x1 km grid, is 3 km² and based on a 2x2 km grid is 12 km².

Habitat

Wood-poppy is typically found in species-rich woods in forested ravines and slopes, ravine bottoms, along woodland streams, and at the base of bluffs. In Ontario, wood-poppy is at the northern limit of its global range and is found in deciduous forest of till plains, wooded ravines and valley slopes.

Biology

The species is a typical deciduous forest “summer green” herb. It starts growing in mid- to late April, from a short, stocky rhizome. It flowers in May to early June with the seeds dispersed by late June to July. The vegetative parts stay green until late September or early October and then die back. Seeds set readily on flowers that may pollinate themselves or receive pollen from other flowers. Seeds require a cold period of dormancy before they germinate. Plants may flower in their first year, but usually don’t do so in the wild. Once established, plants often survive for 5 or more years. They generally grow in dense stands or clumps, but outlying individuals are observed in the southern Ontario population.

Population sizes and trends

The three known populations of wood-poppy in Canada contained about 255, 250 and 24 mature plants respectively in 2006. The largest known population was partially covered by fill in 1993 and reduced from about 800 plants to about 170. Since then it has increased slightly to about 250 individuals, although this is not based on a detailed census. The other two populations have both increased slightly since 2004, but it is not clear if this is a short-term natural fluctuation or a trend.

Limiting factors and threats

Threats identified for wood-poppy in Canada are habitat destruction and modification, impacts from adjacent development, competition from invasive species, recreation activities and genetic contamination. Wood-poppy has likely never been abundant in Canada, surviving in relative isolation. Recruitment from the nearest population in Michigan and Ohio is unlikely.

Special significance of the species

Wood-poppy in Canada is at the edge of its global range and appears to be genetically distinct from the main population. Apart from some popularity as a garden plant it has no known uses.

Existing protection or other status designations

Wood-poppy is listed as Endangered in Canada (COSEWIC, 2000), and Ontario. The species and its habitat are protected under the Ontario Endangered Species Act and the Provincial Policy Statement. Two populations are located on private land, the third in a conservation area. Wood-poppy is also of conservation concern in four other jurisdictions, including Alabama, Arkansas, Georgia, and Virginia. A number of actions have been taken to mitigate risks to the species as the result of actions taken by the Recovery Team established in 1997.

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 entities (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 science members and the co-chairs of the species specialist subcommittees and the Aboriginal Traditional Knowledge subcommittee. The Committee meets to consider status reports on candidate species.

Definitions (2007)

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

Data Deficient (DD) ***
A category that applies when the available information is insufficient (a) to resolve a species’ eligibility for assessment or (b) to permit an assessment of the species’ risk of extinction.

* Formerly described as “Vulnerable” from 1990 to 1999, or “Rare” prior to 1990.
** Formerly described as “Not In Any Category”, or “No Designation Required.”
*** Formerly described as “Indeterminate” from 1994 to 1999 or “ISIBD” (insufficient scientific information on which to base a designation) prior to 1994. Definition of the (DD) category revised in 2006.

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

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