COSEWIC Assessment and Status Report on the Foothill Sedge Carex tumulicola in Canada ENDANGERED 2008 COSEWIC status reports are working documents used in assigning the status of wildlife species suspected of being at risk. This report may be cited as follows: COSEWIC. 2008. COSEWIC assessment and status report on the foothill sedge Carex tumulicola in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 37 pp. (www.sararegistry.gc.ca/status/status_e.cfm). Production note: COSEWIC would like to acknowledge Michael T. Miller, Matt Fairbarns, and Sharon Hartwell for writing the status report on the foothill sedge (Carex tumulicola) in Canada. COSEWIC also gratefully acknowledges the financial support of the BC Conservation Data Centre and the BC Ministry of Environment for the preparation of this report. The COSEWIC report review was overseen by Erich Haber, Co-chair (Vascular Plants), of the COSEWIC Plants and Lichens Specialist Subcommittee, with input from members of COSEWIC. That review may have resulted in changes and additions to the initial version of the report. For additional copies contact: COSEWIC Secretariat c/o Canadian Wildlife Service Environment Canada Ottawa, ON K1A 0H3 Tel.: 819-953-3215 Fax: 819-994-3684 E-mail: COSEWIC/[email protected] http://www.cosewic.gc.ca Également disponible en français sous le titre Ếvaluation et Rapport de situation du COSEPAC sur le carex tumulicole (Carex tumulicola) au Canada. Cover illustration: Foothill sedge — Line drawing in Hitchcock et al. 1969 and Douglas et al. 2001; reproduced with permission from University of Washington Press. ©Her Majesty the Queen in Right of Canada, 2008. Catalogue No. CW69-14/553-2008E-PDF ISBN 978-0-662-48926-9 Recycled paper COSEWIC Assessment Summary Assessment Summary – April 2008 Common name Foothill sedge Scientific name Carex tumulicola Status Endangered Reason for designation This perennial species is known from 10 localized and highly fragmented sites in southwestern British Columbia where it occurs in meadows and shrub thickets within Garry oak ecosystems, a critically imperiled habitat in Canada. The total Canadian population likely consists of fewer than 1000 mature individuals. Factors such as competition and habitat degradation from invasive alien plants, altered fire regimes, urbanization, trampling and mowing place the species at risk. Occurrence British Columbia Status history Designated Endangered in April 2008. Assessment based on a new status report. iii COSEWIC Executive Summary Foothill Sedge Carex tumulicola Species information Foothill sedge (Carex tumulicola) is a grass-like plant in the sedge family that forms loose tufts up to 80 cm high, or sods. Distribution The range of foothill sedge extends from southwest British Columbia south to Oregon and California. It has been (possibly erroneously) reported from Idaho. In Canada, it is known only from the southeast coast of Vancouver Island. The actual area of habitat occupied by the species is << 1km2; this has increased from a few m2 at the original location to an estimated 100 ha. The COSEWIC Area of Occupancy for the 10 populations, if based on a 1x1 km grid, is 10 km2 and 32 km2 if a 2x2 km grid is applied. The Extent of Occurrence (EO) is now estimated at 1, 700 km2. Habitat In Canada, foothill sedge is known from vernally moist meadows and shrub thickets in Garry oak and associated ecosystems. Increasing urbanization around Victoria and Nanaimo, alien plant invasions, and secondary succession due to fire suppression have altered the ecology of the region to such an extent that the amount of area suitable for supporting this species may now be substantially reduced compared with historical levels. Biology Foothill sedge is a perennial that flowers and fruits in mid-to late summer. The flowers are wind-pollinated and the seeds have no innate dispersal mechanism. In addition to reproducing via seed, foothill sedge spreads vegetatively from short rhizomes, and establishes readily from rhizome fragments. It appears able to tolerate high moisture levels in the winter and very low moisture levels in the summer, and is adapted to either sun or shade. iv Population sizes and trends Foothill sedge was first collected in Canada in 1990, but intensive searches for the species did not begin until 1999. By 2006, a total of ten populations had been recognized. In two cases, populations consist of just a single tussock, possibly representing a single individual. Other populations are comprised of single or scattered patches ranging in area from <1 m2 to spread out over about 30 ha. Because of the species’ rhizomatous habit, obtaining reliable population counts is difficult. However, the total population likely numbers less than 1000 individuals. Limiting factors and threats Foothill sedge has only been monitored in Canada for less than a decade, thus the reasons for its present rarity are unclear. Nevertheless, several factors now appear to be threatening its persistence. These include (in approximate order of importance): competition from introduced alien species; altered fire regimes; habitat conversion (urbanization); all-terrain vehicle traffic; hydrologic alterations; trampling and mowing; and loss of habitat due to bank slumping. Special significance of the species The species’ present disjunct distribution in northwestern North America may be a relict of a once broader distribution that prevailed during the warm, dry, postglacial period, 4,000-6,000 years before present, called the Hypsithermal Interval. Until recently, the species was confused with the European sedge Carex divulsa, that has been used for horticultural purposes and some land reclamation work in the Pacific Northwest. Existing protection or other status designations Foothill sedge is Red-listed in British Columbia and has a provincial conservation rank of S1 (critically imperiled), but has no species-specific protection in Canada or elsewhere. However, it is possible that the species can be added to the list of species under the BC Wildlife Amendment Act (2004). Eight of the ten populations do occur in areas that receive some site protection by virtue of their location in either municipal parks or on DND (Department of National Defence) or Parks Canada Agency property. v 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 (2008) 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. Environment Canada Environnement Canada