COSEWIC Assessment and Update Status Report on the Cryptic Paw Nephroma occultum in Canada SPECIAL CONCERN 2006 COSEWIC COSEPAC COMMITTEE ON THE STATUS OF COMITÉ SUR LA SITUATION ENDANGERED WILDLIFE DES ESPÈCES EN PÉRIL IN CANADA AU CANADA 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 2006. COSEWIC assessment and update status report on the cryptic paw Nephroma occultum in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 28 pp. (www.sararegistry.gc.ca/status/status_e.cfm). Previous report: Goward, T. 1995. COSEWIC status report on the cryptic paw Nephroma occultum in Canada. Committee on the Status of Endangered Wildlife in Canada. 1-40 pp. Production note: COSEWIC would like to acknowledge Patrick Williston for writing the update status report on the cryptic paw Nephroma occultum in Canada, prepared under contract with Environment Canada, overseen and edited by René Belland, Co-chair (Mosses and Lichens), COSEWIC Plants and Lichens Species Specialist Subcommittee. For additional copies contact: COSEWIC Secretariat c/o Canadian Wildlife Service Environment Canada Ottawa, ON K1A 0H3 Tel.: (819) 997-4991 / (819) 953-3215 Fax: (819) 994-3684 E-mail: COSEWIC/[email protected] http://www.cosewic.gc.ca Ếgalement disponible en français sous le titre Ếvaluation et Rapport de situation du COSEPAC sur le lichen cryptique (Nephroma occultum) au Canada – Mise à jour. Cover illustration: Cryptic Paw Lichen —. Photo by Stephen Sharnoff. ©Her Majesty the Queen in Right of Canada 2006 Catalogue No. CW69-14/62-2006E-PDF ISBN 0-662-43244-4 Recycled paper COSEWIC Assessment Summary Assessment Summary – April 2006 Common name Cryptic paw Scientific name Nephroma occultum Status Special Concern Reason for designation This foliose lichen is endemic to western North America where it is known in Canada from 45 locations, however there are likely more undiscovered locations. The Canadian sites account for more than 50% of the global range with only 5 locations protected from forest harvesting. The species has restricted habitat requirements and grows in mid to lower canopy of old growth coastal and interior humid cedar-hemlock forest. It reproduces only by vegetative propagules with limited dispersal distance. The species is vulnerable to forest harvesting, changes in understory humidity, insect defoliation (hemlock looper), and fire. Occurrence British Columbia Status history Designated Special Concern in April 1995 and in April 2006. Last assessment based on an update status report. iii COSEWIC Executive Summary Cryptic paw Nephroma occultum Species information Nephroma occultum is a rare lichen, endemic to Western North America. It is strongly associated with humid old growth forests and is characterized by a yellowish, greenish, or bluish-grey upper surface with net-shaped ridges, and a hairless tan to sometimes blackish lower surface. It is commonly is 2-7 cm broad and has rounded lobes 4-12 mm wide. It produces many asexual propagules, called soredia, along the margins and the ridges of the upper surface, and lacks apothecia, the spore-producing sexual stage of reproduction. Distribution The global distribution of Nephroma occultum is captured within the geographic boundaries of Alaska (6 localities), British Columbia (45), Washington (8) and Oregon (182). The Canadian portion of the range accounts for more than 50% of the total spatial distribution, and coincides with the intermontane valleys of the Coast Range and the Columbia Mountains. Habitat In Canada, Nephroma occultum is confined to moist old growth forests at elevations below 1200 m. All Canadian populations occur in the Coastal Western Hemlock Zone and the Interior Cedar-Hemlock Zone of the British Columbia Biogeoclimatic Ecosystem Classification system (Meidinger and Pojar 1991). Avoidance of summer drought is a key attribute of N. occultum habitat. In coastal localities the macro-climate provides sufficient moisture for N. occultum to inhabit the upper forest canopy. In inland regions where the macro-climate is often too dry, N. occultum is restricted to the lower canopy of humid old growth forests. Biology Nephroma occultum produces large numbers of asexual soredia which are thought to be dispersed by wind, rain and animals. The soredia of N. occultum are larger than those of most lichens, and poor propagule dispersal appears to be a factor which limits distribution. N. occultum does not have sexual structures (apothecia) and may have low genetic variation. Furthermore, N. occultum is a poor competitor and is displaced by mosses or liverworts where these are the dominant epiphytes. iv Population sizes and trends As of 2004, the global distribution of Nephroma occultum comprises approximately 241 known extant populations, of which 45 are located in Canada. Extirpation at two sites within Canada is attributable to forest harvesting. Populations vary in size among extant localities from single thalli to 40 or more within a single stand. With a conservative estimate of 10 thalli per stand, there are probably more that 2,410 individuals of Nephroma occultum worldwide. Limiting factors and threats Nephroma occultum is limited by the availability of suitable habitat (humid old growth forests) and poor dispersal efficiency. Humid, old growth cedar-hemlock forests have diminished in abundance in step with the progressive expansion of forest harvesting. Additional threats from hemlock looper infestations and fire are predicted to increase in severity and frequency as mean annual temperatures rise, reflecting global warming. Cumulative effects of harvesting, climate change, insect infestations and fire are expected to have a negative influence on remaining N. occultum habitat. Special significance of the species Nephroma occultum is endemic to western North America, and Canada accounts for more than 50% of the entire global range. Only five Canadian populations are protected from forest harvesting. N. occultum is a “flagship” species among a suite of rare and uncommon lichens and bryophytes that are dependent upon humid, old growth forests, many of which exhibit an unusual coastal-inland disjunct distribution. Where regulations require rigorous lichen surveys (for instance, in Oregon), the discovery of this lichen has led to progressive forest management practices encouraging the retention of remnant old growth tree patches. However, throughout the Canadian portion of the range, N. occultum habitat is in progressive decline, primarily due to forest harvesting. This trend is most pronounced in the inland areas where suitable habitat is geographically restricted by the availability of forests with humid micro-climates. Existing protection or other status designations Nephroma occultum was designated a species of Special Concern by COSEWIC in 1995 based upon recommendations from the initial status report (Goward 1995a). In British Columbia it is ranked S2S3 and is not protected by provincial legislation. Five Canadian localities for N. occultum are situated within parks or protected areas. The remaining populations occur on Crown Land and are not protected from forest harvesting or other disturbances. In Washington (S1) and Oregon (S3), N. occultum is a listed species on the Northwest Forest Plan, meaning that developers must survey and manage for this species according to the plan’s guidelines. N. occultum also occurs in Alaska where it is not protected. 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 5th 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 (2006) 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