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Indicator 1.2.2 - Population levels of selected forest-associated species core indicator 
Some forest-associated species rely on particular characteristics of their habitat (e.g., stand age, forest structure, ecological processes, stand composition) for their survival and reproduction. Population levels of such species are often monitored to indicate the status of other species that are associated with similar habitat conditions. The selection of forest-associated indicator species should include species that are 1) from a variety of forest habitat types; 2) from different taxonomic groups (e.g., mammals, birds, amphibians, and reptiles) because each of these groups responds differently to stress; and 3) part of a long-term monitoring program. The previous C&I report (CCFM 2000) used a selection of species representative of three forest seral stages (young, pole, mature). Although new information is lacking for some, current data and trends for the same species suggest that populations of most of these species have been maintained or have increased (Table 1.2a). The number of monitoring programs for game animals such as moose, deer (mule and whitetailed), black bear, grizzly bear, and wapiti (elk), and furbearers such as fisher, lynx, and American marten varies from one jurisdiction to the other. Collecting data on these species across Canada's vast forest area is difficult and expensive; thus estimates of population numbers or trends are unavailable for some species in some parts of the country. Still, monitoring these species helps to ensure population stability and to determine allowable harvest levels or to contribute to the recovery planning of populations at risk. A decade-long study showed that populations of the American black bear and its habitat appear to be secure in Canada (Williamson 2002). However, poaching and illegal trade of gallbladders and other body parts remain a concern. The quality of management for the grizzly bear in Canada also appears to have improved over the past years (Peek et al. 2003). In 2002, COSEWIC assigned this species to the special concern category. British Columbia grizzly bears make up about half of the total Canadian population. In March 2003, an independent scientific panel, appointed on recommendations from the International Association for Bear Research and Management, confirmed that the British Columbia government is managing grizzly bears effectively and using sound population estimates (Peek et al. 2003). British Columbia is currently developing a provincial grizzly bear management plan to address the panel's recommendations for dealing with habitat issues, maintaining grizzly bear populations, and establishing grizzly bear management areas (CITES 2004). Small furbearers are stable or increasing in just over half of the provincial estimates, which collectively represent large areas of these species ranges. American marten, an indicator species for mature forest structure, is the subject of a case study for Indicator 1.2.3. Lynx populations are cyclical (10-year period) and are considered stable in most of Canada. Selected forest-associated ungulate populations are either stable or increasing across Canada except for woodland caribou in British Columbia and Alberta, and moose in Nova Scotia. Woodland caribou populations, associated with large tracts of undisturbed old forests, are generally decreasing throughout their distributions (see Indicator 1.2.3 for a case study on this species). Declines in populations of American marten or woodland caribou are important because both occur in mature and old forests, areas where forest management activities frequently take place. Birds are useful indicator species for various reasons: 1) they are widely and easily monitored; 2) they occupy a broad range of ecosystems; 3) their high position in the food chain makes them sensitive to changes at lower food chain levels; 4) they are the best known and documented major taxonomic group especially in terms of the sizes and trends of populations and distributions; and 5) they are sensitive to many kinds of environmental changes or disturbance (BirdLife International 2004). Although selected forest-associated bird species are monitored by a variety of organizations in Canada, the Breeding Bird Survey (BBS) provides the best compilation available. Volunteers who drive along roads, stopping at intervals to record species by their songs, collect the BBS data. The BBS trend data between 1966 and 2003 suggest a decrease in populations of some birds associated with old forests (Table 1.2b). For example, the gray-cheeked thrush breeds in areas with a closed canopy of small shrubs and a dense understory, from spruce forests of the Boreal Shield up to where tundra begins. The inclusion of beetles, weevils, ants, caterpillars, cicadas, and other insects in its diet helps to control destructive insect pests, while the consumption of berries contributes to the propagation of plants. The gray-cheeked thrush population has continued to decrease since the last report. Of the 32 selected forest-associated bird species examined in the last report, two have been placed in a higher category of risk after reassessment by COSEWIC: the northern goshawk laingi subspecies found on Vancouver Island and the Queen Charlotte Islands, and the white-headed woodpecker. In addition, the red crossbill percna subspecies, found in Newfoundland, was designated endangered for the first time by COSEWIC in May 2004. COSEWIC has designated a total of 14 forest-associated bird species (Table 1.2b). In Canada, the white-headed woodpecker occurs only in extreme southern British Columbia and there have been no significant changes in its distribution over the past century. The white-headed woodpecker has always been rare in the northern part of its range, however, and the quality of its habitat has undoubtedly declined over the last century as logging has removed many of the mature ponderosa pines in British Columbia and fire suppression has led to denser forests of younger trees. These forests have few snags for roosting and nesting, and produce fewer pine cones (CWS 2004a). Although the trend for the red crossbill percna subspecies in Canada between 1966 and 2003 is a decline of 1%, the Newfoundland population decreased by 12.5% during the same time period. The reason for this population's decline may be competition for food (black spruce cones) with the red squirrel. Red squirrels were introduced in 1963-1964 in Newfoundland to provide prey for the American marten. The outcome of these interactions, both for the woodpecker and the crossbill, underscores the importance of understanding the functional relationship of species in an ecosystem. Indicator 1.2.3 presents a case study on the northern goshawk. Table 1.2a Population estimates (thousands) and trends by province/territory for selected forest-associated mammals. (Source: Provincial and territorial agencies unless otherwise indicated)
MC: Montane Cordillera GL–SL: Great Lakes–St. Lawrence BP: Boreal Plains C: Carolinian (Mixedwood Plains) BS: Boreal Shield AM: Atlantic Maritime Forest Age Class Y: Young (shrub, sapling) P: Pole (pole, small tree) M: Mature and old Values S: Stable n/o: Never occurred R: Rare I: Increasing ?: Unknown D: Decreasing X: Extirpated with year of extirpation noted a Newfoundland data do not include Labrador. b Alvo (1998). c COSEWIC 2002a . d Boreal population. e Forest–tundra migratory population. f Gaspé population. g COSEWIC 2002b. Table 1.2b Status of selected forest-associated bird species (Canada population trends from the Breeding Bird Survey unless otherwise indicated). (Sources: Sauer et al. 2004; CWS 2003a, b, 2004b; Blackburn et al. 2001)
b Very small sample size. c The declining trend for northern spotted owl caurinasubspecies is documented at http://wlapwww.gov.bc.ca/wld/documents/spottedowl.pdf. Accessed June 2006. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||