6.7 Wildlife Diversity and Habitat Relationships 9 6.7.1 Introduction A description of ecosystems without a discussion of wildlife would ignore a major dynamic element of those systems. The term "wildlife" is usually used to describe all vertebrates, but interest in invertebrate animals is increasing. Wildlife are important components in forests ecosystems and play a role in nutrient cycling, seed dispersal, plant distribution, predator- prey relationships, and herbivore-plant relationships, and sometimes have a major economic impact through damage to forest crops. Without doubt, the conservation of biological diversity will have a large impact on forestry practices and the forests of the future. The maintenance of biological diversity should be an integral part of all forest management. In the past, wildlife habitat management was a byproduct of forest management. However, as public awareness grows, there has been greater emphasis on forest management specifically for wildlife. Timber management is wildlife management, but the degree to which it is good wildlife management depends on how effectively it addresses the requirements of wildlife. This section provides a very brief discussion of some of the wildlife habitats and issues in the areas covered by this handbook. 6.7.2 Biological diversity Biodiversity refers to the full range of life in all its natural forms, including genes, species, ecosystems, and ecological processes. All species in an ecosystem are important components of biodiversity, but some may be of greater concern to the manager because: 9 Prepared by A.E. Derocher, Research Wildlife Ecologist, Vancouver Region. Information presented here has been compiled from several sources, including W. Klenner, unpub.; D. Seip, unpub.; Meidinger and Pojar (1991); Banner et al. (1993); Backhouse (1993); and Steeger and Fenger (1992). Specific references are not cited in the text. 230 • they are considered at risk. •they create habitat used by other species (e.g., primary cavity nesters). • they require specific habitats that are adversely affected by land use practices. • they are commercially important. • they are of public interest. Recognizing that the public views wildlife to include a wider spectrum of wild species than just terrestrial vertebrates and freshwater fish, and the need to manage on an ecosystem basis, the Provincial Wildlife Strategy is directed to all wild vertebrates and the habitat they depend on, as well as invertebrates and plants considered to be vulnerable, threatened, or endangered. B.C. currently classifies all indigenous terrestrial and freshwater fish. The criteria used to classify species are: abundance, distribution, habitat integrity, population trend, reproductive potential, threats to the population, susceptibility to large-scale disturbances, national status, and international status. Species are classified as "Species at Risk" or "Species Not at Risk." Species at risk are subdivided into two groups: RED LIST This group includes: •Extirpated10 species: any formerly indigenous species or subspecies no longer existing in the wild in B.C., but that occurs elsewhere. • Endangered species: any indigenous species or subspecies threatened with imminent extinction or extirpation throughout all or a significant portion of its range in B.C. • Threatened species: any indigenous species or subspecies that is likely to become endangered in B.C. if factors affecting its vulnerability are not reversed. BLUE LIST • Sensitive or vulnerable species that are not threatened but are particularly at risk. Species Not at Risk are placed in the Yellow List. 10 Extirpated refers to extinction of local populations. 231 YELLOW LIST • Species that are monitored to ensure that they do not become more vulnerable. • Species that are habitat sensitive. • Species viewed or harvested by the public. • Species that are an important component of the fauna of B.C. • Species for which B.C. has a large proportion of the global population. • Non-native species. 6.7.3 Wildlife habitats and habitat components The B.C. Wildlife Act defines habitat as "the air, soil, water, food, and cover components of the environment on which wildlife depend directly or indirectly in order to carry out their life processes." OLD-GROWTH FORESTS have a major ecological role in contributing to biodiversity. Some species in the Vancouver Forest Region are either partially or totally dependent on old-growth habitats for all or part of their life cycle, while many other species are most abundant in old-growth ecosystems. The diminishing amount of old-growth forest has made it the focus of the biodiversity strategy. These ecosystems are the subject of ongoing research. The features that make old-growth forests important habitat are: • multiple canopy layers. • wide variation in trees sizes and spacing. • canopy gaps. • large trees with large limbs suitable for nesting for many birds. • large volume of coarse woody debris in all stages of decay and wide range of sizes. • numerous snags and wildlife trees. • broken top trees that provide nesting habitat for large birds and Vaux's Swift. • cool, moist, and moderated environment. • abundant understorey vegetation. • abundant epiphytic lichens that provide food. • abundant mycorrhizal fungi that are food for several mammals. • high snow interception. 232 Three species of special management concern that use old- growth in the Vancouver Forest Region are the Spotted Owl, Marbled Murrelet, and Keen's long-eared myotis (a species of bat). RIPARIAN AREAS are adjacent to and influenced by lakes, rivers, streams, and wetlands. These sites vary from narrow bands along wetlands and lakes and small streams to large floodplains, and are important or critical habitat for many species. The features that contribute to the ecological importance of riparian habitats are: • lush understorey vegetation providing abundant food and cover. • high horizontal and vertical structure providing a diversity of niches. • moderate and stable environment. • proximity to salmon and invertebrates as food sources. • moist microclimate and access to water. • corridors for dispersal. In general, the majority of the structural components in riparian ecosystems must be maintained to allow them to remain functionally intact. Development in these areas should closely follow the B.C. Coastal Fisheries Forestry Guidelines to maintain their integrity. WETLANDS are the primary habitat of many wildlife species. They are highly productive areas and provide important forage for waterfowl, shorebirds, amphibians, and mammals. Many cavity-nesting birds (e.g., Goldeneye, Wood Ducks, and Bufflehead) use the forest fringe of wetlands. Rodent populations can be high in these areas. Marshes are the most productive and bogs the least productive wetlands, but both support a diversity of species. DECIDUOUS FORESTS in the Vancouver Forest Region are comprised of alder, black cottonwood, vine maple, bigleaf maple, birch, trembling aspen, cherry, and Garry oak. Deciduous forests are typically early to middle seral stages that established after disturbance. As succession proceeds, the deciduous forests are replaced by mixed coniferous and deciduous forests, which continue to provide forage and nesting habitats. Even when deciduous forests occur in small (< 1 ha) patches, they can be important habitats for many species. 233 SHORELINE FORESTS AND ESTUARIES provide habitat for those species adapted to marine, estuarine, and forest habitats. Estuaries are important as rearing and staging grounds for migratory salmon. The deltas at the mouth of rivers and streams provide important habitat for grizzly bears and migratory birds. The Ancient Murrelet found in the Queen Charlotte Islands is a typical shoreline forest-user and nests in colonies under the roots of large trees or logs. SOUTH ASPECTS are important habitats for species such as deer and elk. These areas tend to have lower snow accumulations due to the greater exposure to the sun. South aspects provide forage earlier in the spring. 6.7.4 Important habitat components at the stand level WILDLIFE TREES These are living or dead, naturally occurring trees that provide present or future important habitat for the maintenance or enhancement of wildlife. Without careful management, we will face a shortage of wildlife trees as old-growth forests are replaced by second-growth stands. More than 16% of our native wildlife species can be considered wildlife tree users. Wildlife trees provide critical habitat for nest cavities, nest platforms, dens, roosts, hunting perches, foraging sites, and display stations during breeding. The value of a wildlife tree varies with factors such as age, size, structure, rot, species, elevation, and proximity to critical habitats. Implementing a successful wildlife tree management program will, however, result in greater volumes of timber left standing on-site. Snags and moribund trees are critical habitat elements for many primary11 and secondary cavity nesters such as Woodpeckers, Chickadees, some Owls, Wood Ducks, marten, fisher, ermine, northern flying squirrels, Keen's long-eared myotis, and black bears. Snags are also used as perches by birds of prey and insectivorous birds (e.g., Swallows and Flycatchers), which help control forest pests. Taller and larger-diameter snags are used by more species 11Primary cavity excavators are birds such as Woodpeckers, Nuthatches, and Chickadees that are able to excavate their own nest holes. Woodpeckers make new holes each year as part of their courtship