Environment and Effects 3 Biological Elements Biodiversity Aquatic Ecosystems and Essential Fish Habitat Fire Management Insects and Diseases Forested Vegetation Plants Wildlife Biological Elements 3-41 Environment and Effects 3 Biodiversity Introduction Biodiversity includes the ecosystems, plant and animal communities, species, genes, and processes through which individual organisms interact with one another and with their environment. Natural disturbance processes and human influences both affect the biodiversity of an area. Human induced changes in landscape pattern can be assessed by comparing ecological conditions that existed prior to modern human settlement of the area to current conditions. Most species of plants and animals on the Chugach National Forest are protected by using a coarse filter strategy (entire ecosystems and landscapes) of maintaining the components of vegetation composition and structure that are essential to their habitat needs. Rare species with narrow ecological amplitudes requiring specific habitat conditions are managed through a fine filter strategy (individual species and their habitats). Potential impacts to fragmentation, perforation, late successional and old growth forests, and landscape patterns characteristic of forested cover types are specifically assessed. The conservation of biological diversity or “biodiversity” is of national and global concern. Biodiversity may be defined as “the full variety of the life in an area, including the ecosystems, plant and animal communities, species, and genes, and processes through which individual organisms interact with one another and their environments” (USDA Forest Service 1992b). Biodiversity combines the physical environment with the biological environment. Both are influenced by, and in turn influence, the human environment. The physical environment consists of soils, water, and air. The biological environment is the pool of available species that successfully compete for existence in an area. This includes the full complement of living organisms - from inconspicuous soil bacteria and fungi to the more visible vascular plants and animals. Biodiversity is understood in terms of the natural and historic numbers and distributions of plants and animals, habitats, and communities. To evaluate the biodiversity of the Chugach, it is necessary to examine this variability over time. Over these long periods, plants and animals have fluctuated with changes in climate. Their number and distribution have changed because of the species interactions, migrations into and out of the region, and other factors. Natural processes. One way to promote biodiversity is to accept, where appropriate, the outcomes such natural processes as fire, windstorms and insect infestations. Many plants and animals evolved in response to such disturbances are suited to live in an environment in which they occur. For instance, wildfire has played a role in the origin of the mixed conifer and hardwood stands on the Kenai Peninsula (Potkin 1997). Insects and diseases, and the conditions that favor them, further shape the structure and composition of the spruce and mixed spruce forest communities on the Kenai Peninsula. Biodiversity 3-42 Environment and Effects 3 Human influences. Human influences also play a role. Some species, such as the Sitka black-tailed deer, mink, and noxious weeds, have been intentionally (or unintentionally) introduced to the Forest while others, such as the Kachemak gray wolf, have been extirpated. Humans have also had a profound effect on disturbance regimes particularly on the Kenai Peninsula. Variability. Biodiversity is never stable through time; it fluctuates in response to ever-changing human and environmental influences. Some of the Forest exists in the same conditions that were present in the area before large-scale human development began. The Kenai Peninsula and Copper River Delta are currently undergoing responses to large-scale environmental conditions that have changed vegetation succession patterns or stand conditions. On the Kenai the changes are in response to a spruce beetle (Dendroctonus rufipennis Kirby) infestation that has affected over 40 percent of the forests since the late 1950s (DeLapp et al. 2000). Vegetation on the Copper River Delta is undergoing extensive succession in response to the 1964 earthquake, which uplifted the area between 6 and 11 feet (DeVelice et al. 1999b). Scales of biodiversity. Biodiversity occurs at the following four scales (Noss 1990): • Genetic diversity - the genetic variation within and among individuals and populations of the species that influences such things as adaptability and resistance to stress. • Species diversity - the variety of different species found in an area. Some species are commonplace; others have small, reduced, or even threatened populations. • Community or ecosystem diversity - the association of different species and their interactions with one another and physical environment. • Landscape or regional diversity - the variety of communities or ecosystems over a larger area. Conservation of biological diversity requires a dual strategy that addresses both the habitat needs of individual species and entire ecosystems (course filter analysis). The traditional species-by-species approach is important for management indicator species, sensitive species, and other species of special concern (fine filter analysis). In this analysis, biodiversity is described in terms of: 1. Ecoregions; 2. Habitat Diversity; 3. Expected Range of Variability; and, 4. Wildlife – Coarse Filter. Biodiversity 3-43 Environment and Effects 3 Legal and Administrative Framework • The National Forest Management Act of 1976 (NFMA) states that the forest plan must “provide for the diversity of plant and animal communities based on the suitability and capability of the specific land area.” • Ecosystem Management In 1992, the Chief of the Forest Service issued a statement committing the Forest Service to the practice of ecosystem management, which is an ecological approach to managing national forest and grasslands for multiple purposes. • The Endangered Species Act of 1973 governs the protection of listed species and the ecosystems upon which they depend. • The Forest Service Manual (2672) requires the Regional Forester to identify sensitive species occurring within the region. • The Forest Service Manual (2672.4) requires that a biological evaluation (BE) be prepared for all Forest Service activities to address impacts to Forest Service sensitive species. • 36 CFR 219.27 (g) states that management prescriptions, when appropriate and to the extent practicable, shall preserve and enhance the diversity of plant and animal communities. • 36 CFR 219.19 requires the Forest Service to identify and prevent the destruction or adverse modification of habitat determined to be critical for threatened and endangered species. It states that fish and wildlife habitat shall be managed to maintain viable populations of existing native and desired non-native vertebrate species. Viable populations are defined as those with sufficient numbers and distribution of reproductive individuals to ensure their continued existence in the planning area. Key Indicators • Changes in the regional landscape • Changes in land cover, vegetation and forest structure • Bioenvironmental classes (generalized climate, vegetation, and landforms) • Wildlife species richness by prescription category • Wildlife species richness by land cover class and habitats of special interest Resource Protection Measures Ecosystem processes influence plant productivity, soil fertility, water quality, and many other environmental conditions affecting the health of the Chugach Biodiversity 3-44 Environment and Effects 3 National Forest. These processes are controlled by the diversity of plant and animal species present on the Forest. Much of the Chugach National Forest remains largely unaltered by direct human activities. The Kenai Peninsula is where the bulk of historic large-scale changes in vegetation have occurred in response to human activities (including mining, logging, land clearing, and fire disturbances). Natural and human-caused events may diminish the natural diversity of plant and animal species and habitats. When conditions are outside of the range of natural variability, management action (or inaction) may be necessary in order to restore healthy ecosystem processes. NFMA regulations require that viable and well-distributed populations of all native (and desirable non-native) resident species be maintained across the national forest. All management activities on national forest lands are evaluated in order to satisfy these regulations. Affected Environment Introduction A regional landscape approach was used to assess how well various alternatives will allow the Forest to meet the following goals: “Maintain the abundance and distribution of habitats necessary to support viable populations of existing native and desired non-native species.” “Maintain habitat to produce sustainable wildlife populations that support the use of fish and wildlife resources for hunting, fishing, subsistence, and other values.” “Emphasize maintenance of fish and wildlife habitat in 501(b) area of the Chugach National Forest.” Biological diversity encompasses the variety of genetic stocks, plant and animal species and subspecies, ecosystems, and the ecological processes through which individual organisms interact with one another and their environments. The National Forest Management