AFFECTED ENVIRONMENT

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THREATENED AND ENDANGERED SPECIES AND SPECIES OF CONCERN

This section describes the threatened and endangered species (including species of concern and designated critical habitat) that may be affected by the proposed action to rehabilitate Highway 62 West in Crater Lake National Park.

Under the Endangered Species Act of 1973, as amended, an endangered species is defined as any species in danger of extinction throughout all or a significant portion of its range. A threatened species is defined as any species likely to become an endangered species in the foreseeable future throughout all or a significant portion of its range.

The U.S. Fish and Wildlife Service has provided a current list of threatened and endangered species, species of concern, and designated critical habitats that may be affected by the proposed action to rehabilitate Highway 62 West in Crater Lake National Park (appendix 4) (USFWS 2002a). The National Park Service uses this list, along with relevant biological studies, literature reviews, views of species experts, and site inspections to determine if the proposed project may affect listed or proposed species, or proposed or designated critical habitat. In addition to the U.S. Fish and Wildlife Service list that contains eight species, Crater Lake National Park routinely addresses additional rare species, including those listed by the Oregon Fish and Wildlife Department. A table of endangered and threatened species, as well as species of concern identified by the U.S. Fish and Wildlife Service and the Oregon Fish and Wildlife Department, is provided in appendix 4.

According to the Oregon Natural Heritage Program, there are no occurrence records (e.g., electronic records of species, sub-species, varieties, hybrids, and/or natural communities) of federal or Oregon endangered, threatened, sensitive, or rare wildlife and plant species in the vicinity of Highway 62 West (T31S R5E Sections 11, 12, 13, 14) (Murray pers. comm. 2002a).

Following analysis of potential habitat and species present in the park, the northern spotted owl (Strix occidentalis caurina) is the wildlife species state and/or federally listed as threatened that is discussed in more detail below and assessed for impacts related to Highway 62 West rehabilitation. In addition, the U.S. Fish and Wildlife Service stated that critical habitat for the northern spotted owl may occur on Crater Lake National Park (USFWS 2002a).

Northern spotted owls in Oregon were reported to number 1,977 pairs during an early 1990s survey (Thomas et al. 1993 in NatureServe 2002j). Potential suitable habitat is found in patches within Crater Lake National Park, with a higher density of patches (including some of large size) southwest of a diagonal line running from the northwest corner to the southeast corner of the park (Tuss 1998). Ten years of northern spotted owl survey records have documented presence and resulted in recordation of 18 nesting and activity centers within the park (Crater Lake National Park 2002a).

The Highway 62 West corridor passes through northern spotted owl habitat; the nearest activity center is located approximately 900 meters north (slightly over 0.5 mile) of the western project terminus (Crater Lake National Park 2002b). This location would place the activity center north of Castle Creek and well-screened from the corridor in dense mountain hemlock forest habitat. This location is known as the Castle Creek site and its associated activity center is located north of Castle Creek and is well-screened from the Highway 62 West corridor in dense mountain hemlock forest habitat.

The Castle Creek site supports one pair of northern spotted owls and the site has been occupied from 1992–95 and 2001–02, at a minimum (NPS, CRLA 2002b). Northern spotted owls have nested at this site and produced juveniles in 1994 and in 2002. Both adults have been banded, the female in 2001 and the male in 2002. One juvenile owl was observed at the Castle Creek site as late as 1 July 2002; however, by 15 July 2002, the juvenile and adult female owl could not be detected. Both a female goshawk (Accipiter gentilis) and a barred owl (Strix varia), potential predators, were observed/heard in the vicinity of the nest tree (NPS, CRLA 2002b). The adult male was observed during August 2002, approximately 125 meters north of Highway 62 West and approximately 1 kilometer south of the nest tree. It would not accept a mouse offered by biologists, indicating that it was likely not feeding a juvenile owl.

The male northern spotted owl was last detected 6 August 2002, near Highway 62. The following morning a pile of adult northern spotted owl feathers was located and a goshawk was observed nearby. It has been speculated that the juvenile and adult male from the Castle Creek site are dead, and the fate of the female is unknown (NPS, CRLA 2002). The presence of the adult male near Highway 62 West was thought to be the result of displacement from the nest tree by the barred owl and/or the goshawk.

The park is considered at the eastern edge of the northern spotted owl range; however, habitat, sightings, and nesting has occurred within park boundaries (Crater Lake National Park, FMP 2002a). Approximately 32,260 acres of suitable northern spotted owl habitat has been identified in the park, and all known northern spotted owl activity centers occur in areas identified as suitable habitat. Stonum (1993 in NPS–Crater Lake National Park 2002) reported that 29 individual northern spotted owls were documented within the park following a 1992 survey of potential habitat. Tuss (1998) reported that 18 different northern spotted owls or pairs of owls were located in the park from 1994–1996. The typical timing for surveys in Oregon is from February to June (Laye pers. comm. 2002), and surveys are typically conducted during two successive years. Additional northern spotted owl surveys will be conducted at Castle Creek during 2002 to determine status. However, conclusive evidence is unlikely to be found this season and the 2003 nesting season will provide the best opportunity to prepare conclusions about the Castle Creek site northern spotted owl pair. These surveys will be resumed during May 2003, and will report any nesting or significant activity to the U.S. Fish and Wildlife Service (NPS-CRLA 2002a, USFWS 2002b).

Northern spotted owls occupy forests with moderate to high canopy closure; a multilayered, multispecies canopy dominated by large overstory trees; a high incidence of large trees with large cavities, broken tops, and other indications of decadence; numerous large snags; heavy accumulations of logs and other woody debris on the forest floor; and considerable open space within and beneath the canopy (Thomas et al. 1990 in NatureServe 2002j). Generally, such habitat conditions are found in old-growth stands (at least 150 to 200 years old), but sometimes occur in younger forests that include patches of older growth. Within Oregon, coniferous forests begin to develop conditions suitable for northern spotted owls about 80 to 120 years following clearcutting (NatureServe 2002j). In southwestern Oregon, the northern spotted owl consistently selected old-growth forest habitat for foraging and roosting (Carey et al. 1992 in NatureServe 2002j).

Common prey for the northern spotted owl consists of small mammals, particularly nocturnal arboreal, or semi-arboreal species and includes flying squirrels, lagomorphs, and deer mice (NatureServe 2002j). Northern spotted owls typically roost during the day and hunt at dusk and at night.

Nesting occurs on broken treetops, ledges of cliffs, natural tree cavities, stick platforms in a tree, caves, and often in abandoned hawk or mammal nests. Nest sites are located where the proportion of old growth and mature forest habitat is great. Pairs tend to occupy the same nesting territories in successive years if the habitat remains suitable (NatureServe 2002j). Northern spotted owl pair territories may range from as small as 530 km2 in old mixed conifer forest to 2,900 km2 in old Douglas-fir forest (Carey et al. 1992 in NatureServe 2002j). They may move nest sites frequently within the territory (Laye pers. comm. 2002). Breeding and egg laying occur in early April in Oregon and the typical clutch size is two. The female incubates the eggs for about 30 days, and during this time is fed by the male. Young owls leave the nest at about five weeks old and fledge at about six weeks old. They become independent from the adults by about October. Northern spotted owls first breed at two to three years of age and may not breed every year (NatureServe 2002j).

Northern spotted owl pairs and individuals have been negatively affected by activities resulting in habitat loss or fragmentation. These can include natural disturbances such as intense fires, but are most often caused by logging mature and old growth forest stands. Recently, the barred owl has expanded its range into the Pacific Northwest and could possibly compete with or displace the northern spotted owl (very rare occurrences of hybridization have also been detected) (Hamer et al. 1994 in NatureServe 2002j).

A conservation strategy has been described that defines habitat conservation areas containing a minimum of 20 pairs of northern spotted owls. Further, sound management practices should include efforts to control factors that adversely affect survival of adult females (NatureServe 2002j). Where old growth is lacking, silvicultural manipulation of vegetation and creative snag or den tree management could be used to accelerate the development of northern spotted owl habitat.