Recovery Plan for the Northern Spotted Owl - DRAFT

occurs. The act also prohibits federal agencies from authorizing, funding, orcarrying out action that would jeopardize a listed species, or destroy or adverselymodify its critical habitat.In addition to federal measures specifically protecting owls, the states arepursuing additional measures for owl conservation, and for wildlife habitatconservation in general (see section II.C.). These measures are developingrapidly and further change is expected. Various legal proceedings also haveresulted in changes in management practices. Because of the differences inland ownership patterns, state regulatory mechanisms, and the pace ofchange, it is difficult to accurately quantify the impact of these conservationmeasures and the relative risk to the owl.Despite these developments, the lack of effective, coordinated, rangewideconservation measures is one of the most significant threats to the northernspotted owl. The recovery plan will serve to integrate conservation measuresnow in place, and will provide biological principles to guide development andimplementation of additional measures.Vulnerability to Natural Disturbance. There is significant risk that fire,windthrow, insects, or diseases will reduce habitat, with effects on spotted owlpopulations. Although these disturbance events may occur in any of theprovinces, the eastern Cascades of Oregon and Washington, and the Cascadesand Klamath provinces of California are especially vulnerable (Appendix F).Although fire currently may represent a threat to spotted owls, the habitat inwhich they evolved owed its structure and species composition to fire (Agee1991a). Historically, owls occupied a dynamic landscape that often consistedof large areas of burned and unburned forest (Henderson 1990, Teensma et al.1991). Populations undoubtedly shifted with the changing pattern of thislandscape. Today habitat is greatly reduced and fragmented, and owl populationshave become increasingly vulnerable to loss of habitat due to fire.4. Threats by Province within WashingtonOlympic PeninsulaThe Olympic Peninsula is a relatively isolated province, bordered on threesides by bodies of water. A high mountain range encompasses the centralportion of the peninsula and high-elevation ridges radiate from the central areathroughout Olympic National Park and Olympic National Forest.Currently, spotted owls generally are located in mid-elevation forests alongmajor river systems draining the mountains. A smaller number of owls resideon primarily nonfederal lands at lower elevations in the western portion of thepeninsula. Major threats to spotted owls on the Olympic Peninsula include lowpopulation levels and poor population distribution, habitat loss, isolation, andnatural disturbances.Low Populations. Population estimates for the Olympic Peninsula rangebetween 175 and 225 current pairs, with 111 currently known pairs and 26territorial singles on the Olympic Peninsula (WDW 1991). Survey intensity hasvaried among ownerships, with the most intensive surveys historically conductedin Olympic National Forest and the Hoh-Clearwater land block of theWashington Department of Natural Resources.Private and other state lands received little survey effort until summer 1991.when more intensive survey efforts were undertaken. Currently, activity41