Recovery Plan for the Northern Spotted Owl - DRAFT

Low Populations. Population levels are low in this province. There are only71 known sites, or only about 6 percent of the known sites in California. Pairshave been verified at about 35 sites from 1986 through 1990. The density ofsites found since 1970 is only 1.0 per township.Declining Populations. Owls and owl habitat are present across a range ofecological conditions within the province, but habitat is fragmented. Owls areknown from only 40 percent of the townships in the province and from 51percent of the townships where possibly suitable habitat exists. Even thoughthe area is fairly well surveyed, 48 percent of the townships with owls haveonly one known owl site, and only 5 percent have more than four owl siteseach. Even where owls occur, population densities are low in the province.Demographic information for owls in the study area is scarce. There is nodemographic information from field studies. The only available information islimited to survey and inventory work with anecdotal observations of reproduction,Forest Service monitoring sites, and private lands surveys which havebeen conducted only in the last 2 years.Limited Habitat. The California Cascades province is small, containing onlyabout 110 townships. Twenty-three of these townships probably do notcontain suitable owl habitat and another 43 contain only marginal habitat.Habitat is mainly found on parts of the Klamath and Shasta-Trinity NationalForests and interspersed private lands. There are about 500,000 acres of landsuitable for timber harvest on the Shasta portion of the Shasta-Trinity NationalForest. About 220,000 of these acres are in stands with crown diametersgreater than 13 feet and canopy closure greater than 40 percent. However,much of this area does not meet the Interagency Scientific Committee's (ISC)"50-11-40" standard for dispersal habitat (Thomas et al. 1990).Declining Habitat. Timber harvesting often extends over large areas, butcommonly does not involve clear-cutting. Habitat loss in this area is difficult toestimate because of the patchy distribution of habitat chosen by the owls,perhaps the result of previous tree cutting and/or thinning and the possiblylow historical levels of suitable habitat due to fire history.Distribution of Habitat and Populations. Habitat is fragmented throughoutthe province. Landscape-scale fragmentation is demonstrated by the divisionof the 44 townships where owls are found in six separate clusters. Suitablehabitat is fragmented on a local level and individual owl sites are often widelyseparated from nearest neighbors. This fragmentation and the isolation ofindividual sites may be natural in part and partially the result of timberharvest. There is only one area where the ISC found a block of contiguoushabitat sufficiently large to form a habitat conservation area that would support16 sites.The eight sites north of Goosenest Mountain in the Klamath National Forestand private lands are the only isolated population in the province. Naturalbarriers (Shasta Valley, Klamath River Canyon, and a high-elevation pass)separate this area from the remainder of the province and from other adjacentprovinces.Province Isolation. The California Cascades province is bordered on the westand north by the California and Oregon Klamath provinces, the westernOregon Cascades and the eastern Oregon Cascades provinces. It abuts therange of the California spotted owl to the southeast. Although the province isbounded by others on three sides, it is somewhat isolated from those provinces.The Shasta Valley separates the northern California Klamath provincefrom the Goosenest section of the California Cascades by 20 miles. The63