Recovery Plan for the Northern Spotted Owl - DRAFT

In comparison, the southern part of the province is typified by dry, brushcovered,south-facing slopes and forested, north-facing slopes. Owls occur in96 percent of the townships in the southern part. Only 4 percent of thetownships have more than four owl sites each, while 24 percent and 42 percentof the townships in the eastern and north/central parts of the province,respectively, have more than four known sites per township.Province Isolation. This province is located between the other two Californiaprovinces and is continuous with the Oregon Klamath province. Owls and' habitat occur along the borders with the three other provinces except whereareas of natural habitat fragmentation occur along the southwest and northeastboundaries. The Klamath province is contiguous with the California Coastprovince for the first 115 miles south from the Oregon border. It is probablycontiguous with the same province for another 105 miles but the habitat in theadjoining California Coast province supports mostly dispersal habitat and littlebreeding/roosting habitat.The Klamath province is contiguous with the California Cascades for about1 0 miles. However, suitable owl habitat only occurs along the mutual borderbetween the two provinces for the 55 miles south of Shasta Valley. Habitathere is not contiguous and is found as pockets of suitable habitat among areasof higher elevations, unsuitable soils, or past timber harvest. South ofRedding, the remainder of the eastern border of this province directly abutsCalifornia's Central Valley, which is not suitable habitat. Suitable habitat inthe range of the California spotted owl is 35 to 80 miles to the east in theSierra Nevada.Predation and Competition. Great horned owls occur naturally throughoutthe province. Predation on spotted owls by great horned owls has been notedin field studies in the province. Additional studies will be required to determinewhether great horned owl numbers are increasing.Barred owls have been identified in the Klamath province during the last 8years. This number has grown dramatically in the last 3 years from 4 to 15known sites. Pairs of barred owls were found at one-third of these sites in thelast 2 years. The potential for competition may be increasing rapidly, but theeffects on local spotted owls are not known.Vulnerability to Natural Disturbance. Fire is the major disturbance eventlikely in the Klamath province. This area has a history of many natural fires.However, fire suppression during the last 70 to 100 years has resulted inincreased accumulation of fuels and has made large and hot fires more likelythan was true historically. This has led to a recent history of large fires (e.g.,Hog fire on Klamath National Forest; 1987 fires on Klamath, Shasta-Trinityand Mendocino National Forests).Wind damage is a relatively small problem compared to other parts of thePacific coast. Drought and drought-caused insect and disease problems are ofconcern, especially in some of the drier areas.California Cascades62The California Cascades province is located in the north central portion of thestate, between the Oregon Cascades provinces, the Klamath province, and therange of the California spotted owl at the north end of the Sierra Nevada.Suitable owl habitat generally is fragmented on a broad scale by the ShastaValley, Mt. Shasta, and other high-elevation areas of unsuitable soils, andareas of marginal, low-elevation habitats. Suitable forest habitat is mostly onnational forests, although there are significant blocks and checkerboard areaswhere forests occur on mostly industrial private lands.