Conservation assessment for the northern goshawk in southeast Alaska.

摘要: Iverson, George C.; Hayward, Gregory D.; Titus, Kimberly; DeGayner, Eugene; Lowell, Richard E.; Crocker-Bedford, D. Coleman; Schempf, Philip F.; Lindell, John. 1996. Conservation assessment for the northern goshawk in southeast Alaska. Gen. Tech. Rep. PNW-GTR-387. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 101 p. (Shaw, Charles G., III, tech. coord.; and resource assessments Tongass land management plan revision). The conservation status goshawks Alaska is examined through developing an understanding ecology relation to past, present, potential future habitat conditions region under current plan. ecosystem dynamics are described, a history forest National reviewed. Nearly 900,000 acres most productive old-growth temperate rain (public private lands) have been harvested during past 90 years changed early seral conifer forests. Goshawk relations described review literature. Significant preliminary findings study include following: select forests with > 60 percent all adult telemetry relocations occurring this cover type; nonforest, clearcut, alpine types were least used avoided relative their availability; median breeding season minimum convex polygon use areas was about 10,000 acres. Goshawks predominantly gentle slopes (70 relocations) at elevations below 800 feet (54-74 relocations); 24 occurred riparian zones, nearly 20 within beach fringe extending 1,000 inland from ocean shoreline. nesting nonrandom subset landscape significantly higher proportion 600-acre analysis area surrounding known nests. probability persistence has declined over 50 owing loss likely will continue decline regimes; however, population not immediate peril. predicted consequences several alternative approaches compared. This suggests that long rotation forestry (e.g., 300 years) uneven-aged silvicultural may maintain characteristics important sustaining populations well distributed across region. Although reserves considered essential component forest-wide strategy, reserves, combination extended rotations, be where intensity actions precluded opportunity attain desired age classes achieveable rotations. Reserves critical if extensive clearcut logging continues.