Northwest Forest Plan—the first 20 years (1994-2013): status and trends of northern spotted owl habitats

Abstract

This is the third in a series of periodic monitoring reports on northern spotted owl (Strix occidentalis caurina) habitat status and trends on federally administered lands since implementation of the Northwest Forest Plan (NWFP) in 1994. The objective of this monitoring is to determine if the NWFP is providing for conservation and management of northern spotted owl (NSO) habitat as anticipated. This report focused on the amount, distribution, and spatial arrangement of NSO habitats across the NWFP area; and how these have changed as a result of disturbance and ingrowth starting with the year of the NWFP analyses in 1993. Results showed a net decrease from 9,089,700 ac to 8,954,000 ac (-1.5 percent) of nesting/roosting habitat on NWFP federal lands. This occurred despite gross losses from wildfire of 5.2 percent (474,300 ac), 1.3 percent from timber harvest (116,100 ac), and 0.7 percent from insects or other causes (59,800 ac), indicating that processes of forest succession have compensated for some of the losses resulting from disturbance. Dispersal habitat on NWFP federal lands increased by 2.2 percent (net change), but dispersal-capable landscapes experienced a 5 percent net decrease owing to habitat losses on the surrounding nonfederal lands. Large wildfires continue to be the leading cause for loss of NSO habitat on federal lands. Most of these losses occurred within the network of large reserves designed for NSO conservation.

Citation

Davis, Raymond J.; Hollen, Bruce; Hobson, Jeremy; Gower, Julia E.; Keenum, David. 2016. Northwest Forest Plan—the first 20 years (1994-2013): status and trends of northern spotted owl habitats. Gen. Tech. Rep. PNW-GTR-929. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 54 p.