SNFPA Draft Supplemental Environmental Impact Statement

June 2003

Chapter 3: Affected Environment

3.2.2.3. California Spotted Owl

New information has evolved since the writing of the SNFPA FEIS affected environment for this species (Volume 3, Chapter 3.4, pp 69 -- 112). This information includes Franklin et al. 2003 (Population Dynamics of the California Spotted Owl: A Meta-Analysis), baseline GIS overview of number of PACs burned and amount of PAC acres burned, an assessment of fire effects on PACs since 1993, the southern California drought related mortality, corrections for PAC numbers, and the FWS 12 Month Findings for a Petition to List the California Spotted Owl (Strix occidentalis occidentalis) (FR Volume 68, No. 31, 7589-7608), and contribution of private timberland to owl habitat.

Population Trends: Demographic studies (5) within the range of the California Spotted Owl have been ongoing for a number of years. One of the primary objectives of these studies is to monitor fluctuations or rate of change (lambda) in owl populations. There has been considerable debate over the most appropriate measure of the finite rate of population change in spotted owl populations. Historically, spotted owl researchers have estimated the rate of change using a Leslie Projection Matrix that is based on estimates of age- or stage-specific survival and fecundity (Caswell 1989, Franklin et al. 1996a). This method was the best available at the time for estimating rates of population change. Nevertheless, a debate on rates of population change using lambda has centered on 2 issues; unknown rates of juvenile emigration from the study areas and potential bias in estimates of juvenile survival (Stein pers. comm. 2002).

In 2001 PSW brought together a cross-section of 16 scientists to develop and present results of a meta-analysis using data gathered from 5 California Spotted Owl population studies in an effort to assess status and trends of California Spotted Owl populations. This group decided to use a different approach to estimate changes in owl numbers within the study areas, a recently developed analytical technique to estimate lambda directly from the capture-recapture data (Pradel 1996, Nichols and Hines 2002). Table 3.2.2.3a compares the results of lambda utilizing the original Projection Matrix and the more recent capture-recapture method.

Table 3.2.2.3a. Comparison of Lambda (λ) Utilizing two methods, Projections Matrix and Capture-Recapture.

Select to access Table 3.2.2.3a.

As displayed in the table above, there are varying differences in Lambda between study areas and between analysis methods. It must be noted that in general both methods show a declining trend in populations. The capture-recapture method indicates that the rate of decline may not be as great as originally predicted using the projection matrix method. However, the capture-recapture methodology is not statistically different than λ = 1.

A great deal of uncertainty regarding range wide population trends still resides in the meta-analysis. The group did not know if the results of the meta-analysis were representative of owl demographics trends throughout the Sierra Nevada. If at the inception of these studies, habitat management on the study areas was different than the surrounding areas or changed as a result of the study location (i.e. study areas were preferentially protected from management activities) than general inference beyond the study areas cannot be made (Franklin et al. 2003).

Fire Effects on PACs: Concerns continues to arise regarding the actually urgency (Volume 2, Chapter 3.5, pp. 238 -- 260) or necessity of fuels treatment to protect resources including California Spotted Owl habitat. Two GIS exercises were conducted during the review period to determine the number of PAC acres burned from 1970 -- 2001 and the number of PACs burned in the same timeframe. Table 3.2.2.3b exhibits the number of PAC acres burned during this same time period. (The actual relationship between fire and PACs is presently being analyzed and will be presented in the FEIS).

Table 3.2.2.3b. PAC Acres Burned.

Select to access Table 3.2.2.3b.

Since 1970, approximately 112,209 acres have burned within PACs randomly across the Sierra Nevada bioregion. Of those acres, 3,825 have experienced two burns. The resulting change in vegetation composition and structure is unknown. The effects from fire within PACs since 1993 is presently under investigation and will be presented in the Final SEIS.

Table 3.2.2.3c illustrates the number PACs influenced by fire since 1970. It is assumed that each of these PACs experience some change in vegetation composition and/or structure.

Table 3.2.2.3c. PAC influenced by fire.

Select to access Table 3.2.2.3c.

As illustrated above, 573 (42.5%) of the PACs within the Sierra Nevada bioregion have experienced some level of fire since 1970. Twenty-eight of those have experienced fire at least twice.

A number of conflagrations have occurred over the past 3 or 4 years to include the Buck Incident (1999) Plumas National Forest, Storrie Incident (2000) on the Lassen and Plumas National Forests, the Manter Incident (2001) and McNally Incident (2002) on the Sequoia National Forest, the Star Incident (2001) on the Eldorado and Tahoe National Forests, and the Gap Incident (2001) on the Tahoe National Forest. Each of these fires influenced one or more PACs, the magnitude of which will not be fully understood for many years. However, most of these fires did lead to total or partial lose of PACs. Over this period of time 47 PACs have experienced fire. This would suggest that the rate of PACs being effected in on the rise. Of the total PACs effects, it appears that 18 could be considered lost. Table 3.2.2.3d identifies those PAC having significant acres burned to be considered lost.

Table 3.2.2.3d. PACs experiencing significant acreage loss.

Select to access Table 3.2.2.3d.

Some of the PACs identified above have replacement acres within their surrounding Home Range Core Areas. Others have little to no options for replacement and will be removed from the system. There have been an average of 4.5 PACs lost or severely modify per year since 1998. This equates to an annual loss of approximately 0.34 percent per year.

Fuels Treatments. In 2002, approximately 9,200 acres of mechanical treatments and 7,900 acres of prescribed fire treatments were conducted in the WUI. None of the treated acres were located in PACs. Projections for 2003 indicate that approximately 35,400 acres of mechanical and prescribed fire treatments are planned in WUIs.

Southern California Drought Related Mortality: Southern California forests in the San Bernardino, Riverside, and San Diego counties are experiencing the worst drought in more than 450 years (Loe pers. Comm.). As a result, the spotted owl populations in these areas may be at a significant risk. The big cone Douglas fir and mixed conifer types stress by drought, combined with overstocked conditions, pollution, mistletoe, root disease, and bark beetle infestations are experiencing mortalities of > 40 percent in some areas (Loe pers. comm.). As larger, older trees and the associated canopy layers are lost due to mortality, the effects to spotted owl nesting and prey habitat will likely continue. The San Jacinto Mountains are experiencing especially high mortality. In October of 2002, it was estimated that 66,000 acres across all vegetation typed was affected. The total acreage effect to date is in excess of 354,000 acres. In April 2003 an estimated 175,000 acres of pine and mixed conifer have been affected, much of which is considered as spotted owl habitat. The high level of mortality being experienced in this area lies in what is considered as the "heart" of the spotted owl population in Southern California. The San Bernardino National Forest is attempting to remove the hazardous fuels as rapidly as possible and will continue to do so over an unknown period of time. Seventy known activities centers are presently being monitored to determine the affects of this drought and subsequent fuels treatments (Loe, pers. comm.).

Corrections to PAC numbers: The FEIS considered 1,310 PACs for analysis (FEIS Chapter 3, Part 4.4, page 84). Subsequent to the ROD, the Sierra Nevada national forests have been directed to evaluate spotted owl sighting data and apply the criteria for establishing PACs outlined in the ROD (Appendix A-33). For the Draft SEIS, updated maps for PACs were received from several forests (Lassen, Plumas, Eldorado, Tahoe, and Toiyabe) resulting in 1,321 PACs included in the current analysis.

Also, there is little specific number information on HRCAs in the FEIS. There are 1,320 HRCAs included in this analysis. Describing the average HRCA size is not meaningful because sizes are variable across the bioregion and some are smaller than the required acreage due to land ownership patterns.

FWS 12-Month Findings for a Petition to List the California Spotted Owl (Strix occidentalis occidentalis) (FR Volume 68, No. 31, 7589-7608): After the FWS reviewed the best available science and commercial information available, the FWS found that the petitioned action is not warranted. The Finding statement acknowledged the SNFPA ROD and its associated California Spotted Owl strategy as management direction being implemented across the Sierra Nevada's. The Findings did recognize two factors, "The first is a management review of the SNFPA (USFS 2002b) and the second is planning for implementation of an Administrative Study on the Lassen and Plumas National Forest that would evaluate the effects of extensive fuels treatment on the California spotted owl (67 FR 72136) . . . we will monitor the development of management direction, offer scientific assistance, and review the effects at a later date, if necessary." (FWS 68 FR 7604)

USDA Forest Service · Pacific Southwest Region