Appendix C. CALIFORNIA SPOTTED OWL TEAM REPORT

We conducted a two-part analysis to assess the effects of SPLATs on California spotted owls (Strix occidentalis occidentalis). First, we performed a retrospective analysis using 20 years of demographic data collected at 74 spotted owl territories that included the Last Chance Study Area (LCSA) and the nearby Eldorado Study Area (ESA). This approach deviated from our original plan to directly estimate the effects of SPLATs on spotted owls at Last Chance using a Before-After Control-Impact experimental design, similar to the approach used by some of the other SNAMP Science Teams. The revised approach was necessary because too few owls were present on the LCSA and the delay in implementing the Last Chance fuels-reduction project resulted in only one year of post-treatment data collection. As a result, we needed to spatially and temporally expand the retrospective analysis to achieve sufficient power to detect changes in owl demographic parameters (Popescu et al. 2012). The drawback to our revised approach was that we could no longer specifically estimate the effects of SPLATs on owls because many different types of timber harvest, as well as wildfire and forest succession, occurred within owl territories during our study period (1993-2012). Second, we performed a prospective analysis (30 years into the future) of the effects of SPLATs and wildfire on spotted owl habitat and demography within the LCSA only. This analysis represented our integration effort with the The retrospective analysis has been published in a peer-reviewed journal (Tempel et al. 2014), and we have reproduced this paper in the first section of this appendix. We assessed the effects of forest conditions, timber harvest, and wildfire on spotted owl reproduction, non-juvenile survival, and territory occupancy using the previously mentioned 20-year data set. All habitat and timber harvest variables that we extracted from our vegetation maps were time-varying and could change annually because of natural disturbance, timber harvest, or regrowth. We categorized timber harvest into three broad categories for analytical purposes—low-intensity, medium-intensity, and high-intensity. The classification scheme was based on the expected change in forest structure and was developed after consultation with three local forest managers who were naïve to the objectives of our study. SPLATs and other U.S. Forest Service treatments conducted prior to the adoption of SPLATs were considered to be medium-intensity harvests. Adult survival and territory colonization were relatively high, while territory extinction was relatively low, in territories that had greater amounts of high-canopy-cover forest (≥70% …