The British Columbia Ministry of Forests has invested substantial funding to research and implement partial cutting trials with the goal of maintaining arboreal lichen in managed forests for mountain caribou (Rangifer tarandus caribou; Waterhouse et al. submitted, Stevenson et al. 2001). Many of these high-retention (70% retention) partial cut systems have been implemented by licensees operating in caribou habitat, based on the recommendations of Stevenson et al. (2001). As well, historic partial cutting systems (intermediate utilization [IU] or understory retention [UR]; 15-25% retention) were implemented across large areas of caribou habitat 20-30 yrs ago, resulting in various amounts of stand-level retention available on the landscape. Numerous studies have reported the response of arboreal lichen to the aforementioned partial cutting systems (Stevenson and Coxson 2003, Lewis 2004, Lewis et al. 2006, Waterhouse et al. submitted). These studies generally reveal that partial cuts maintain or accumulate lichen biomass that may be sufficient for caribou foraging. However, few, if any studies have reported or even begun to examine the actual caribou response to these alternative harvest systems. One reason for this lack of research is that partial cut experimental trials are often on a scale too small to be meaningful to wide-ranging ungulates. However, operational partial cutting has been implemented across much larger scales, at varying levels of retention, patterns, and time-since harvest. This source of variation provides the opportunity to examine relationships among retention levels, time-since harvest, and caribou use. Caribou foraging patterns in old-growth forests have been well documented (Terry et al. 2000, Kinley et al. 2003, Serrouya et al. submitted). Over the past 3 years, we have expanded this work by conducting snow trailing to evaluate the use of different stand-types (partial cuts, clearcuts, uncut forests) by caribou (Serrouya et al. 2006) and to quantify caribou foraging intensity and selection of forest attributes within partial cuts (lichen biomass, tree size, density, and vigour; Lewis et al. 2006). Our study has begun to evaluate within-stand selection of forest attributes in partial cuts and the selection of partial cut stands relative to clearcut and uncut, primary forests at a fine scale of resolution. Snow trailing provides distinct advantages over VHF telemetry including improved spatial resolution (<10 m vs. 250 m), continuous tracking, and the ability to distinguish foraging vs. movement behaviour. However, because of variety of stands available, we require additional sampling to obtain the precision required to confidently draw inference from our results. We require 1 more winter of sampling to obtain necessary precision of our estimates and to prepare a final report. The research outlined in this proposal will provide the necessary context to complete work that can be used to compare the relative use among partial cuts, clearcuts, and primary forests, both in terms of habitat use and foraging requirements. We realize that the current, proximate decline in mountain caribou is linked to apparent competition (Holt 1977, 1984), likely caused by incidental predation on caribou because of the changing predator-prey system (Seip 1992, Wittmer et al. 2005a, 2005b, 2006 in prep.). However, if the altered predator-prey system is resolved, the role of partial cuts to maintain forage for caribou will continue to be a significant management issue because foraging attributes for caribou tend to conflict with traditional 100-yr forestry rotations (Terry et al. 2000, Kinley et al. 2003, Serrouya et al. submitted). Project Theme/Topic/Priority: Theme 1.0 Ecosystem structure, function and processes, and biodiversity related to forest management. Topic 1.4 Effectiveness of stand-level structures and habitat in maintaining biodiversity Research priority b: What are appropriate stand-level targets and configurations
Serrouya, Robert, Lewis, Douglas W.; McLellan, Bruce N.; Pavan, Gary. 2007. Selection of movement paths by mountain caribou during winter within managed landscapes: 4-year results of snow trailing. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), Mountain, caribou, British, Columbia
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