In 2007, bark beetle infection levels will reach their peak in Interior BC forests, including our study sites (Fig 1). With field work and analyses of existing data, we will evaluate the impacts on wildlife communities of epidemic and post-epidemic MPB conditions and of beetle management activities. The health of mixed coniferous forests is a critical management issue in BC with implications and impacts on the forest industry, biodiversity conservation and regional land use planning. Interior BC forests have high biodiversity (>200 vertebrate species), and many wildlife species have strong preferences for large and decayed trees for nesting and feeding (Martin et al. 2004, Drever & Martin 2007). As salvage operations focus on mature pine stands, retention of remaining old mixed forests will become increasingly important to support the rich assemblage of resident and migrant wildlife (Martin et al. 2006). Insect outbreaks and fire are the two major natural disturbance factors structuring the succession of mature conifer stands (Kilgore 1978). The current outbreak of mountain pine beetle in interior BC is at a larger scale and intensity than previously experienced, raising the concern that wildlife species may be strongly impacted by these dramatic changes in forest health (Conner et al. 2001). Wildlife population dynamics may become unstable due to the cumulative effects of changes on the landscape caused by cutting of old forest, declines in tree health caused by insect outbreaks, increases of >2.5 deg C in winter and spring minimum temperatures, beetle management activities resulting in a major uplift of the AAC, and fire suppression. Despite the regularity of insect outbreak events, the vast amounts of forest habitat involved, and the importance of understanding natural disturbance regimes for effective ecosystem management, beetle outbreaks remain a natural disturbance type that is essentially unstudied for BC forest ecosystems, or elsewhere in North America. Since 1995, we have conducted population and community level studies on >180 wildlife species in the Cariboo-Chilcotin region of interior BC to determine the critical habitat attributes and wildlife responses to several silvicultural treatments (selection cutting with variable retention, beetle hazard reduction, salvage cutting; Martin et al. 2002). We monitored tree health conditions annually using standard forest inventory, wildlife tree and forest health techniques for >10,000 tagged trees on 29 mixed stands. We have determined critical habitat attributes and population trends for many species in healthy old forest stands (Martin et al. 2004). From 1995-2005, the percent of dead and dying conifers increased from 6% to 55%, with numbers of dead trees rising sharply in 2004 (Martin et al. 2006). Over this period, 40% of 101 bird and mammal species showed significant population changes, with some increasing and others in sharp decline (Drever & Martin 2007). For many insectivorous cavity nesters, bark beetle-attacked stands initially represented an enhancement of habitat quality for foraging (Bull et al. 1986). Since 2001, cavity nester populations increased, and moved to nesting patches with high density MPB-attacked trees, with year round residents showing greater increases than migratory species (K. Martin, Unpubl data). However, as the epidemic proceeds, conditions can deteriorate as the supply of forest insects and old trees decline (Stone 1995). On our study sites, MPB benefits declined as tree mortality exceeded 40%; by 2006 several species were in steep decline. We urgently need to determine which forest conditions will support wildlife populations through peak and post-epidemic conditions. We describe below how we will address this question. In 2007, we will evaluate the role of insect outbreaks and beetle management activities on wildlife biodiversity at the peak and in post-epidemic conditions in mature mixed conifer forests. We will also evaluate the lo ...
Norris, Andrea R., Martin, Kathy; Aitken, Kathryn E.H.; Drever, Mark C.; Davidson, Peter; Easton, Wendy. 2008. Predicting biodiversity maintenance after bark beetles and MPB management. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2008MR399
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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