Forest Investment Account (FIA) - Forest Science Program
FIA Project Y083062

    Coarse filter approaches for the conservation biology of canopy lichens in wet cedar-hemlock and sub-boreal spruce forests of central-interior BC
Project lead: Coxson, Darwyn (University of Northern British Columbia)
Author: Coxson, Darwyn S.
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
Recently, there has been growing recognition of conservation biology concerns facing canopy lichens in wetbelt forests. Past resource use, for instance, logging in toe-slope positions, has inadvertently targeted many areas of high biodiversity significance. In recognition of these pressures, the Chief Forester, in his 2002 AAC determination for the Prince George Timber Supply Area (PGTSA) called for more research within wet ICH and SBS forests “in light of a number of information gaps on rare and sensitive species such as cyanolichens”. Industry licensees have also had to consider SFI standard 4.1.4, which stipulates that licensees will have “plans in place to protect species or communities that are vulnerable at the global, national, or regional level based upon conservation status ranking systems”. A major indicator of compliance is the "Collection of information on critically imperiled and imperiled species and communities and other biodiversity-related data through forest inventory processes, mapping or participation in external programs”. Forest industry licensees are increasingly considering silvicultural practices that may promote the conservation of canopy lichens. These include shelterwood and variable retention (VR) harvesting, as well as greater green-tree retention in clearcut harvest blocks. Several information needs arise from this consideration of new forest management practices. These include: Will sensitive species be retained and grow under silvicultural systems that maintain some of the structural attributes of old-growth forests? Old forest retention targets in the PGTSA are aspatial, and are currently set at 53 and 48% respectively for the ICHvk2 and SBSvk. Although preliminary studies have noted the importance of topographic position and stand age there are currently no criteria that would allow resource managers to predict lichen biodiversity in wetbelt forests when using current coarse filter planning tools such as Predictive Ecosystem Mapping (PEM) and/or the Vegetation Resource Inventory (VRI). Can we identify coarse filter attributes that are associated with sensitive lichen species within the ICHvk2 and SBSvk? The research being conducted to address these questions has three major components: Component 1. Stand Structural Attributes and Canopy Lichen Diversity. The first step in determining lichen responses to changes in managed forests, and ultimately recommending harvesting practices that promote stand structural attributes, is to find out how lichen communities respond to the natural range of variation in stand structural attributes. We have taken measurements of lichen biodiversity and stand structural attributes across broad regional landscapes of the Upper Fraser River watershed, focusing on the mesic and submesic ICHvk2 and adjacent SBSvk. These mesic and submesic site series account for the majority of the ICH and SBS landbase in the PGTSA. These landscape level assessments address the question: “What coarse filter attributes are required to achieve biodiversity goals with respect to maintaining species populations?” Fieldwork under this project component was conducted in Year 1 and 2 of the proposal, with follow-up data analysis and extension/publication of results occurring in Years 2 and 3. This project component will provide information that can be used, in combination with the Vegetation Resource Inventory (VRI), to extend the utility of Predictive Ecosystem Mapping to include canopy lichen biodiversity. Component 2. Lichen Biodiversity Response to Partial-Cutting Silvicultural Systems. The second major component of our proposed research program involves the reassessment of cyanolichen and Calicioid lichen biodiversity (both major indicator groups), in long-term study plots located in the group-retention area of the Lunate Creek Silvicultural Systems trial. Initial post-harvest assessments in these plots (2001) confirmed the presence of Aold-growth@ indicator species (eg. Chaenothecopsis tasmanica) within retained forest patches. Assessments of their status in 2006 (Yr 2), five years after harvesting, will provide important information on whether or not sensitive species can be retained under a partial-cutting silvicultural system that maintains selected attributes of old-growth forest. These assessments of lichen diversity for key indicator groups will address the FSP priority research topic “Can current management practices, such as variable retention, create structures and processes that are effective in maintaining key elements of biodiversity at landscape scales?” Component 3. Evaluating Edge Effects on Lichen Growth and Productivity within Landscape Mosaics Created by Forest Harvesting. The third major project component would be studies examining the impact of forest harvesting on lichen viability. This component examines the interaction of harvest type and edge effects. Traditional clearcut harvest blocks create an abrupt transition from closed-canopy conditions at the edge of harvest blocks (so-called “hard” edges). The resultant changes in boundary layer climate of surrounding forest canopy can have major impacts on lichen communities. Leave tree retention within harvest blocks may reduce the magnitude of these edge effects (so-called “soft edges”). This has major implications for conservation biology of canopy lichens, where even small reductions in the ratio of “edge” to “interior” forest habitats can have a large influence on landscape level patterns of lichen retention. This study component uses growth rates of Lobaria pulmonaria and L. retigera as indicators of canopy cyanolichen viability in the ICHvk2. Lichen growth rate enclosures were placed in the canopy of retained trees within recent harvest blocks and in trees along transects from block edges into adjacent stands. These edge effect studies are replicated in three harvest blocks with high levels of green-tree retention (shelterwood or variable retention) and three with little or no green-tree retention (clearcuts). This examination of how forestry practices can influence edge effects is a critical element in determining the effectiveness of designated landscape level planning elements on lichen biodiversity. This project component was established in collaboration with TRC Cedar Ltd in 2003 under FIA funding. The continuation of this research under FSP auspices allows us to obtain a multiyear data set, which is important because lichen growth rates are known to vary among years. This assessment of lichen growth responses in landscape mosaics created by forest harvesting provides important information in support of the question “which stand and landscape approaches work best/worst for which species”.
Related projects:  FSP_Y061062FSP_Y072062


Stand Structural Attributes and Canopy Lichen... (Report) (0.8Mb)
Canopy Lichens Report (1.1Mb)
Predicted Lichen Biodiversity (Map) (0.3Mb)

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Updated August 16, 2010 

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