Forest Investment Account (FIA) - Forest Science Program
FIA Project Y072062

    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
Contributing Authors: Coxson, Darwyn S.; Stevenson, Susan K.
Subject: Forest Investment Account (FIA), Lichens, British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
Both interior cedar-hemlock (ICH) and sub-boreal spruce (SBS) stands in the wet-belt zone of central-interior BC were historically characterized by long ecological continuity (time between major disturbances). This has favoured the development of what have now been recognized as globally significant epiphytic lichen assemblages (1). At the same time, there has been growing recognition of conservation biology challenges faced by these lichen communities. In his AAC determination for the Prince George Timber Supply Area (PGTSA), the Chief Forester called for more research, in light of a number of information gaps on rare and sensitive species such as cyanolichens in wetbelt forests (2). 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 with this standard 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'. The listing of the cyanolichen Nephroma occultum as a species of special concern by COSEWIC has further highlighted this need. Preliminary steps to address these information gaps include studies by Benson and Coxson (3), who found that canopy structure was a major determinant of lichen response in wetbelt forests, and studies by Radies and Coxson (4), who found that naturally even-aged stands were essentially devoid of canopy cyanolichens 120-140 years after stand initiation. This later finding is a major concern in landscapes where rotation ages will typically be 100 years or less. Today, licensees are increasingly considering silvicultural practices such as variable retention (VR) harvesting, which may promote the conservation of canopy lichen communities. This raises two major questions: Can we identify coarse filter attributes that are associated with sensitive lichen species within regional landscapes? Will sensitive species be retained (and grow) under silvicultural systems that maintain selected attributes of old-growth forests? The need for landscape level planning tools has been highlighted by Ministry of Sustainable Resource Management (MSRM) recommendations that old-growth management targets be met through aspatial designations. Although preliminary studies have noted the importance of topographic position (1) and stand age (5), there are currently no criteria that would allow resource managers to predict lichen biodiversity when using current coarse filter planning tools such as Predictive Ecosystem Mapping (PEM) and/or the Vegetation Resource Inventory (VRI). We would therefore propose development of a set of coarse filter attributes associated with the occurrence of sensitive lichen species in the ICHvk2 and SBSvk. In this way, our field results, when combined with VRI and PEM databases, could be applied to predict lichen biodiversity in wetbelt forests. Our proposed research program would have three major components addressing these information gaps: The first is the measurement of stand structural attributes and canopy lichen diversity in polygons from mesic and submesic ICHvk2 stands (which account for the majority of ICH landbase in the PGTSA) and mesic SBSvk stands, using PEM mapping from Canfor. Measurements of stand structural attributes will follow DeLong et al. (6), measurements of canopy closure will be modeled on Lertzman and co-authors (7), while lichen biodiversity assessments will use methods of McCune et al. (8). Pilot studies testing these methodologies for use in the ICHvk2 and SBSvk were conducted this past summer in conjunction with the Sustainable Forest Management Network. These landscape scale assessments will address FSP priority research topic 1.3, including question 1: 'What coarse filter attributes are required to achieve biodiversity goals with respect to maintaining species populations?' Fieldwork under this project component will be conducted in year one of the proposal, with data analysis and extension/publication of results occurring in years one and two. The second major research program component involves reassessments of lichen diversity by Trevor Goward in long-term research plots from the group-retention harvest area at Lunate Ck (this site part of the Northern Wetbelt Silvicultural Systems LTRI). Initial post-harvest assessments in these plots were taken in summer 2001. These plots focus on Caliciales (or pin lichens) and foliose cyanolichens, groups that have been proposed as important indicators of lichen biodiversity. Field sampling will be conducted in year 2 of the proposed research project, with follow-up taxonomic determinations, data analysis, and presentation of research results in year 3. These assessments address the priority FSP research theme topic 1.3, including both questions 1 (above), and question 2:'Can current management practices, such as variable retention, create structures and processes that are effective in maintaining key elements of biodiversity at landscape scales?' Given the long-term nature of lichen responses to changes in their surrounding environments, this investment of time and resources in monitoring previously established plots provides far greater scientific return (and benefits to stakeholders) than would equivalent investments in new projects. The third major project component will also examine the impact of current management practices on lichen biodiversity; measuring growth rates of the cyanolichens Lobaria pulmonaria and L. retigera on both retained trees within previously established harvest blocks (variable retention and other silvicultural systems), and on trees within the surrounding stands (ie. edge effects). This examination of edge effects is a critical element in determining the effectiveness of designated landscape level planning elements on retaining lichen biodiversity. Sensitivity analysis by MSRM staff in Prince George, for instance, show that the effectiveness of currently designated old-growth management areas in the ICHvk2 are highly dependant upon edge effects (S. Carson, pers., comm..), which are currently unknown for these canopy lichen communities. This project component was established in collaboration with TRC Cedar Ltd in 2002 under FIA funding. The continuation of this research under FSP auspices will allow us to obtain critical multiyear data sets that provide important new knowledge about lichen responses to forestry practices. Lichen growth assessments will be conducted in each of years one through three, with final deliverables (publications and extension) scheduled for year three. In combination, this research will: provide feedback on the success of current practices in maintaining lichen biodiversity at landscape scales; enable the development of predictive landscape planning tools (coarse filter approaches) for identifying and maintaining lichen species of concern in regional landscapes; and provide guidance to the development of silvicultural systems that promote retention of canopy lichen biodiversity.
Related projects:  FSP_Y061062FSP_Y083062


Forest Ecology and Management 235, Issues 1-3
Forest Ecology and Management 242 (2007) 5-16
Executive Summary (24Kb)

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Updated August 16, 2010 

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