Forest Investment Account

Abstract of FIA Project 6065002 and 6067002

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Avian Community Dynamics in a Coastal Forest Landscape - Clearcuts, Grouped Retention, Old-growth Benchmarks

Author(s): Dunsworth, Glen; Preston, Michael I.
Subject: British Columbia, Biodiversity, Biology, Ecology, Forestry, Landscape ecology
Series: Forest Investment Account (FIA) - Land Base Investment Program - Innovative

Abstract

The Adaptive Management program was designed to examine the effectiveness of retention systems (regimes in which patches of forest or individual trees are retained) and stewardship zoning (involves partitioning the forest into different intensities of variable retention management) in maintaining those forest attributes necessary to sustain biodiversity and essential ecosystem functions.
Monitoring all species is not feasible. We selected groups of focal species intended to expose insufficiencies in habitat elements or forest planning. Informative focal species are forest dwelling, sensitive to forest practices, practical to monitor and provide information that can guide management. Species selected encompass a range of life history characteristics - slow to fast dispersers, small to large home ranges, and reliance on a variety of different habitat elements or forest ages. Monitoring examines on occurrence, relative abundance and trends in population.
Organisms evaluated for monitoring included vascular plants, bryophytes, lichens, fungi, invertebrates and vertebrates. The most useful information from vascular plants results from tracking potential expansion of the range and abundance of exotic species, change in range of less common plants, and effects of variable retention on species assumed dependent on forest continuity or forest interior. Bryophytes (focusing on epixylics) and lichens (focusing on pendant lichens) are potentially useful in assessing biological contributions of live and dead trees and down wood retained by variable retention. They also may indicate how well small patches or dispersed trees sustain small, relatively immobile organisms that are prone to desiccation. Sampling mycorrhizal fungi can evaluate effects of edge on their distribution and help assess best patterns of variable retention to promote mycorrhizal persistence in young forests; associations with down wood can help guide retention of down wood in cutovers and patches. Most invertebrates are too poorly known to be informative. Some, such as Carabid beetle species, appear more common in old forest and can help assess efficacy of retention patches in sustaining suites of invertebrates associated with older forests. Some carabids and gastropods are poor dispersers and show promise in revealing the role of retention in facilitating dispersal of relatively immobile organisms and the potential effects of opening size and isolation of patches. Vertebrates are directly connected to public concerns and their habitat relations are best known.
We chose focal vertebrate species from taxa of concern (considering red and blue lists, proportion of range in Weyerhaeuser's coastal tenure, long-term downward trends, and assumed sensitivity to forest practices) plus other species that could inform management by their associations with habitat elements. Selected species include songbirds, snails and slugs, frogs, carabid beetles, epiphytes, and fungi. In addition we assessed stand structural attributes in Variable Retention harvest sites and benchmark sites. These studies are intended to compare relative abundance or trends of vertebrates in retention treatments and indicate types and levels that benefit various focal species selected to represent specific threats. Tracking long-term trends will direct efforts to include species with declining (or markedly increasing) trends. Some vertebrates are more wide-ranging and responsive to impacts that may be apparent only over large areas. Combined with existing knowledge, results from monitoring can aid development of species habitat models. Testing such models refines our knowledge of species requirements and help forecast impacts of forest management.


For further information, please contact Glen Dunsworth, Weyerhaeuser - BC Coastal Group - Nanaimo Timberlands Services (glen.dunsworth@weyerhaeuser.com)

Updated September 08, 2005 

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