Forest managers must focus on individual taxa or groups of taxa for a variety of reasons (Table 1), but primarily because species can act as ‘indicators’ of the effects of forestry and of the success of management actions.1-3 Conservation actions may vary from monitoring aspects of life history, like population size or breeding success, to ensuring adequate habitat elements, like dead wood at multiple scales. A central challenge of species-focused management is that actions designed to support one species may impact other species, some favourably and some not. The ultimate goal of species-focused management is to minimize the risk of extinction or extirpation. Decision making may require an assessment of the extinction risks involved in a suite of management scenarios using formal methods like Population Viability Analysis.
Table 1. Some criteria to use in selecting species to manage in harvested forests.
|Sensitivity||Species can act as ‘indicators’ of the effects of forestry and the success of management actions. Sensitivity to forest harvesting results from habitat requirements that are narrow or that conflict with logging, such as the requirement for old forests or large unlogged areas, life-history characteristics, like concentrated breeding or over-wintering (e.g. snake and bat hibernacula), and other factors.|
|Extinction-prone||Globally rare species, those in decline, or those threatened by factors that may or may not include logging, and species with certain life history characteristics (e.g. large body size) may be prone to extinction or extirpation from logged areas.|
|Functional Role||‘Keystone’ species affect the ecosystem proportionally more than other species. Examples include carnivores that limit prey population size and species that create habitat for other species, such as beavers and cavity excavators like the Pileated Woodpecker Dryocopus pileatus.|
|‘Umbrella’||Some species, like wolverines Gulo gulo, have spatially large habitat requirements. It is assumed that management for such species will ‘cover’ the requirements of other species, particularly those with smaller spatial requirements.|
Since resources for conservation are limited, some taxa must be prioritized over others. In addition to ‘indicator’ taxa, criteria such as social value or stewardship responsibility measured by the extent of global range or population within an area also may be used to identify species requiring management focus. For example, managers are solely responsible for the stewardship of species that are endemic (confined) to particular areas, including the operating tenure of a forest company or the entire province of British Columbia.
1Thompson, I.D. and P. Angelstam. 1999. Special Species. In M.L. Hunter (ed.) Maintaining biodiversity in forest ecosystems (pp. 434-459). Cambridge University Press, Cambridge, UK.
2Lindenmayer, D.B., C.R. Margules and D.B. Botkin. 1999. Indicators of biodiversity for ecologically sustainable forest management. Conservation Biology 14: 941-950.
3Simberloff, D. 1998. Flagships, umbrellas and keystones: is single-species management passé in the landscape era? Biological Conservation 83: 247-257.