Approach
A species is considered maladapted when its environment changes at a rate beyond the species’ ability to adapt and accommodate those changes. Species at the southern or highest elevational extent of their geographic range are especially vulnerable to habitat loss, and some of these species are expected to decline rapidly as conditions change. Monitoring or inventory data for some species may already show evidence of decline at a particular site, although their decline may not be attributed to a single cause, but to a combination of causes that may include varying degrees of interaction with climate change. Models that incorporate climate change and species’ life history characteristics may identify other species that are likely to decline. Species declines may require rapid and aggressive management responses to maintain forest cover and ecosystem function during periods of transition. In ecosystems where the dominant species are likely to decline substantially or disappear, this may mean strongly altering the species assemblage through active or passive means.
Tactics
- Removing unhealthy individuals of a declining species in order to promote other species expected to fare better. This does not imply that all individuals should be removed, and healthy individuals of declining species can be retained as legacies.
- Anticipating and managing rapid decline of species with negative prognoses in both the short and long term (e.g. hemlock, ash) by having adequate seed stock of a desired replacement species expected to do well under future climate conditions.
- Protecting healthy legacy trees that fail to regenerate while deemphasizing their importance in the mix of species being promoted for regeneration.
- Planting disease-resistant cultivars of elm or chestnut where they are likely to have suitable habitat.
- Planting southern species, such as shortleaf pine, north of its current range on suitable sites based upon its projected range expansion.
Strategy
Strategy Text
This strategy seeks to maintain overall ecosystem function and health by gradually enabling and assisting adaptive transitions of species and communities in suitable locations. Species composition in many forest ecosystems is expected to change as species adapt to a new climate. Many of the approaches in this strategy attempt to mimic natural processes, but may currently be considered unconventional management responses. In particular, some approaches incorporate assisted migration, which remains a challenging and contentious issue. It is suggested that managers thoroughly investigate potential consequences to the native ecosystem before attempting to introduce new species. This strategy is best implemented with caution, incorporating due consideration of the uncertainties inherent in climate change, the sparse record of previous examples, and continued uncertainties of forest response. Outcomes from early efforts to transition communities can be evaluated to provide both information on future opportunities and specific information related to methods and timing.
Shannon, P.D.; Swanston, C.W.; Janowiak, M.K.; Handler, S.D.; Schmitt, K.M.; Brandt, L.A.; Butler-Leopold, P.R.; Ontl, T.A. (in review). Adaptation Strategies and Approaches for Forested Watersheds. Ecological Applications.,