Approach
Introducing species from the local region that are adapted to novel site conditions or stressors associated with climate change such as flooding, drought, and road salt pollution may transform vulnerable wetlands into sustainable and functional systems. Introducing species or genotypes from other geographic regions that theoretically are adapted to future projected conditions in a given state or region has associated risks, particularly in terms of the potential for outbreeding depression, maladaptation, and inadvertent introduction of aggressive genotypes or invasive species; research using common garden, controlled environment, and genomic studies is essential before this tactic can be safely executed. Confining movement of species within their current or historic range (‘facilitated adaptation’) or slightly beyond that is considered to be a more conservative approach that minimizes these risks, as does moving only common or widespread species with ample information on their life histories.
Tactics
- Plant flood-tolerant species in wetlands that are vulnerable to flooding, but that currently do not support such species. Look to nature for candidates, such as native species associated with emergent and submergent marsh communities.
- Plant drought-tolerant species in sites that are expected to experience more frequent dry conditions throughout the growing season (e.g., due to soil or hydrological characteristics).
- Plant salt-tolerant plants in wetlands that are likely to receive runoff from paved roads in winter, but that currently do not support such species.
- Employ the NatureServe Climate Vulnerability Index web-based tool to assess vulnerability of individual species to climate change. Favor and restore species that have low vulnerability rankings.
- Use geographic information system (GIS) software and species distribution modeling (SDM) software to support decision making relating to seed provenancing. A decision support framework for this approach may also be useful.
- Employ “climate-adjusted provenancing” by supplementing locally collected seed with seed collected along a linear climate gradient that aligns with climate change projections.
- Hand pollinate at-risk species in declining populations affected by pollinator disruption (e.g., decline of specific insect pollinators) to accommodate gene flow and outcrossing of species where it may improve seed set.
Strategy
Strategy Text
This strategy seeks to enable transitions of communities to new desirable states through shifts in plant species composition while maintaining or producing desired wetland functions. Climate change may drive major alterations in wetland plant community composition and net primary productivity, as well as geographic shifts of some wetland types. Climate parameters are changing at a rapid and unprecedented pace, setting up conditions where local plants may no longer be ideally suited to local conditions. Habitat fragmentation and isolation further reduce the fitness and adaptive capacity of plant populations by causing reduced gene flow and inbreeding recession. For native wetland species that are already rare, these threats may render populations vulnerable to extirpation or extinction, forcing consideration of drastic measures such as assisted migration. Managers may determine that resisting such threats and changes is not feasible at some sites, and that managing for a range of acceptable trajectories is more practicable; monitoring outcomes and periodically re-evaluating restoration targets is essential when uncertainty is high.