Legacy FAR1 strategy/approaches.
Very few species are able to withstand the prolonged flooding characteristic of wet bottomland forests. Therefore, even a loss of a few species could dramatically alter community composition.
If conditions become drier, as are projected to occur under some models during the summer or fall, some mesic bottomland species may be able to migrate into areas previously occupied by wet bottomland species. If that occurs, the mesic bottomland specis may out-compete some wet bottomland species.
Model projections for more common species like boxelder, red maple, and cottonwood are more reliable and project stable or increasing habitat suitability. However, the models available are not equipped to capture the complex hydrologic processes that occur in these systems, so actual habitat suitability might differ from what is projected.
Impact model projections suggest habitat suitability for green ash will persist across a range of climate scenarios. However, emerald ash borer is likely to arrive in the area and dramatically reduce ash populations for reasons other than climate change.
These species are relatively rare across the landscape as a whole. In order for model projections to be reliable, there needs to be a large enough sample size to properly characterize current, and thus future, habitat suitability. Therefore, there is not enough information to reliably predict habitat suitability for some of these rare species.
This community type is characterized by prolonged, frequent flooding and wet, poorly drained soils. The dry conditions that are possible later in the growing season may be too dry for some species.
Because both heavy precipitation and some drier conditions are expected to occur with climate change, heavier flooding in lower elevation areas and drier conditions in higher elevation areas may narrow the range of places suitable for mesic bottomland forests.
Seeds from species like sycamore, elm, sweetgum, cottonwood, and hackberry are able to disperse long distances, and are further facilitated by being near rivers that can carry them long distances.
Many mesic bottomland forests have been altered from their original state due to the placement of dams and other water control structures. This has already disrupted natural flood regimes, which will likely be further altered by the direct effects of changes in precipitation and indirect effects of human demands on water during drought periods.
The models available are not equipped to capture the complex hydrologic processes that occur in these systems, so actual habitat suitability might differ from what is projected. With that caveat in mind, multiple models models tend to agree that habitat suitability for boxelder may increase. Boxelder is not currently a dominant species in mesic bottomland forests, but may increase in dominance from increased habitat suitability.
