Forested watershed

Acid Peatlands are widely distributed across northern Minnesota, but they are typically small and isolated. They are confined to particular hydrologic regimes, soil types, and landscape positions. Also, many of the species found in Acid Peatlands are associated with acidic soil conditions. Therefore, these systems are not expected to expand to new territory within the assessment area or outcompete other forest types. Because of their acid conditions, however, these forests may face less competition from other forest types.

Multiple forest impact models tend to agree that these species are more likely to decrease in suitable habitat and biomass across a range of climate scenarios by the end of the century. Black spruce and tamarack are at the southern edge of their ranges in Minnesota, and therefore may not tolerate warmer conditions. Minnesota is also approaching the southern range limit for sphagnum moss. Acid peatlands also contain a suite of rare and endemic plant species that are adapted to acidic, nutrient-poor conditions.

Peatlands function in a relatively narrow window of water table conditions and can respond in a matter of years to water table changes. Higher water levels could result in a transition to open peatland systems, but lower water levels could allow other forest types to invade as peat layers dry and decompose. The effects of roads, beaver dams, drainage ditches, or other watershed modifications may be intensified by climate change. Acid Peatlands typically occur on perched water tables without connection to groundwater.

Forested Rich Peatlands are widely distributed across northern Minnesota, but are confined to particular hydrologic regimes, soil types, and landscape positions. Therefore, they are not expected to expand to new territory within the assessment area or outcompete other forest types.

Higher growing-season temperatures may increase evapotranspiration rates and lower water tables in peat systems. This would reduce the rate of peat accumulation. Peat might also start to degrade over time in these systems as a result of increasing decomposition rates due to warmer conditions or lower water levels.

Multiple forest impact models tend to agree that these species are more likely to decrease in suitable habitat and biomass across a range of climate scenarios by the end of the century. Most species in this system are at the southern edge of their ranges in Minnesota, and therefore may not tolerate warmer conditions. Minnesota is also approaching the southern range limit for sphagnum moss.

Forested Rich Peatlands function in a relatively narrow window of water table conditions and can respond in a matter of years to water table changes. Higher water levels could result in a transition to open peatland systems, but lower water levels could allow other forest types to invade as peat layers dry and decompose. The effects of roads, beaver dams, drainage ditches, or other watershed modifications may be intensified by climate change. Forested Rich Peatlands in large complexes fed through groundwater may be somewhat buffered from seasonal or short-term moisture deficits.

Invasive species such as European buckthorn and reed canarygrass are generally expected to benefit from longer growing seasons, disrupted environments, and warmer temperatures, but it's hard to predict exactly how they may be affected by climate change.

The ongoing decline in black ash documented in northern Minnesota already presents problems for the health of Wet Forests. It also seems very likely that the emerald ash borer will reduce the amount of black ash in northern Minnesota. This is particularly concerning for black ash swamps that don't contain many other species. If ash are removed, there is a risk that water tables will rise in these Wet Forests and they may not be able to maintain tree cover.

Multiple forest impact models tend to agree that these species are more likely to increase in suitable habitat and biomass across a range of climate scenarios by the end of the century.