Ecological dynamics
This site is a peatland characterized by a plant community dominated by shrub and fine-leaved graminoids. Tree cover is often present, but may be sparse. Shrub cover is variable ranging from sparse to dense. Graminoid cover is generally >50% and dominated by sedges. Sphagnum and brown mosses are present. In the absence of anthropogenic disturbances, these sites are relatively stable and maintain a mosaic of shrub, graminoid, or shrub-graminoid plant dominance.
State 1
Reference State
The reference state is dominated by conifer or tall shrub communities. Soils are mucky peat or peat. The shrub layer is composed of speckled alder, shrubby cinquefoil, bog rosemary, alder, willows, Labrador tea, and bog laurel. The ground layer is predominately sphagnum moss with forbs and graminoids intermixed. Peat continues to form and accumulate over time. Species to the reference state are not mutually exclusive, but will have a higher productivity compared to acid peatlands.
Dominant plant species
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black spruce (Picea mariana), tree
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arborvitae (Thuja occidentalis), tree
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bog Labrador tea (Ledum groenlandicum), shrub
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bog laurel (Kalmia polifolia), shrub
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gray alder (Alnus incana), shrub
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bog rosemary (Andromeda polifolia var. glaucophylla), shrub
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common reed (Phragmites australis), grass
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bunchberry dogwood (Cornus canadensis), other herbaceous
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Canada mayflower (Maianthemum canadense), other herbaceous
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starflower (Trientalis borealis), other herbaceous
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bluebead (Clintonia borealis), other herbaceous
Community 1.1
Mature Spruce-Tamarack
This site has a canopy of mature black spruce and/or tamarack. In cases where tamarack is monotypic, it is usually due to a lack of seed source for black spruce, or mortality of black spruce caused by species-specific insects or disease (MN DNR Forestry).
Sphagnum dominates the moss layer. The forb layer is dominated by bunchberry (Cornus canadensis) and starflower (Trientalis borealis) (MN DNR 2003). Both a tall shrub and low shrub layer commonly occur. Shrub layer is more prevalent than acid peatlands.
Canopy cover exceeds 50%, more shade-tolerant species can be present in the understory, including creeping snowberry (Gaultheria hispidula), soft-leaved sedge (Carex disperma) , ferns (Dryopteris spp.), clubmosses (Lycopodium annotinum), and bunchberry (Cornus canadensis) (MN DNR 2003).
Community 1.2
Cedar Bog
Cedar bogs are dominated by white cedar, balsam fir, and black spruce. Balsam fir and black spruce are rarely dominate in this community. The shrub and forb layer has a more diverse presence in this community compared to spruce dominated communities. Commonly occur adjacent of mineral areas and are influenced by mineral rich subsurface water flow (MN DNR 2003). Occurs where peat accumulation has started to limit direct access of shallowly rooted plants to nutrient rich soils with through flow present.
Community 1.3
Alder Swamp
Tall shrub wetlands dominated by speckled alder on peat soils and may be more prevalent along the margins of peatlands. Tree cover less than 25% and tall-shrub layer dominates. Shrub layer is dominated by speckled alder, red-osier dog wood, swamp gooseberry, common gooseberry, and swamp red currant (MN DNR 2003).
Alder swamps communities are intermixed with other peatland communities commonly especially by drainageways.
Dominant plant species
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paper birch (Betula papyrifera), tree
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black ash (Fraxinus nigra), tree
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speckled alder (Alnus incana ssp. rugosa), shrub
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redosier dogwood (Cornus sericea ssp. sericea), shrub
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hairystem gooseberry (Ribes hirtellum), shrub
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red currant (Ribes triste), shrub
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skunk currant (Ribes glandulosum), shrub
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bluejoint (Calamagrostis canadensis var. canadensis), grass
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fowl mannagrass (Glyceria striata), grass
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softleaf sedge (Carex disperma), grass
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bristlystalked sedge (Carex leptalea), grass
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dwarf red blackberry (Rubus pubescens), other herbaceous
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crested woodfern (Dryopteris cristata), other herbaceous
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yellow marsh marigold (Caltha palustris), other herbaceous
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touch-me-not (Impatiens), other herbaceous
State 2
Logged State
This state describes the removal black spruce and some tamarack through logging. The natural plant community has been severely disturbed and the site has been impacted by heavy equipment. Compositional changes in canopy cover and soil/water disturbances impact all layers of the plant community. Best management practices can help reduce site damage and the implementation of post-logging timber stand improvement practices can enhance tree regeneration.
Community 2.1
Logged Community
This state describes the removal of black spruce and some tamarack. With the disturbance of the site by heavy equipment. Canopy cover has been removed and shrub density will increase. Species composition will vary depending on the type, timing, and severity of disturbance.
State 3
Invaded State
The plant community is still an open peatland dominated by shrubs and graminoids; however, invasive species are now present on site and will increase with the absence of management inputs.
Community 3.1
Disturbed State
Water ponding for a longer than normal duration results in canopy mortality of tamarack and spruce trees and opening of the understory to light. Alder and willow shrubs often remain on edge zones. Site disturbance such as logging often allows for the introduction of non-native vegetation on these sites. The plant community is dominated by shrubs and graminoids; however, invasive species are now present on site and will increase with the absence of management inputs.
State 4
Open State
This community is dominated by fine-leaved sedges, graminoids, and shrubs. Soils are mucky peat or peat. The shrub layer is composed of bog birch, shrubby cinquefoil, bog rosemary, alder, willows, bog Labrador tea, and leatherleaf. Tamarack trees may be present but are scattered. The ground layer is predominately graminoids which includes multiple sedge species. Marsh cinquefoil (purple marshlocks), Labrador bedstraw, marsh bellflower, and eastern marsh fern are usually present.
Community 4.1
Graminoid Communities
The peatland system of northeastern Minnesota forms a mosaic of plant community variations across the landscape. Dominated by a diversity of wet-tolerant graminoid species. Multiple species of native sedges are present on site. The shrub layer is variable but usually sparse to scattered.
Community 4.2
Shrub Community
Numerous low and tall shrubs may be present in this community. Tall shrub species include bog willow (Salix pedicellaris), bog birch (Betula pumila), speckled alder (Alnus incana), balsam willow (Salix pyrifolia), slender willow (Salix petiolaris), and meadowsweet (Spiraea alba) . Common low shrubs include leatherleaf (Chamaedaphne calyculata), Labrador tea (Ledum groenlandicum), small cranberry (Vaccinium oxycoccos), bog rosemary (Andromeda polifolia), and sweetgale (Myrica gale). Tamarack seedling and saplings are usually present. Multiple species of willow and sedges occur. Water depth, microtopography, peat depth, and other soil characteristics will influence the plant community composition.
Community 4.3
Marsh Community
Zones within this site may have areas that can be described as a sedge-cattail marsh. Cattail and sedges are dominant. Emergent forbs such as broad-leaved arrowhead (Sagittaria latifolia), marsh skullcap (Scutellaria galericulata), bedstraws (Galium spp.), and beggarticks (Bidens spp.) are common. Areas of open water may be present. Areas of deeper water will contain floating and submerged forbs such as duckweed (Lemna spp.), smartweed (Polygonum spp.), and American white water lily (Nymphaea odorata).
Pathway 4.1A
Community 4.1 to 4.2
Lack of fire and/or periodic drought will allow shrub species to increase.
Pathway 4.1B
Community 4.1 to 4.3
An substantial increase in water levels including ponding will begin to transition the community to a more open structure. Tree death will occur as water deepens. This scenario can be caused by beaver dam construction.
Pathway 4.2A
Community 4.2 to 4.1
More frequent surface fires will reduce shrub density. Also, an increase in precipitation level with associated ponding can reduce shrub density.
Pathway 4.2B
Community 4.2 to 4.3
An increase in water levels such as long-term ponding such as caused by beaver dam construction.
Pathway 4.3A
Community 4.3 to 4.1
Removal of beaver dam and return to unobstructed hydrology.
Pathway 4.3B
Community 4.3 to 4.2
Removal of obstructions, such as beaver dams, will reduce ponding and increase areas for shrub regeneration.
Transition T1A
State 1 to 2
This transition involves logging, usually clearcutting, but with reserves for seed sources, site preparation, control for disease and invasive species, and seeding, in order to maintain the site as a viable commercial timber harvesting state. This transition is only possible, or desirable, when the management is applied to phases in which radial growth has been prolific and trees have reached maturity, exhibiting taller, more commercially viable trees.
Transition T1B
State 1 to 3
Impoundment or maintenance of water on-site, and/or establishment of invasive species. Beaver activity, roads, drainage, and other alterations in hydrology can transition the Acid Peatlands out of Reference to an Impounded State, where water is ponded on site for longer durations and receives excessive nutrients from overland surface flow.
Transition T1C
State 1 to 4
Impoundment or maintenance of water on-site. Beaver activity, roads, drainage, and other alterations in hydrology can transition the Acid Peatlands out of Reference to an Open State, where water is on site for longer durations and receives excessive nutrients from overland surface flow causing stunted tree growth.
Transition T2A
State 2 to 3
Introduction and establishment of non-native invasive species.
Restoration pathway R4A
State 4 to 1
Draining or maintenance of water on-site causing alterations in hydrology that can transition the Open state back to the Reference State, where water is on site for shorter durations and receives less nutrients from overland surface flow causing increased tree growth.
Transition T4A
State 4 to 3
Introduction and establishment of non-native invasive species.
