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Scientific Name: Twisted Sedge Cobble Rivershore; State Rank: S4
This is a new community type in Maine, to describe the 'plain vanilla' rivershore type. Photos and maps will come soon!
- Community Description
- Soil and Site Characteristics
- Similar Types
- Conservation, Wildlife and Management Considerations
- Characteristic Plants
- Associated Rare Plants
- Associated Rare Animals
- Examples on Conservation Lands You Can Visit
Community Description: Vegetation on these rivershores may be sparse to dense depending on degree of flooding, length of exposure, and substrate type. Characteristic perennial species that tolerate inundation and flood scouring include twisted sedge and low-growing willow species. Associated species tend to vary widely from site to site and may be diverse; they include tufted hairgrass, red-osier dogwood, sweet gale, water parsnip, water hemlock, cardinal flower, flat-topped aster, and smartweeds. Nonvascular plants are usually sparse but where present may include Bryum species. Invasive, exotic species may be problematic in these areas, especially coltsfoot, purple loosestrife, and Japanese knotweed. Back to top.
Soil and Site Characteristics: This herbaceous and shrub vegetation occurs on coarse substrates deposited along medium- to high-energy river channels and, less frequently, exposed lakeshores with heavy wave action. Seasonal flooding and ice-scour maintain the open nature of these communities; generally, they develop in areas of the active channel that are exposed at low water or in drought years. Back to top.
Diagnostics: Herbs and graminoids are dominant or co-dominant with shrubs in a rivershore or streamshore setting. Back to top.
Similar Types: Laurentian River Beaches are found along the St. John river and contain certain indicator species such as sand cherry and freshwater cordgrass. Rivershore Shrub Thickets may be adjacent to (landward) of these types and are dominated by shrubs rather than herbs. Rivershore Outcrops occur on bedrock outcrops rather than cobble or gravel. The Riverwash Sand Barren is restricted sand and gravel bars of the Saco River and contains beach heather as a characteristic species. Back to top.
Conservation, Wildlife and Management Considerations: This community is linked to naturally fluctuating water levels and occasional ice scour. The rivershore habitat of this natural community suggests that threats from development are relatively low. Hydrologic alteration (i.e., impoundments) would compromise the disturbance regime, but new dams are unlikely on medium and large rivers. Exotic or agricultural species are common at some sites.
The rare White Mountain tiger beetle (Cicindela ancocisconensis) occurs in this habitat type. Another rare insect, the cobblestone tiger beetle (Cicindela marginipennis), is currently under consideration for federal listing and in our area is known from Vermont, New Hampshire, and New Brunswick but not Maine. Back to top.
Distribution: One of the predominant rivershore types in the New England - Adirondack Province and Laurentian Mixed Forest Province. Extends in all directions from Maine. Landscape Pattern: Small to large patch, linear. Back to top.
Characteristic Plants: These plants are frequently found in this community type. Those with an asterisk are often diagnostic of this community.
- Blue-joint grass
- Cardinal flower
- Flat-topped aster
- Mad-dog skullcap
- Purple-stemmed aster
- Red-osier dogwood
- Spotted joe-pye weed
- Sweet gale
- Tufted hairgrass
- Twisted sedge
- Virgin's bower
- Water hemlock
- Water parsnip
There are no documented rare plants associated with this natural community.
- White Mountain tiger beetle
Examples on Conservation Lands You Can Visit
There are no documented examples on conservation lands that you can visit associated with this natural community.