Common (Translated Scientific) Name: Prairie Cordgrass - Mat Muhly - Prairie Dropseed - Prairie Goldenrod - Flat-top Goldentop Riverscour Sparse Vegetation

Colloquial Name: River Ledge Limestone Pavement

Hierarchy Level:  Association

Type Concept: This river ledge pavement community is found in the United States and Canada, ranging from northern Michigan, northern Wisconsin and southern Ontario to northern New York. Stands occur as small patches on limestone ledges along a river''s shore; these ledges are scoured by river water and ice during periods of peak water flow. Typically, the community has an open canopy with less than 10% cover of trees or shrubs. The ground layer is dominated by grasses and sedges, or a mosaic of pavement patches and grassy patches. Cover of herbs is variable, with some areas having nearly 100% cover. Other areas have a lot of exposed rock pavement, with as little as 15% cover of herbs, and are confined to linear rock crevices. Characteristic species include Euthamia graminifolia, Muhlenbergia richardsonis, Oligoneuron album, Spartina pectinata, and Sporobolus heterolepis.

Diagnostic Characteristics: No Data Available

Rationale for Nominal Species or Physiognomic Features: No Data Available

Classification Comments: This community type is not considered alvar because the river shoreline processes (including annual flooding and ice-scouring) seem to be more important influences of plant species composition and structure than the processes characteristic of alvar communities (such as alternating wet and dry soil moisture regimes and infrequent fire). This community also seems distinct from alvar types because of the dominance of Spartina pectinata and Muhlenbergia richardsonis, which are not found in other alvar types (Reschke et al. 1998).

Similar NVC Types: No Data Available

note: No Data Available