Name:
Basalt - Diabase Cobble - Gravel Great Lakes Shore Sparse Vegetation
Reference:
NatureServe Biotics 2019
Description:
The basalt cobble - gravel Great Lakes shore type is commonly found along the northern Great Lakes shores of the United States and Canada. Stands occur between volcanic bedrock exposures composed of both basalt and Copper Harbor conglomerates. Size of the gravel and cobble vary from less than 2 cm to over 20 cm. Size range varies depending on the wave energy acting on the shoreline and the nature of the bedrock being eroded. These steep shores are typically devoid of vegetation. At Isle Royale National Park, this cobble - gravel lakeshore is a sparsely vegetated community on cobble or gravel beaches. This community occurs as a mosaic of sparse grassland with over 25% cover, and sparsely vegetated areas with less than 25% cover. The most abundant herbs are grasses, mostly <i>Elymus trachycaulus</i> (average 29% cover); other characteristic herbs are <i>Lathyrus palustris</i> and <i>Oenothera biennis</i>; characteristic shrubs are <i>Rubus idaeus, Cornus sericea</i>, and <i>Alnus viridis</i> (each with <5% cover). The shrub zone is dominated by low shrubs, which vary from 20-60% cover. The most abundant shrubs are <i>Rosa acicularis, Rubus idaeus, Diervilla lonicera, Physocarpus opulifolius, Ribes oxyacanthoides, Alnus incana</i>, and <i>Sorbus decora</i>. There may be scattered trees (0-5% cover) including <i>Picea glauca, Abies balsamea, Thuja occidentalis</i>, and <i>Betula papyrifera</i>. Cover of herbs varies from 10-40%; the most common herbs are <i>Lathyrus palustris, Oenothera biennis, Cornus canadensis, Calamagrostis canadensis</i>, and <i>Equisetum hyemale</i>. <i>Carex atratiformis, Polygonum viviparum</i>, and <i>Trisetum spicatum</i> have been reported at the inner margin of the island's cobble lakeshore, near the tree edge. Elsewhere, in Minnesota, <i>Lathyrus japonicus</i> is characteristic.
Accession Code:
urn:lsid:vegbank.org:commConcept:34013-{F0EB4607-1101-4EFB-A76D-1F386E30FD29}
Plot-observations of this Community Concept:
6
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