Name:
Juniperus communis - (Juniperus virginiana) - Rhus aromatica - Viburnum rafinesqueanum / Oligoneuron album Shrubland
Reference:
NatureServe Biotics 2019
Description:
The juniper alvar shrubland type occurs throughout the Great Lakes region of the United States and Canada, in northern New York, southern Ontario, northern Ohio, northern Michigan, and eastern Wisconsin. Stands occur on very shallow soils (usually less than 30 cm deep) over flat limestone outcrops (pavements). Moisture varies over the season, but summer droughts are typical. Juniper alvar shrublands often occur in a patchy landscape mosaic with other alvar communities, including tufted hairgrass wet alvar grassland, little bluestem alvar grassland, annual alvar pavement-grassland, alvar nonvascular pavement, and poverty grass dry alvar grassland. Grikes (eroded cracks in the rock up to 2 m or more deep and extending 5-30 m in length) may occur, with shrubs and trees rooted in the cracks. Shrubs dominate, with over 25% cover of tall, short, and dwarf-shrubs; the average is about 43% cover of shrubs, with less than 10% of that being tall shrubs. Characteristic tall shrubs (2-5 m tall) are scrub forms of trees such as <i>Juniperus virginiana, Thuja occidentalis</i>, and <i>Quercus macrocarpa</i>. Tree forms (>5 m tall) of these species may be present, but trees have less than 10% cover in the community. Other less common trees (>5 m tall) that may be present include <i>Carya ovata, Ulmus thomasii</i>, and <i>Fraxinus americana</i>. Characteristic short shrubs (0.5-2 m tall) include <i>Juniperus communis, Cornus racemosa, Rhus aromatica, Prunus virginiana</i>, and <i>Viburnum rafinesqueanum</i>. Some dwarf-shrubs (under 0.5 m tall) are usually present, including <i>Arctostaphylos uva-ursi</i> and <i>Symphoricarpos albus</i>. Characteristic vines include <i>Toxicodendron radicans</i> and <i>Vitis riparia</i>. The herb layer forms a dry, grassy meadow between the shrubs; average cover of herbs is about 23%. The most abundant herbs are <i>Danthonia spicata, Oligoneuron album</i>, and <i>Carex umbellata</i>. Less than 50% of the ground surface is exposed limestone bedrock, which is usually covered with lichens, mosses, and algae.
Accession Code:
urn:lsid:vegbank.org:commConcept:33975-{BF0A10ED-5055-4385-8E86-405BCD4219D0}
Plot-observations of this Community Concept:
17
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