Temperate Calcareous Outcrop

Ecology and Physical Setting 

These outcrops are found in the warmer regions of the state, on summits and other natural openings on calcareous bedrock such as limestone, dolostone, marble, or calcareous schist, usually below 2,000 feet elevation. Some of these rock types are susceptible to weathering and so can develop deep fissures where water seeps into cracks, enlarging them over millennia. These fissures add to the overall droughtiness of these areas, draining water away very quickly. Weathering also releases nutrients held in the calcareous bedrock. Thus, lime-loving plants characterize these outcrops. 

Vegetation

Temperate Calcareous Outcrops are patchworks of bare rock and soil pockets that support a diverse array of calcium-loving plants. In some cases, they are dominated by grasses, sedges, and bryophytes; in other cases, they are shrub-dominated. Still other outcrops have little vegetation, and herbs may dominate locally. There are often scattered trees, but as on all outcrop communities, they are stressed by periodic drought and do not reach great size. Some characteristic species include northern white cedar, yellow oak, snowberry, downy arrowwood, pasture rose, smooth shadbush, ebony spleenwort, Kalm’s brome grass, and ebony sedge. Like other natural calcareous openings, this community supports an unusually high number of rare plants.

Wildlife Habitat

Temperate Calcareous Outcrops are typically found as small forest openings or on cliff tops, and the wildlife present is most associated with the adjacent forest. Several reptiles, including DeKay’s brownsnake and the rare eastern ratsnake and five-lined skink, are known to use these sun-warmed outcrops for basking. Chipping sparrows forage in the openings and nest in stunted trees in the outcrop, or in trees or shrubs at the forest edge.

Related Communities

• Temperate Calcareous Cliff shares many species in common with Temperate Calcareous Outcrop but has slopes greater than 60 degrees. 
  
   
• Temperate Acidic Outcrop shares some species and many ecological processes with Temperate Calcareous Outcrop, but species diversity is lower and calcium-dependent plants are absent. There are intermediates between the two, on neutral to slightly acidic bedrock. 
  
   
• Red Cedar Woodland often interfingers with open outcrops.

Conservation Status and Management Considerations

Temperate Calcareous Outcrop is an uncommon community in Vermont. Throughout New England and New York, low and mid-elevation calcareous bedrock is rare, so our outcrops are of regional conservation value. A number of high quality examples of Temperate Calcareous Outcrop are on conserved lands in Vermont, but additional examples should be sought for protection.

These outcrops can offer expansive views and can be popular places to visit. Visitors should use care to avoid trampling the vegetation. 

Distribution/Abundance

This community is known from the Champlain Valley, Vermont Valley, and Taconic Mountains biophysical regions. An outlying example is known from the Southern Green Mountains. These outcrops are regionally uncommon.

Characteristic Plants

Trees

White ash – Fraxinus americana

Eastern red cedar – Juniperus virginiana

Northern white cedar – Thuja occidentalis

Red oak – Quercus rubra

White oak – Quercus alba

Yellow oak – Quercus muehlenbergii

Shagbark hickory – Carya ovata

Hophornbeam – Ostrya virginiana

Shrubs 

Downy arrowwood – Viburnum rafinesquianum

Pasture rose – Rosa carolina

Shrubby cinquefoil – Dasiphora fruticosa

Smooth shadbush – Amelanchier laevis

Snowberry – Symphoricarpos albus

New Jersey tea – Ceanothus americanus

Herbs

Cow-wheat – Melampyrum lineare

Ebony spleenwort – Asplenium platyneuron

Rock sandwort – Minuartia michauxii

Little bluestem – Schizachyrium scoparium

Ebony sedge – Carex eburnea 

Woodland sedge – Carex pensylvanica

Common pinweed – Lechea intermedia

Woodland sunflower – Helianthus divaricatus

Poverty grass – Danthonia spicata

Wild columbine – Aquilegia canadensis

Field chickweed – Cerastium arvense

Balsam ragwort – Packera paupercula

Four-leaved milkweed – Asclepias quadrifolia

Non-native Plants

Canada bluegrass – Poa compressa

Rare and Uncommon Plants 

Richardson’s sedge – Carex richardsonii

Hairy honeysuckle – Lonicera hirsuta

Lyre-leaved rock cress – Arabidopsis lyrata

Creeping juniper – Juniperus horizontalis

Purple clematis – Clematis occidentalis

Snowy aster – Solidago ptarmicoides

Bronze sedge – Carex foenea

Smooth false-foxglove – Aureolaria flava

Harsh sunflower – Helianthus strumosus

Downy arrowwood – Viburnum rafinesquianum

Hairy beardtongue – Penstemon hirsutus

Yellow oak – Quercus muehlenbergii 

Fragrant sumac – Rhus aromatica

Canada buffaloberry – Shepherdia canadensis 

Golden corydalis – Corydalis aurea

Hoary whitlow-grass – Draba cana

Longleaf bluet – Houstonia longifolia

Spring forget-me-not – Myosotis verna

Wiry witchgrass – Panicum flexile

Prickly rose – Rosa acicularis

Rough dropseed – Sporobolus compositus

Biltmore hawthorn – Crataegus biltmoreana 

Seneca snakeroot – Polygala senega

Kalm’s brome grass – Bromus kalmii

Rock spike-moss – Selaginella rupestris

Associated Animals

DeKay’s brownsnake – Storeria dekayi

Chipping sparrow – Spizella passerina 

Rare and Uncommon Animals

Eastern ratsnake – Pantherophis alleghaniensis

Common five-lined skink – Plestiodon fasciatus

Columbine duskywing – Erynnis lucilius

Places to Visit

Shaw Mountain Natural Area, Benson, The Nature Conservancy



Pease Mountain, Charlotte, University of Vermont Natural Area



Button Bay State Park, Ferrisburgh, Vermont Department of Forests, Parks, and Recreation