Natural Community Systems -- Photo Guide

Temperate ridge - cliff - talus system

aerial view of the temperate ridge - cliff - talus system at Rattlesnake Mtn. in Rumney (photo by Dan Sperduto for the NH Natural Heritage Bureau)
aerial view of the temperate ridge - cliff - talus system
at Rattlesnake Mtn. in Rumney (photo by Dan Sperduto)

Description: This system is found on steep slopes and adjacent rocky ridges at elevations below 2,200 ft., primarily in southern and central New Hampshire. It typically expresses itself as a complex mosaic of rocky woodlands, rock outcrops, cliffs, and talus slopes with an abundance of oaks, pitch or white pines, and other temperate species. Rocky ridge communities typically occupy ridgetops and upper slopes and have a woodland or sparse woodland structure with extensive bedrock exposure. These bedrock outcrops include slabs with less than 65 degree slopes. Slabs with slopes greater than 65 degrees are classified as temperate acidic cliffs. Where erosion of cliffs and slabs produces accumulations of large boulders, talus communities are formed. These include temperate lichen talus barrens, which are lichen-dominated boulder fields with little vascular plant cover, and wooded talus communities such as red oak - black birch wooded talus, which generally have an open woodland structure. Wooded talus communities have variable and patchy understories of tall shrubs, herbs, vines, and rock polypody (Polypodium virginianum) on boulders depending on local soil development. Large talus slopes with big boulders can produce a cold micro-climate created by late-melting ice which supports species with more northern affinities, such as red spruce or mountain ash.

At elevations below 1,000 feet, species of Appalachian distribution are common, such as white oak (Quercus alba), black oak (Quercus velutina), chestnut oak (Quercus montana), pitch pine (Pinus rigida), and hickories (Carya spp.). Red oak (Quercus rubra) and white pine (Pinus strobus) are also common in these areas. Sites with Appalachian communities such as Appalachian oak - pine rocky ridge and chestnut oak forest/woodland are generally restricted to the southern tier of the state. Above 1,000 feet elevation, Appalachian species disappear and Quercus rubra (red oak) is often the dominant tree in rocky woods and on forested talus communities. Dry-site species dominate the understory, including an abundance of blueberries, huckleberries, grasses and sedges, and lichens.

At higher elevations in the mountains, this system is replaced by the montane rocky ridge system, montane acidic talus system, and/or montane cliff system. Large montane ridges, cliffs, and talus slopes in the mountains are classified as independent systems because they are considerably larger and support more diverse complexes of communities than their temperate counterparts. These systems are differentiated from the temperate system by the presence of communities dominated by red spruce (Picea rubens) and/or red pine (Pinus resinosa), and the absence of red oak.


Diagnostic natural communities 

      
• Appalachian oak - pine rocky ridge (S3)

      • Chestnut oak forest/woodland (S1S2)

      • Red oak - pine rocky ridge (S3S4)

      • Pitch pine rocky ridge (S1)

      • Red oak - black birch wooded talus (S3S4)

      • Appalachian wooded talus (S1S2)

      • Temperate lichen talus barren (S2S3)

      • Temperate acidic cliff (S4)

Peripheral or occasional natural communities

      
• Dry red oak – white pine forest (S3S4)

      • Dry Appalachian oak forest (S3)

      • Temperate circumneutral cliff (S2) 

      • Circumneutral rocky ridge (S1)


Landscape settings:  steep slopes and ridges with exposed bedrock -- outcrops, cliffs, and talus

Soils:  variable soils; little to no soil development on open talus, cliffs, and rock outcrops; variable organic development or coarse to fine mineral soil colluvium among talus boulders or in gullies; mostly shallow, draughty, acidic soils on ridges and slopes

Spatial pattern:  elliptical to irregularly linear along steep slope contours (150+ acres)

Physiognomy:  mosaic of sparsely vegetated barrens on talus, cliffs and outcrops, and woodlands and sparse woodlands on talus and dry slopes

Distribution:  Mostly below 2,200 ft. elevation, primarily in southern and central New Hampshire


Characteristic species:

Trees
   Quercus rubra (red oak)
   Quercus alba (white oak)
   Quercus velutina (black oak)
   Quercus montana (chestnut oak)
   Quercus ilicifolia (scrub oak)
   Carya spp. (hickories)
   Pinus strobus (white pine)
   Pinus rigida (pitch pine)
   Betula lenta (black birch)
   Ostrya virginiana (ironwood)
   Acer spicatum (mountain maple)

Shrubs and vines (lianas)
   Vaccinium pallidum (hillside blueberry)
   Gaylussacia baccata (black huckleberry)
   Juniperus communis (ground juniper)
   Comptonia peregrina (sweet fern)
   
Arctostaphylos uva-ursi (bearberry)
   Hamamelis virginiana (witch hazel)
   Rubus spp. (raspberries and blackberries)
   Sambucus racemosa (red elderberry)
   Fallopia cilinodis (fringed bindweed)
   Parthenocissus quinquefolia (Virginia creeper)

Herbs
   Aureolaria pedicularia var. intercedens (fern-leaved false foxglove)
   Solidago odora (sweet goldenrod)
   Schizachyrium scoparium (little bluestem)
   Deschampsia flexuosa (common hairgrass)
   Polypodium virginianum (rock polypody)
   Dryopteris marginalis (marginal wood fern)
   Maianthemum canadense (Canada mayflower)
   Aralia nudicaulis (wild sarsaparilla)


Associated natural community systems: This system represents the combination of three system types described in the 2005 systems classification: Appalachian oak rocky ridge system, temperate acidic talus system, and temperate cliff system, as well as red oak – pine rocky ridge communities, previously included in the montane rocky ridge system.  Individual rocky ridge, cliff or talus landscape settings at lower elevations rarely occur at system-level scales that support more than 1 or 2 natural community types.  However, system-level complexes of communities are found where ridge, cliff, and talus formations co-occur at single sites (or at least two out of three).  In these circumstances, each setting may only contain one or two communities, but collectively form repeating assemblages of 3-6 communities.  

In the mountains, the montane rocky ridge system, montane cliff system, and montane acidic talus system will remain separate, as they tend to occur at larger scales and with a greater diversity of communities, meriting their system status. Ridge, cliff, and talus examples that support more mineral-rich conditions over significant areas are classified as separate systems due to the distinctly different assemblage of communities.


Temperate ridge - cliff - talus system at Holts Ledge in Lyme (photo by Dan Sperduto for the NH Natural Heritage Bureau)
Temperate ridge - cliff - talus system at Holts Ledge in Lyme
(photo by Dan Sperduto)


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