Natural Community Systems -- Photo Guide

Montane cliff system

montane cliff system at Cannon Cliff in Franconia Notch (photo by Dan Sperduto for the NH Natural Heritage Bureau)
montane cliff system at Cannon Cliff in Franconia Notch (photo by Dan Sperduto) 


Description: Montane cliffs in NH are generally found above 1,000 ft. in elevation (mostly >1,200 ft.) and are thus concentrated in the White Mountain region and sparingly at higher elevations in the Sunapee Uplands and Sebago-Ossipee Hills and Plains subsections of central NH.  Cliffs from around 9001,200 ft. elevation along the low elevation valleys of the White Mountains are transitional to temperate ridge - cliff - talus systems.  The most common natural community in this system is montane - subalpine acidic cliff, which dominates the entire area of many cliffs.  Montane - subalpine circumneutral cliff communities are relatively uncommon within this system, and when they do occur they are often restricted to only certain zones of a cliff, with the remainder of the cliff corresponding to montane - alpine acidic cliff.  A few large montane cliffs (e.g., Cannon Cliff) have alpine cliffs, but most alpine cliffs are found as part of the complex community mosaic in alpine ravine/snowbank systems.

Many cliffs have both acidic and circumneutral zones on their faces.  Circumneutral cliffs are associated with at least two circumstances: 1) where the matrix bedrock is calcareous (lithologies include: intermediate, mafic, calc-silicate, or carbonate-bearing); and/or 2) where groundwater emerges from fractures in the rock (particularly under overhangs), transporting mineral nutrients (specifically, base-cations) to the cliff face.  Circumneutral portions of cliffs vary from very small, restricted areas (e.g., tens of square feet) to more extensive areas (e.g., acres).  Only a few cliffs in New Hampshire have close to uniformly circumneutral conditions across the entire cliff face. Bryophytes are excellent and sensitive indicators of pH conditions.

Cliff seeps are also relatively common in these systems.  Typically the seeps occupy relatively small areas but occasionally cover an acre or more in extent.  The plants that occur on cliff seeps are very distinct from those that typify more dry or mesic cliff conditions; the difference is equivalent to that seen when going from a fen to an upland forest.  They range from acidic to circumneutral conditions and are indicated by wetland species.


Diagnostic natural communities:

      • Montane - subalpine acidic cliff (S4)

      • Montane - subalpine circumneutral cliff (S2S3)


Peripheral or occasional natural communities:

      • Red spruce - heath - cinquefoil rocky ridge (S3S4) -- on less steep, slab portions of cliff system



Landscape settings: steep outcrops on hill side slopes

Soils: dry to wet, acidic to circumneutral, turfy mineral to organic substrates in cracks and on benches

Spatial pattern: steep outcrops (>65 degrees slope) to overhanging; <1–100+ acres; irregular

Physiognomy: sparsely vegetated to partially wooded

Distribution: mostly above 1,000 ft. elevation in the White Mountains and northward, and scattered in adjacent subsections to the south


Characteristic species:

Montane - alpine acidic cliff:
   
Picea rubens (red spruce)
   Abies balsamea (balsam fir)
   Potentilla tridentata (three-toothed cinquefoil)
   Juncus trifidus (highland rush)
   Paronychia argyrocoma var. albimontana (silverling)*
   Aster acuminatus (whorled aster)
   Betula alleghaniensis (yellow birch)

On both montane - alpine and temperate acidic cliffs:
   
Deschampsia flexuosa (common hair-grass)
   Polypodium virginianum (rock polypody)
   Cystopteris tenuis (Mackay's brittle fern)
   Cystopteris fragilis (fragile fern)

Montane - alpine circumneutral cliff:
Vascular plants
   Campanula rotundifolia (harebell)
   Dryopteris fragrans (fragrant fern)*
   Potentilla floribunda (shrubby cinquefoil)
   Thuja occidentalis (northern white cedar)
   Woodsia ilvensis (rusty woodsia)

Bryophytes 
   Tortella tortuosa (moss)
   Gymnostomum aeruginosum (moss)
   Distichium capillaceum (moss)
   Myurella siberica (liverwort)
   Amphidium mougeotii (moss)

On both montane - alpine and temperate circumneutral cliffs:
   
Asplenium trichomanes (maidenhair spleenwort)
   Woodsia ilvensis (rusty woodsia)
   Sambucus racemosa ssp. pubens (red elderberry)

Cliff seeps:
Acid seepage indicators:
   Drosera rotundifolia (round-leaved sundew)
   Houstonia caerulea (bluets)
   Viola spp. (violets)
   Circaea alpina (small enchanter's nightshade)

Subacid to circumneutral seepage indicators:
Vascular plants
   Scirpus hudsonianus (northern cotton club rush)
   Pinguicula vulgaris (common butterwort)
   Woodsia glabella (smooth woodsia)

Bryophytes
   Preissia quadrata (liverwort)
   Mnium thomsonii (moss)
   Cryptomnium hymenophylloides (moss)
   Conocephalum conicum (liverwort)


Associated natural community systems: Cliff systems are often but not always associated with talus systems; massive cliffs with little fracturing tend not to have much talus debris at their bases, whereas those with considerable fracturing do have talus slopes.  Montane cliffs are also frequently associated with montane rocky ridge and slab systems and subalpine heath - krummholz/rocky bald systems.  

montane cliff system at Bondcliff (photo by Ben Kimball)
montane cliff system
at Bondcliff (photo by Ben Kimball)



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