User:Choess/Serpentine barrens

Serpentine barrens are ecosystems in eastern North America characterized by the replacement of the surrounding forest by grassland and savanna due to the effects of the underlying serpentine soil. (The serpentine barrens of western North America are also underlain by serpentine soils, but are much more sterile, with very little plant life of any sort; the plant communities there are significantly different from those in eastern North America.) Serpentine outcrops occur along the eastern edge of the Appalachian Mountains from Alabama to Newfoundland and Quebec; serpentine barrens are found in a portion of that range from North Carolina to New York state. To the north of that point, a covering of glacial till has hindered the development of serpentine soils. The serpentine tablelands of Newfoundland and Quebec are significantly affected by snow and wind as well as soil and, while often referred to as "barrens," more closely resemble tundra than the grasslands and savanna of the southern Appalachians.

These ecosystems have historically been maintained by fire and grazing, and the cessation of these activities has greatly reduced the area of the barrens. While far less rich in endemic species than the western serpentine barrens, the eastern serpentine barrens harbor a few endemics as well as a number of disjunct occurrences of prairie species.

Geology and soils
Tyndall & Hull don't say much. Note that soils can be very diverse, due to: different types of serpentine rock and degree of metamorphosis, degree of weathering post-exposure.

Edaphic factors (T&H): often but not always low-moisture. May be different in pH from surrounding soils. Contain toxic metals, wrong ratios of nutrients. Worldwide (p. 77), serpentine soils have low availability of 1 or more nutrients (esp. Ca, K, N, P), low Ca:Mg ratio, high levels of Ni and Cr, strong vertical pH gradients. No single explanation for edaphic factor. Ca:Mg ratio for mid-Atlantic from 0.03 to 1.86, mean 0.49. (p. 78) Serpentine plants typically better at excluding or tolerating Mg and scavenging Ca. No known Ni hyperaccumulators in the east. Study at Soldiers Delight shows that neither Cr nor Ni detected in soils or plant tissues! Elevated Mg conc. (vs. Ca) was principal serpentine factor there.

Current
Georgia
 * Track Rock Gap?

North Carolina
 * Buck Creek

The State Line group runs, etc.
 * Robert E. Lee Park
 * Cherry Hill, Hartford Co. (location in NHP NL prep is error)
 * Goshen-where? maybe a ref to E. Goshen, PA?
 * Travilah, Montgomery Co., preserved as serpentine woodland (not a barrens)->historical?
 * Soldiers Delight and others
 * Goat Hill Barrens along Octoraro, PA-MD border. TNC and PA state forest (+ Camp Horseshoe). Nottingham County Park immediately to east.
 * Pilot Preserve, Chrome Barrens
 * Lancaster County, New Texas and Rock Springs.

Chester Group
 * Willisbrook (Sugartown or Serpentine Ridge), Unionville Barrens, Pink Hill, Brinton's Quarry, Fern Hill
 * Sconneltown, Strode's Mill, Marshallto(w)n-all in East Bradford, see Ebert & Holt report for the twp.

New York
 * Grymes Hill, Staten Island (Bloodroot Valley isn't really a barrens)

Historical
Chester Group: see R. Latham, Pink Hill report re. destruction
 * Fawkes Run
 * Preston Run
 * Bear Hill
 * Blue Hill
 * Middletown Twp. assorted-destroyed except Pink Hill
 * Cedar Barrens

Centreville Barrens, due to Hoopes Reservoir.

Author's notes

 * Things to address:
 * Geology and soil types: what's the rock, how did it get there, what associated soil types?
 * Locations: a tiny bit in Georgia, some in NC (S. rhiannon!), VA?, barrens groups in PA and MD, extirpated Centreville Barrens, ditto Staten Island
 * Vegetation: different vegetative communities: grassland/savanna/forest/fens, endemics
 * Fauna: short section, not much known
 * Conservation: how barrens were maintained, present fate, possible conservation plans (R.E. Latham)
 * Should serpentine tablelands be treated separately? NatureServe suggests they have affinity with the small ultramafic outcrops in Vermont etc. which don't really seem like barrens. This reduces endemic taxa to Cerastium velutinum var. villosissimum and Symphyotrichum rhiannon, as Adiantum viridimontanum, Aspidotis densa and Minuartia marcesans occur in these areas only. Question: if R. treats A. densa as endemic to serpentine in the east, why not add A. aleuticum? Perhaps because the latter supposedly occurs on dolomitic substrates in the NE.
 * Actually, how are we going to write that article? Would like to treat the Vermont outcrops, but those aren't exactly tablelands either.