Habitats of North Carolina
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Floodplain Forests
Rich Wet-Mesic Hardwood Forests
General Description The hardwood forests that comprise this habitat are associated nutrient-rich soils and cool, shaded, and humid microclimates. Over most of the state, these conditions occur on forested slopes with underlying mafic or other base-rich rock formations. They are particularly associated with slopes that have east- or north-facing exposures, limiting insolation especially during the hottest parts of the day. Species in this habitat are not restricted to slopes, however. They are tolerant of short-term flooding and can occur well out into rich bottomlands.

These conditions are relatively frequent in the Mountains, especially in rich cove forests and northern hardwood forests, and are also widespread, if scattered, across the Piedmont. In the Coastal Plain, the largest examples are associated with brownwater rivers, which carry sediments derived from rich soils in the Mountains and Piedmont. These sediments coat not only the floodplain but are often deposited well up on the adjoining slopes. This is especially true for the lower Roanoke valley, where the rich sediments reach all the way to the top of the bluffs, completely covering the sandy soils that are typical of the Coastal Plain (LeGrand and Hall, 2014). A few isolated examples are associated with areas closely underlain by marl, a calcium-rich rock formed from deposits of fossil mollusk shells.

With 137 species identified so far as belonging to this habitat, this is one of the most biodiverse of any found within the state. For both plants and many species of the invertebrates, this reflects the sheltered, cool, moist conditions as well as the high pH and abundance of nutrients needed by the plants. It also reflects the long biogeographic history of mesic forests in the Southern Appalachians, the center of diversity for many of the taxonomic groups that characterize this habitat.

This habitat strongly overlaps with others that are also associated with nutrient-rich, high pH soils. These include Rich Wet Hardwood Forests, whose Determining Species are much more confined to the wet soils of bottomlands; the Rich Dry-Wet Hardwood Forests, whose species occupy the widest moisture range in this group, occurring on dry ridges down to floodplains; and the Rich Dry-Mesic Hardwood Forests, whose species are highly flood-intolerant and occur only in uplands, but only where the soils are high in nutrients and pH.

Other intersecting types of hardwood-dominated habitats require cool, moist conditions but are not as tied to high nutrient soils. These include the General Wet-Mesic Hardwood Forests and General Mesic Hardwood Forests. Others are less general in distribution and occur in either the Mountains or the Coastal Plain.

Abiotic Factors Geographic Regions: Lower Coastal Plain to High Mountains. USDA Hardiness Zones: 6-8. Landform: slopes, bottomlands, and wet flats and occasionally on ridges. Slope Aspect: north and east facing on slopes, otherwise flat. Soil Moisture: Mesic to wet. Soil texture: loamy to silty, permitting burrowing by fossorial species; rocks are often present on the slopes and in the mountains extensive areas of talus can be present. Soil pH: circumneutral. Soil Nutrient Content: rich in mafic or calcareous minerals. Microclimate: Cool and humid. Hydrological Features: springs and seeps are common, particularly at the interface between slopes and bottomlands. Flood Frequency: upper slopes usually never flood but lower slopes and bottomlands may flood several times per year. Flood Duration: hours to days in the bottomlands and lower slopes. Fire Frequency: very rare. Drought Frequency: uncommon to rare. Ice Storm Damage: low to moderate. Wind Storm Damage: moderate. Insolation: canopies are well insolated, lower strata are deeply shaded.

Biotic Structure Vegetation Type: Closed-canopy forests composed of broadleaf, deciduous trees (Loblolly Pines may be present but are not a key feature). Strata Subcanopy, shrub, and herb-layers well-developed and often lush. Woody debris and leaf litter plentiful except in flood channels or other areas frequently scoured by floods.

Co-evolved Species Groups Phagic and Competitory Symbioses:
Acer floridanum-Acer saccharum //Cameraria saccharella-Peridea basitriens-Phyllonorycter lucidicostella
Aesculus species // Cameraria aesculisella-Trigrammia quadrinotaria complex
Apocarya Hickory species // Catocala agrippina-Catocala nebulosa
Asimina species // Eurytides marcellus-Omphalocera munroei-Talponia plummeriana
Cardamine species // Anthocharis midea
Carya cordiformis // Catocala subnata
Carya laciniosa-Carya ovata // Catocala luctuosa
Juglans nigra // Baileya australis-Caloptilia blandella-Hypena madefactilis
Juglans species // Acrobasis juglandis-Catocala neogama-Hypena madefactalis-Pediopsoides distinctus
Laportea canadensis // Hypena sordidula
Podophyllum peltatum // Papaipema rutila
Trillium species // Scopula ordinata
Ulmus species // Acronicta morula-Nerice bidentata
Urticaceae species // Hypena humuli-Polygonia comma

Flower // Pollinator Mutualistic Symbioses:
Geranium maculatum // Andrena distans
Claytonia virginica // Andrena eriginiae

Competitor Guilds:
Light Competitors:
Florida Maple is shade-tolerant (Jones, 1990) persists under climax conditions. Bitternut Hickory and Black Walnut are shade-intolerant (Smith, 1990; Williams, 1990); Black Walnuts produce allelopathic chemicals that limit the growth of competing tree species. Shagbark Hickory is intermediate in terms of shade tolerance but is a climax species in many stands (Graney, 1990). Slippery Elm and Sugarberry are shade-tolerant (Cooley and Sambeek, 1990; Kennedy, 1990).

Determining Species
Andrena distansS3S40.00132
Andrena erigeniaeSpring Beauty AndrenaS3S40.00132
Conotrachelus retentusSNR
Geothlypis formosaKentucky WarblerG5S3S4S3S40.00132
Anthocharis mideaFalcate OrangetipG5S5S50.00000
Eurytides marcellusZebra SwallowtailG5S5S50.00000
Polygonia commaEastern CommaG5S5S50.00000
Polygonia interrogationisQuestion MarkG5S5S50.00000
Adiantum pedatumNorthern Maidenhair-fernG5S5S50.00000
Amauropelta noveboracensisNew York FernG5S5S50.00000
Athyrium asplenioidesSouthern Lady FernG5S5S50.00000
Phegopteris hexagonopteraBroad Beech FernG5S5S50.00000
Erigenia bulbosaHarbinger-of-springG5S1S10.33330
Polemonium reptansJacob's-ladderG5S1S10.33330
Ranunculus micranthusRock ButtercupG5S1S10.33330
Viola walteriProstrate Blue VioletG4G5S1S10.33330
Collinsonia tuberosaPiedmont HorsebalmG3G4S1S2S1S20.11107
Cardamine dissectaDissected ToothwortG4S2S20.03699
Cardamine douglassiiDouglass's BittercressG5S2S20.03699
Enemion biternatumEastern IsopyrumG5S2S20.03699
Euonymus atropurpureusEastern WahooG5S2S20.03699
Hylodesmum glutinosumPointedleaf Tick-trefoilG5S2S20.03699
Mertensia virginicaVirginia BluebellsG5S2S20.03699
Tradescantia virginianaVirginia SpiderwortG5S2S3S2S30.01230
Chaerophyllum procumbensSpreading ChervilG5S3S30.00407
Coreopsis tripterisTall TickseedG5S3S30.00407
Cypripedium parviflorumYellow Lady's-slipper G5S3S30.00407
Delphinium tricorneDwarf LarkspurG5S3S30.00407
Erythronium americanumAmerican Trout-lilyG5S3S30.00407
Euphorbia obtusataWoodland SpurgeG4S3S30.00407
Eurybia mirabilisBouquet Aster G3S3S30.00407
Nanopanax trifoliusDwarf GinsengG5S3S30.00407
Phacelia covilleiButtercup Phacelia, Buttercup Scorpion-weedG3S3S30.00407
Scrophularia marilandicaCarpenter's Square FigwortG5S3S30.00407
Symphyotrichum phlogifoliumThinleaf Late Purple AsterG5S3S30.00407
Trillium cuneatumLittle Sweet TrilliumG4G5S3S30.00407
Trillium rugeliiSouthern Nodding TrilliumS30.00407
Aconitum uncinatumBlue MonkshoodG4S3S4S3S40.00132
Arisaema dracontiumGreen DragonG5S3S4S3S40.00132
Panax quinquefoliusGinsengG3G4S3S4S3S40.00132
Actaea pachypodaWhite BaneberryG5S4S40.00041
Actaea racemosaCommon Black-cohosh, Early Black-cohoshG5S4S40.00041
Aruncus dioicusCommon GoatsbeardG5S4S40.00041
Cardamine angustataSlender ToothwortG5S4S40.00041
Cardamine concatenataCutleaf ToothwortG5S4S40.00041
Corydalis flavulaYellow CorydalisG5S4S40.00041
Dicentra cucullariaDutchman's BreechesG5S4S40.00041
Dioscorea quaternataFourleaf Wild-yamS40.00041
Galearis spectabilisShowy OrchisG5S4S40.00041
Geum virginianumPale AvensG5S4S40.00041
Hydrophyllum canadenseBlunt-leaf WaterleafG5S4S40.00041
Menispermum canadenseCanada MoonseedG5S4S40.00041
Nemophila aphyllaSmall-flower Baby-blue-eyesG5S4S40.00041
Asarum reflexumReflexed Wild-gingerGNRS4S5S4S50.00010
Amsonia tabernaemontanaEastern BluestarG5S5S50.00000
Cardamine diphyllaTwo-leaf ToothwortG5S5S50.00000
Caulophyllum thalictroidesBlue CohoshG5S5S50.00000
Circaea canadensisBroadleaf Enchanter's-nightshadeG5S5S50.00000
Claytonia virginicaNarrow-leaved Spring BeautyG5S5S50.00000
Collinsonia canadensisCanada Horse-balmG5S5S50.00000
Cryptotaenia canadensisCanada HonewortG5S5S50.00000
Geranium maculatumWild Crane's-billG5S5S50.00000
Geum canadenseWhite AvensG5S5S50.00000
Iris cristataCrested Dwarf IrisG5S5S50.00000
Laportea canadensisWood NettleG5S5S50.00000
Persicaria virginianaJumpseedG5S5S50.00000
Podophyllum peltatumMay AppleG5S5S50.00000
Sanguinaria canadensisBloodrootG5S5S50.00000
Smallanthus uvedaliaYellow-flowered LeafcupG5S5S50.00000
Thaspium barbinodeHairy-jointed Meadow-parsnipG5S5S50.00000
Tiarella cordifoliaHeart-leaved FoamflowerG5S5S50.00000
Viola eriocarpaSmooth Yellow Violet +G5S5S50.00000
Carex crebrifloraa sedgeG4S2S20.03699
Carex jamesiiJames's SedgeG5S2S20.03699
Carex bromoides ssp. bromoidesCommon Brome SedgeG5T5S3S30.00407
Elymus macgregoriiEarly Wild-ryeG5S3S30.00407
Bromus pubescensHairy Wood Brome GrassG5S4S40.00041
Carex blandaWoodland SedgeG5S4S40.00041
Chasmanthium latifoliumIndian Sea-oats, River OatsG5S4S40.00041
Luzula acuminataHairy WoodrushG5S4S40.00041
Poa cuspidataBluegrassG5S4S40.00041
Leersia virginicaVirginia CutgrassG5S5S50.00000
Magnolia macrophyllaBigleaf MagnoliaG5S2S20.03699
Carya cordiformisBitter-nut HickoryG5S4S40.00041
Carya ovataShag-bark HickoryG5S4S40.00041
Juglans nigraBlack WalnutG5S4S40.00041
Acer floridanumSouthern Sugar Maple, Florida MapleG4G5S5S50.00000
Celtis laevigataSugarberryG5S5S50.00000
Morus rubraRed MulberryG5S5S50.00000
Ulmus rubraSlippery ElmG5S5S50.00000
Dikrella maculataSNR
Pediopsoides distinctusSNR
Omphalocera cariosaa pyralid moth
Catocala luctuosaan underwing mothG4S1S10.33330
Acrobasis juglandisPecan Leaf Casebearer MothGNRSUS2S30.01230
Acrobasis latifasciellaGNRS2S3S2S30.01230
Cameraria aesculisellaa leaf blotch miner mothGNRSUS2S30.01230
Catocala orbaOrb UnderwingG4S2S3S2S30.01230
Glaucolepis saccharella GNRSUS2S30.01230
Papaipema rutilaMayapple BorerG4S2S3S2S30.01230
Phyllonorycter lucidicostellaLesser Maple Leaf Blotch Miner MothGNRSUS2S30.01230
Caloptilia packardellaS2S40.00407
Catocala agrippinaan underwing mothG5S2S4S2S40.00407
Papaipema polymniaeCup Plant BorerG4SUS2S40.00407
Talponia plummerianaSpeckled Talponia Moth, Pawpaw Peduncle BorerGNRS2S4S2S40.00407
Acrobasis demotellaWalnut Shoot MothGNRS3S4S3S40.00132
Acronicta hamamelisPuzzling Dagger MothG4S3S4S3S40.00132
Acronicta morulaOchre Dagger MothG5S3S4S3S40.00132
Caloptilia blandellaa Gracillarid mothGNRS3S4S3S40.00132
Canarsia ulmiarrosorellaElm LeaftierGNRS3S4S3S40.00132
Catocala maestosaan underwing mothG5S3S4S3S40.00132
Catocala subnataan underwing mothG5S3S4S3S40.00132
Dypterygia rozmaniAmerican Bird's-wing MothG5S3S4S3S40.00132
Ecdytolopha manaa tortricidS3S40.00132
Hypena abalienalisWhite-lined HypenaG5S3S4S3S40.00132
Hypena humuliHop Vine MothG5S3S4S3S40.00132
Hypena sordidulaSordid Bomolocha, Sordid HypenaG4S3S4S3S40.00132
Omphalocera munroeiAsimina Webworm MothGNRS3S4S3S40.00132
Scopula ordinataa geometrid mothGUS3S4S3S40.00132
Baileya levitansPale Baileya MothG5S4S40.00041
Catocala nebulosaClouded UnderwingG5S4S40.00041
Catocala neogamaThe BrideG5S4S40.00041
Catocala piatrixThe PenitentG5S4S40.00041
Nerice bidentataDouble-toothed ProminentG5S4S40.00041
Peridea basitriensOval-Based ProminentG5S4S40.00041
Trigrammia quadrinotariaFour-spotted AngleG4S4S40.00041
Baileya australisSmall BaileyaG5S4S5S4S50.00010
Baileya dormitansSleeping BaileyaG5S4S5S4S50.00010
Hypena madefactalisGray-edged Bomolocha MothG5S4S5S4S50.00010
Besma endropiariaStraw Besma MothG5S5S50.00000
Caloptilia juglandiellaSHS1
Crataegus spathulataLittle-lip HawthornG5S1S2S1S20.11107
Dirca palustrisLeatherwoodG4S3S30.00407
Philadelphus inodorusScentless Mock OrangeG4G5S3S30.00407
Cornus alternifolia (= Swida alternifolia)G5S4S40.00041
Staphylea trifoliaAmerican BladdernutG5S4S40.00041
Aesculus sylvaticaPainted BuckeyeG5S5S50.00000
Asimina trilobaPawpawG5S5S50.00000
Calycanthus floridusSweet-shrubG5S5S50.00000
Corythucha juglandisWalnut Lace BugSNR
Ampelopsis cordataHeartleaf PeppervineG5S2S20.03699
Vitis ripariaRiverbank GrapeG5S2S20.03699
Vitis labruscaNorthern Fox GrapeG5S4S40.00041
Smilax hispidaBristly Greenbrier, HellfetterG5S5S50.00000
Nr = Number of Ranked Species = 139
Ner = Number of Extant, Ranked Species = 138
Nv = Number of Historic and Extirpated Species = 0
Nar = Number of Species at Risk of Extirpation (State rank > S5) = 102
Nss = Number of Secure Species (State Rank = S5) = 36
Pss = Proportion of Secure Species (Nss/Ner) = 0.26087
ENE = Expected Number of Extirpations (Sum of PE) = 2.51891
Average PE (ENE/Ner) = 0.01825
Habitat Risk Index = (Nar+Nv) x Average PE = 102 x 0.01825 = 1.8615

Estimated Risk to the Determining Species Seven species in this habitat are state-ranked as S1 or S1S2; 11 listed as S2. The Average PE for this habitat is quite high, the equivalent of a State Rank of S2.

Estimated Risk to the Co-evolved Species Groups
Estimated Security of the Habitat 35 species are listed as S5, or completely secure within North Carolina and the Proportion of Secure species is 0.26. This is a moderately low value, indicating that the habitat overall lacks very large single expanses or has fairly weak connections between smaller units.

Index of Habitat Imperilment With a high Average PE and an especially large number of species, the ENE for this habitat is quite high, with multiple species expected to become extirpated in a twenty-year period. The PSS score, conversely, is fairly low and has only a moderate lowering effect on the score of ENE. As a result, this habitat belongs to our Tier 2 Level of Conservation Concern (5 ≥ HRI > 0.5), giving it a high priority for conservation efforts.

Identified Risks The steep slopes and floodplains occupied by this habitat are somewhat protected from development or conversion to agriculture. Steep slopes are also somewhat safe from timber harvest. Upland habitats, however, are all vulnerable to at least some form of residential development and in the case of steep slopes, there can be secondary impacts from adjacent development even when the slopes themselves are spared. These impacts include increased insolation if the ridge tops are deforested, leading to increased heating and drying of the slopes below. Erosion is also likely to increase, due to stormwater runoff from the developed area or from construction of non-carefully designed trails. Non-buildable slopes are also the sites where landscaping fill, sewerlines, pump stations, and other infrastructure serving the development are often placed, usually involving forest clearance. Additionally, runoff of landscaping chemicals, escape of exotic species, invasion of the natural habitats by pets, and increased populations of human tolerant wildlife, including deer, coyotes, raccoons, skunks, squirrels, etc. can have major impacts on all adjacent natural areas. Deer overbrowsing -- due to the great increase in their numbers -- is having a particular impact on the shrub and herb layers of the forest. In addition to the plants, this is having an impact on moths and other herbivorous species of insects, as well as the Kentucky Warbler that requires both rich herbs and shrub cover for nesting and foraging (Tymkiw, 2010; Magee and Van Clef, 2016; H. Wiley, pers. comm. to Hall).

Augmenting these impacts, mesic slopes will become increasingly vulnerable to droughts and fire due to the effects of climate change. This is also true for wet bottomlands, which are subject to different set of impacts than the slopes, as described in several of the habitats more closely confined to floodplains (e.g., see Rich Wet Hardwood Forests).

Observed Trends Residential development along river and stream bluffs and hill crests are common sights in the urbanizing portions of the Piedmont; how much damage this is doing to the slopes below is not well documented.

Distribution Map
Distribution Examples of this habitat occur from the high mountains to the lower Coastal Plain but are less well represented in the Coastal Plain, due to its typically acidic, nutrient-poor soils. Within that region, the rich alluvial soils associated with the four brownwater rivers provide at least some degree of exception from that general rule.

Major Conservation Reserves For preserves for rich floodplains, see Rich Wet Hardwood Forests. For rich mesic slopes, the following areas represent major preserves. In the Mountains: GSMNP; Joyce-Kilmer and other wilderness or designated areas in the Nantahala Pisgah National Forests; Gorges, Chimney Rock, Mt. Mitchell, Grandfather Mountain, New River, Mt. Jefferson, Stone Mountain State Parks; 31 state game lands (see https://www.ncwildlife.org/Hunting/Where-To-Hunt-Shoot/Public-Places/Mountain-Game-Land-Maps); plus several privately owned nature preserved. In the Piedmont: South Mountains, Pilot Mountain, Hanging Rock, Mayo River, Eno River, Raven Rock, Medoc Mountain, and Morrow Mountain State Parks, Occoneechee Mountain State Natural Area; wilderness and designated natural areas in the Uwharrie National Forest; 28 state game lands; and several privately owned preserves. In the Coastal Plain: steep coastal bluffs in the Croatan National Forest and Camp Lejuene Marine Corps Base.

Priority Areas for Surveys and Conservation Protection
Stewardship and Management Recommendations Magee and Van Clef, 2016
References Cooley, J.H. and Sambeek, J.W.V. 1990. Ulmus rubra Muhl. Slippery Elm. In: R. Burns and B. Honkala (Technical coordinators). Silvics of North America, 2. Available online at: https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/silvics_v2.pdf

Graney, D.L. 1990. Carya ovata (Mill.) K. Koch. Shagbark Hickory. In: R. Burns and B. Honkala (Technical coordinators). Silvics of North America, 2. Available online at: https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/silvics_v2.pdf

Jones, E.R. Acer barbatum Michx. Florida Maple. In: R. Burns and B. Honkala (Technical coordinators). Silvics of North America, 2. Available online at: https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/silvics_v2.pdf

Kennedy, H.E. 1990. Celtis laevigata Willd. Sugarberry. In: R. Burns and B. Honkala (Technical coordinators). Silvics of North America, 2. Available online at: https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/silvics_v2.pdf

Magee, C.S. and Van Clef, M., 2016. Plant structure of hooded and Kentucky warbler breeding sites in New Jersey. Cassinia, 76, pp.30-35. Available online at:https://dvoc.org/wp/wp-content/uploads/2018/01/Cassinia76_30_35_MageeVanClef.pdf

Smith, H.C. 1990. Carya cordiformis (Wangenh.) K. Koch. Bitternut Hickory. In: R. Burns and B. Honkala (Technical coordinators). Silvics of North America, 2. Available online at: https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/silvics_v2.pdf

Tymkiw, E.L., Bowman, J.L. and Shriver, W.G., 2013. The effect of white‐tailed deer density on breeding songbirds in Delaware. Wildlife Society Bulletin, 37(4), pp.714-724.

Williams, R.D. 1990. Juglans nigra L. Black Walnut. In: R. Burns and B. Honkala (Technical coordinators). Silvics of North America, 2. Available online at: https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/silvics_v2.pdf

Updated on 2022-06-14 14:25:09