Habitats of North Carolina
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General Shrublands
General Corylaceous Thickets and Understories
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General Description The key factor for this habitat is the presence of hornbeams, hop-hornbeams, or hazelnuts, members of the former family Corylaceae and now a subfamily within the Betulaceae. These species are shrubs and occasionally subcanopy species within hardwood forests. Habitat conditions range from wet bottomlands and swamp margins -- including Blackwater as well as Brownwater examples -- occupied by American Hornbeam, to rich mesic forests occupied by American Hazelnut and American Hop-Hornbeam, to dry-xeric rocky forests occupied by Beaked Hazelnut.

The ranges of these plants are more restricted than the habitat as a whole and they are consequently treated only as habitat factors, not the Determining Species of this habitat. The insect herbivores that specialize on this plant group, on the other hand, do make use of the entire range occupied by this group and are consequently considered Determining of this particular habitat. MOst of these species have been documented to feed on two or more of the plant species of the "Corylaceae". They do not, however, feed at least regularly on either birches or alders, the other main genera of the Betulaceae.

Abiotic Factors Geographic Regions: Lower Coastal Plain to High Mountains. USDA Hardiness Zones: 6-8. Landform: ridges, slopes, bottomlands, and wet flats. Slope Aspect: occurs on all slopes aspects as well as on ridges and flats. Soil Moisture: Dry to wet. Soil texture: loamy to alluvial. Soil pH: circumneutral to acidic. Soil Nutrient Content: poor in the blackwater floodplains occupied by American Hornbeam but rich in mafic or calcareous minerals in slopes occupied by Hop-hornbeam and the Hazelnut species. Microclimate: Warm to cool, dry to humid. Hydrological Features: springs and seeps are common, particularly at the interface between slopes and bottomlands. Flood Frequency: the bottomlands occupied by American Hornbeam may flood several times per year; the ridges and upper slopes occupied by Hop-hornbeam and Hazelnuts rare flood, if ever . Flood Duration: hours to days in the bottomlands and lower slopes. Fire Frequency: occasional on ridges and upper slopes, rare in bottomlands Drought Frequency: occasional on upper slopes, rare in bottomlands. Ice Storm Damage: low to moderate. Wind Storm Damage: moderate. Insolation: the shrub layers belonging to this habitat are generally deeply shaded.

Biotic Structure Key Species: Corylus, Carpinus, or Ostrya must be present. Vegetation Type: closed-canopy forest composed of broadleaf, deciduous trees. Strata: subcanopy and shrub layers are well developed. Organic Shelter, Foraging and Nesting Structures: the shrubs and small trees that provide the structure for this habitat are generally open and do not produce large woody debris; many of the species that belong to this habitat are leaf miners and the others rely on camouflage rather than protected hiding places.

Co-evolved Species Groups Phagic and Competitory Symbioses:
Carpinus-Corylus-Ostrya // Acronicta laetifica-Baileya ophthalmica-Caloptilia ostryaeella-Cameraria ostryarella-Coleophora ostryae-Ectoedemia quadrinotata-Hypena palparia-Pyreferra citrombra-Zale phaeocapna
Corylus species // Cameraria corylisella-Olethreutes corylana-Phyllonorycter intermixta
Ostrya virginiana // Acrobasis sylviella

Determining Species
Acrobasis sylviellaIronwood Tubemaker MothGNRS2S3S2S30.01230
Pyreferra citrombraCitrine SallowGNRS2S3S2S30.01230
Cameraria corylisellaGNRSUS2S40.00407
Coleophora ostryaeGNRSUS2S40.00407
Ectoedemia quadrinotataGNRSUS2S40.00407
Phyllonorycter intermixtaGNRS2S4S2S40.00407
Caloptilia ostryaeellaGNRSUS3S40.00132
Cameraria ostryarellaGNRSUS3S40.00132
Olethreutes corylanaGNRS3S4S3S40.00132
Zale phaeocapnaPhaeocapna ZaleG5S3S4S3S40.00132
Acronicta laetificaPleasant Dagger MothG5S4S40.00041
Baileya ophthalmicaEyed BaileyaG5S4S5S4S50.00010
Hypena palpariaMottled Bomolocha, Mottled HypenaG5S4S5S4S50.00010
Acrobasis normellaGNRSUSH?
Nr = Number of Ranked Species = 14
Ner = Number of Extant, Ranked Species = 13
Nv = Number of Historic and Extirpated Species = 0
Nar = Number of Species at Risk of Extirpation (State rank > S5) = 13
Nss = Number of Secure Species (State Rank = S5) = 0
Pss = Proportion of Secure Species (Nss/Ner) = 0.00000
ENE = Expected Number of Extirpations (Sum of PE) = 0.04677
Average PE (ENE/Ner) = 0.00360
Habitat Risk Index = (Nar+Nv) x Average PE = 13 x 0.0036 = 0.0468

Estimated Risk to the Determining Species The Average Probability of Extirpation is the equivalent under our model to a state rank of S3. This indicates that this habitat has at least a minimal level of conservation concern.

Estimated Risk to the Co-evolved Species Groups All Determining Species of this habitat belong to co-evolved complexes. As a group, consequently, they have the same level of conservation concern as the habitat as a whole.

Estimated Security of the Habitat None of the species of this habitat appear to be completely secure. Most of these species are associated primarily with Hazels or Hop Hornbeams, which tend to be fairly patchy in their distributions. In those species, large blocks of habitat or clusters of smaller patches -- the more likely case -- were probably uncommon to begin with and have become more fragmented due to habitat conversion. The two species that appear to be the most secure, Eyed Baileya and Mottled Hypena, are associated with American Hornbeam, a bottomland shrub that is much more widely and continuously distributed. Even so, these species appear to be less common than their host plants, although that may may represent a sampling artifact.

Index of Habitat Imperilment In absence of Secure Species or Vanished Species, the HRI value is determined solely by the Expected Number of Extirpations, which in this group is only moderately high. Although one species, Acrobasis normella, has not been recorded in North Carolina since the 1960s, we do not believe that there have sufficient surveys conducted for this species to formally rank it as either SH or SX. With only a moderate number of species, the HRI value falls within our Tier 4 Level of Conservation Concern (0.05 ≥ HRI > 0.005), indicating only a low priority for conservation efforts.

Identified Risks Habitat conversion and fragmentation of upland stands of hardwoods is the major threat to this habitat.

Observed Trends Essentially not monitored.
Distribution Map
Distribution The patchy distribution shown on the range map is mainly due to the patchy nature of moth sampling in this habitat type. Nonetheless, it indicates that this habitat is found across the state, with concentrations found in both the Mountains and Piedmont.

Major Conservation Reserves
Priority Areas for Surveys and Conservation Protection
Stewardship and Management Recommendations
Updated on 2022-06-23 23:45:15