Habitats of North Carolina
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Members of General Hardwood Forests:
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General Hardwood Forests
Ash Forests
Habitat Overview Ashes (Fraxinus sp.), along with oaks, hickories, and maples, are major components of the vast network of hardwood forests that cross the state. However, they now face catastrophic collapse: all of our native species of ash are threatened by the Emerald Ash Borer (Agrilus planipennis), an exotic beetle that has killed millions of ash trees since it was first detected in North America in 2002 (see Threats and Trends below). Along with the ashes themselves, Wagner and Todd (2016) have identified close to 100 species of herbivorous Arthropods that specialize on (Fraxinus) species and whose fate, consequently, is intimately tied to that of their host plants.

The ashes themselves are found under a wide range of habitat conditions. White Ash (Fraxinus americana), Biltmore Ash (Fraxinus biltmoreana), and Small's Ash (Fraxinus smallii) are major constituents of dry-to-mesic upland stands of hardwoods, particularly on rich soils. Green Ash (Fraxinus pennsylvanica) is a common to dominant member of Piedmont alluvial forests and brownwater floodplains in the Coastal Plain. Carolina Ash (Fraxinus carolina), Pumpkin Ash (Fraxinus profunda), and Swamp White Ash Fraxinus pauciflora) are found in even more hydric habitats, including both brownwater and blackwater swamps. About the only hardwood habitats not occupied by one species of ash or another are dry, acidic uplands, including felsic ridges, sandhills, and barrier islands, and forests growing on peatland soils.

For all of the insect members of this group, the presence of one or another of the ash species is the critical habitat factor. Although specialists on (Fraxinus), most of these species feed on all members of this genus, with some also feeding on other members of our native Oleaceae, including Fringe Tree (Chionanthus virginicus); that species is also included as a member of this habitat group since it generally co-occurs with ash species; has an overlapping set of specialist herbivores; and may also be threatened by the Emerald Ash Borer.

The Emerald Ash Borer itself, as a non-native species, is not included as a defining species although -- like the native ash symbionts -- it is capable of feeding on all species of ash, as well as other members of the Lauraceae. The overwhelming nature of the threat posed by this species is the main unifying environmental feature of this habitat, outweighing the differences in substrates, moisture, and other abiotic factors that separate the plant members of this habitat. Although the Ashes could be treated simply as environmental factors rather than as Defining Species, they have more conservation significance when considered as part of this habitat than they would as members of more the more general hardwood forest habitats associated with those various abiotic factors.


Related NHP Natural Communities White Ash is a dominant or important member of the following NHP Natural Communities (Schafale and Weakley, 1990; Schafale, 2012): Northern Hardwood Forest (Rich Subtype), Rich Cove Forest (Montane Intermediate Subtype), Rich Cove Forest (Montane Intermediate Subtype), Rich Cove Forest (Montane Rich Subtype), Rich Cove Forest (Foothills Rich Subtype), Basic Mesic Forest (Piedmont Subtype), Basic Mesic Forest (Coastal Plain Subtype), High Elevation Red Oak Forest (Rich Subtype), Montane Oak–Hickory Forest (Basic Subtype), Dry-Mesic Basic Oak–Hickory Forest (Piedmont Subtype), Dry Basic Oak–Hickory Forest, Montane Red Cedar–Hardwood Woodland, Granitic Dome Basic Woodland, Xeric Hardpan Forest (Basic Hardpan Subtype). Green Ash is likewise a dominant species in the following communities: Brownwater Levee Forest (High Levee Subtype), Brownwater Levee Forest (Medium Levee Subtype), Brownwater Levee Forest (Low Levee Subtype), Brownwater Bottomland Hardwoods (High Subtype), Brownwater Bottomland Hardwoods (Swamp Transition Subtype), Oxbow Lake (Brownwater Subtype), Montane Alluvial Forest (Large River Subtype), Montane Floodplain Slough Forest, Piedmont Levee Forest (Typic Subtype), Piedmont Bottomland Forest (High Subtype), Piedmont Swamp Forest, Rocky Bar and Shore (Mixed Bar Subtype), Low Elevation Seep (Floodplain Subtype), Natural Lake Shoreline Swamp (Rich Subtype), Tidal Swamp (Mixed Subtype). Finally, Carolina Ash and Pumpkin Ash are important constituents of the following: Cypress–Gum Swamp (Brownwater Subtype), Cypress-Gum Swamp (Intermediate Subtype), Cypress--Gum Swamp (Blackwater Subtype), Cypress–Gum Swamp (Blackwater Cove Subtype), Nonriverine Swamp Forest (Cypress-Gum Subtype), Maritime Swamp Forest (Typic Subtype).

Determining Species
Taxa Global RankState RankProbability of Extirpation (PE)
MOTHS
Ceratomia undulosa - Waved Sphinx G5S50.0000
Copivaleria grotei - Grote's Sallow G5S40.0007
Manduca jasminearum - Ash Sphinx G4G5SU0.0020
Marmara fraxinicola GNRS2S30.0164
Olceclostera angelica - Angel Moth G5S3S40.0020
Palpita illibalis - Inkblot Palpita Moth GNRS2S30.0164
Palpita magniferalis - Splendid Palpita Moth GNRS4S50.0002
Papaipema furcata - Ash Tip Borer Moth GNRSU0.0020
Plagodis kuetzingi - Purple Plagodis Moth G5S3S40.0020
Podosesia aureocincta - Banded Ash Clearwing Moth GNRSU0.0020
Sphinx chersis - Great Ash Sphinx G4G5SH
Sphinx franckii - Franck's Sphinx G4SU0.0020
Sphinx kalmiae - Laurel Sphinx G5S3S40.0020
Sympistis chionanthi - Fringe-Tree Sallow G5SU0.0020
SHRUBS
Chionanthus virginicus - Fringetree G5S50.0000
HARDWOODS
Fraxinus americana - White Ash G5S50.0000
Fraxinus biltmoreana - Biltmore Ash G5S40.0007
Fraxinus caroliniana - Carolina Ash G5S50.0000
Fraxinus pauciflora - Swamp White Ash GNRSU0.0020
Fraxinus pennsylvanica - Green Ash G5S50.0000
Fraxinus profunda - Pumpkin Ash G4S40.0007
Fraxinus smallii - Small's Ash GNRS40.0007
Expected Number of Extirpations with a PE value (Sum of PE) = 0.0538
N = Number of Extant Species with a PE value = 16
Average PE = ENE/N = 0.0034
Number of S5 species = 5
Proportion of Secure Species = Number of S5 Species/N = 0.3125
Habitat Risk Index = ENE x (1 – PSS) = 0.0370

Phagic and Competitory Symbioses: (Fraxinus species-Chionanthus virginicus/Ceratomia undulosa-Copivaleria grotei-Manduca jasminearum-Marmara fraxinicola-Olceclostera angelica-Palpita magniferalis-Plagodis kuetzingi-Podosesia aureocincta-Sphinx chersis-Sphinx franckii-Sphinx kalmiae-Sympistis chionanthi)

Candidates for Inclusion Close to 100 species of insects, including a wide range of families and genera, were identified as ash-specialists by Wagner and Todd (2016), many of which they considered to be either endangered or significantly threatened by loss of ash species due to the Emerald Ash Borer. A number of these species, including the Eastern Hercules Beetle (Dynastes tityus) and Rhinoceros Beetle (Xyloryctes jamaicensis) -- two of our largest and most spectacular insect species -- are included on their list, along with a number of other species that have been reported from North Carolina. Until we establish taxonomic websites for the various groups to which they belong, however, we do not have a good means of determining their current distribution, habitat uses, population trends and other factors that we use to set conservation values and to determine management recommendations in this website.

Habitat Sub-sets Five of the insect species may be confined to the Mountains and could be split off into a separate habitat. However, their host plants are not confined to the same region, with all of the ashes that occur in that region also extending across the Piedmont and even into the Coastal Plain. If a Montane Ash Forests habitat were to be created none of the ash species would belong to it; all would be considered habitat factors instead. For the same reasons given above for including all of the Ash species within this habitat, despite their separate abiotic associations, all of the Ash symbionts are better considered within this otherwise environmentally heterogeneous habitat.

Distribution Map
Distribution For a widespread habitat occupied by fairly to highly vagile species, the overall level of constancy is relatively low: no county exceeds 60% of the total value and even leaving out the five species that may be confined to the mountains, the highest percentage is only 73% for Wake County. It seems unlikely that the low constancy represents unrecovered local extirpation resulting from habitat fragmentation. More likely is lack of thorough surveys for the habitat members. Sphinx moths, which make up 37% of the total, in fact are difficult to sample as adults unless mercury vapor lights are used and several of the ash species also need close examination in order to correctly identify them.
Survey Coverage Map
Survey Coverage
Survey Priorities
Average Imperilment of Habitat Members
Habitat Conservation Status
High Quality Habitat Occurrence Table
High Quality Habitat Occurrences
Protected Habitat Occurrences
Threats and Trends
Status Summary
Stewardship Recommendations
References Pautasso, M., Aas, G., Queloz, V. and Holdenrieder, O., 2013. European ash (Fraxinus excelsior) dieback – a conservation biology challenge. Biological Conservation 158:37-49.
Updated on 2020-10-20 14:16:32