Plants and Animals
Somatochlora incurvata Incurvate emerald
Key Characteristics
The Incurvate emerald is above-average in size for the Somatochlora genus (total length about 2 inches or 6.3 cm). The face is yellowish-brown with dark, metallic greenish markings and large, green eyes. The thorax (upper body) is brown with metallic blue-green reflections and a pair of yellowish-brown elongate spots on each side. The abdomen (lower body) is black with a dull greenish sheen, with pale areas on sides of segments 2 and 3, and smaller dull yellow-brown spots on the rear portions of segments 4 to 9. The legs are black, and brownish at the base.
Status and Rank
US Status: No Status/Not Listed
State Status: SC - Special Concern (rare or uncertain; not legally protected)
Global Rank: G5 - Secure
State Rank: S3S4 - Rank is uncertain, ranging from vulnerable to apparently secure
Occurrences
| County | Number of Occurrences | Year Last Observed |
|---|---|---|
| Alger | 4 | 2017 |
| Chippewa | 17 | 2020 |
| Delta | 11 | 2006 |
| Keweenaw | 3 | 2011 |
| Luce | 3 | 2021 |
| Mackinac | 11 | 2022 |
| Schoolcraft | 2 | 2022 |
Information is summarized from MNFI's database of rare species and community occurrences. Data may not reflect true distribution since much of the state has not been thoroughly surveyed.
Habitat
This species is typically associated with small pools of spring water in sphagnum bogs. This species also has been found in patterned peatlands and northern fens. These wetlands are associated with peat or marl and contain flowing groundwater rich in calcium and magnesium carbonates. Dominant vegetation in these communities includes sedges (Carex spp.), bulrushes (Scirpus spp.), rushes (Eleocharis spp.), and shrubby cinquefoil (Potentilla fruticosa). Northern fens also contain calciphiles such as false asphodel (Tofielda glutinosa) and grass-of-parnassus (Parnassia glauca) and bog plants such as leatherleaf (Chamaedaphne calyculata), Labrador tea (Ledum roenlandicum), and small cranberry (Vaccinium oxycoccos). These wetland communities are often bordered by forest such as rich conifer swamps and white cedar (Thuja occidentalis).
Specific Habitat Needs
Depositional spring needed in: Headwater stream (1st-2nd order), pool.
Natural Community Types
- Bog
- Coastal fen
- Headwater stream (1st-2nd order), pool
- Northern fen
- Patterned fen
- Rich conifer swamp
For each species, lists of natural communities were derived from review of the nearly 6,500 element occurrences in the MNFI database, in addition to herbarium label data for some taxa. In most cases, at least one specimen record exists for each listed natural community. For certain taxa, especially poorly collected or extirpated species of prairie and savanna habitats, natural community lists were derived from inferences from collection sites and habitat preferences in immediately adjacent states (particularly Indiana and Illinois). Natural communities are not listed for those species documented only from altered or ruderal habitats in Michigan, especially for taxa that occur in a variety of habitats outside of the state.
Natural communities are not listed in order of frequency of occurrence, but are rather derived from the full set of natural communities, organized by Ecological Group. In many cases, the general habitat descriptions should provide greater clarity and direction to the surveyor. In future versions of the Rare Species Explorer, we hope to incorporate natural community fidelity ranks for each taxon.
Management Recommendations
The most likely threat to this species is habitat loss and alteration. For example, commercial and residential development have resulted in the destruction and/or alteration of numerous wetlands in the state. Given that this species has been recorded from so few sites in Michigan and across its range, all known populations should be protected at this time. Maintaining the ecological integrity of the habitat is most important for the continued survival of this species at a site. It is important to maintain the hydrology and water quality of an occupied site. Clearcutting adjacent to occupied sites may adversely impact the incurvate emerald and a number of invertebrate species by altering the site's microclimate (e.g., loss of proper humidity gradient) and reducing the amount of feeding habitat and shelter during the maturation period prior to breeding. Maintaining a no cut or selective cut buffer around the wetlands would help minimize the potential for adversely impacting this and associated species.
Survey Methods
Males are usually seen during sunny weather conditions from mid-morning to mid-afternoon. In contrast, females appear to be most active on warm, but overcast, days when very few males are evident. Feeds high in clearings until after sundown, sometimes in swarms of other species. Males are not territorial and fly widely over the bog about a yard up, occasionally hovering low over small pools, or perching obliquely on a bare twig. Adults are best sampled with the use of a mesh aerial net. The bilge pump is used to clear crayfish burrows where the larvae tend to hide.
Aerial net
Survey Period: From second week of June to second week of October
Time of Day: Morning (after sunrise)
Cloud Cover: Clear
Survey Method Comment: Males
Survey Period: From third week of June to second week of October
Time of Day: Morning (after sunrise)
Cloud Cover: Overcast
Air Temperature: Warm
Survey Method Comment: Females
Bilge pump
Survey Period: From first week of January to fourth week of December
Time of Day: Daytime
Water Level: Low Water Levels
Water Turbidity: Low Turbidity
Survey Method Comment: Larvae
D-frame net, dip net
Survey Period: From first week of January to fourth week of December
Time of Day: Daytime
Water Level: Low Water Levels
Water Turbidity: Low Turbidity
Survey Method Comment: Larvae
References
Survey References
- Martin, J.E.H. 1977. The Insects and Arachnids of Canada (Part 1): Collecting, preparing, and preserving insects, mites, and spiders. Publication 1643. Biosystematics Research Institute, Ottawa.
Technical References
- Dunkle, S.W. 2000. Dragonflies through Binoculars. Oxford University Press, Oxford. 266pp.
- Lee, Y. 1999. Special Animal Abstract for Somatochlora incurvata (Incurvate emerald dragonfly). Michigan Natural Features Inventory, Lansing, MI. 2pp.
- McCafferty, W. P. 1981. Aquatic Entomology: The fisherman's and ecologists' illustrated guide to insects and their relatives. Jones and Bartlett Publishers, Boston. 448pp.
- Merritt, R.W. and K.W. Cummins. 1996. An introduction to the aquatic insects of North America, 3rd ed. Kendall/Hunt Publishing Company, Dubuque. 862pp.
- Walker, E. M. 1958. The Odonata of Canada and Alaska, Vol. 2: The Anisoptera- Four Families. University of Toronto Press, Toronto. 318pp.