Somatochlora forcipata (Scudder, 1866)
Basis for Listing
The Forcipate Emerald (Somatochlora forcipata) is a widespread species in North America, but populations are limited to very specific habitats and are usually localized, with few individuals per population in the Upper Great Lakes area. In Minnesota, it has been collected from only six counties (Roseau, Lake of the Woods, Koochiching, Itasca, Lake, and Cook) in the northeastern part of the state (Laurentian Mixed Forest Province), and these records mark the westernmost limit of this species in the United States. Wisconsin has listed the Forcipate Emerald as a species of special concern.
This species breeds in small spring-fed streams and sphagnum pools, with adjacent forested habitat. Threats to the Forcipate Emerald include disruptions to groundwater supplies that feed springs and watershed disturbances such as clear-cutting and impoundments. Given the restricted range and isolation of known populations of the species in Minnesota and the low abundance of individuals in each population, the Forcipate Emerald was listed as a species of special concern in 2013.
Like all of the striped emeralds (Somatochlora spp.), the Forcipate Emerald is dark bodied, with metallic green and bronze highlights on the thorax. It has an average length of about 5 cm (2 in.). It has two oval bright yellow thoracic side spots, the first slightly larger than the second. And there are dull orange/yellow spots at the front edge of the sides of abdominal segments 5-7 in males and 3-7 in females. The cerci (terminal appendages) of the male are long, sharp-tipped, slightly inward-pointing, and arched down in side view. The female’s ovipositor is long and laid flat against the abdomen; it is about as long as abdominal segment 9.
The Forcipate Emerald occurs in small forested or open streams flowing through mirey regions (Paulson, 2011). In Minnesota, they prefer spring fed fens and rich fens (water track), in large patterned peatlands. Adults feed in shrubby or conifer dominated spruce swamps or tamarack swamps. They may also breed in pools among alder (Alnus spp.) stands in large fen complexes with signicant laminar water flow (northern shrub shore fen).
Biology / Life History
Males patrol along small streams flowing through peatlands. Females oviposit, in a leisurely fashion, in open water ranging from small shallow streams to minute pools among moss. Adults are indiscriminate predators of flying insects in open areas, including along roads through alder stands (Paulson 2012). The flight period of the Forcipate Emerald is from early June through mid-August. Very little is known about this species' life cycles or habits.
Conservation / Management
This species, like most of the members of the genus, is very selective about its habitat. There is work underway to help delineate the specific factors that guide this selection (Robert DuBois, personal communication), but at present these factors are still mostly a mystery. Long term protection of this species will be contingent on learning what biotic and abiotic factors drive habitat selection.
There has been some recent activity hinting toward a renewed interest in peat mining in Minnesota. Conservation of the species requires protection of the hydrological conditions that create and maintain the fen habitat, which peat mining would obviously disrupt. Any activity that would alter hydrology and either drown or dry out the habitat has to be prevented.
Conservation Efforts in Minnesota
One population of Forcipate Emeralds is in Sand Lake Peatland Scientific and Natural Area. State Scientific and Natural Areas provide the highest level of conservation protection.
The non-profit Minnesota Dragonfly Society is looking for the Forcipate Emerald (among many other species of Odonata) throughout Minnesota through surveys and educational workshops. These surveys are conducted by volunteers and are supported through an Enbridge Ecofootprint Grant through 2018.
Kurt Mead, (MNDNR), 2018
(Note: all content ©MNDNR)
References and Additional Information
Abbott, J. C. 2006-2017. Odonata Central: An online resource for the distribution and identification of Odonata [web application]. <http://www.odonatacentral.org>. Accessed 21 March 2017.
Dunkle, S. 2000. Dragonflies through binoculars: a field guide to dragonflies of North America. Oxford University Press, New York, New York. 266 pp.
Legler, K., D. Legler, and D. Westover. 2013. Dragonflies of Wisconsin-Edition 5.1, copyright Karl Legler, self-published.
Mead, K. 2009. Dragonflies of the North Woods (North Woods naturalist series). Second edition. Kollath-Stensaas Publishing, Duluth, Minnesota. 200 pp.
Minnesota Department of Natural Resources. 2003. Field guide to the native plant communities of Minnesota: the Laurentian mixed forest province. Ecological Land Classification Program, Minnesota County Biological Survey, and Natural Heritage and Nongame Research Program. Minnesota Department of Natural Resources, St. Paul, Minnesota. 352 pp.
NatureServe. 2009. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. <http://www.natureserve.org/explorer>. Accessed 27 June 2009.
Paulson, D. 2009. Dragonflies and damselflies of the west (Princeton field guides). Princeton University Press, Princeton, New Jersey. 536 pp.
Paulson, D. 2012. Dragonflies and damselflies of the east (Princeton field guides). Princeton University Press, Princeton, New Jersey. 544 pp.
Steffens, W. P., and W. A. Smith. 1999. Status survey for special concern and endangered dragonflies of Minnesota: population status, inventory and monitoring recommendations. Final report submitted to the Natural Heritage and Nongame Research Program, Minnesota Department of Natural Resources. 54 pp.
Walker, E. M., and P. S. Corbet. 1975. 1998 reprint. The Odonata of Canada and Alaska - Volume 3. University of Toronto Press, Toronto, Ontario, Canada.
Wisconsin Odonata Survey. 2009. Wisconsin dragonflies and damselflies. Wisconsin Aquatic and Terrestrial Resources Inventory and Wisconsin Department of Natural Resources. <http://wiatri.net/inventory/odonata/SpeciesAccounts/>. Accessed 25 June 2009.