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Somatochlora hineana, Hine's Emerald Dragonfly

The Hine’s Emerald Dragonfly, Somatochlora hineana, is the only endangered dragonfly in the United States. Distinguishable by bright its green eyes and yellow thoracic stripes, this dragonfly can be found in temperate wetlands, especially calcareous marshes ( Burton, 2001). Due to urbanization, however, such habitat is quickly being degraded; the Hine’s Emerald now exists only as a handful of small populations scattered across Illinois and Wisconsin, with a few additional populations now being discovered in neighboring states. Habitat destruction poses the greatest single threat to these dragonflies. The most effective means of conservation would therefore be preserving as much of the critical habitat as possible, although with wetlands disappearing at such a high rate, this task has proven to be anything but simple. Conservation efforts have been further impeded by the difficulty associated with obtaining information about the ecology of the Hine’s Emerald (Foster & Soluk, 2002).

Since its listing as an Endangered Species in 1995, the Hine’s Emerald Dragonfly has been studied much more extensively than it had been previously (Foster & Soluk, 2002). Much of this research has revolved around the species’ habitat use, as well as whether or not additional breeding populations exist. The species was first observed in Ohio, where it was subsequently been extirpated (Steffens, 1998). Small breeding populations have since been discovered in neighboring states. As recently as 1997, several new sites were discovered in Michigan, almost 200 kilometers from the nearest previously known sites (Steffens, 1998). These discoveries, although encouraging, have presented conservationists with the additional problem of protecting and managing the habitat utilized by these new populations. The largest known population to date is located in Door County, Wisconsin, and is harbored largely in part by the Ridges Sanctuary ( Burton, 2001), which has effectively protected the Hine’s Emerald thus far. Generally speaking, existing preserves have been effective conservation mechanisms for this species, which is threatened primarily by habitat destruction, pollution, and ground water contamination (FWS, 2002). Selecting and acquiring land suitable for new preserves is therefore the chief concern of conservationists. There are numerous difficulties associated with this task, especially due to the dwindling amounts of suitable habitat remaining within the species’ range. The lack of information concerning the Hine’s Emerald presents another rather obvious difficulty, although this aspect of the dilemma can be addressed, at least in part, through the investigation of similar populations elsewhere in the world.

South Africa has also been experiencing a great deal of wetland destruction, as well as the subsequent imperilment of dragonfly populations, and can therefore lend important insight into the possible outcomes of various experimental conservation methods. One important observation in the history of South African dragonfly conservation has been the positive effect farm dams have had on populations; with wetlands quickly being fragmented and/or destroyed, farm dams now provide some of the best sanctuaries for dragonflies (Samways, 1992). Following this trend of combining the needs of the public with those of the species at hand, scientists have also been working towards expanding the National Botanic Gardens, Pietermaritzburg, to include an attractive wetland area (Samways, 1992). Such tactics would provide an excellent opportunity for bolstering public interest in endangered species, and also serve as a means for supporting the management needs of protected areas.

As previously mentioned, farm dams have, in some cases, proven to be extremely effective in providing the necessary habitat for dragonflies that would normally inhabit natural wetlands. In a 1989 study, M.J. Samways addressed the possibility of farm dams acting as miniature wetlands, as they provide the necessary plant diversity to sustain conditions ideal for dragonflies. In addition, this study revealed that farm dams actually serve as a sanctuary for dragonflies, providing an environment that is considerably safer than natural lowland wetlands. Natural waters at higher altitudes tend to be safer, however, providing their inhabitants with a suitable protection; farm dams at higher altitudes had a considerably diminished effect on the impact of overall conservation efforts (Samways, 1989). The results of this study could have important implications for North American dragonfly conservation as well, demonstrating how powerful an impact small-scale conservation efforts can have. Of equal importance, however, is the study’s revelation that simply taking conservation measures without an adequate base of ecological knowledge (in this case, through the indiscriminate construction of sanctuaries) could result in a tremendous waste of resources and time.

Indeed, one of the main difficulties scientists face in their efforts to conserve the Hine’s Emerald dragonfly is the shortage of information about the species. Adults have proven to be very difficult to study, as they are extremely rare and difficult to catch (Foster and Soluk, 2000). This has severely impeded research and conservation advancements, as it is difficult to make relevant conclusions about the habitat use of Hine’s Emeralds, in light of the fact that dragonflies exhibit a great deal of diversity in their responses to environmental factors, not only between species, but also between sexes (McGeoch & Samways, 1991). For example, different dragonflies utilize different parts of the habitat at different periods of the day and season; changes in a habitat, whether pronounced or subtle, greatly effect how inhabiting dragonflies behave and utilize it (McGeoch & Samways, 1991). Even seemingly inconsequential factors may noticeably impact different populations: small patches of grass can provide small additionally-sheltered areas with higher humidity levels, just as the color of a rock may influence the sex of the individuals who chose to bask on it (females and males often have different eye-colors that blend or contrast with the rock, thus decreasing or increasing their susceptibility to predation) (McGeoch & Samways, 1991).

One of the current challenges concerning the study and conservation of the Hine’s Emerald dragonfly is the explanation of a noticeable disparity in the number of males and female individuals that has appeared over the course of multiple studies. In several surveys, a considerably larger number of males were counted; females were highly underrepresented (Foster & Soluk, 2002). This discrepancy could be the result of a variety of phenomena, but research has shown that roughly the same number of male and female larvae reach adulthood, indicating that either a higher female mortality rate or sex-dependant difference in habitat use is the probable cause of this particular imbalance (Foster & Soluk, 2002). If, in fact, the diminished number of females resulted from higher female mortality rates, perhaps due to high costs associated with reproduction, conservationists would have to be concerned with maintaining high enough levels of genetic diversity for each population (Foster & Soluk, 2002). The size of a given population’s gene pool is limited by the number of females it contains, and populations in which the gene pool is too greatly diminished tend to be much more susceptible to stochastic events, and therefore the possibility of eradication. If, however, the skewed ratio is a consequence of differences in habitat use, scientists would need to focus their efforts on the assessment of the habitat characteristics required by each sex, and ensure that both sets of characteristics be adequately provided in future sanctuaries.

In spite of the obstacles resulting from such a small base of knowledge concerning the Hine’s Emerald Dragonfly, multiple studies have indicated that conservation efforts are not in vain. Based on the distributions of closely related Somatochlora species, the Hine’s Emerald’s range could potentially expand to reach between Minnesota and Maine, and extend as far south as Texas and Georgia ( Illinois State Museum, 2002). Given the scarcity of wetland habitat, the fact that such a large portion of the United States is climatically suitable for Hine’s Emeralds is extremely encouraging. A great deal can be done to build upon current conservation efforts; the Ridges Sanctuary serves as an excellent model for future large-scale endeavors, while the prospect of micro-habitat scale conservation remains largely unexplored in the United States. Especially in light of the observed success of farm dams serving as sanctuaries in South Africa, such small-scale tactics provide highly promising possibilities for future efforts (Samways, 1989). Despite the pressure to conserve the Hine’s Emerald and other wetland-dependant species, however, wetland destruction is still rampant throughout the United States, as the ever-expanding population increases commercial and residential demands on land. A great deal of research remains to be done, especially on adult Hine’s Emeralds, in order to maximize the efficiency and impact of the resources and effort expended in the conservation process. Nevertheless, previous research conducted on both this and other dragonfly species indicates promising steps towards recovery if the needed support and research can be attained.


McGeoch, MA and MJ Samways. Dragonflies and the thermal landscape: implications for their conservation. 1991. Odontologica 20(3): 303-320

Samways, MJ. Dragonfly conservation in South Africa: a biogeographical perspective. 1992. Odontologica 21:(2) 165-180

Samways, MJ. Farm dams as nature reserves for dragonflies at various altitudes in the Natal Drakensberg Mountains, South Africa. 1989. Biological Conservation. 48:181-187

Steffens, Wayne. New distribution records of Somatochlora hinean. 1998. The Great Lakes Entomologist. (31,1)


Written by: Piper Corp 2002

Updated: Eric Denemark 2008

Image credit: M.F. O'Brien