New York Natural Heritage Program
Common Sanddragon
Progomphus obscurus (Rambur, 1842)
Insects

Threats [-]
Generally, Coastal Plain Ponds on Long Island are threatened by the introduction of grass carp, alterations to hydrology and water quality, as well as herbicides used to clear aquatic weeds from ponds. The most significant threat to their hydrology comes from commercial and residential development causing increases in the demand for fresh water. This causes drawdowns of the water table, altered hydroperiods and a general diminishment of the pond extent (NYNHP 2011). The expansion of Phragmites and decline of water quality due to increased recreation during the dragonfly flight season are possible threats at the two inhabited Coastal Plain Ponds. It is unclear what threats may be a concern at the Hudson/Schroon River locales. In general, lotic habitats for this sand-dependent species could be altered by dams which change the sedimentation dyamics of flowing waters.


Conservation Strategies and Management Practices [-]
The most important management concern for Coastal Plain Ponds is the maintenance of a natural hydrologic regime and good water quality. Water supplies for new development and ditching, draining or impoundment activities should be weighed carefully. Storm water run-off, herbicide and pesticide use should also be minimized or eliminated in the vicinity of ponds. Where practical, wide (> 100') vegetated buffers should be managed to reduce storm-water, pollution, sediment and nutrient run-off. Habitat alteration within the wetland and surrounding landscape should be minimized (NYNHP 2011).



Research Needs [-]
Because the northernmost localities across this species' range (Wisonsin to Maine) lie along nearly the same latitude, an understanding of the factors limiting the northward extent of populations could illumninate reasons why Sanddragons are so rare in New York. Further habitat research at the occupied sites on Long Island may allow more insight into why the great majority of seemingly similar Coastal Plain ponds remain uninhabited, especially because the species is quite common on the Coastal Plain in southeastern Massachusetts (Carpenter 1991; Nikula et al. 2003). During the NYDDS (White et al. 2010) two unconfirmed records were reported that could use follow-up searches: 1) the Bog River in extreme southeast St. Lawrence County; and 2) the confluence of the Mohawk and Hudson Rivers.