New York Natural Heritage Program
Delaware River Clubtail
Gomphus septima delawarensis (Donnelly and Carle, 2000)
Insects

Threats [-]
Donnelly (1993) described how New York City water supply dams on the headwaters of the east and west branches of the Delawarer River likely negatively affect sediment (i.e., larval habitat) dynamics far downstream. At the same time, much of the inhabited stretch of the river is currently being managed as a coldwater trout fishery, through increased dam releases (of cold reservoir water) to lower river temperatures in summer. Invasive Japanese Knotweed has become well established along the shoreline, including areas used for spring emergence, although at present it is unclear what the effects, if any, dense stands of this plant have on this species.

Conservation Strategies and Management Practices [-]
There is a presumed uninhabited stretch of about 65 Km between Callicoon, the northern-most known locale on the upper Delaware to Downsville in Delaware County on the east Branch, where a male and a female were collected in 1995 (Donnelly and Carle, 2000). Further inventory along this stretch as well as along the west Branch, north of Hancock and the Beaverkill (upstream of the confluence with the East Branch) is urgently needed. The effects of managing the upper Delaware River as a coldwater trout sport fishery (via hypolimnial water releases from the upstream NYC water supply dams) should be investigated. In addition, the possible effects of the establishment of dense stands of invasive Japanese Knotweed (Fallopia japonica) along the riverbanks may alter ecological processes along this reach of the river.

Research Needs [-]
This taxa is sorely in need of taxonomic revision to full species status (see Donnelly and Carle, 2000).