Bick, G.H. 1983. Odonata at risk in conterminous United States and Canada. Odonatologica 12(3): 209-226.

Abstract
32 spp. (8% of the odon. fauna) considered to be at risk in the United States and Canada are assigned to Red Data Book categories as follows: Rare-20 (62%), Vulnerable-5 (16%), Endangered-3 (9%), Insufficiently known-3 (9%), Probably extinct-I (3%). Most (82%) of the threatened spp. are associated with flowing water. The loss of high-quality, undisturbed streams is the most significant actor endangering odonates in the US and Canada. The threatened spp. occur in 3 eastern Canadian Provinces and in 31 states, most of which are east of the Mississippi River. There is no one small area where conservation efforts could be marshaled for the simultaneous protection of more than one narrow endemic sp. However, the southeastern Highlands and the southern Gulf Coast are considered important for future conservation efforts.