Three Research Natural Areas (RNAs) that lie in the Snake River ACEC on the South Fork of the Snake River are managed to protect natural riparian vegetation from encroachment and from any direct of indirect modification of ecological processes.  Use of RNAs is limited to non-destructive, non-manipulative research, study and observation. 

The shapes and sizes of the islands (6 in all) change periodically as a result of the River's dynamic forces.

The Pine Creek RNA is actually 2 islands that lie about one mile downstream of the mouth of Pine Creek, in bald eagle nesting territory.  Narrowleaf cottonwood and red osier dogwood cover the islands' 54 acres.

The most pristine of the three sets of islands, the Reid Canal RNA, consists of 3 islands (29 acres) in the South Fork, about two-and-a-quarter miles down river from the Sunnydell rookery.  Red osier dogwood and reed canarygrass mix with narrowleaf cottonwood vegetation.  Yellow-billed cuckoos have been spotted on the islands.

The Squaw Creek RNA is a single island (38 acres) at the mouth of the creek of the same name.  It is drier than the other 2 RNAs, which can make its vegetation more susceptible to encroachment.  Water birch complements narrowleaf cottonwood.