Climate change is listed as the third greatest threat to seabirds globally (Croxall et al. 2012). It is predicted to decrease the land area of low-lying Pacific islands and cause complete inundation of some islands (IPCC 1997) leading to substantial population declines (Hatfield et al. 2012). Although no current data or predictions are available specific to this IBA climate change represents a potential threat to this site owing to the risk of future sea level rise leading to inundation, and increased frequency of storms.
Military operations during and post WWII on Johnston Atoll caused the displacement and disruption to large portions of the breeding seabirds now present there (http://www.fws.gov/refuges/profiles/index.cfm?id=12515).
Although Johnston Atoll is now a US National Wildlife Refuge it is under the jurisdiction of the US Air Force. The Air Force therefore reserves the right to post military personnel back to Johnston Atoll in the future.
Several significant contaminant issues exist: closure of the chemical weapons disposal plant; dioxin (Agent Orange), which contaminates at least four acres of land and has migrated to the marine environment; plutonium from two abortive missile launches during high-altitude nuclear and missile testing in the 1950s and 1960s; and a subsurface plume of PCB-contaminated petroleum product.
Contaminants tracking involves monitoring seabirds, fishes, and marine invertebrates. Refuge personnel also monitor fish populations and threatened green sea turtles, which use the waters of Johnston Atoll as an important foraging location. Also, soil and sediment samples are used to establish the degree and extent of contamination (http://www.fws.gov/refuges/profiles/index.cfm?id=12515).
The affect that this contamination has on the seabird populations is not known, or how far the effects could reach in the marine environment.
Conservation responses/actions for key biodiversity
The removal of military personnel and infrastructure has allowed the bird populations to recover significantly.
Johnston Atoll is a US National Wildlife Refuge, which is administered by the US Air Force who control all access.