Assessing ecological effects of storm surges on Arctic bird populations in the outer Mackenzie Delta, Northwest Territories

Abstract

Coastal areas in the Western Canadian Arctic are predicted to experience increases in the frequency and intensity of storm surges as rapid climate change continues. Although storm surges have the potential to cause widespread and persistent vegetation loss, little information is available about the influence of decreasing disturbance intervals (between storms), expected timelines of recovery for vegetation, and how vegetation change alters habitat availability and (or) quality for local wildlife populations. We investigated how Arctic bird diversity is affected by heterogeneous vegetation recovery post-storm. Specifically, we employed field survey protocols from the Program for Regional and International Shorebird Monitoring to investigate how avian community assemblages were affected by heterogeneous re-vegetation 20 years following a record 1999 storm surge. Comparisons of these bird survey data with vegetation and habitat factors showed that the drier, post-storm vegetation barrens were preferred by ground-nesters and species that use open habitats such as Lapland longspur ( Calcarius lapponicus) and semipalmated plover ( Charadrius semipalmatus), whereas the wetter (usually with surface water) revegetated habitats were frequented by species of ducks ( Anas spp.), red-necked phalarope ( Phalaropus lobatus), and savannah sparrow ( Passerculus sandwichensis). Overall, this research shows that areas that have revegetated after the 1999 storm can be considered as functionally recovered in comparison to our Reference (i.e., unaffected) sites in terms of vegetation and bird communities, but that areas still exist ∼20 years post-storm that do not show evidence of recovery.