An evaluation of 60 years of shorebird response to environmental change at Utqiaġvik (Barrow), Alaska

Abstract

The Arctic is experiencing climate-induced changes in environmental conditions faster than any other region of the world. We examined the effect of such changes on shorebird populations at Utqiaġvik (formerly Barrow), Alaska, over the last six decades (1950s to 2010s). First, we identified three environmental changes at Utqiaġvik that are likely to affect shorebirds: (1) warmer and longer summers, (2) drying of the landscape, and (3) changes in tundra vegetation. We then examined evidence for each of these being a primary driver of changes in shorebirds’ nest density and probability of breeding. The Black-bellied Plover (Pluvialis squatarola), Ruddy Turnstone (Arenaria interpres), and Baird’s Sandpiper (Calidris bairdii), shorebirds with broad distributions in Alaska but a preference for dry, open tundra, declined at Utqiaġvik from the 1950s to the 2010s, whereas the Western Sandpiper (C. mauri), Semipalmated Sandpiper (C. pusilla), Long-billed Dowitcher (Limnodromus scolopaceus), and Red-necked Phalarope (Phalaropus lobatus), which typically breed in the Low Arctic, have increased. No species preferring wet or moist habitats decreased in nest density or probability of breeding over the six decades. These patterns suggest northward shifts in the distribution of Low Arctic shorebirds with warmer and longer summers, and also downplay the likelihood of a drier landscape being an important factor driving changes in nest density or probability of breeding. We also found that in the 2000s flight-feather molt of the Dunlin (C. alpina) extended over a significantly longer period, overlapping less with breeding than during the 1960s. These findings increase our understanding of the characteristics of shorebirds’ life history that are likely to show more sensitivity or adaptability to future environmental change,and enable us to predict which species should become more or less common at Utqiaġvik and elsewhere in the Arctic in future decades.