Dunlin (Calidris alpina)
The arcticola subspecies of Dunlin (Calidris alpina) has been identified as a focal species of conservation concern due to recent rates of habitat loss in nonbreeding areas where the species tends to aggregate, suspected species declines, gaps in knowledge about factors limiting population size, and inadequate monitoring data for population trend determinations. C. a. arcticola, with an estimated population of between 200,000 and 750,000, is one of three subspecies of Dunlin breeding in North America; the other two subspecies, C. a. pacifica, and C. a. hudsonia, are also thought to be declining. Breeding arcticola Dunlin use moist-wet tundra that typically are in pondy, polygonal or strangmoor landforms. Nonbreeding arcticola Dunlin are common in estuarine mudflats and are also found in coastal and adjacent agricultural habitats. C. a. arcticola breeds in northern Alaska (and possibly Canada), and unlike the other two species that winter in the Americas, spends the nonbreeding season distributed from Japan to the People’s Republic of China.
The greatest threat to this subspecies appears to be habitat loss from reclamation of intertidal areas for food production, shrimp farms, changes in water hydrology (e.g. dams) and agricultural practices. Climate change will have broad-scale impacts on breeding and nonbreeding habitat and the position, frequency and seasonality of storms that will affect the subspecies migration. Other threats to Dunlin include human disturbance, oil spills, and contaminants.
Fernández, G., J.B. Buchanan, R.E. Gill, Jr., R. Lanctot, and N. Warnock. 2008. Conservation Plan for Dunlin with Breeding Populations in North America (Calidris alpina arcticola, C. a. pacifica, and C. a. hudsonia), Version 1.0. Manomet Center for Conservation Sciences, Manomet, Massachusetts.
December 2, 2011