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Ecology and Vulnerability Red Knot
Displayed are DSL Landscape Capability (LC) data for the Red Knot for 2010 (DSL Current); higher values shown in dark red. LC incorporates habitat, climate, and prevalence to estimate suitable and accessible conditions for the species. LC values can't be compared across species. Courtesy of K. McGarigal, UMass.
HideDisplayed are DSL Landscape Capability (LC) data for the Red Knot for 2010 (DSL Current); higher values shown in...
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Ecology and Vulnerability
Red Knot
Background
Red knots are stocky, medium-sized shorebirds with gray molted bodies and distinct rusty red breasts. Red knots breed in the arctic region, nesting in both... Read More
Background
Red knots are stocky, medium-sized shorebirds with gray molted bodies and distinct rusty red breasts. Red knots breed in the arctic region, nesting in both northern Canada and Alaska, and winter primarily in South America and the Gulf of Mexico 8,11. These migratory shorebirds use Atlantic coastal areas for stopover to refuel during both fall and spring migrations. Red knot populations wintering in South America and North America have different foraging habitats, food sources, and flight feather molt timing, which may have different implications for their respective migration timing 4. Populations can also differ in their stopover durations throughout the Atlantic coast 4. Red knot populations have recently experienced significant declines, with the eastern subspecies of red knots declining by 75% since the 1980s 7,8. In southern South America, red knots experienced a 50% decline between 2001 and 2003 alone 1,7,8. Red knots have historically used both inland and coastal habitats of Massachusetts during migrations 4. Although they have never been observed nesting in Massachusetts, the beaches and mudflats of Cape Cod and other coastal habitats in the state provide excellent foraging grounds where red knots feed on bivalves, crustaceans, and other marine organisms.
In Canada and Alaska, nesting occurs in sparsely vegetated tundra usually within 50 km of the coast. During migration and wintering periods, red knots use sandy beaches and intertidal areas to feed. Red knots, along with other coastal shorebirds, are highly dependent on horseshoe crab eggs for energy during their northward migration. Red knots can double their weight during a 3 week-long stopover just by feeding on horseshoe crab eggs. Consequently, horseshoe crab eggs have been used to predict the distribution, timing, and abundance of red knots 6. Horseshoe crab abundance has declined due to overexploitation for bait and biomedical uses; this has negatively affected migrating red knots through decreased energy storage and overall health, thus impacting adult survival and the success of offspring 1. Red knots are further threatened by unregulated hunting in the Caribbean and northern South America 8.
Climate Impacts
Migratory bird populations are potentially vulnerable to the direct and indirect impacts of climate change through altered migration patterns and behavior, mismatches in optimal resources, and disruption of important life history stages. Red knots and other long-distance migrants are particularly at risk due to changes in the availability of resources across their range 5,9. For example, climate change has the potential to impact the timing of food availability in different seasonal habitats, such as on overwintering and foraging grounds critical for determining the abundance and survival of this species. Recently, evidence of red knot body shrinkage has been observed, resulting in shorter bill lengths, which has impaired their feeding ability in wintering habitats, resulting in decreased overall fitness 3. Red knot breeding habitat is threatened by warming temperatures and rising sea levels in northern regions, while critical refueling habitat in coastal areas of the Atlantic east coast is vulnerable to rising sea level and coastal erosion 2,10. A sea level rise of 2 feet by 2100 could reduce shorebird foraging areas, including for the red knot, by 57% or more in Delaware Bay, which is an important stop over site on their migration to northern habitats 12.
1. Baker A.J., P.M. Gonzalez, T. Piersma, J.L. Niles, De Serrano Do Nascimento. 2004. Rapid population decline in Red Knots: fitness consequences of decreased refuelling rates and late arrival in Delaware Bay. Proceedings of the Royal Society of London B 271: 875–882.
2. Galbraith, H., D.W. DesRochers, S. Brown, and J.M. Reed. 2014. Predicting vulnerabilities of North American shorebirds to climate change. PLoS ONE 9:e108899.
3. Gils, J.A.V., S. Lisovski, T. Lok, W. Meissner, A. Ozarowski, J.D. Fouw, E. Rakhimberdiev, M.Y. Soloviev, T. Piersma, and M. Klaassen. 2016. Body shrinkage due due to Arctic warming reduces red knot fitness in tropical wintering range. Science 352:819-821.
4. Harrington, B.A., N.P. Hill, and B. Nikula. 2010. Changing use of Migration Staging Areas by Red Knots: An Historical Perspective from Massachusetts. Waterbirds 33:188-192.
5. Jones T., W. Cresswell. 2010. The phenology mismatch hypothesis: are declines of migrant birds linked to uneven global climate change? Journal of Animal Ecology 79: 98–108.
6. Karpanty, S.M., J.D. Fraser, J. Berkson, L.J. Niles, A. Dey, and E.P. Smith. 2006. Horseshoe Crab Eggs Determine Red Knot Distribution in Delaware Bay. Journal of Wildlife Management 70:1704-1710.
7. Morrison R.I.G., R.K. Ross, L.J. Niles. 2005. Declines in Wintering Populations of Red Knots in Southern South America. Condor 106:60–70.
8. Natural Heritage & Endangered Species Program (NHESP). 2015. Red Knot. Massachusetts Division of Fisheries and Wildlife. Accessed 5/2/16. Available at: http://www.mass.gov/eea/docs/dfg/nhesp/species-and-conservation/nhfacts/...
9. Saino N., R. Ambrosini, D. Rubolini, J.V. Hardenberg, A. Provenzale, et al. 2011. Climate warming, ecological mismatch at arrival and population decline in migratory birds. Proceedings of the Royal Society B 278: 835–842.
10. Whitman, A., A. Cutko, P. De Maynadier, S. Walker, B. Vickery, S. Stockwell, and R. Houston. 2013. Climate change and biodiversity in Maine: vulnerability of habitats and priority species. Report SEI-2013-03. Manomet Center for Conservation Sciences (in collaboration with Maine Beginning with Habitat Climate Change Working Group), Brunswick, ME.
11. Willis, Nancy Carol. 2006. Red Knot: a shorebird’s incredible journey. Birdsong Books, Chicago, IL.
12. Galbraith, H., R. Jones, P. Park, J. Clough, S. Herrod-Julius, B. Harrington, and G. Page, 2002: Global climate change and sea level rise: potential losses of intertidal habitat for shorebirds. Waterbirds, 25(2), 173-183.
This species was identified as extremely vulnerable to climate change because of the following factors:
- Moderate loss of breeding habitat
- Major loss of wintering... Read More
This species was identified as extremely vulnerable to climate change because of the following factors:
- Moderate loss of breeding habitat
- Major loss of wintering habitat
- Major loss of migration habitat
- High dependence on ecological synchronicities
- Migration distance
- High degree of habitat specialization
Galbraith, H., D.W. DesRochers, S. Brown, and J.M. Reed. 2014. Predicting vulnerabilities of North American shorebirds to climate change. PLoS ONE 9:e108899.
This species was identified as highly vulnerable to climate change because of the following factors:
- Exhibits high degree of habitat specialization
- Habitat loss ... Read More
This species was identified as highly vulnerable to climate change because of the following factors:
- Exhibits high degree of habitat specialization
- Habitat loss
- Likely disruption of environmental cues for critical life stages
Whitman, A., A. Cutko, P. De Maynadier, S. Walker, B. Vickery, S. Stockwell, and R. Houston. 2013. Climate change and biodiversity in Maine: vulnerability of habitats and priority species. Report SEI-2013-03. Manomet Center for Conservation Sciences (in collaboration with Maine Beginning with Habitat Climate Change Working Group), Brunswick, ME.
Related Adaptation Strategies and Actions
Related Habitats (broad)
Related Habitats (detailed)
Related Species Groups
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