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Ecology and Vulnerability
Saltmarsh Sparrow
Profile: Saltmarsh Sparrow ▾▸
Background
Saltmarsh sparrows nest exclusively in salt marshes1. The breeding range for this species is limited to a narrow band of tidal marsh that extends from Maine to Virginia, with up to half...
Background
Saltmarsh sparrows nest exclusively in salt marshes1. The breeding range for this species is limited to a narrow band of tidal marsh that extends from Maine to Virginia, with up to half of the global population estimated to breed in southern New England2. Females nest close to the ground in areas that are prone to flooding3 and their reproductive cycle is adapted to the ebbs and flows of the tide4,5. Their nesting is synchronized to the tidal cycle and is timed to occur between extreme tide events to avoid flooding of nests4,5. Despite this, flooding is still the major source of nest losses, accounting for 60% of failures2.
Climate Impacts
Climate change is expected to result in rising sea levels due to melting of glacial ice and thermal expansion of water (water expands and has more volume when warmed)6. Sea levels have been rising at an accelerated rate for at least the past 50 years in New England, exceeding average global rates7,8. In addition, there is an expected increase in the frequency of severe storms along with higher storm surges, which is likely to result in increased flooding of tidal areas during storms9,10. The northeast in particular has experienced approximately one foot of sea-level rise since 1900, and is projected to experience anywhere between 1.5 to 6 feet of additional sea-level rise over the next century8,11.
Because saltmarsh sparrows have developed a finely tuned reproductive strategy to cope with a flood prone environment, there is concern that the above changes could have a large impact on this species through increased nest failure2,3. Sparrow nests appear to be extremely vulnerable to even slight increases in sea level, leading some to suggest a bleak future for this species2. For instance, the maximum tide height for successful nests without being flooded was just 6 cm higher on average than failed nests2. In addition to the direct effects of nest flooding, changes in sea level may result in changes to the distribution and character of coastal wetlands7, which could have additional impacts on saltmarsh sparrows. Modeling studies conducted by the University of Massachusetts that incorporate landscape characteristics and climate change, predict a 41% reduction in the capability of the northeast landscape to support saltmarsh sparrow populations by 208012. A study conducted for the Chesapeake Bay suggested that saltmarsh sparrows could lose up to 100% of their population with a 3.3-6.6 ft rise in sea levels by 210013.
References
1. Gjerdrum, C., C.S. Elphick, and M. Rubega. 2005. Nest site selection and nesting success in saltmarsh breeding sparrows: the importance of nest habitat, timing, and study site differences. The Condor 107:849-862.
2. Bayard, T.S., and C.S. Elphick. 2011. Planning for sea-level rise: quantifying patterns of saltmarsh sparrow (Ammodramus caudacutus) nest flooding under current sea-level conditions. The Auk 128:393-403.
3. Meiman, S., D. Civco, K. Holsinger, and C.S. Elphick. 2012. Comparing habitat models using ground-based and remote sensing data: saltmarsh sparrow presence versus nesting. Wetlands 32:725-736.
4. Gjerdrum, C., K. Sullivan-Wiley, E. King, M.A. Rubega, and C.S. Elphick. 2008. Egg and chick fates during tidal flooding of saltmarsh sharp-tailed sparrow nests. The Condor 110:579-584.
5. Shriver, W.G., P.D. Vickery, T.P. Hodgman, and J.P. Gibbs. 2007. Flood tides affect breeding ecology of two sympatric sharp-tailed sparrows. The Auk 124:552-560.
6. Rahmstorf, S. 2007. A semi-empirical approach to projecting future sea-level rise. Science 315:368-370.
7. Warren, R.S., and W.A. Niering. 1993. Vegetation change on a northeast tidal marsh: interaction of sea-level rise and marsh accretion. Ecology 74:96-103.
8. Horton, R., G. Yohe, W. Easterling, R. Kates, M. Ruth, E. Sussman, A. Whelchel, D. Wolfe, and F. Lipschultz. 2014. Ch. 16: Northeast. Climate Change Impacts in the United States: The Third National Climate Assessment. Pages 371-395 in J.M. Melillo, T.(.C.). Richmond, and G. W. Yohe, editors. U.S. Global Change Research Program.
9. Thorne, K.M., J.Y. Takekawa, and D.L. Elliott-Fisk. 2012. Ecological effects of climate change on salt marsh wildlife: a case study from a highly urbanized estuary. Journal of Coastal Research 28:1477-1487.
10. Anthes, R.A., R.W. Corell, G. Holland, J.W. Hurrell, M.C. MacCracken, and K.E. Trenberth. 2006. Hurricanes and global warming-potential linkages and consequences. Bulletin of the American Meteorological Society 87:623-628.
11. Horton, R., C. Little, V. Gornitz, D. Bader, and M. Oppenheimer. 2015. Chapter 2: Sea Level Rise and Coastal Storms. Pages 36-44 in New York City Panel on Climate Change 2015 Report. Annals of the New York Academy of Sciences, New York, NY.
12. DeLuca, W., and K. McGarigal. 2014. DSL Project Component: Species. Available at < http://www.umass.edu/landeco/research/dsl/documents/dsl_documents.html> (Accessed 1 June 2015).
13. Wilson, M. and B. Watts, 2009: Impacts of sea level rise on marsh birds. The Center for Conservation Biology. May 1, 2009, Accessed May 2016. Online at: http://www.ccbbirds.org/2009/05/01/impacts-of-sea-level-rise-on-marsh-birds/
Climate Change Vulnerability Assessment: Saltmarsh Sparrow (Maine)
Ranking
Highly Vulnerable
Confidence
Very High
Climate scenario
None specified
Location
Maine
Time period
None specified
Climate Change Vulnerability Assessment: Saltmarsh Sparrow (North Atlantic Coast)
Ranking
Moderately Vulnerable
Confidence
Very High
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
North Atlantic Coast
Time period
2050
Climate Change Vulnerability Assessment: Saltmarsh Sparrow (Mid-Atlantic Coast)
Ranking
Highly Vulnerable
Confidence
Very High
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
Mid-Atlantic Coast
Time period
2050
Climate Change Vulnerability Assessment: Saltmarsh Sparrow (New York)
Ranking
Moderately Vulnerable
Confidence
Very High
Climate scenario
SRES A1B (Mid-range emissions scenario)
Location
New York
Time period
2050
Climate Change Vulnerability Assessment: Saltmarsh Sparrow (Connecticut)
Ranking
Highly Vulnerable
Confidence
Not assessed
Climate scenario
SRES B1/A1B/A2 (Lowest/mid-range/low emissions scenario)
Location
Connecticut
Time period
2080