If you’ve ever visited the beach or perhaps the shores of one of the Great Lakes, it’s likely that you’ve seen a shorebird. This category of birds called shorebirds includes birds such as plovers, sandpipers, stilts, and Avocets2. Climate change has begun to cause shorebird population around the globe to decline. The biggest challenges climate change poses for shorebirds is the loss of intertidal habitat due to rising sea levels and changes in time of food availability and abundance. As sea levels rise the amount of intertidal habitat and quality shorebird habitat is reduced. These intertidal and coastal areas should gradually migrate inland, however humanmade barriers and coastal developments prevent them from doing so2. This leads to the overall reduction in suitable shorebird habitat, which could mean we may not get to snap as many photos of these cute little birds as we stroll down the beach2.
Photo: Florida Fish and Wildlife Service / Public Domain.
Many Shorebird species are migratory, which means that they travel to different locations throughout the year for breeding and wintering and often have areas they use for migratory refueling. For these migratory shorebirds, climate change poses an even larger threat. Migratory flights are often lengthy and energetically expensive, for this reason, migratory shorebirds, such as the Red Knot (Calidris canutus) not only use shores and intertidal habitats for their breeding and wintering grounds, but they rely on these habitats for places to rest and refuel for their long and tolling journeys1. Some of these sites they use throughout their journey are considered “staging sites” which are sites in which a large proportion of the population utilizes during their migratory journey. Rising sea-levels could potentially reduce the amount of available habitat at these sites, and ocean acidification and rising temperatures could reduce the quality of these sites and its available food resources3.
Photo: Doug Wechsler/VIREO
How exactly do ocean acidification and rising global temperatures affect the food resources available to shorebirds at these staging sites? Many species of shorebirds rely on plankton and other types of invertebrates as their primary food source. Acidification of the oceans could potentially reduce the fitness of many plankton species by reducing calcification and other physiological processes3. Rising temperatures could reduce the number of invertebrates available to shorebirds by altering ecological synchronicities (the timing of ecological events and synchronization of two or more of those events)3. Some shorebird species breed in the Arctic and temperatures in the Arctic are on the rise. The rise in Arctic temperatures could potentially result in earlier ice melts and spring thaws which could cause invertebrates to hatch earlier because in the Arctic invertebrate emergence temperature dependent. This could result in a misalignment between the arrival of shorebirds and the hatching of their invertebrate food resource3.
If a staging site experiences a reduction in invertebrates due to climate change, this will likely have negative effects on the shorebird population that utilizes it. If a group of shorebirds arrives at a staging site and there is a reduced abundance of invertebrates, there will be a reduction in the amount of energy available for each bird. If shorebirds cannot properly refuel at these staging sites for their long migratory journies, then it will likely affect their survival or reproductive ability, also known as their fitness3.
Hope is not lost for all of the shorebirds, as we still have time to take action! We can help prevent further decline of shorebirds by protecting the habitat they do have left and by preventing further development of coastal areas. Simple things, such as keeping your dog on a leash, picking up trash, or preventing a nest from being harmed, help to protect shorebirds and their habitat. Shorebirds are already experiencing a large amount of stress, and our goal should be to help lighten that stress load they’re under and to protect the coastal and intertidal areas.
References
- Iwamura, Takuya, et al. 2013. Migratory Connectivity Magnifies the Consequences of Habitat Loss from Sea-Level Rise for Shorebird Populations. Proceedings. Biological Sciences, The Royal Society, www.ncbi.nlm.nih.gov/pmc/articles/PMC3652437/.
- Aiello-Lammens et al. 2011. The impact of sea‐level rise on Snowy Plovers in Florida: integrating geomorphological, habitat, and metapopulation models. Global Change Biology, 17(12)3644-3654
- Galbraith, Hector, et al. 2014. Predicting Vulnerabilities of North American Shorebirds to Climate Change.” PLoS ONE, 9(9), doi:10.1371/journal.pone.0108899.
- Galbraith, H., et al. 2002. Global Climate Change and Sea Level Rise: Potential Losses of Intertidal Habitat for Shorebirds. Waterbirds, 25(2)p.173., doi:10.1675/1524-4695(2002)025[0173:gccasl]2.0.co;2.