The Atlantic flyway is the most densely populated of the four waterfowl migration flyways in North America (Ducks Unlimited, 2019). Climate change poses significant threats to migrating waterfowl in the Atlantic flyway. Specifically, sea level rise, changes in temperature patterns, and flooding are the most significant climate change threats to migrating waterfowl. These climate change hazards are having significant impacts on waterfowl nesting, feeding and migration areas within the Atlantic flyway. Climate change in the Atlantic flyway is negatively impacting the resources waterfowl rely on, therefore causing changes in species population, migration timing, and viable food sources.
The Atlantic flyway spans 3000-miles from northern Canada to the Southern United States (Ducks Unlimited, 2019). Waterfowl including ducks, geese, and swans use the flyway to migrate south from northern breeding grounds during wintering months. Specifically, waterfowl that migrate through the Atlantic flyway rely on coastal wetlands, farm fields and timber areas for survival. In 1995, the United States took a formal approach to management and adopted an adaptive harvest management plan (Johnson, 1999). This management plan attempts to unify waterfowl harvest management across temporal, spatial, and bio-organizational scales (Johnson, 1999). It is estimated that twenty million birds are harvested annually and the United States total economic benefit from waterfowl is $11 billion (Johnson, 1999).
Climate Change Hazards
Sea Level Rise
Sea level rise along the east coast of North America 1-2 feet since 1900 (Romero-Lankao, 2014). The IPCC expects that within the next century, the east coast of North America will experience at least 1 meter of sea level rise (Romero-Lankao, 2014). Along the Eastern coast of the United States, many coastal communities and ecosystems exist right at sea level. The expected 1-meter sea level rise will flood and destroy many of these coastal ecosystems. As salt water begins to spread further inland, it will have damaging effects to sensitive aquatic ecosystems and wetlands (Cloern, 2015). Overtime these coastal freshwater ecosystems will be replaced by an ecosystem that thrives in salt water.
Flooding and Drought
Droughts during the summer months pose significant threats to crops and wetland ecosystems. The U.S. National Climate Change Assessment predicts a significant increase in the number of summer days over 90 degrees Fahrenheit in the Northeast (USGCRR, 2018). Therefore, as climate change progresses current crops in the Northeast are going to need to be switched with crops better suited for the heat. Wetlands need water to survive, so drought will only further damage wetland ecosystems. Increased flooding is also expected in North America as severe weather events increase with climate change (USGCRR 2018). Flooding damages aquatic and wetland ecosystems as they become overwhelmed with water and water quality decreases.
Global warming is going to impact the temperature patterns across North America. The IPCC expects a 2-degree Celsius increase in average annual temperatures by mid 21st century (Romero-Lankao, 2014). Additionally, the U.S. National Climate Change Assessment predicts that if emissions continue to increase, warming of 4.5°F to 10°F can be expected by the 2080s; If global emissions were reduced substantially, they project a warming from about 3°F to 6°F by the 2080s (USGCRR 2018). These changes in temperature patterns will have a significant impact on the duration and amount of snow cover in North America. Wintering ecosystems such as lakes and wetlands will have to adapt to changes in snow cover and temperature patterns.
Exposure and Vulnerabilities
As a sea level rise destroys coastal wetlands and ecosystems, waterfowl will be exposed to these changes. Coastal ecosystems that were once fresh or brackish marsh will be replaced by intruding salt marsh or open water. Salt marsh is less diverse and does not hold many of the same food and nest sources for migrating waterfowl (Ducks Unlimited, 2019). The American Black Duck is extremely vulnerable as they rely on the sea grass beds for food and habitat while migrating and wintering on coastal waters (Ringelman, 2015). As seas level rise destroys many of these freshwater coastal wetlands, the competition between Black Ducks and Mallards may increase for those resources. Therefore, sea level rise induces unwarranted population stress on Black Ducks and Mallards as they compete for the limited remaining resources (Ringelman, 2015). In addition, sea level rise forces humans and waterfowl closer together as both relocate inland. As humans are forced to move inland, Ducks Unlimited anticipates significant waterfowl habitat destruction. Therefore, proactive planning by humans is going to be required to maintain high value inland ecosystems. As sea level rise increases, the vulnerable ecosystems in the Atlantic flyway become increasingly threated and destroyed.
Food and Habitat
As temperatures increase over the next century, current crops in the Northeast become threatened. Currently, waterfowl rely on corn and other crops grown in the northeast as a food source during the winter migration. The leftover crops in the field provide waterfowl with enough food to survive throughout the winter (Schumer, 2017). Therefore, as new crops are introduced that thrive in a warmer climate, the ability for these new crops to provide food for waterfowl is threatened. In addition, warmer temperatures increase drought and flooding, exposing waterfowl to unsuitable nesting and feeding habitats. Specifically, Wood Ducks breed and nest in wooded swamps and wetlands. Drought and flooding that damage these ecosystems will reduce the amount of viable breeding habitat and resources available to Wood Ducks (Ducks Unlimited, 2019).
Based on the projections of rising air temperatures and reduced snow cover, delayed autumn-winter migration is expected for all species, with the least delays for the Northern Pintail and the greatest delays for the Mallard (Notaro, 2016). Dabbling ducks are likely to spend more time in the Northeast, which would impact existing wetlands through increased foraging pressure. Waterfowl use changes in temperature as key indicators for winter and spring migration (Reilly, 2017). The recent trend of longer winters and a late spring has delayed the Northward spring migration. The delayed return migration has had significant impacts on breeding for certain waterfowl species. Waterfowl such as Snow Geese, will fear to breed if they arrive at their Arctic tundra breeding grounds to late. There is a critical window of time in the summer that waterfowl use to breed in the Arctic (Notaro, 2016).
Adaptation and Resilience
Waterfowl such as Canada Geese have already begun to adapt to changes in temperature patterns caused by climate change. Specifically, Canada Geese have recently began breeding heavily in the Northeast United States. In many states, there is an over population of resident Canada Geese that threaten many wetland ecosystems (Ducks Unlimited, 2019). The warmer temperatures cause by climate change allow Canada Geese to inhabit that Northeast year-round. Other species of waterfowl that rely on specific Arctic conditions to nest breed are the most threatened. The resilience of waterfowl significantly depends on the species ability to adapt to the ecosystem transformation caused by climate change.
Waterfowl in the Atlantic flyway are very exposed and vulnerable to the impacts of climate change. The effects of climate change are going to destroy many of the natural ecosystems waterfowl use for survival. Over the next century, the resilience of waterfowl in the Atlantic flyway is going to tested as the climate and available resources change. Proactive management of resources and waterfowl can help mitigate the disproportional effects of climate change.
About the Author
Parker Hall graduated with a bachelors degree from St. Lawrence University in 2019. He was a double major in Environmental Studies and Business in the Liberal Arts. On campus, he was the Treasurer of the St. Lawrence University Ducks Unlimited Club. He was responsible for helping to develop and orchestrate a Ducks Unlimited fundraising event in the North Country. The event goal was to raise more than $5000 for the Ducks Unlimited charity for waterfowl habitat conservation. This fundraising event educated and connected students and community members with the common goal of conservation. Post St. Lawrence University, Parker attended Rochester Institute of Technology to receive his Master's in Business Administration. He made this website for Professor Jon Rosales' Climate Change Adaptation class in spring 2019.
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