WETLANDS OF THE DELTA
The lifeblood of Cordova's wildlife adjusts to a shifting climate
Story by Kristin Kessler
Photos by Denise Silfee, Rhys Marshall, Peter Lucas, and Haley Justus
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"The freshwater on the delta is also important habitat for all five species of pacific salmon who spawn in the streams or swim up the Copper River to spawning areas in Chugach mountains. Salmon and other fish are a fundamental food source for other animals on the delta."
"This summer, record-breaking temperatures were reached all over Alaska and sustained for days or even weeks in some places. The warmed waters and had detrimental effects on salmon populations. Salmon are a basis of the food chain on the Copper River Delta and losing them would irreversibly damage the ecosystem."
From above, the Copper River looks like an infinite number of streams weaving together and apart. The river runs from the Chugach Mountains to Prince William Sound, cutting across 700,000 acres of wetlands called the Copper River Delta. The interior marshes of the Copper River Delta are home to bears, moose, wolves and various other land animals who feed on the lush vegetation or hunt fish and other small animals while the coastal tidal flats of the delta host the largest gathering of migratory shorebirds in the western hemisphere.
On March 27th 1964, the strongest earthquake in North American history reshaped the coast of South East Alaska. The Great Alaskan Earthquake registered a 9.2 magnitude (out of 10) on the Richter Scale. The epicenter of the quake was only 80 miles from the mouth of the Copper River and the vibrations raised portions of the delta up to nine feet, drastically changing the terrain of the existing wetlands.
Because some of the land was raised out of reach of the tides, the delta is now drier in some areas than it was before the earthquake, and the system is now influenced more by freshwater from rainfall and glacial melt than tidal water. As sea salt leached out of the soil, trees, grasses and shrubbery extended their reach toward the coastline. This has benefited bears and moose who feed on the plentiful vegetation in the spring and throughout the summer.
Initially, there was concern that the drying out of some of the land would be unfavorable for the waterfowl that live on the delta or stop over during their migrations, but the delta still supports an estimated 12 million shorebirds every spring and the interior delta is still a critical habitat for thousands of water birds in the summer. The freshwater on the delta is also important habitat for all five species of pacific salmon who spawn in the streams or swim up the Copper River to spawning areas in Chugach mountains. Salmon and other fish are a fundamental food source for other animals on the delta.
Erin Cooper, program manager for the National Forest Service and resident of the nearest municipality, Cordova, calls the Copper River Delta “a diverse mosaic of wetland habitats and within there, you have all these different wildlife species that use it. It's an enchanting place.”
The delta is also an important resource for the people of local community. “This wetland is the grocery store for Cordova,” says Cooper. People from Cordova come to the delta to hunt moose and waterfowl, collect berries to save through the winter and gather medicinal plants that grow in the vegetation. Having healthy habitat for salmon is also critical to Cordovans because their economy is based on the salmon industry.
“In a lot of ways [the wetlands is] the provider for a lot of the community,” says Cooper.
The Copper River Delta is a thriving habitat, but some of the changes brought about by the earthquake have created challenges for wildlife residents. After the upheaval, the National Forest Service currently stepped in to manage changes that have become inconveniences to some of the species living in the delta.
“We manage in such a way to assist in resiliency of the landscape to mitigate for some of these more drastic changes that have occurred,” explained Cooper.
Dusky Canada geese are one of the species whose life cycle was most hindered by the major changes in the wetland’s terrain. The Copper River Delta is a primary nesting ground for the geese, who are the smallest subspecies population of geese in north America. Dusky Canada Geese traditionally nest on islands in the delta to protect their nests and young from foragers like weasels and wolves, but since areas of the wetlands have dried up since the earthquake, there have been fewer islands to nest on and dusky Canada geese’s nests have been exposed. The geese have also been more vulnerable to airborne predators like eagles because more Sitka spruce and cottonwood trees have been able to grow on on the delta since the earthquake, offering the birds higher perch sites around the geese’s nests.
To aid the geese, the National Forest Service (NFS) builds artificial nest islands for the geese and clears Sitka spruce and cottonwoods from the areas around nesting sites. Clearing the undesirable trees also benefits moose because they have been crowding out willows trees which are one of moose’s major food sources. The NFS has even begun to use prescribed fires to clear the undesirable trees as a way to encourage the growth of willows and increase their nutritional content.
Beyond trying to compensate for the less fortunate changes caused by the earthquake, the NFS also protects the wetlands battling the invasive species elodea. Elodea is a water plant that grows rapidly and could potentially choke the water systems if it were to spread outside of the three ponds it already grows in on the delta. The NFS is testing herbicides to determine if they will be safe to use to keep the elodea under control with the hopes of eventually eradicating it from the wetlands. They closely monitor the impacts of herbicides to ensure that it is not negatively impacting anything besides the elodea.
NFS programs mitigate tangible threats, but some of the threats to the productivity of the Copper River Delta are outside of their control.
Rising temperatures are disrupting ecosystems all over the globe, and in turn they also threaten the productivity of the Copper River Delta. This summer, record-breaking temperatures were reached all over Alaska and sustained for days or even weeks in some places. The warmed waters and had detrimental effects on salmon populations. Salmon are a basis of the food chain on the Copper River Delta and losing them would irreversibly damage the ecosystem.
Increase in average temperatures is also causing glaciers to melt more each summer. Because the Copper River Delta’s wetlands are fed by the surrounding glaciers, this is a looming threat to the abundance of the delta.
“Once glaciers recede enough that they're not melting and you don't have that water input into the system as you'll end up with a drying and some of these wetlands are going to disappear, the productivity adjacent,” says Cooper.
"The river runs from the Chugach Mountains to Prince William Sound, cutting across 700,000 acres of wetlands called the Copper River Delta."
"Salmon are a basis of the food chain on the Copper River Delta and losing them would irreversibly damage the ecosystem."
From above, the Copper River looks like an infinite number of streams weaving together and apart. The river runs from the Chugach Mountains to Prince William Sound, cutting across 700,000 acres of wetlands called the Copper River Delta. The interior marshes of the Copper River Delta are home to bears, moose, wolves and various other land animals who feed on the lush vegetation or hunt fish and other small animals while the coastal tidal flats of the delta host the largest gathering of migratory shorebirds in the western hemisphere.
On March 27th 1964, the strongest earthquake in North American history reshaped the coast of South East Alaska. The Great Alaskan Earthquake registered a 9.2 magnitude (out of 10) on the Richter Scale. The epicenter of the quake was only 80 miles from the mouth of the Copper River and the vibrations raised portions of the delta up to nine feet, drastically changing the terrain of the existing wetlands.
Because some of the land was raised out of reach of the tides, the delta is now drier in some areas than it was before the earthquake, and the system is now influenced more by freshwater from rainfall and glacial melt than tidal water. As sea salt leached out of the soil, trees, grasses and shrubbery extended their reach toward the coastline. This has benefited bears and moose who feed on the plentiful vegetation in the spring and throughout the summer.
Initially, there was concern that the drying out of some of the land would be unfavorable for the waterfowl that live on the delta or stop over during their migrations, but the delta still supports an estimated 12 million shorebirds every spring and the interior delta is still a critical habitat for thousands of water birds in the summer. The freshwater on the delta is also important habitat for all five species of pacific salmon who spawn in the streams or swim up the Copper River to spawning areas in Chugach mountains. Salmon and other fish are a fundamental food source for other animals on the delta.
Erin Cooper, program manager for the National Forest Service and resident of the nearest municipality, Cordova, calls the Copper River Delta “a diverse mosaic of wetland habitats and within there, you have all these different wildlife species that use it. It's an enchanting place.”
The delta is also an important resource for the people of local community. “This wetland is the grocery store for Cordova,” says Cooper. People from Cordova come to the delta to hunt moose and waterfowl, collect berries to save through the winter and gather medicinal plants that grow in the vegetation. Having healthy habitat for salmon is also critical to Cordovans because their economy is based on the salmon industry.
“In a lot of ways [the wetlands is] the provider for a lot of the community,” says Cooper.
The Copper River Delta is a thriving habitat, but some of the changes brought about by the earthquake have created challenges for wildlife residents. After the upheaval, the National Forest Service currently stepped in to manage changes that have become inconveniences to some of the species living in the delta.
“We manage in such a way to assist in resiliency of the landscape to mitigate for some of these more drastic changes that have occurred,” explained Cooper.
Dusky Canada geese are one of the species whose life cycle was most hindered by the major changes in the wetland’s terrain. The Copper River Delta is a primary nesting ground for the geese, who are the smallest subspecies population of geese in north America. Dusky Canada Geese traditionally nest on islands in the delta to protect their nests and young from foragers like weasels and wolves, but since areas of the wetlands have dried up since the earthquake, there have been fewer islands to nest on and dusky Canada geese’s nests have been exposed. The geese have also been more vulnerable to airborne predators like eagles because more Sitka spruce and cottonwood trees have been able to grow on on the delta since the earthquake, offering the birds higher perch sites around the geese’s nests.
To aid the geese, the National Forest Service (NFS) builds artificial nest islands for the geese and clears Sitka spruce and cottonwoods from the areas around nesting sites. Clearing the undesirable trees also benefits moose because they have been crowding out willows trees which are one of moose’s major food sources. The NFS has even begun to use prescribed fires to clear the undesirable trees as a way to encourage the growth of willows and increase their nutritional content.
Beyond trying to compensate for the less fortunate changes caused by the earthquake, the NFS also protects the wetlands battling the invasive species elodea. Elodea is a water plant that grows rapidly and could potentially choke the water systems if it were to spread outside of the three ponds it already grows in on the delta. The NFS is testing herbicides to determine if they will be safe to use to keep the elodea under control with the hopes of eventually eradicating it from the wetlands. They closely monitor the impacts of herbicides to ensure that it is not negatively impacting anything besides the elodea.
NFS programs mitigate tangible threats, but some of the threats to the productivity of the Copper River Delta are outside of their control.
Rising temperatures are disrupting ecosystems all over the globe, and in turn they also threaten the productivity of the Copper River Delta. This summer, record-breaking temperatures were reached all over Alaska and sustained for days or even weeks in some places. The warmed waters and had detrimental effects on salmon populations. Salmon are a basis of the food chain on the Copper River Delta and losing them would irreversibly damage the ecosystem.
Increase in average temperatures is also causing glaciers to melt more each summer. Because the Copper River Delta’s wetlands are fed by the surrounding glaciers, this is a looming threat to the abundance of the delta.
“Once glaciers recede enough that they're not melting and you don't have that water input into the system as you'll end up with a drying and some of these wetlands are going to disappear, the productivity adjacent,” says Cooper.