A Water Boatmen or Corixidae viewed through a microscope. They have a thin bubble of air trapped against their body, allowing them to stay underwater for long periods of time.
Prey Availability
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By Saline Lake Ecosystems Integrated Water Availability Assessment
April 2, 2025
Migratory wildlife need to balance the benefits of migration and reproduction with the physiological costs. This is particularly challenging in dynamic environments like wetlands, where food levels can vary greatly from year to year. For shorebirds in the Great Basin region, saline or terminal lakes provide essential habitats during their annual life cycle. To understand how changes in hydrology and water quality impact food resources (prey availability) for shorebirds we are conducting studies across the Great Basin saline lakes system.
Background
Media
Sources/Usage: Public Domain. View Media Details
Prey availability is critical to most aspects of the annual waterbird cycle, including movements and habitat selection, reproduction, physiology, and survival. Prey availability sampling allows us to assess community composition, density, biomass, and caloric value of prey. These factors in turn help us to better understand when and where shorebirds feed and why they use specific habitats. Additionally, sampling prey across space and time within the Great Basin saline lakes allows us to better understand habitat availability across the entire region.
Lakes that are important for shorebird migration were prioritized for prey availability sampling. They include Malheur, Abert, and Summer in Oregon, Honey and Mono in California, Carson Sink, Stillwater, and Carson Lake in Nevada, and Great Salt Lake in Utah, shown here. These lakes range in salinity from freshwater to hypersaline. Although studies have been conducted on prey availability at some of these lakes, more information is needed across the system.
Sampling at priority lakes will help us to better understand how changes to hydrology and water chemistry impact the density and caloric value of invertebrates. We know that, in general, the salinity of terminal lakes in the Great Basin is increasing and approaching the limit of what freshwater invertebrates can tolerate. This trend could lead to declines in invertebrate mass and caloric value. These potential changes in prey quality could impact migratory shorebirds who depend on high caloric fueling during their long-distance migrations.
What are our goals?
- Understand the carrying capacity of lakes for birds, or how many birds a lake or habitat can support, and for how long.
- Measure prey availability changes across time, space, depth, and different water chemistry levels.
Media
Field work supplies used to take macroinvertebrate samples to determine prey availability in terminal lakes.
Sources/Usage: Public Domain. View Media Details
Media
USGS ecologist taking a macroinvertebrate sample in Malheur Lake.
Sources/Usage: Public Domain. View Media Details
Prey composition changes due to water quality
Organisms require a very specific set of circumstances to thrive in a body of water. One example is brine shrimp which thrive in environments that are hypersaline but cannot survive in water that is too fresh or too salty. Outside of this happy medium, brine shrimp will decline in condition, reproduce less, and die if conditions are extreme. This salinity gradient ultimately defines what kind of organisms exist in a body of water. The availability of tasty prey present will also impact what birds will come to feed!
Case Study: Lake Abert
Lake Abert, a hypersaline lake in south-central Oregon supports hundreds of thousands of waterbirds annually. Aquatic prey there consists primarily of brine flies and brine shrimp. At Lake Abert, we are using a repeated sampling approach where we sample at the same sites monthly from April to October. However, as the lake level recedes seasonally, sampling sites track consistent water depths and sites move father out into the lake.
Media
Sources/Usage: Public Domain. View Media Details
Over the 2024 sampling season at Lake Abert, we have collected:
- 89 water column prey community/energetics samples
- 45 benthic prey community/energetics samples
- 27 water’s edge measurements to assist in remote sensing
Water chemistry data at every site
Media
A water boatman viewed through a microscope. They have a thin bubble of air trapped against their body, allowing them to stay underwater for long periods of time.
Sources/Usage: Public Domain. View Media Details
Media
Brine shrimp seen swimming in Lake Abert, These shrimp provide an important source of prey to shorebirds stopping in the area to rest and refuel on their long migration journeys.
Sources/Usage: Public Domain. View Media Details
Media
Brine shrimp viewed up close.
Sources/Usage: Public Domain. View Media Details
Looking forward:
We will refine sampling methods to better capture variability in certain invertebrate groups like brine fly larvae.
We’ll sample at additional lakes like Eagle Lake. These lakes that are not considered as important to shorebirds could potentially support them in future years when other lakes are not available.
We’ll be adding limited sampling at sites where waterbirds are actively foraging across the lakes to better understand habitat selection processes.
Learn More About this Work from our Partners
Water Boatmen Back
A Water Boatmen or Corixidae viewed through a microscope. They have a thin bubble of air trapped against their body, allowing them to stay underwater for long periods of time.
Water Boatmen Head
A water boatmen, scientific name Corixidae, is an aquatic insect that lives in both freshwater and saline ecosystems. They're commonly found as a source of prey for migratory birds across the Saline Lakes.
A water boatmen, scientific name Corixidae, is an aquatic insect that lives in both freshwater and saline ecosystems. They're commonly found as a source of prey for migratory birds across the Saline Lakes.
Saline Lakes IWAA Fall 2024 Webinar Series: Waterbird Prey Availability
The fifth webinar in the Saline Lakes Ecosystems IWAA Fall 2024 Webinar Series is on waterbird prey availability in Great Basin terminal lakes.
By
Ecosystems Mission Area, Water Resources Mission Area, Species Management Research Program, Water Availability and Use Science Program, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, Nevada Water Science Center, Oregon Water Science Center, Utah Water Science Center, Western Ecological Research Center (WERC), Saline Lake Ecosystems Integrated Water Availability Assessment
The fifth webinar in the Saline Lakes Ecosystems IWAA Fall 2024 Webinar Series is on waterbird prey availability in Great Basin terminal lakes.
By
Ecosystems Mission Area, Water Resources Mission Area, Species Management Research Program, Water Availability and Use Science Program, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, Nevada Water Science Center, Oregon Water Science Center, Utah Water Science Center, Western Ecological Research Center (WERC), Saline Lake Ecosystems Integrated Water Availability Assessment
Macroinvertebrate sampling supplies
To get and process bugs, scientists use these supplies at Saline Lakes to gather macroinvertebrate data. These help them to better understand the lakes habitat and know how many birds that can be supported.
To get and process bugs, scientists use these supplies at Saline Lakes to gather macroinvertebrate data. These help them to better understand the lakes habitat and know how many birds that can be supported.
Macroinvertebrate processing on Malheur Lake
Macroinvertebrates are largely important to the life cycle of migratory birds in the Saline Lakes. Researchers work to understand what food is available to them, and how changes can impact bird habitat and populations.
Macroinvertebrates are largely important to the life cycle of migratory birds in the Saline Lakes. Researchers work to understand what food is available to them, and how changes can impact bird habitat and populations.
Brine Shrimp Swimming
Brine shrimp seen swimming in Lake Abert, one of many Saline Lakes in the Great Basin. These shrimp provide an important source of prey to shorebirds stopping in the area to rest and refuel on their long migration journeys.
Brine shrimp seen swimming in Lake Abert, one of many Saline Lakes in the Great Basin. These shrimp provide an important source of prey to shorebirds stopping in the area to rest and refuel on their long migration journeys.
Brine shrimp in Lake Abert
Brine shrimp are an integral part of Lake Abert's ecosystem, contributing to its biodiversity and supporting many birds and other species. Brine shrimp have a high tolerance for salinity and are able to withstand freezing temperatures and are the lake's only winter residents.
Brine shrimp are an integral part of Lake Abert's ecosystem, contributing to its biodiversity and supporting many birds and other species. Brine shrimp have a high tolerance for salinity and are able to withstand freezing temperatures and are the lake's only winter residents.
Migratory wildlife need to balance the benefits of migration and reproduction with the physiological costs. This is particularly challenging in dynamic environments like wetlands, where food levels can vary greatly from year to year. For shorebirds in the Great Basin region, saline or terminal lakes provide essential habitats during their annual life cycle. To understand how changes in hydrology and water quality impact food resources (prey availability) for shorebirds we are conducting studies across the Great Basin saline lakes system.
Background
Media
Sources/Usage: Public Domain. View Media Details
Prey availability is critical to most aspects of the annual waterbird cycle, including movements and habitat selection, reproduction, physiology, and survival. Prey availability sampling allows us to assess community composition, density, biomass, and caloric value of prey. These factors in turn help us to better understand when and where shorebirds feed and why they use specific habitats. Additionally, sampling prey across space and time within the Great Basin saline lakes allows us to better understand habitat availability across the entire region.
Lakes that are important for shorebird migration were prioritized for prey availability sampling. They include Malheur, Abert, and Summer in Oregon, Honey and Mono in California, Carson Sink, Stillwater, and Carson Lake in Nevada, and Great Salt Lake in Utah, shown here. These lakes range in salinity from freshwater to hypersaline. Although studies have been conducted on prey availability at some of these lakes, more information is needed across the system.
Sampling at priority lakes will help us to better understand how changes to hydrology and water chemistry impact the density and caloric value of invertebrates. We know that, in general, the salinity of terminal lakes in the Great Basin is increasing and approaching the limit of what freshwater invertebrates can tolerate. This trend could lead to declines in invertebrate mass and caloric value. These potential changes in prey quality could impact migratory shorebirds who depend on high caloric fueling during their long-distance migrations.
What are our goals?
- Understand the carrying capacity of lakes for birds, or how many birds a lake or habitat can support, and for how long.
- Measure prey availability changes across time, space, depth, and different water chemistry levels.
Media
Field work supplies used to take macroinvertebrate samples to determine prey availability in terminal lakes.
Sources/Usage: Public Domain. View Media Details
Media
USGS ecologist taking a macroinvertebrate sample in Malheur Lake.
Sources/Usage: Public Domain. View Media Details
Prey composition changes due to water quality
Organisms require a very specific set of circumstances to thrive in a body of water. One example is brine shrimp which thrive in environments that are hypersaline but cannot survive in water that is too fresh or too salty. Outside of this happy medium, brine shrimp will decline in condition, reproduce less, and die if conditions are extreme. This salinity gradient ultimately defines what kind of organisms exist in a body of water. The availability of tasty prey present will also impact what birds will come to feed!
Case Study: Lake Abert
Lake Abert, a hypersaline lake in south-central Oregon supports hundreds of thousands of waterbirds annually. Aquatic prey there consists primarily of brine flies and brine shrimp. At Lake Abert, we are using a repeated sampling approach where we sample at the same sites monthly from April to October. However, as the lake level recedes seasonally, sampling sites track consistent water depths and sites move father out into the lake.
Media
Sources/Usage: Public Domain. View Media Details
Over the 2024 sampling season at Lake Abert, we have collected:
- 89 water column prey community/energetics samples
- 45 benthic prey community/energetics samples
- 27 water’s edge measurements to assist in remote sensing
Water chemistry data at every site
Media
A water boatman viewed through a microscope. They have a thin bubble of air trapped against their body, allowing them to stay underwater for long periods of time.
Sources/Usage: Public Domain. View Media Details
Media
Brine shrimp seen swimming in Lake Abert, These shrimp provide an important source of prey to shorebirds stopping in the area to rest and refuel on their long migration journeys.
Sources/Usage: Public Domain. View Media Details
Media
Brine shrimp viewed up close.
Sources/Usage: Public Domain. View Media Details
Looking forward:
We will refine sampling methods to better capture variability in certain invertebrate groups like brine fly larvae.
We’ll sample at additional lakes like Eagle Lake. These lakes that are not considered as important to shorebirds could potentially support them in future years when other lakes are not available.
We’ll be adding limited sampling at sites where waterbirds are actively foraging across the lakes to better understand habitat selection processes.
Learn More About this Work from our Partners
Water Boatmen Back
A Water Boatmen or Corixidae viewed through a microscope. They have a thin bubble of air trapped against their body, allowing them to stay underwater for long periods of time.
A Water Boatmen or Corixidae viewed through a microscope. They have a thin bubble of air trapped against their body, allowing them to stay underwater for long periods of time.
Water Boatmen Head
A water boatmen, scientific name Corixidae, is an aquatic insect that lives in both freshwater and saline ecosystems. They're commonly found as a source of prey for migratory birds across the Saline Lakes.
A water boatmen, scientific name Corixidae, is an aquatic insect that lives in both freshwater and saline ecosystems. They're commonly found as a source of prey for migratory birds across the Saline Lakes.
Saline Lakes IWAA Fall 2024 Webinar Series: Waterbird Prey Availability
The fifth webinar in the Saline Lakes Ecosystems IWAA Fall 2024 Webinar Series is on waterbird prey availability in Great Basin terminal lakes.
By
Ecosystems Mission Area, Water Resources Mission Area, Species Management Research Program, Water Availability and Use Science Program, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, Nevada Water Science Center, Oregon Water Science Center, Utah Water Science Center, Western Ecological Research Center (WERC), Saline Lake Ecosystems Integrated Water Availability Assessment
The fifth webinar in the Saline Lakes Ecosystems IWAA Fall 2024 Webinar Series is on waterbird prey availability in Great Basin terminal lakes.
By
Ecosystems Mission Area, Water Resources Mission Area, Species Management Research Program, Water Availability and Use Science Program, Forest and Rangeland Ecosystem Science Center, Fort Collins Science Center, Nevada Water Science Center, Oregon Water Science Center, Utah Water Science Center, Western Ecological Research Center (WERC), Saline Lake Ecosystems Integrated Water Availability Assessment
Macroinvertebrate sampling supplies
To get and process bugs, scientists use these supplies at Saline Lakes to gather macroinvertebrate data. These help them to better understand the lakes habitat and know how many birds that can be supported.
To get and process bugs, scientists use these supplies at Saline Lakes to gather macroinvertebrate data. These help them to better understand the lakes habitat and know how many birds that can be supported.
Macroinvertebrate processing on Malheur Lake
Macroinvertebrates are largely important to the life cycle of migratory birds in the Saline Lakes. Researchers work to understand what food is available to them, and how changes can impact bird habitat and populations.
Macroinvertebrates are largely important to the life cycle of migratory birds in the Saline Lakes. Researchers work to understand what food is available to them, and how changes can impact bird habitat and populations.
Brine Shrimp Swimming
Brine shrimp seen swimming in Lake Abert, one of many Saline Lakes in the Great Basin. These shrimp provide an important source of prey to shorebirds stopping in the area to rest and refuel on their long migration journeys.
Brine shrimp seen swimming in Lake Abert, one of many Saline Lakes in the Great Basin. These shrimp provide an important source of prey to shorebirds stopping in the area to rest and refuel on their long migration journeys.
Brine shrimp in Lake Abert
Brine shrimp are an integral part of Lake Abert's ecosystem, contributing to its biodiversity and supporting many birds and other species. Brine shrimp have a high tolerance for salinity and are able to withstand freezing temperatures and are the lake's only winter residents.
Brine shrimp are an integral part of Lake Abert's ecosystem, contributing to its biodiversity and supporting many birds and other species. Brine shrimp have a high tolerance for salinity and are able to withstand freezing temperatures and are the lake's only winter residents.