Flathead Lake: Water Quality and Limnology
Flathead Lake is the largest natural freshwater lake in the western US, and one of the cleanest large lakes in the world. However, its world renowned water clarity and ecological health continue to be threatened by human-caused increases in nutrients and sediments, as well as the potential arrival of new Aquatic Invasive Species.
The FLBS record of research began in 1899, the year FLBS was founded, when Dr. Morton J. Elrod initiated the first scientific investigations of the lake. FLBS has remained the “Sentinel of Flathead Lake” ever since.
In 1977, in response to threats of large-scale coal mining in the North Fork Flathead River in British Columbia, Canada, FLBS instituted a scientifically rigorous water quality research and monitoring program and now has one of the best long-term continuous datasets in the world for a large lake and river system.
Our regular (roughly monthly) monitoring program provides a clear, consistent record of physical, chemical and biological lake characteristics and changes over time, and reveals threats before they become problems. Our scientific data, especially pertaining to nutrients, have been used by state and federal agencies in the development of water quality standards via the Clean Water Act’s Total Maximum Daily Load (TMDL) process.
Our research continues to address cutting edge questions about the ecological conditions of the lake. For example in 2012, FLBS researchers installed a network of telemetered environmental sensors (weather and water quality) to enhance the resolution of knowledge of lake conditions. Currently FLBS scientists are utilizing this data in concert with the long-term dataset to drive a lake model that will help predict future conditions in the lake related to changes such as increasing temperature, the arrival of new species and the removal of existing ones (e.g., lake trout).
FLBS research and expertise regularly help managers and politicians make informed decisions that have resulted in significant water quality conservation successes, including a ban on Phosphorus-containing detergents, the upgrade of watershed sewage treatment systems, and the prevention of mining in the North Fork Flathead River.
Maintaining the high quality of water that many people in the Flathead Valley take for granted does not come without effort. If you would like to help with efforts to maintain Flathead water quality now and for future generations, visit the FLBS charitable giving page
Flathead Lake Trophic Cascade
Introduced species have altered Flathead Lake’s biological community dramatically over the last 100+ years. Of particular note was the introduction of Mysis diluviana. This freshwater shrimp’s introduction resulted in dramatic food web changes that were documented by FLBS scientists.
Introduced widely in the 1960s and 1970s throughout Western North America as a food source for salmon and trout, in Flathead Lake the Mysis shrimp voraciously consumed zooplankton, the food of the kokanee salmon they were introduced to help. This unexpected effect resulted in the collapse of the kokanee population, which eliminated a reliable food source for hundreds of bald eagles and bears that annually migrated to the kokanee spawning grounds in the Flathead River system.
At the same time, populations of nonnative lake trout and lake whitefish, which were themselves an introduced species, exploded with Mysis shrimp as a food source. With the increase in both Mysis shrimp and lake trout, native bull and cutthroat trout populations have dramatically declined, and Flathead Lake’s fish community is now dominated by nonnative species. Additionally, as Mysis shrimp consume native zooplankton which eat algae, the amount of algae in Flathead Lake has increased.
Therefore, the introduction of Mysis shrimp not only influenced the biological community of Flathead Lake but also directly affected the lake’s water quality.
FLBS researchers were among the first to empirically document this Trophic Cascade in a lake ecosystem, and they continue to track the ongoing ecological effects.
Over the years, FLBS researchers have conducted a wide array of studies on lakes, examining the influence of a variety of factors including: physical (eg, temperature, depth, habitat), chemical (eg, nutrients, pollutants, sediments) and biological (eg, competition, predation, introduced species). In addition to our flagship Flathead Lake Research and Monitoring Program, FLBS scientists and students have:
FLBS conducts research examining the physical characteristics and processes of freshwater ecosystems. Physical conditions are the template on which biological organisms and processes are overlain, and therefore they can significantly influence ecology. Since resources are not evenly distributed throughout lakes and rivers, physical drivers such as water currents are examined to determine how they deliver nutrients and other needed materials. FLBS scientists and students have examined water conditions (eg, temperature, depth) and water movement (eg, currents and waves); as well as sediment erosion, transport and deposition, and the creation of beaches to curb shoreline erosion. Investigations into the response of aquatic organisms to the sound of rivers has even spawned a collaborative performance with UM’s School of Theatre and Dance.
Floodplain Biocomplexity : Shifting Habitat Mosaic
River flood plains are hot spots of biodiversity and productivity due to dynamic interactions between water, sediments, vegetation, and other organisms. Connectivity between surface and ground waters plays an important role in floodplain ecology and habitat diversity, particularly through the exchange of water and materials between the river and the alluvial aquifer that lies just under the surface. This extensive surface and groundwater connectivity also sustains water quantity and quality. Due to human development, floodplains are one of the most endangered ecosystems in the world.
For decades, FLBS researchers have been studying these processes and how they influence organisms at the Nyack Floodplain Research Natural Area on the Middle Fork Flathead River, located between Glacier National Park and the Great Bear Wilderness. This research has demonstrated the vital importance of surface and ground water exchange and has fundamentally molded contemporary river science, management, and conservation.
Currently, FLBS PhD student Amanda DelVecchia is studying how naturally occurring methane gas may subsidize productivity on the flood plain. Amanda is characterizing microbial and invertebrate communities in relation to the environmental gradients of the alluvial aquifer to better understand utilization of methane and organic matter. Her work aims to understand how organisms use, cleanse, and enrich water as it flows through the aquifer, information that is needed to sustain the ecological integrity of rivers around the world. Large stoneflies are iconic players in this story as analyses show that they feed on microbes that use methane as an energy source.
Hyporheic Corridor Concept of River Ecosystems
A wide variety of previously unknown biota, including stoneflies and other large-bodied organisms, exist within alluvial aquifers of the expansive flood plains of the Flathead and other gravel-bed rivers. This amazing discovery led to the “hyporheic corridor concept” of river ecosystems, which first formalized the fundamental importance of water and materials interchange between the river channel and near-surface groundwater. Organisms living in the groundwater utilize organic matter form the river and floodplain as a food source, thereby filtering, or cleansing the river water as it moves through the porous bedsediments.
Ecological Effects of Dams: Regulated Rivers and the Serial Discontinuity Concept
River ecosystems are altered dramatically by the presence of dams and reservoirs. Reservoirs directly convert river habitat into lakes, environments for which most river organisms are not well suited. Dams interrupt the continuity of conditions and transportation of materials in streams and rivers as flow moves downstream.
After the major dam building era in the US, 1940s–1960s, FLBS researchers were among the first to scientifically examine the ecological effects of dams, pioneering the field, writing the first text book, and founding the first journal about Regulated Rivers.
Findings have shown that rivers are changed but can reset or recover from the deleterious impacts of dams in relation to mode of dam operations and distance downstream from the dam. This discovery was formalized into the “Serial Discontinuity Concept” of river ecosystems, which predicts the ecological effects of dam operations and allows water, temperature, and material fluxes to be normalized, thereby ameliorating impacts of river regulation on biota, sediment transport, habitat characteristics, riparian vegetation, and other important attributes of rivers.
FLBS research has helped shape today’s dialogue balancing the ecological costs of dams with their benefits to society. This is particularly important as many dams in the US are currently undergoing re-licensing, a process that determines future dam operations for the next 20-50 years. This process now requires the consideration of ecological effects, which at times has even resulted in the recommendation of dam removal.
Life History Energy Balance of Organisms
Most aquatic organisms are "cold blooded" (ectotherms), meaning that their body temperature, metabolism, and ecological activity are determined by the temperature of their surrounding environment. Therefore water temperature is one of the most important determinants of occurrence, growth, reproduction, survival, and all around success for aquatic organisms (e.g. insects, frogs, and fish).
FLBS research has shown that water temperature drives biological patterns observed on the landscape. For example, aquatic insects and other organisms are distributed predictably along stream corridors from headwaters to piedmont valleys in relation to temperature patterns. On floodplains, thermal characteristics of different habitat types throughout the year determine which aquatic organisms are able to thrive (or just survive) in which locations during different life history stages.
These discoveries about life history energy balance of organisms in montane environments have important ramifications for predicting the consequences of climate change.
Conservation Genetics and Non-Native Species
New tools in quantitative genetics allow FLBS researchers to gain a more detailed understanding of the relationships between native and non-native species and to explore their interactions within the context of climate change and other environmental influences.
More information is available on the FLBS Conservation Genetics page.
Landscape Ecology of Pacific Salmon
FLBS in cooperation with other organizations documented salmonid biodiversity and productivity of a suite of pristine Pacific salmon river ecosystems observatories. The research focused on salmonid habitat requirements that appeared to vary with life history stage and population structure. We believed that productivity of habitat is controlled by non-linear biophysical processes that create and maintain a dynamic or constantly Shifting Habitat Mosaic (SHM). Our research also addressed how salmon rivers and their stocks respond to climate change. Runoff and temperature patterns are primary determinants of physical habitat in rivers and therefore critically influence salmon productivity. Since both variables may be changed significantly by climate warming, better resolution of climate effects was needed to produce robust conservation strategies for salmon and salmon related biodiversity. Human activities tend to reduce or dampen the variable nature of rivers in ways that should be predictable and, therefore, correctable given a robust understanding and modeling of salmon productivity and population dynamics in the context of the SHM concept.
Climate Change and Salmon Conservation
A presidential task force recently released a report requesting all federal agencies to consider climate-related risks and vulnerabilities as part of their policies and practices. However, climate change is seldom considered in salmonid conservation decision making, despite major declines in these ecologically and economically critical species. Protecting native salmonids and their riverscapes against the impacts of climate change demands better understanding of the interactive influences of environmental variation (especially water temperature and flow), habitat and anthropogenic stressors (e.g., landuse change), genetics/genomics, and population demographics (e.g., abundance). To meet this challenge, FLBS researchers continue work on applying a prototype decision support system (DSS) to aid in the decision-making process for conserving salmonids and their habitats under a changing climate.
Brown Trout Ecology in the Rio Grande, Argentina
The Rio Grande brown trout study objective was to determine population parameters and factors controlling productivity of sea trout (sea-run brown trout) in the Rio Grande of Tierra del Fuego, Argentina. FLBS used the catch and release fly fishing operations of NWA and EMB as a basis for a mark and recapture study of the brown trout population within various study reaches of the river in association with other ecological measures encompassing the freshwater life cycle.
The project goal was to use the accumulated information as a basis for development of a strategy to sustain high-quality angling and ecotourism income in the Rio Grande and to use scientific results to better inform salmon and trout management worldwide.
Satellite and Aerial Imagery: Viewing Ecology from Above
FLBS scientists have extensively utilized, and in fact pioneered, aspects of the use of aerial sensors and imagery (satellite and aircraft mounted) to examine ecological characteristics and patterns. At the watershed scale, FLBS has used multi-spectral imagery from both satellites and aircraft, in concert with on-the-ground Acoustic Doppler Profilers which can measure water depth, velocity and sediment movement, to develop techniques to classify, quantify, and map aquatic and riparian habitat. Additionally, by using Light Detection and Radar (LIDAR), FLBS researchers have constructed detailed topographic maps and information about river flood plains and lake shorelines.
At the global scale, FLBS researchers have worked extensively with NASA’s satellite remote sensing programs (eg Landsat, MODIS and SMAP) and have been involved in the development and oversight of new sensors and analysis techniques. These technologies have resulted in extensive discoveries pertaining to the earth’s soil moisture, drought, freeze thaw cycles, and climate variability.
Grizzly Bear Gardeners: Influencing Distribution of Glacier Lilies
Grizzly bears dig extensively for bulbs of glacier lilies growing in alpine meadows and, in the process, control soil nitrogen dynamics and meadow plant assemblages, including the subsequent abundance and nutritive quality of the lilies. This is an original demonstration of large herbivore influences on terrestrial ecosystems.
Kodiak Brown Bears and Salmon Abundance
The FLBS Kodiak brown bear project is focused on understanding how bears of Southwest Kodiak Island, Alaska, behave in response to changing sockeye salmon abundance. The work, conducted by FLBS graduate student Will Deacy and other volunteers, is focused around Karluk Lake, the heart of the Kodiak National Wildlife Refuge. Although the refuge was established to protect Kodiak’s famous large bears and robust salmon runs, both bear and salmon numbers have been declining. U.S. Fish and Wildlife Service (FWS) data show that bear densities in the Karluk watershed have declined more than 45% in ten years, and this shocking population reduction created a need to better understand the relationship between salmon and bears. Plentiful salmon are critical to maintaining healthy populations of large Kodiak brown bears, so we have embarked upon a cooperative research program with the FWS using innovative field techniques to collect high resolution bear and salmon data across a suite of streams. To do this, we developed a process using remote time-lapse camera systems to count the number of salmon and bears at each of the streams around Karluk Lake.
The Fish and Wildlife Service reached out to the Flathead Lake Biological Station (FLBS) to tackle this project because of our experience researching salmon ecosystems around the Pacific. Both the FWS and FLBS have made significant investments over the first three years of this project. We are now looking for partners to complete the final two years of the project and to collect the data needed to fully understand the impacts of salmon declines on Kodiak bears. While many bears still roam the Kodiak wilderness, long-term data suggests their numbers are declining in parallel with salmon abundance. It is critical that we understand the drivers of the salmon-bear relationship to protect this pristine landscape and the giants that roam it.
Evolutionary Intricacy of Animal Behaviors
Long-term research on Sierra dome spiders that live on the Station grounds has demonstrated a novel evolutionary intricacy of animal behavior. Females choose a mate from a wide variety of male suitors that brawl with one another on the delicate dome-shaped webs built by the female. Mate choice by females determines the success or failure of the population.