Community Science in Grand Canyon Active
Bug Flows: Community science in action
Experimental flows informed by light trapping
What you take away: A Colorado River reflection
A young woman reflects on her Partners in Science trip through Grand Canyon
Aquatic insects are important components of riverine foodwebs as they are prey for fish, birds, bats, lizards, and spiders. The closure of Glen Canyon Dam in 1963 fundamentally altered the hydrology, water temperature, and turbidity of the Colorado River through Grand Canyon. These changes, along with competition with invasive species and limited food availability have led to the decline and extirpation of native fish. Monitoring aquatic insects is critical for understanding population dynamics of fish and other predators in Grand Canyon.
Conducting research in Grand Canyon is logistically challenging.The river is deep, swift, cold, and access to most field sites requires multi-day rafting expeditions. To access these remote sites, we collaborate with river guides, private boaters, and educational groups to collect data on emergent aquatic insects, fish, bats, and water quality on their expeditions. Data from these efforts are yielding fundamentally new insights into the Colorado River ecosystem.
If you are interested in including science on your next river trip in Grand Canyon, please send an email with your trip dates to science_the_river@usgs.gov
Sampling Aquatic Insects with Light Traps
Aquatic insects are a key component of the aquatic and terrestrial food web in and around rivers. Understanding their abundance and distributions over time and space is important to understanding the health of an ecosystem. However, sampling aquatic insects on a large scale, over long periods of time, is impossible for typical research groups of only a few people. However, working cooperatively with people who are on the river every day (professional river guides and private boaters), our group has been able to collect samples throughout 250+ miles of Grand Canyon, throughout the year. The dataset, based on light traps set at the river’s edge every evening that collect adult aquatic insects, currently contains several thousand samples and several million insects. This community science effort allows us to ask and answer questions about the Colorado River in Grand Canyon that are truly unprecedented in scale, such as how hydropower releases from Glen Canyon Dam affect aquatic insect populations, how the phenology (seasonal timing) of aquatic insects varies by species and with distance downstream from the Dam, and how aquatic insect populations vary from year-to-year throughout the entire Grand Canyon.
Methods
Every night in camp, collectors set out a light trap at the river’s edge for one hour at dusk. Traps consist of a fluorescent black light placed on top of a plastic pan containing ethanol. At the end of the hour, the sample is poured into a bottle, and eventually brought back to the lab where its contents are counted and identified by USGS personnel.
Results
Our results demonstrate that the abundance and diversity of aquatic insects in the Colorado River is constrained by hydropower production at Glen Canyon Dam. Hydropower production at Glen Canyon Dam causes large hourly changes in river discharge, and these discharge waves create an artificial intertidal zone along river margins that is present >250 miles downstream where the Colorado River enters its next reservoir, Lake Mead. Our light trap data show that at places in the Grand Canyon where the Colorado River experiences daily low flows at dusk, aquatic insects are over 3 times more abundant compared to places where the daily high flows happen at dusk. Using a series of other experiments and modeling, we found that differential mortality of insect eggs laid along river margins is the underlying cause of these differences in adult insect abundance. These results inform the design of environmental flow experiments ('Bug Flows') that could mitigate mortality of aquatic insect eggs while still allowing for the production of renewable hydropower that society needs.
Recording Bat Acoustic Activity
Community scientists have recorded 19 different species of bats foraging along the Colorado River in Grand Canyon using ultrasonic acoustic detectors. We supply collectors with specialized microphones that connect with tablets, providing a live visual feed of bat foraging activity. By pairing acoustic data of bats with our light trap sampling, we have learned that aquatic insects, particularly aquatic flies in the family Chironomidae, are important prey for bats common to the river corridor.
Bug Flows: Improving Food Web Health on the Colorado River
Insect Drift
Aquatic Insects
Bat activity and insect abundance data along the Colorado River in Grand Canyon, AZ
Invertebrate data (2012-2021) from the Colorado River in Grand Canyon and flow data (1921-2021) from the Lees Ferry gage (09380000) on the Colorado River near Page, AZ
Adult net-spinning caddisfly (Hydropsyche spp.) catch rates and morphology from large rivers of the southwestern United States, 2015-2016
Locality based caddisfly (Hydropsyche oslari) sampling data and CO1 sequences from the southwestern United States, 2013-2016
Insect catch rates and angler success data during Bug Flows at Glen Canyon Dam, 2012-2018
Angel Lichen Moth Abundance and Morphology Data, Grand Canyon, AZ, 2012
Flow management for hydropower extirpates aquatic insects, undermining river food websData
Insectivorous bat foraging tracks the availability of aquatic flies (Diptera)
Little bugs, big data, and Colorado River adaptive management: Preliminary findings from the ongoing bug flow experiment at Glen Canyon Dam
Applied citizen science in freshwater research
Net-spinning caddisfly distribution in large regulated rivers
Spatial population structure of a widespread aquatic insect in the Colorado River Basin: Evidence for a Hydropsyche oslari species complex
Bug flows: Don’t count your midges until they hatch
Phenology of the adult angel lichen moth (Cisthene angelus) in Grand Canyon, USA
Flow management for hydropower extirpates aquatic insects, undermining river food webs
APPLICATION - Grand Canyon Aquatic Ecology Web Application
This application allows for the exploration of a select set of insect emergence data collected as part of a citizen science project initiated by the Grand Canyon Monitoring and Research Center (GCMRC). Data present in this application relate to a recent BioScience publication from USGS scientists and collaborators that investigated the effects of dam operations on downstream aquatic insects.
- Overview
Aquatic insects are important components of riverine foodwebs as they are prey for fish, birds, bats, lizards, and spiders. The closure of Glen Canyon Dam in 1963 fundamentally altered the hydrology, water temperature, and turbidity of the Colorado River through Grand Canyon. These changes, along with competition with invasive species and limited food availability have led to the decline and extirpation of native fish. Monitoring aquatic insects is critical for understanding population dynamics of fish and other predators in Grand Canyon.
Conducting research in Grand Canyon is logistically challenging.The river is deep, swift, cold, and access to most field sites requires multi-day rafting expeditions. To access these remote sites, we collaborate with river guides, private boaters, and educational groups to collect data on emergent aquatic insects, fish, bats, and water quality on their expeditions. Data from these efforts are yielding fundamentally new insights into the Colorado River ecosystem.
If you are interested in including science on your next river trip in Grand Canyon, please send an email with your trip dates to science_the_river@usgs.gov
Sampling Aquatic Insects with Light Traps
Aquatic insects are a key component of the aquatic and terrestrial food web in and around rivers. Understanding their abundance and distributions over time and space is important to understanding the health of an ecosystem. However, sampling aquatic insects on a large scale, over long periods of time, is impossible for typical research groups of only a few people. However, working cooperatively with people who are on the river every day (professional river guides and private boaters), our group has been able to collect samples throughout 250+ miles of Grand Canyon, throughout the year. The dataset, based on light traps set at the river’s edge every evening that collect adult aquatic insects, currently contains several thousand samples and several million insects. This community science effort allows us to ask and answer questions about the Colorado River in Grand Canyon that are truly unprecedented in scale, such as how hydropower releases from Glen Canyon Dam affect aquatic insect populations, how the phenology (seasonal timing) of aquatic insects varies by species and with distance downstream from the Dam, and how aquatic insect populations vary from year-to-year throughout the entire Grand Canyon.
Methods
Every night in camp, collectors set out a light trap at the river’s edge for one hour at dusk. Traps consist of a fluorescent black light placed on top of a plastic pan containing ethanol. At the end of the hour, the sample is poured into a bottle, and eventually brought back to the lab where its contents are counted and identified by USGS personnel.
Results
Our results demonstrate that the abundance and diversity of aquatic insects in the Colorado River is constrained by hydropower production at Glen Canyon Dam. Hydropower production at Glen Canyon Dam causes large hourly changes in river discharge, and these discharge waves create an artificial intertidal zone along river margins that is present >250 miles downstream where the Colorado River enters its next reservoir, Lake Mead. Our light trap data show that at places in the Grand Canyon where the Colorado River experiences daily low flows at dusk, aquatic insects are over 3 times more abundant compared to places where the daily high flows happen at dusk. Using a series of other experiments and modeling, we found that differential mortality of insect eggs laid along river margins is the underlying cause of these differences in adult insect abundance. These results inform the design of environmental flow experiments ('Bug Flows') that could mitigate mortality of aquatic insect eggs while still allowing for the production of renewable hydropower that society needs.
Recording Bat Acoustic Activity
Community scientists have recorded 19 different species of bats foraging along the Colorado River in Grand Canyon using ultrasonic acoustic detectors. We supply collectors with specialized microphones that connect with tablets, providing a live visual feed of bat foraging activity. By pairing acoustic data of bats with our light trap sampling, we have learned that aquatic insects, particularly aquatic flies in the family Chironomidae, are important prey for bats common to the river corridor.
- Science
Bug Flows: Improving Food Web Health on the Colorado River
Native and desired nonnative fish downstream of Glen Canyon Dam are food limited—meaning that if more or larger invertebrate food items were available, there would be more and larger fish. Aquatic insects have complex life cycles that include egg, larvae, and pupal stages that are aquatic while adults have wings and are typically terrestrial. Aquatic insects are a fundamental component of river...Insect Drift
All aquatic invertebrates drift downstream at some point in their life cycle. Invertebrates may drift to find more preferable habitats, to leave the water during their transition from aquatic larvae to terrestrial adults, or accidentally such as when swept off the river bed by a flood. Regardless, when they enter the drift, invertebrates become particularly susceptible to predation by several...Aquatic Insects
Aquatic insects live in the water as larvae most of their lives, then emerge onto land for a brief period as winged adults. Sampling these emerged adults on land is therefore a useful tool for understanding the condition of the aquatic insect population that is in the water, particularly in large rivers where sampling the larvae on the river bed is impractical. Our group uses a variety of methods... - Data
Bat activity and insect abundance data along the Colorado River in Grand Canyon, AZ
These data were compiled to improve our understanding of bat foraging along the Colorado River in Grand Canyon. Objectives of our study were to determine whether bat activity was influenced primarily by variation in prey availability relative to other environmental or geomorphic factors. These data represent 1,428 paired samples of bat activity and insect abundance calculated as catch rates collecInvertebrate data (2012-2021) from the Colorado River in Grand Canyon and flow data (1921-2021) from the Lees Ferry gage (09380000) on the Colorado River near Page, AZ
These data were compiled for an outreach article published in the Boatman's Quarterly Review, which is a magazine published by Grand Canyon River Guides Association. The objectives of our study was to describe the outcomes of the 2018-2020 Bug Flows experiment to a general audience. These data represent 10 years (2012-2021) of invertebrate data and 100 years (1921-2021) of flow data. These data weAdult net-spinning caddisfly (Hydropsyche spp.) catch rates and morphology from large rivers of the southwestern United States, 2015-2016
These data describe the distribution and abundance of Hydropsyche, a widespread and diverse genus of net-spinning caddisflies, in the Colorado River Basin. Abundance data, measured as catch rates, were collected by citizen scientists using light traps. We subsampled Hydropsyche spp. from light trap samples collected throughout the Colorado River Basin and measured the lengths and widths of mesothoLocality based caddisfly (Hydropsyche oslari) sampling data and CO1 sequences from the southwestern United States, 2013-2016
These data were compiled for a mtDNA (CO1 gene) analysis of net-spinning caddisflies (Hydropsyche oslari) in the Colorado River Basin of the western United States. They were incorporated in a study that investigated the genetic diversity and population structure of H. oslari relative to the river network structure in the Upper and Lower Colorado River Basins. The data were collected from 2015 to 2Insect catch rates and angler success data during Bug Flows at Glen Canyon Dam, 2012-2018
These data were compiled to evaluate the effects of low steady weekend flows on emergent aquatic insects during the first year of experimental Bug Flows below Glen Canyon Dam (2018) and recreation in Glen Canyon in the second year of Bug Flows (2019). Bug Flows are experimental flows that were released from Glen Canyon Dam in 2018 and 2019. The flows consist of low steady flows on weekends and havAngel Lichen Moth Abundance and Morphology Data, Grand Canyon, AZ, 2012
Two unique datasets on the abundance and morphology of the angel lichen moth (Cisthene angelus) in Grand Canyon, Arizona, USA were compiled to describe the phenology and life history of this common, but poorly known, species. The abundance data were collected from 2012 to 2013 through a collaboration with river runners in Grand Canyon National Park. These citizen scientists deployed light traps frFlow management for hydropower extirpates aquatic insects, undermining river food websData
Two unique datasets were gathered to document whether flow management for hydropower affects the abundance and diversity of aquatic insect assemblages. The first dataset was collected in Grand Canyon from 2012-2014 by citizen scientists rafting the Colorado River. Simple light traps were set out each night in camp and used to capture the adult life stages of aquatic insects that emerged from the C - Publications
Insectivorous bat foraging tracks the availability of aquatic flies (Diptera)
Rivers and their adjacent riparian zones are model ecosystems for observing cross-ecosystem energy transfers. Aquatic insects emerging from streams, for example, are resource subsidies that support riparian consumers such as birds, spiders, lizards, and bats. We collaborated with recreational river runners in Grand Canyon, Arizona, USA, to record acoustic bat activity and sample riparian insects uAuthorsAnya Metcalfe, Carol Fritzinger, Theodore J. Weller, Michael Dodrill, Jeffrey Muehlbauer, Charles Yackulic, Brandon P. Holton, Cheyenne Maxime Szydlo, Laura E. Durning, Joel B. Sankey, Theodore KennedyLittle bugs, big data, and Colorado River adaptive management: Preliminary findings from the ongoing bug flow experiment at Glen Canyon Dam
The undammed Colorado River in Grand Canyon was characterized by spring snow-melt floods that sometimes exceeded 100,000 cubic feet per second (cfs). These were followed by occasional flash floods during summer monsoons, then by low flows from fall through early spring (Figure 1; Topping and others, 2003). This seasonally variable flow regime carried huge loads of sediment and was an important driAuthorsTheodore Kennedy, Anya Metcalfe, Bridget Deemer, Morgan Ford, Cheyenne Maxime Szydlo, Charles Yackulic, Jeffrey MuehlbauerApplied citizen science in freshwater research
Worldwide, scientists are increasingly collaborating with the general public. Citizen science methods are readily applicable to freshwater research, monitoring, and education. In addition to providing cost-effective data on spatial and temporal scales that are otherwise unattainable, citizen science provides unique opportunities for engagement with local communities and stakeholders in resource maAuthorsAnya N. Metcalfe, Theodore A. Kennedy, Gabriella A. Mendez, Jeffrey D. MuehlbauerNet-spinning caddisfly distribution in large regulated rivers
Most of the world's large rivers are dammed for the purposes of water storage, flood control, and power production. Damming rivers fundamentally alters water temperature and flows in tailwater ecosystems, which in turn affects the presence and abundance of downstream biota.We collaborated with more than 200 citizen scientists to collect 2,194 light trap samples across 2 years and more than 2,000 rAuthorsAnya Metcalfe, Jeffrey Muehlbauer, Theodore Kennedy, Charles Yackulic, Kimberly L. Dibble, Jane C. MarksSpatial population structure of a widespread aquatic insect in the Colorado River Basin: Evidence for a Hydropsyche oslari species complex
Structural connectivity and dispersal ability are important constraints on functional connectivity among populations. For aquatic organisms that disperse among stream corridors, the regional structure of a river network can, thus, define the boundaries of gene flow. In this study, we used mitochondrial DNA (mtCO1 barcoding gene) to examine the genetic diversity and population structure of a caddisAuthorsAnya N. Metcalfe, Theodore A. Kennedy, Jane C. Marks, Aaron D. Smith, Jeffrey D. MuehlbauerBug flows: Don’t count your midges until they hatch
Usually when people hear about a “bug problem” it’s due to an undesirable overabundance of insects (think plague of locusts). In the Colorado River in Grand Canyon, however, we are faced with the opposite predicament: the river is essentially devoid of bugs. Aquatic insects are a fundamental component of a healthy river ecosystem. Most aquatic insects spend their juvenile life stages (egg, larva,AuthorsAnya Metcalfe, Jeffrey Muehlbauer, Morgan Ford, Theodore KennedyPhenology of the adult angel lichen moth (Cisthene angelus) in Grand Canyon, USA
We investigated the phenology of adult angel lichen moths (Cisthene angelus) along a 364-km long segment of the Colorado River in Grand Canyon, Arizona, USA, using a unique data set of 2,437 light-trap samples collected by citizen scientists. We found that adults of C. angelus were bivoltine from 2012 to 2014. We quantified plasticity in wing lengths and sex ratios among the two generations and acAuthorsAnya N. Metcalfe, Theodore A. Kennedy, Jeffrey D. MuehlbauerFlow management for hydropower extirpates aquatic insects, undermining river food webs
Dams impound the majority of rivers and provide important societal benefits, especially daily water releases that enable on-peak hydroelectricity generation. Such “hydropeaking” is common worldwide, but its downstream impacts remain unclear. We evaluated the response of aquatic insects, a cornerstone of river food webs, to hydropeaking using a life history–hydrodynamic model. Our model predicts thAuthorsTheodore A. Kennedy, Jeffrey D. Muehlbauer, Charles B. Yackulic, D.A. Lytle, S.A. Miller, Kimberly L. Dibble, Eric W. Kortenhoeven, Anya N. Metcalfe, Colden V. Baxter - Web Tools
APPLICATION - Grand Canyon Aquatic Ecology Web Application
This application allows for the exploration of a select set of insect emergence data collected as part of a citizen science project initiated by the Grand Canyon Monitoring and Research Center (GCMRC). Data present in this application relate to a recent BioScience publication from USGS scientists and collaborators that investigated the effects of dam operations on downstream aquatic insects.
- Partners