Craig Stricker, PhD
Craig Stricker is a Research Biologist at the Fort Collins Science Center.
Science and Products
Fort Collins Science Center Labs and Facilities
The Fort Collins Science Center has scientists working in several diverse locations as well as three in house highly specialized laboratories, studying subjects from molecular ecology to brown treesnakes, dendroecology to streamflows, and macroinvertebrate species to Burmese pythons. Our extraordinary scientists work in each of these locations advancing studies in their particluar areas of study...
Contaminant Biology: Stable Isotope Applications
Environmental contaminants of natural and anthropogenic origin represent a major stressor to ecosystems, including human and wildlife populations.
Biogeography: Stable Isotope Applications
The distribution of species across the landscape is of great interest to conservation biology. Habitat quality and quantity are thought to be important drivers of occurrence and distribution, and numerous studies have demonstrated fitness-related consequences. However, for species with cryptic or migratory life histories, we often lack sufficient detail about habitat usage and in many cases...
Biogeochemistry: Stable Isotope Applications
Biogeochemical cycling is a cornerstone of ecosystem function and structure. Much has been learned about element cycles in a variety of systems using standard geochemical techniques.
Ecological Applications of Stable Isotopes
Environmental contaminants of natural and anthropogenic origin represent a major stressor to ecosystems, including human and wildlife populations. FORT scientists are studying these stressors in order to understand the contaminant cycling under natural environmental conditions. Stable isotope techniques are extremely useful in resolving trophic pathways by which contaminants become bioavailable...
Foraging Ecology Using Stable Isotopes
Understanding species habitat requirements is incomplete without insight into nutrition, including various aspects of foraging ecology. Traditional diet studies can be challenging because of logistics, issues related to resource availability, and observations are often short-term in nature based on gut contents or scat. Additionally, perturbations such as species introductions, habitat degradation...
Filter Total Items: 15
Silicified wood from around Old Faithful Geyser, Yellowstone National Park
Old Faithful Geyser in the Upper Geyser Basin of Yellowstone National Park is one of the best studied geysers in the world. Under research permit YELL-SCI-8030, samples from 13 silicified tree remnants were collected adjacent to the Old Faithful Geyser cone in April and November 2019. The silicified wood samples were dated using the radiocarbon (14C) method and were analyzed by scanning electron m
Modeled Pacific salmon escapement biomass and nutrient and contaminant concentrations across western North America, 1976-2015
The data contain yearly modeled estimates of Pacific salmon escapement (in annual metric tons of wet mass) from 1976 to 2015 across four regions of western North America. A second data file contains modeled estimates of contaminant or nutrient concentrations in Pacific Salmon. The modeled estimates were derived from Bayesian generalized linear models (contaminant or nutrient concentrations) or fro
Total mercury, methylmercury, and isotopic composition in various life stages of boreal chorus frogs (Pseudacris maculata) at two subalpine ponds in the Rocky Mountains, CO, USA, 2015
Mercury is an atmospherically transported contaminant found even in relatively pristine habitats. Once accumulated at the base of the food web, mercury can move between animals that are linked trophically. Pond-breeding amphibians may be particularly important vectors of mercury flux from remote freshwater to terrestrial systems because they feed on algae and detritus as tadpoles and metamorphose
Mercury concentrations, isotopic composition, biomass, and taxonomy of stream and riparian organisms in the vicinity of Yellow Pine, Idaho, 2015-2016.
This data release includes sampling location data; field-collected stream attribute data; laboratory-analyzed chemistry concentrations (total mercury, methyl mercury) and isotopic composition (total mercury, carbon, and nitrogen) for stream biota (seston, periphyton, benthic insects, emerging adult insects, riparian spiders, and fish); density, body length, and taxonomic information for benthic in
Dataset for temporal influences on selenium partitioning, trophic transfer, and exposure in a major U.S. river
The trace element selenium is an essential element with a narrow window between concentrations needed to support life and those that cause toxicity to egg laying organisms. Selenium bioaccumulation in aquatic organisms is primarily the result of trophic transfer through food webs and is poorly predicted by dissolved concentrations in freshwater bodies. To better understand the hydrologic and biolo
Chemistry of water, stream sediment, wildfire ash, soil, dust, and mine waste for Fourmile Creek Watershed, Colorado, 2010-2019
In response to the 2010 Fourmile Canyon fire near Boulder, Colorado, the U.S. Geological Survey collected data to support investigations into the magnitude and critical drivers of water-quality impairment after wildfire. We analyzed chemistry of stream water, sediment, wildfire ash, soil, dust, and mine waste for metals and other parameters in order to evaluate the effects of legacy mining and wil
Radiogenic strontium isotope data for non-native walleye otoliths collected from select areas of the Upper Colorado River Basin
This dataset includes radiogenic strontium isotope compositions of non-native walleye otoliths collected from select areas of the Upper Colorado River Basin (UCRB). Strontium isotope data have been widely used to assess natal areas for a variety of fish species. Following on previous work, this project sought to fill data gaps for walleye collected from the Colorado River (river miles 11-109.3), t
Stable carbon isotope and wood component concentration data for riparian cottonwood tree rings, Little Missouri River, North Dakota
This dataset includes stable carbon isotope values, lignin, cellulose, and hemicellulose concentrations (expressed as percent of ash-free dry mass) for riparian cottonwood (Populus deltoides) tree rings growing on the Little Missouri River floodplain, Theodore Roosevelt National Park, North Dakota. Drought stress induces stomatal closure and the carbon isotope ratio of annual tree rings tends to
Stable carbon and nitrogen isotope data for Siberian barn swallow subspecies collected during the breeding season
This dataset includes stable carbon and nitrogen isotope values for the inner tail retrices of three subspecies of barn swallow (Hirundo rustica rustica, H. r. tytleri, and H. r. gutturalis). Sampling was conducted in Russia (summer 2013), China (summer 2014), Mongolia (summer 2014), Japan (summer 2014), and western China (summer 2015) using mist nets. Stable carbon and nitrogen isotope data are u
Ovary mass and stable hydrogen isotope data for resident and migratory female dark-eyed juncos
This dataset includes ovary mass and stable hydrogen isotope compositions of feathers and claws from resident and migratory female dark-eyed juncos (Junco hyemalis) collected during early spring at Mountain Lake Biological Station, Pembroke, Virginia. A total of 18 migrant and 15 resident female dark-eyed juncos, a songbird that exhibits seasonal sympatry, were caught during March-April. Stable hy
Lignin phenol data for solid phase peat cores collected from the Alligator River and Great Dismal Swamp National Wildlife Refuges
This dataset includes lignin phenol monomer concentrations normalized to 100 mg of organic carbon. These analyses were conducted on select intervals from peat cores collected at the Alligator River (AR) and Great Dismal Swamp (GDS) National Wildlife Refuges in North Carolina and Virginia/North Carolina, USA, respectively. The eight lignin phenol monomers provide unique proxy information on the sou
Stable carbon and nitrogen isotope data for: 'Ecotoxicoparasitology of the gastrointestinal tracts of pinnipeds: effect of parasites on bioavailability of total mercury (THg)'
Parasites, such as acanthocephalans, cestodes, and some species of nematodes acquire nutrients from the lumen contents within the host gastrointestinal (GI) tract. For ubiquitous toxicants like mercury, both the host species and parasites are potentially exposed. The focus of this study was to determine if there is an effect of parasites on the dietary availability and therefore exposure to mercur
Filter Total Items: 82
Complex life histories alter patterns of mercury exposure and accumulation in a pond-breeding amphibian
Quantifying how contaminants change across life cycles of species that undergo metamorphosis is critical to assessing organismal risk, particularly for consumers. Pond-breeding amphibians can dominate aquatic animal biomass as larvae and are terrestrial prey as juveniles and adults. Thus, amphibians can be vectors of mercury exposure in both aquatic and terrestrial food webs. However, it is still
Authors
Freya Elizabeth Rowland, Erin L. Muths, Collin Eagles-Smith, Craig A. Stricker, Johanna M. Kraus, Rachel A. Harrington, David Walters
Animal tracing with sulfur isotopes: Spatial segregation and climate variability in Africa likely contribute to population trends of a migratory songbird
Climatic conditions affect animals but range-wide impacts at the population level remain largely unknown, especially in migratory species. However, studying climate–population relationships is still challenging in small migrants due to a lack of efficient and cost-effective geographic tracking method.Spatial distribution patterns of environmental stable isotopes (so called ‘isoscapes’) generally o
Authors
Vojtech Brlik, Petr Prochazka, Bengt Hansson, Craig A. Stricker, Elizabeth Yohannes, Rebecca L Powell, Michael B. Wunder
Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics
Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator-prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under-ice food web to meet their energy needs. Here, we assessed whe
Authors
Karyn D. Rode, Brian D. Taras, Craig A. Stricker, Todd C. Atwood, Nicole P Boucher, George M. Durner, Andrew E. Derocher, Evan S. Richardson, Seth Cherry, Lori T. Quakenbush, Lara Horstmann, Jeffrey F. Bromaghin
Summer/fall diet and macronutrient assimilation in an Arctic predator
Free-ranging predator diet estimation is commonly achieved by applying molecular-based tracers because direct observation is not logistically feasible or robust. However, tracers typically do not represent all dietary macronutrients, which likely obscures resource use as prey proximate composition varies and tissue consumption can be specific. For example, polar bears (Ursus maritimus) preferentia
Authors
Craig A. Stricker, Karyn D. Rode, Brian D. Taras, Jeffrey F. Bromaghin, Lara Horstmann, Lori T. Quakenbush
Increased mercury and reduced insect diversity in linked stream-riparian food webs downstream of a historical mercury mine
Historical mining left a legacy of abandoned mines and waste rock in remote headwaters of major river systems in the western United States. Understanding the influence of these legacy mines on culturally and ecological important downstream ecosystems is not always straight-forward because of elevated natural levels of mineralization in mining-impacted watersheds. To test the ecological effects of
Authors
Johanna M. Kraus, JoAnn Holloway, Michael Pribil, Ben N. Mcgee, Craig A. Stricker, Danny Rutherford, Andrew S. Todd
The reuse of avian samples: Opportunities, pitfalls and a solution
Tissue samples are frequently collected to study various aspects of avian biology, but in many cases these samples are not used in their entirety and are stored by the collector. The already collected samples provide a largely overlooked opportunity because they can be used by different researchers in different biological fields. Broad reuse of samples could result in multispecies or large-scale s
Authors
Vojtěch Brlík, Pavel Pipek, Kate Brandis, Nikita Chernetsov, Fábio J. V. Costa, L. Gerardo Herrera M., Yosef Kiat, Richard B. Lanctot, Peter P. Marra, D. Ryan Norris, Chima J. Nwaogu, Petra Quillfeldt, Sarah T. Saalfeld, Craig A. Stricker, Robert L. Thomson, Tianhao Zhao, Petr Procházka
Energetic and health effects of protein overconsumption constrain dietary adaptation in an apex predator
Studies of predator feeding ecology commonly focus on energy intake. However, captive predators have been documented to selectively feed to optimize macronutrient intake. As many apex predators experience environmental changes that affect prey availability, limitations on selective feeding can affect energetics and health. We estimated the protein:fat ratio of diets consumed by wild polar bears us
Authors
Karyn D. Rode, Charles T. Robbins, Craig A. Stricker, Brian D. Taras, Troy N Tollefson
Temporal influences on selenium partitioning, trophic transfer, and exposure in a major U.S. river
Hydrologic and irrigation regimes mediate the timing of selenium (Se) mobilization to rivers, but the extent to which patterns in Se uptake and trophic transfer through recipient food webs reflect the temporal variation in Se delivery is unknown. We investigated Se mobilization, partitioning, and trophic transfer along approximately 60 river miles of the selenium-impaired segment of the Lower Gunn
Authors
Jessica E Brandt, James Roberts, Craig A. Stricker, Holly Rogers, Patricia Nease, Travis S. Schmidt
Breeding at higher latitude is associated with higher photoperiodic threshold and delayed reproductive development in a songbird
Many seasonally breeding animals exhibit a threshold day length (critical photoperiod; CPP) for gonadal growth, and populations breeding at higher latitudes typically have a higher CPP. Much less is known about latitudinal variation in CPP in migratory population that winter away from their breeding range and must time their reproduction to match favorable conditions at their destination. To addre
Authors
Devraj Singh, S. M. Reed, A. A. Kimmitt, K. A. Alford, Craig A. Stricker, P. D. Polly, Ellen D. Ketterson
Evidence of post-breeding prospecting in a long-distance migrant.
Organisms assess biotic and abiotic cues at multiple sites when deciding where to settle. However, due to temporal constraints on this prospecting, the suitability of available habitat may be difficult for an individual to assess when cues are most reliable, or at the time they are making settlement decisions. For migratory birds, the postbreeding season may be the optimal time to prospect and inf
Authors
Max Ciaglo, Ross Calhoun, Scott W Yanco, Michael B. Wunder, Craig A. Stricker, Brian D Linkhart
Short- and long-term responses of riparian cottonwoods (Populus spp.) to flow diversion: Analysis of tree-ring radial growth and stable carbon isotopes
Long duration tree-ring records with annual precision allow for the reconstruction of past growing conditions. Investigations limited to the most common tree-ring proxy of ring width can be difficult to interpret, however, because radial growth is affected by multiple environmental processes. Furthermore, studies of living trees may miss important effects of drought on tree survival and forest cha
Authors
Derek M. Schook, Jonathan M. Friedman, Craig A. Stricker, Adam Z. Csank, David J. Cooper
Juvenile Coho and Chinook salmon growth, size, and condition linked to watershed-scale salmon spawner abundance
Anadromous Pacific salmon Oncorhynchus spp. are semelparous, and resource subsidies from spawning adult salmon (marine-derived nutrients [MDN]) benefit juvenile salmonids while they rear in freshwater. However, it is unclear if juvenile salmon populations respond predictably to the abundance of spawning salmon at the watershed scale. To address whether hypothesized benefits to rearing juveniles sc
Authors
Philip J. Joy, Craig A. Stricker, Renae Ivanoff, Shiao Y. Wang, Mark S. Wipfli, Andrew C. Seitz, Jiaqi Huang, Mathew B. Tyers
Non-USGS Publications**
Burton, T.M., Uzarski, D.G., Gathman, J.P. et al. Wetlands (1999) 19: 869. doi:10.1007/BF03161789
Uzarski, D., Burton, T. & Stricker, C. Hydrobiologia (2001) 455: 137. doi:10.1023/A:1011929719866
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Fort Collins Science Center Labs and Facilities
The Fort Collins Science Center has scientists working in several diverse locations as well as three in house highly specialized laboratories, studying subjects from molecular ecology to brown treesnakes, dendroecology to streamflows, and macroinvertebrate species to Burmese pythons. Our extraordinary scientists work in each of these locations advancing studies in their particluar areas of study...
Contaminant Biology: Stable Isotope Applications
Environmental contaminants of natural and anthropogenic origin represent a major stressor to ecosystems, including human and wildlife populations.
Biogeography: Stable Isotope Applications
The distribution of species across the landscape is of great interest to conservation biology. Habitat quality and quantity are thought to be important drivers of occurrence and distribution, and numerous studies have demonstrated fitness-related consequences. However, for species with cryptic or migratory life histories, we often lack sufficient detail about habitat usage and in many cases...
Biogeochemistry: Stable Isotope Applications
Biogeochemical cycling is a cornerstone of ecosystem function and structure. Much has been learned about element cycles in a variety of systems using standard geochemical techniques.
Ecological Applications of Stable Isotopes
Environmental contaminants of natural and anthropogenic origin represent a major stressor to ecosystems, including human and wildlife populations. FORT scientists are studying these stressors in order to understand the contaminant cycling under natural environmental conditions. Stable isotope techniques are extremely useful in resolving trophic pathways by which contaminants become bioavailable...
Foraging Ecology Using Stable Isotopes
Understanding species habitat requirements is incomplete without insight into nutrition, including various aspects of foraging ecology. Traditional diet studies can be challenging because of logistics, issues related to resource availability, and observations are often short-term in nature based on gut contents or scat. Additionally, perturbations such as species introductions, habitat degradation...
Filter Total Items: 15
Silicified wood from around Old Faithful Geyser, Yellowstone National Park
Old Faithful Geyser in the Upper Geyser Basin of Yellowstone National Park is one of the best studied geysers in the world. Under research permit YELL-SCI-8030, samples from 13 silicified tree remnants were collected adjacent to the Old Faithful Geyser cone in April and November 2019. The silicified wood samples were dated using the radiocarbon (14C) method and were analyzed by scanning electron m
Modeled Pacific salmon escapement biomass and nutrient and contaminant concentrations across western North America, 1976-2015
The data contain yearly modeled estimates of Pacific salmon escapement (in annual metric tons of wet mass) from 1976 to 2015 across four regions of western North America. A second data file contains modeled estimates of contaminant or nutrient concentrations in Pacific Salmon. The modeled estimates were derived from Bayesian generalized linear models (contaminant or nutrient concentrations) or fro
Total mercury, methylmercury, and isotopic composition in various life stages of boreal chorus frogs (Pseudacris maculata) at two subalpine ponds in the Rocky Mountains, CO, USA, 2015
Mercury is an atmospherically transported contaminant found even in relatively pristine habitats. Once accumulated at the base of the food web, mercury can move between animals that are linked trophically. Pond-breeding amphibians may be particularly important vectors of mercury flux from remote freshwater to terrestrial systems because they feed on algae and detritus as tadpoles and metamorphose
Mercury concentrations, isotopic composition, biomass, and taxonomy of stream and riparian organisms in the vicinity of Yellow Pine, Idaho, 2015-2016.
This data release includes sampling location data; field-collected stream attribute data; laboratory-analyzed chemistry concentrations (total mercury, methyl mercury) and isotopic composition (total mercury, carbon, and nitrogen) for stream biota (seston, periphyton, benthic insects, emerging adult insects, riparian spiders, and fish); density, body length, and taxonomic information for benthic in
Dataset for temporal influences on selenium partitioning, trophic transfer, and exposure in a major U.S. river
The trace element selenium is an essential element with a narrow window between concentrations needed to support life and those that cause toxicity to egg laying organisms. Selenium bioaccumulation in aquatic organisms is primarily the result of trophic transfer through food webs and is poorly predicted by dissolved concentrations in freshwater bodies. To better understand the hydrologic and biolo
Chemistry of water, stream sediment, wildfire ash, soil, dust, and mine waste for Fourmile Creek Watershed, Colorado, 2010-2019
In response to the 2010 Fourmile Canyon fire near Boulder, Colorado, the U.S. Geological Survey collected data to support investigations into the magnitude and critical drivers of water-quality impairment after wildfire. We analyzed chemistry of stream water, sediment, wildfire ash, soil, dust, and mine waste for metals and other parameters in order to evaluate the effects of legacy mining and wil
Radiogenic strontium isotope data for non-native walleye otoliths collected from select areas of the Upper Colorado River Basin
This dataset includes radiogenic strontium isotope compositions of non-native walleye otoliths collected from select areas of the Upper Colorado River Basin (UCRB). Strontium isotope data have been widely used to assess natal areas for a variety of fish species. Following on previous work, this project sought to fill data gaps for walleye collected from the Colorado River (river miles 11-109.3), t
Stable carbon isotope and wood component concentration data for riparian cottonwood tree rings, Little Missouri River, North Dakota
This dataset includes stable carbon isotope values, lignin, cellulose, and hemicellulose concentrations (expressed as percent of ash-free dry mass) for riparian cottonwood (Populus deltoides) tree rings growing on the Little Missouri River floodplain, Theodore Roosevelt National Park, North Dakota. Drought stress induces stomatal closure and the carbon isotope ratio of annual tree rings tends to
Stable carbon and nitrogen isotope data for Siberian barn swallow subspecies collected during the breeding season
This dataset includes stable carbon and nitrogen isotope values for the inner tail retrices of three subspecies of barn swallow (Hirundo rustica rustica, H. r. tytleri, and H. r. gutturalis). Sampling was conducted in Russia (summer 2013), China (summer 2014), Mongolia (summer 2014), Japan (summer 2014), and western China (summer 2015) using mist nets. Stable carbon and nitrogen isotope data are u
Ovary mass and stable hydrogen isotope data for resident and migratory female dark-eyed juncos
This dataset includes ovary mass and stable hydrogen isotope compositions of feathers and claws from resident and migratory female dark-eyed juncos (Junco hyemalis) collected during early spring at Mountain Lake Biological Station, Pembroke, Virginia. A total of 18 migrant and 15 resident female dark-eyed juncos, a songbird that exhibits seasonal sympatry, were caught during March-April. Stable hy
Lignin phenol data for solid phase peat cores collected from the Alligator River and Great Dismal Swamp National Wildlife Refuges
This dataset includes lignin phenol monomer concentrations normalized to 100 mg of organic carbon. These analyses were conducted on select intervals from peat cores collected at the Alligator River (AR) and Great Dismal Swamp (GDS) National Wildlife Refuges in North Carolina and Virginia/North Carolina, USA, respectively. The eight lignin phenol monomers provide unique proxy information on the sou
Stable carbon and nitrogen isotope data for: 'Ecotoxicoparasitology of the gastrointestinal tracts of pinnipeds: effect of parasites on bioavailability of total mercury (THg)'
Parasites, such as acanthocephalans, cestodes, and some species of nematodes acquire nutrients from the lumen contents within the host gastrointestinal (GI) tract. For ubiquitous toxicants like mercury, both the host species and parasites are potentially exposed. The focus of this study was to determine if there is an effect of parasites on the dietary availability and therefore exposure to mercur
Filter Total Items: 82
Complex life histories alter patterns of mercury exposure and accumulation in a pond-breeding amphibian
Quantifying how contaminants change across life cycles of species that undergo metamorphosis is critical to assessing organismal risk, particularly for consumers. Pond-breeding amphibians can dominate aquatic animal biomass as larvae and are terrestrial prey as juveniles and adults. Thus, amphibians can be vectors of mercury exposure in both aquatic and terrestrial food webs. However, it is still
Authors
Freya Elizabeth Rowland, Erin L. Muths, Collin Eagles-Smith, Craig A. Stricker, Johanna M. Kraus, Rachel A. Harrington, David Walters
Animal tracing with sulfur isotopes: Spatial segregation and climate variability in Africa likely contribute to population trends of a migratory songbird
Climatic conditions affect animals but range-wide impacts at the population level remain largely unknown, especially in migratory species. However, studying climate–population relationships is still challenging in small migrants due to a lack of efficient and cost-effective geographic tracking method.Spatial distribution patterns of environmental stable isotopes (so called ‘isoscapes’) generally o
Authors
Vojtech Brlik, Petr Prochazka, Bengt Hansson, Craig A. Stricker, Elizabeth Yohannes, Rebecca L Powell, Michael B. Wunder
Diet energy density estimated from isotopes in predator hair associated with survival, habitat, and population dynamics
Sea ice loss is fundamentally altering the Arctic marine environment. Yet there is a paucity of data on the adaptability of food webs to ecosystem change, including predator-prey interactions. Polar bears (Ursus maritimus) are an important subsistence resource for Indigenous people and an apex predator that relies entirely on the under-ice food web to meet their energy needs. Here, we assessed whe
Authors
Karyn D. Rode, Brian D. Taras, Craig A. Stricker, Todd C. Atwood, Nicole P Boucher, George M. Durner, Andrew E. Derocher, Evan S. Richardson, Seth Cherry, Lori T. Quakenbush, Lara Horstmann, Jeffrey F. Bromaghin
Summer/fall diet and macronutrient assimilation in an Arctic predator
Free-ranging predator diet estimation is commonly achieved by applying molecular-based tracers because direct observation is not logistically feasible or robust. However, tracers typically do not represent all dietary macronutrients, which likely obscures resource use as prey proximate composition varies and tissue consumption can be specific. For example, polar bears (Ursus maritimus) preferentia
Authors
Craig A. Stricker, Karyn D. Rode, Brian D. Taras, Jeffrey F. Bromaghin, Lara Horstmann, Lori T. Quakenbush
Increased mercury and reduced insect diversity in linked stream-riparian food webs downstream of a historical mercury mine
Historical mining left a legacy of abandoned mines and waste rock in remote headwaters of major river systems in the western United States. Understanding the influence of these legacy mines on culturally and ecological important downstream ecosystems is not always straight-forward because of elevated natural levels of mineralization in mining-impacted watersheds. To test the ecological effects of
Authors
Johanna M. Kraus, JoAnn Holloway, Michael Pribil, Ben N. Mcgee, Craig A. Stricker, Danny Rutherford, Andrew S. Todd
The reuse of avian samples: Opportunities, pitfalls and a solution
Tissue samples are frequently collected to study various aspects of avian biology, but in many cases these samples are not used in their entirety and are stored by the collector. The already collected samples provide a largely overlooked opportunity because they can be used by different researchers in different biological fields. Broad reuse of samples could result in multispecies or large-scale s
Authors
Vojtěch Brlík, Pavel Pipek, Kate Brandis, Nikita Chernetsov, Fábio J. V. Costa, L. Gerardo Herrera M., Yosef Kiat, Richard B. Lanctot, Peter P. Marra, D. Ryan Norris, Chima J. Nwaogu, Petra Quillfeldt, Sarah T. Saalfeld, Craig A. Stricker, Robert L. Thomson, Tianhao Zhao, Petr Procházka
Energetic and health effects of protein overconsumption constrain dietary adaptation in an apex predator
Studies of predator feeding ecology commonly focus on energy intake. However, captive predators have been documented to selectively feed to optimize macronutrient intake. As many apex predators experience environmental changes that affect prey availability, limitations on selective feeding can affect energetics and health. We estimated the protein:fat ratio of diets consumed by wild polar bears us
Authors
Karyn D. Rode, Charles T. Robbins, Craig A. Stricker, Brian D. Taras, Troy N Tollefson
Temporal influences on selenium partitioning, trophic transfer, and exposure in a major U.S. river
Hydrologic and irrigation regimes mediate the timing of selenium (Se) mobilization to rivers, but the extent to which patterns in Se uptake and trophic transfer through recipient food webs reflect the temporal variation in Se delivery is unknown. We investigated Se mobilization, partitioning, and trophic transfer along approximately 60 river miles of the selenium-impaired segment of the Lower Gunn
Authors
Jessica E Brandt, James Roberts, Craig A. Stricker, Holly Rogers, Patricia Nease, Travis S. Schmidt
Breeding at higher latitude is associated with higher photoperiodic threshold and delayed reproductive development in a songbird
Many seasonally breeding animals exhibit a threshold day length (critical photoperiod; CPP) for gonadal growth, and populations breeding at higher latitudes typically have a higher CPP. Much less is known about latitudinal variation in CPP in migratory population that winter away from their breeding range and must time their reproduction to match favorable conditions at their destination. To addre
Authors
Devraj Singh, S. M. Reed, A. A. Kimmitt, K. A. Alford, Craig A. Stricker, P. D. Polly, Ellen D. Ketterson
Evidence of post-breeding prospecting in a long-distance migrant.
Organisms assess biotic and abiotic cues at multiple sites when deciding where to settle. However, due to temporal constraints on this prospecting, the suitability of available habitat may be difficult for an individual to assess when cues are most reliable, or at the time they are making settlement decisions. For migratory birds, the postbreeding season may be the optimal time to prospect and inf
Authors
Max Ciaglo, Ross Calhoun, Scott W Yanco, Michael B. Wunder, Craig A. Stricker, Brian D Linkhart
Short- and long-term responses of riparian cottonwoods (Populus spp.) to flow diversion: Analysis of tree-ring radial growth and stable carbon isotopes
Long duration tree-ring records with annual precision allow for the reconstruction of past growing conditions. Investigations limited to the most common tree-ring proxy of ring width can be difficult to interpret, however, because radial growth is affected by multiple environmental processes. Furthermore, studies of living trees may miss important effects of drought on tree survival and forest cha
Authors
Derek M. Schook, Jonathan M. Friedman, Craig A. Stricker, Adam Z. Csank, David J. Cooper
Juvenile Coho and Chinook salmon growth, size, and condition linked to watershed-scale salmon spawner abundance
Anadromous Pacific salmon Oncorhynchus spp. are semelparous, and resource subsidies from spawning adult salmon (marine-derived nutrients [MDN]) benefit juvenile salmonids while they rear in freshwater. However, it is unclear if juvenile salmon populations respond predictably to the abundance of spawning salmon at the watershed scale. To address whether hypothesized benefits to rearing juveniles sc
Authors
Philip J. Joy, Craig A. Stricker, Renae Ivanoff, Shiao Y. Wang, Mark S. Wipfli, Andrew C. Seitz, Jiaqi Huang, Mathew B. Tyers
Non-USGS Publications**
Burton, T.M., Uzarski, D.G., Gathman, J.P. et al. Wetlands (1999) 19: 869. doi:10.1007/BF03161789
Uzarski, D., Burton, T. & Stricker, C. Hydrobiologia (2001) 455: 137. doi:10.1023/A:1011929719866
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.