Kurt Fausch

Kurt Fausch
Colorado State University | CSU · Department of Fish, Wildlife and Conservation Biology

About

147
Publications
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19,232
Citations

Publications

Publications (147)
Article
Coexistence of species requires equalizing mechanisms that minimize fitness differences, which are balanced by stabilizing mechanisms that enhance negative intraspecific interactions versus interspecific ones. Here, we develop a simple theoretical framework that allows measuring the relative strength of intraspecific versus interspecific competitio...
Article
Networks of direct and indirect biotic interactions underpin the complex dynamics and stability of ecological systems, yet experimental and theoretical studies often yield conflicting evidence regarding the direction (positive or negative) or magnitude of these interactions. We revisited pioneering data sets collected at the deciduous forested Horo...
Article
Similar species that overlap in sympatry may diverge in characters related to resource use as a result of evolution or phenotypic plasticity. Dolly Varden charr (Salvelinus malma) and whitespotted charr (S. leucomaenis) overlap along streams in Hokkaido, Japan, and compete by interference for invertebrate drift-foraging positions. Previous research...
Article
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The natural wood regime forms the third leg of a tripod of physical processes that supports river science and management, along with the natural flow and sediment regimes. The wood regime consists of wood recruitment, transport, and storage in river corridors. Each of these components can be characterized in terms of magnitude, frequency, rate, tim...
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Headwater streams and wetlands are integral components of watersheds that are critical for biodiversity, fisheries, ecosystem functions, natural resource‐based economies, and human society and culture. These and other ecosystem services provided by intact and clean headwater streams and wetlands are critical for a sustainable future. Loss of legal...
Article
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Conserving fluxes of terrestrial invertebrates to streams, which supply about half of the diet of stream fish, is an important goal for aquatic conservation. Riparian land uses such as forestry and grazing could have strong indirect effects on fish, by reducing these prey inputs. A large-scale replicated field experiment was conducted in four weste...
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Water flow is a fundamental characteristic required for the ecological integrity of stream ecosystems. However, populations of many freshwater fishes in the Mediterranean region are threatened by man-induced drought due to water diversion. Mark-recapture methodology is an effective tool for estimating fish abundance and survival probability, but it...
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Shigeru Nakano was a Japanese ecologist whose work crossed boundaries among subdisciplines in ecology, between aquatic and terrestrial habitats, and between different languages and cultures. He published his first paper in 1985 while still an undergraduate, and is well known for his early research on the individual behavior of stream salmonids in d...
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Anthropogenic climate change is causing a wide range of stresses in aquatic ecosystems, primarily through warming thermal conditions. Lakes, in response to these changes, are experiencing increases in both summer temperatures and ice-free days. We used continuous records of lake surface temperature and air temperature to create statistical models o...
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Groundwater pumping for agriculture is a major driver causing declines of global freshwater ecosystems, yet the ecological consequences for stream fish assemblages are rarely quantified. We combined retrospective (1950–2010) and prospective (2011–2060) modeling approaches within a multiscale framework to predict change in Great Plains stream fish a...
Article
Effective conservation of Cutthroat Trout Oncorhynchus clarkii lineages native to the Rocky Mountains will require estimating effects of multiple stressors and directing management toward the most important ones. Recent analyses have focused on the direct and indirect effects of a changing climate on contemporary ranges, which are much reduced from...
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Pacific trout Oncorhynchus spp. in western North America are strongly valued in ecological, socioeconomic, and cultural views, and have been the subject of substantial research and conservation efforts. Despite this, the understanding of their evolutionary histories, overall diversity, and challenges to their conservation is incomplete. We review t...
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Instream and floodplain wood can provide many benefits to river ecosystems, but can also create hazards for inhabitants, infrastructure, property, and recreational users in the river corridor. We propose a decision process for managing large wood, and particularly for assessing the relative benefits and hazards associated with individual wood piece...
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The Columbia Basin once supported a diversity of native fishes and large runs of anadromous salmonids that sustained substantial fisheries and cultural values. Extensive land conversion, watershed disruptions, and subsequent fishery declines have led to one of the most ambitious restoration programs in the world. Progress has been made, but restora...
Technical Report
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In response to an assignment from the Northwest Power and Conservation Council, NOAA Fisheries, and Columbia River Indian tribes, the Independent Scientific Advisory Board (ISAB) reviewed the implications of density dependence in fish populations in the Columbia River Basin. The ISAB’s key findings include: • Many salmon populations throughout the...
Article
Thirty years ago, Fausch (Can J Zool 62:441–451, 1984) proposed a simple model of optimal positions for drift-feeding salmonids in streams, whereby fish maximize their net energy intake (NEI) by selecting focal points in low water velocity near faster currents that deliver abundant drifting invertebrates. The theory was based on earlier observation...
Article
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Non‐native species can affect food web and community structure, including the flow of resources from one habitat to another. In many streams of western North America, non‐native brook trout (Salvelinus fontinalis) have replaced native cutthroat trout (Oncorhynchus clarkii). Because brook trout naturally occur at higher densities and exhibit differe...
Article
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Forecasts of species distributions under future climates are inherently uncertain, but there have been few attempts to describe this uncertainty comprehensively in a probabilistic manner. We developed a Monte Carlo approach that accounts for uncertainty within generalized linear regression models (parameter uncertainty and residual error), uncertai...
Article
Impending changes in climate will interact with other stressors to threaten aquatic ecosystems and their biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments in the Upper Colorado River Basin, owing to past nonnative trout invasion...
Article
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Bioclimatic models predict large reductions in native trout across the Rocky Mountains in the 21st century but lack details about how changes will occur. Through five case histories across the region, we explore how a changing climate has been affecting streams and the potential consequences for trout. Monitoring records show trends in temperature...
Article
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Non-native brook trout (Salvelinus fontinalis) have replaced native cutthroat trout (Oncorhynchus clarkii) in streams across the western USA. Brook trout have been assumed to be functionally equivalent to cutthroat trout, which could argue against extensive control of this species by government agencies. This assumption was assessed by comparing th...
Conference Paper
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Climate change is projected to increase stream temperatures, alter flow regimes, and adversely affect native trout distributions. In addition to improving contemporary habitat conditions, many stream restoration practices - such as restoring riparian vegetation, habitat diversity, or environmental flows - also have the potential to offset climate c...
Conference Paper
Impending changes in climate will combine with other stressors to threaten aquatic ecosystems and biota. Native Colorado River cutthroat trout (CRCT; Oncorhynchus clarkii pleuriticus) are now relegated to 309 isolated high-elevation (>1700 m) headwater stream fragments owing to nonnative trout invasions and habitat loss. Predicted changes in climat...
Conference Paper
Background/Question/Methods Invasion of a species in one habitat can change fluxes of materials and organisms to adjacent or distant habitats, with consequences for food webs and ecosystem processes. Here we summarize findings from experimental and comparative studies of invasive aquatic and terrestrial species that affect linked stream-riparian...
Article
Invasion of a species in one habitat can change fluxes of materials and organisms to adjacent or distant habitats, with consequences for food webs and ecosystem processes. Here we summarize findings from experimental and comparative studies of invasive aquatic and terrestrial species that affect linked stream-riparian ecosystems. In Japan, invading...
Article
Full-text available
Research in forest and grassland ecosystems indicates that terrestrial invertebrates that fall into streams can be an important prey resource for fish, providing about 50% of their annual energy and having strong effects on growth and abundance. However, the indirect effects of land uses like cattle grazing on this important prey subsidy for stream...
Article
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Like many fishes native to western Great Plains streams, the Arkansas darter Etheostoma cragini has declined, apparently in response to changes in flow regimes and habitat fragmentation. We investigated the effectiveness of translocation as a management strategy to conserve this threatened species in the Arkansas River basin of southeastern Colorad...
Article
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Despite the importance of habitat in determining species distribution and persistence, habitat dynamics are rarely modeled in studies of metapopulations. We used an integrated habitat-occupancy model to simultaneously quantify habitat change, site fidelity, and local colonization and extinction rates for larvae of a suite of Great Plains stream fis...
Article
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Evaluating the effectiveness of instream structures for increasing trout populations is complicated by a paucity of long-term studies. We report on a study spanning 23 years to assess the effect of installing log weirs on stream habitat and trout abundance. Structures were installed in a randomly selected half of a 500 m study reach in six small Co...
Article
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Supplementary information to: Non-natives: 141 scientists object Full list of co-signatories to a Correspondence published in Nature 475, 36 (2011); doi: 10.1038/475036a. Daniel Simberloff University of Tennessee, Knoxville, Tennessee, USA. dsimberloff@utk.edu Jake Alexander Institute of Integrative Biology, Zurich, Switzerland. Fred Allendorf Univ...
Conference Paper
Analyzing how climate change may influence fish populations hinges on accurate projections for future climate patterns, models to relate these to fish habitat, and data on the current ecological context for target populations. Within the Rocky Mountain West, warmer summer temperatures have already been recorded, and are predicted to increase by 2.7...
Conference Paper
Maintaining or restoring habitat connectivity is one of the cornerstones of conservation management for native stream fishes. Yet connectivity also represents a risk because intact or restored corridors facilitate invasions by nonnative fishes. Recognizing and balancing the benefits and risks of connectivity for freshwater fish populations is incre...
Conference Paper
Broad-scale studies of climate change effects on freshwater species to date have focused mainly on temperature, ignoring critical drivers such as flow regime and biotic interactions. We used downscaled outputs from general circulation models coupled with a hydrologic model to forecast the effects of altered flows, biotic interactions, and increased...
Conference Paper
Like many fishes native to western Great Plains streams, the Arkansas darter Etheostoma cragini has declined, apparently in response to changes in flow regimes and habitat fragmentation. To increase the number of populations, darters were translocated into 19 streams and ditches, each fragmented to different degrees by road culverts and diversion s...
Article
Across the western Great Plains of North America, groundwater pumping for irrigated agriculture is depleting regional aquifers that sustain streamflow for native fishes. We investigated linkages between groundwater pumping from the High Plains Aquifer and stream fish habitat loss at multiple spatial scales during spring and summer 2005–2007 in the...
Article
Full-text available
Broad-scale studies of climate change effects on freshwater species have focused mainly on temperature, ignoring critical drivers such as flow regime and biotic interactions. We use downscaled outputs from general circulation models coupled with a hydrologic model to forecast the effects of altered flows and increased temperatures on four interacti...
Article
Replacement of a native species by a nonnative can have strong effects on ecosystem function, such as altering nutrient cycling or disturbance frequency. Replacements may cause shifts in ecosystem function because nonnatives establish at different biomass, or because they differ from native species in traits like foraging behavior. However, no stud...
Article
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Recent and projected climate warming trends have prompted interest in impacts on coldwater fishes. We examined the role of climate (temperature and flow regime) relative to geomorphology and land use in determining the observed distributions of three trout species in the interior Columbia River Basin, USA. We considered two native species, cutthroa...
Article
A review of 17 controlled experiments of interspecific competition between juveniles of Atlantic salmon (Salmo salar) and other fishes revealed relatively little evidence to judge competitive effects at any scale. More than half were unreplicated and so inadequate to test either the existence or relative strength of interspecific competition. Most...
Article
Replicate experiments were conducted in the Salmon River, British Columbia, during early summer 1990 to test the relative importance of velocity refuge, visual isolation, and overhead cover to microhabitat selection by steelhead (Oncorhynchus mykiss) parr and age-0 coho salmon (O. kisutch). Four types of artificial Plexiglas structures, the first t...
Article
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To understand how immigration and emigration influence the processes by which invading nonnative brook trout (Salvelinus fontinalis) displace native cutthroat trout (Oncorhynchus clarki), we studied trout movement in long segments of three mountain streams in Colorado during 1999–2001. Over 3500 trout were captured and marked at weirs and during el...
Article
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Movements of brook trout (Salvelinus fontinalis) were studied in two high-elevation (>2700 m) Colorado streams by marking (n = 4005) and recapturing fish using weirs and electrofishing at locations spaced up to 4500 m apart. Movement was most common in the upstream direction during summer, and about equal upstream and downstream between summers. Hi...
Article
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Estimation of stream fish abundance using removal electrofishing is common and allows sampling of fish populations during a single site visit. However, recent evaluations have demonstrated that removal estimators can substantially underestimate fish abundance, raising concerns about using this method. We evaluated removal estimates of trout (family...
Article
A model is developed to predict potential net energy gain for salmonids in streams from characteristics of water velocity and invertebrate drift. Potential net energy gain, or potential profit, is calculated for individuals of three species of juvenile salmonids in a laboratory stream aquarium, based on the energy available from drift minus the cos...
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The recently proposed index of biotic integrity (IBI) was evaluated for several watersheds throughout the midwestern United States. Five of the community metrics comprising the IBI depend on the number of fish species present and must be adjusted for changes in expected species richness with stream size or zoogeography. We use basic relationships o...
Article
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Knowledge of basic life-history attributes, paired with unbiased estimates of species distribution, is critical for the effective conservation of sensitive fish species. We quantified the spawning phenology, habitat use, and detectability for larvae of an assemblage of threatened Great Plains, USA, stream fishes using new occupancy estimation metho...
Article
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Flow alterations caused by reservoir storage, groundwater pumping, diversions, and drought are widespread in North American Great Plains streams and have altered and fragmented habitats and reduced native fish biodiversity. Early life stages of fish are particularly sensitive to altered flow regimes, and reduced growth and survival may negatively a...
Article
Full-text available
During the past decade, research on large in-stream wood has expanded beyond North America's Pacific Northwest to diverse environments and has shifted toward increasingly holistic perspectives that incorporate processes of wood recruitment, retention, and loss at scales from channel segments to entire watersheds. Syntheses of this rapidly expanding...
Article
1. Streams are highly connected to their landscapes and so are easily altered by multiple stressors that affect both uplands and riparian zones, and the streams themselves. These include dams and diversions, channelisation, deforestation, water pollution, biological invasions and climate change. 2. We review research conducted in Hokkaido Island, n...
Article
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Conservation biologists often face the trade-off that increasing connectivity in fragmented landscapes to reduce extinction risk of native species can foster invasion by non-native species that enter via the corridors created, which can then increase extinction risk. This dilemma is acute for stream fishes, especially native salmonids, because thei...
Article
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Subspecies of inland cutthroat trout Oncorhynchus clarkii occupy a fraction of their historic ranges, and displacement by nonnative brook trout Salvelinus fontinalis is among the greatest threats to existing populations in small, headwater streams. Electrofishing is often used to suppress brook trout and enhance cutthroat trout populations, but the...
Article
We review the ecology and conservation of three lesser-known chars (genus Salvelinus): Dolly Varden (S. malma), white-spotted char (S. leucomaenis), and bull trout (S. confluentus). Dolly Varden is distributed across the northern Pacific Rim and co-occurs with bull trout and white-spotted char at the southern extremes of its range. In contrast, bul...
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Lake Superior once supported abundant lake-dwelling brook trout Salvelinus fontinalis called coasters; however, only scattered remnant populations remained by the early 20th century. Owing to their early decline, there is little information about their ecology and life history, yet such information is vital for the ecologically based rehabilitation...
Article
A paradox of invasion biology is that even though native species are locally adapted to environmental conditions, nonnative species without this advantage often invade. Ecologists have advanced four main theories to explain why invaders are successful in some places and not others: biotic resistance, environmental resistance, human disturbance, and...
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Native salmonid fishes often face simultaneous threats from habitat fragmentation and invasion by nonnative trout species. Unfortunately, management actions to address one may create or exacerbate the other. A consistent decision process would include a systematic analysis of when and where intentional use or removal of barriers is the most appropr...
Article
Salmonids like rainbow trout Oncorhynchus mykiss, brook trout Salvelinus fontinalis and brown trout Salmo trutta are potent invaders in various regions throughout the world, but non-native rainbow trout have become established in only a few locations in the U.K. to date. Salmonid invasions in other regions are often driven by repeated authorized in...
Article
Translocation is a key strategy for conserving native subspecies of cutthroat trout Oncorhynchus clarkii that have declined markedly throughout their native range. Previous research showed that successful translocations of cutthroat trout in high-elevation southern Rocky Mountain streams were more likely in streams with warm summer water temperatur...