Ryan Kovach (Former Employee)
Science and Products
Western Waters Invasive Species and Disease Research Program
Researchers at the Northern Rocky Mountain Science Center's Western Waters Invasive Species and Disease Research Program work extensively with federal, state, tribal, regional, and local partners to deliver science to improve early detection and prevention of invasive species and disease; understand complex interactions that promote invasive species and disease, and their impacts (and...
Evolutionary mechanisms influencing the spread of hybridization: genomics, fitness and dispersal
Invasive species and hybridization (reproduction between different species or subspecies) – among the most serious threats to native species and biodiversity – provide some of the richest opportunities for “natural experiments” in evolutionary biology. New genomic technologies, combined with long-term hybridization studies in natural populations, provide exciting opportunities to advance our...
Using the past as a prelude to the future to assess climate effects on native trout across the United States
Future climate change is expected to dramatically alter the structure and function of freshwater ecosystems that support salmonid species. The response of salmonids to climate change will vary through space and time and manifest in both known and currently unknown ways. A potentially rich source of understanding of how salmonids interact with climate lies in a unified retrospective analysis of...
Global status of trout and char: Conservation challenges in the twenty-first century
Freshwater ecosystems are among the most threatened ecosystems in the world (Richter et al. 1997; Strayer and Dudgeon 2010), and freshwater fishes may now be the most threatened group of vertebrates (Ricciardi and Rasmussen 1999; Vorosmarty et al. 2010; Darwall and Freyhof 2016). Of the 7,300 freshwater fish species globally assessed by the...
Muhlfeld, Clint C.; Dauwalter, Daniel C.; D'Angelo, Vincent S.; Ferguson, Andrew; Giersch, J. Joseph; Impson, Dean; Koizumi, Itsuro; Kovach, Ryan; McGinnity, Philip; Schoeffmann, Johannes; Epifanio, John; Vøllestad, Leif Asbjørn Consistent compensatory growth offsets poor condition in trout populations
1. Compensatory growth – when individuals in poor condition grow rapidly to “catch up” to conspecifics – may be a mechanism that allows individuals to tolerate stressful environmental conditions, both abiotic and biotic. This phenomenon has been documented fairly widely in laboratory and field experiments, but evidence for compensatory growth in...
Al-Chokhachy, Robert; Kovach, Ryan; Sepulveda, Adam J.; Strait, Jeff; Shepard, Bradley B.; Muhlfeld, Clint C. An integrated framework for ecological drought across riverscapes of North America
Climate change is increasing the severity and extent of extreme droughts events, posing a critical threat to freshwater ecosystems, particularly with increasing human demands for diminishing water supplies. Despite the importance of drought as a significant driver of ecological and evolutionary dynamics, current understanding of drought...
Kovach, Ryan; Dunham, Jason B.; Al-Chokhachy, Robert; Snyder, Craig; Beever, Erik A.; Pederson, Gregory T.; Lynch, Abigail; Hitt, Nathaniel P.; Konrad, Christopher P.; Jaeger, Kristin; Rea, Alan H.; Sepulveda, Adam J.; Lambert, Patrick M.; Stoker, Jason M.; Giersch, J. Joseph; Muhlfeld, Clint C. Effects of land use on summer thermal regimes in critical salmonid habitats of the Pacific Northwest
The effect of climate change on stream temperature regimes is of significant concern to natural resource managers focused on protecting cold-water-dependent species. Nevertheless, understanding of how human land-use activities may act to exacerbate the effects of climate change on stream temperature regimes is limited. Using extensive stream...
Kovach, Ryan; Muhlfeld, Clint C.; Al-Chokhachy, Robert; Ojala, Jeffrey V.; Archer, Eric Trout in hot water: A call for global action
Trout are one of the most culturally, economically, and ecologically important taxonomic groups of freshwater fishes worldwide (1). Native to all continents in the Northern Hemisphere, trout are a taxonomically diverse group of fishes belonging to 7 genera (Oncorhynchus, Salvelinus, Salmo, Hucho, Parahucho, Brachymystax, and Salvethymus)...
Muhlfeld, Clint C.; Dauwalter, Daniel C.; Kovach, Ryan; Kershner, Jeffrey L.; Williams, Jack E.; Epifanio, John Long-term population dynamics and conservation risk of migratory bull trout in the upper Columbia River basin
We used redd count data from 88 bull trout (Salvelinus confluentus) populations in the upper Columbia River basin to quantify local and regional patterns in population dynamics, including adult abundance, long-term trend, and population synchrony. We further used this information to assess conservation risk of metapopulations using eight...
Kovach, Ryan; Jonathan Armstrong; David Schmetterling; Al-Chokhachy, Robert; Muhlfeld, Clint C. No evidence for ecological segregation protecting native trout from invasive hybridization
We appreciate the comments of Young et al. (2017) on our recent paper (Muhlfeld et al., 2017) concerning spatiotemporal dynamics of hybridization between native westslope cutthroat trout (Oncorhynchus clarkii lewisi; WCT) and introduced coastal rainbow trout (Oncorhynchus mykiss irideus; RBT). Nevertheless, we believe there is no evidence for “...
Kovach, Ryan; Muhlfeld, Clint C.; Al-Chokhachy, Robert K.; Amish, Stephen J.; Kershner, Jeffrey L.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Matson, Phil; Schmetterling, David; Shepard, Bradley; Westley, Peter A. H.; Whited, Diane; Whiteley, Andrew R.; Allendorf, Fred W. Climate-induced trends in predator–prey synchrony differ across life-history stages of an anadromous salmonid
Differential climate-induced shifts in phenology can create mismatches between predators and prey, but few studies have examined predator–prey mismatch across multiple life-history stages. We used long-term data from a warming stream with shifting salmonid migration timings to quantify intra-annual migration synchrony between predatory Dolly...
Bell, Donovan A.; Kovach, Ryan; Vulstek, Scott C.; Joyce, John E.; Tallmon, David A. Genetic responses to rapid change in the environment during the anthropocene
Humans have greatly affected the genetic composition of many different organisms during the Anthropocene. Humans cause genetic changes by affecting the direction and magnitude of evolutionary forces that act to create the Earth's biota. In many cases, we expect the outcome of human actions to be extinction and hybridization of existing species,...
Tallmon, David A.; Kovach, Ryan Global synthesis of the documented and projected effects of climate change on inland fishes
Although climate change is an important factor affecting inland fishes globally, a comprehensive review of how climate change has impacted and will continue to impact inland fishes worldwide does not currently exist. We conducted an extensive, systematic primary literature review to identify English-language, peer-reviewed journal publications...
Myers, Bonnie; Lynch, Abigail; Bunnell, David B.; Chu, Cindy ; Falke, Jeffrey A.; Kovach, Ryan; Krabbenhoft, Trevor J. ; Kwak, Thomas J.; Paukert, Craig P. Legacy introductions and climatic variation explain spatiotemporal patterns of invasive hybridization in a native trout
Hybridization between invasive and native species, a significant threat to worldwide biodiversity, is predicted to increase due to climate-induced expansions of invasive species. Long-term research and monitoring are crucial for understanding the ecological and evolutionary processes that modulate the effects of invasive species. Using a large,...
Muhlfeld, Clint C.; Kovach, Ryan P.; Al-Chokhachy, Robert K.; Amish, Stephen J.; Kershner, Jeffrey L.; Leary, Robb F.; Lowe, Winsor H.; Luikart, Gordon; Matson, Phil; Schmetterling, David A.; Shepard, Bradley B.; Westley, Peter A. H.; Whited, Diane; Whiteley, Andrew R.; Allendorf, Fred W. Population genetics and demography unite ecology and evolution
The interplay of ecology and evolution has been a rich area of research for decades. A surge of interest in this area was catalyzed by the observation that evolution by natural selection can operate at the same contemporary timescales as ecological dynamics. Specifically, recent eco-evolutionary research focuses on how rapid adaptation influences...
Lowe, Winsor H.; Kovach, Ryan; Allendorf, Fred W.
It's not all about temperature for cold-water fish.
Bull trout populations are lower, more variable, and declining where stream habitat is limited, invasive species and land-use (i.e., roads) are prevalent, and stream temperatures are highest, according to a new study led by the USGS.
Climate Change Threatens Native Trout Diversity
Scientists have discovered that the diversity of a threatened native trout species will likely decrease due to future climate change.