Introduced Lake Trout Produced A Four Level Trophic Cascade In Yellowstone Lake

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Introduced Lake Trout Produced a Four-level Trophic Cascade in Yellowstone Lake

Author : Lusha Marguerite Tronstad
Publisher :
ISBN 13 :
Total Pages : 15 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Introduced Lake Trout Produced a Four-level Trophic Cascade in Yellowstone Lake by : Lusha Marguerite Tronstad

Download or read book Introduced Lake Trout Produced a Four-level Trophic Cascade in Yellowstone Lake written by Lusha Marguerite Tronstad and published by . This book was released on 2010 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduction of lake trout Salvelinus namaycush into a system can add a trophic level, potentially affecting organisms at lower trophic levels. Similar to many lakes and reservoirs in the western United States, lake trout were introduced into Yellowstone Lake, Wyoming. Previous studies showed that lake trout reduced the population and altered the size structure of native Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri in Yellowstone Lake, but we sought to determine the degree to which lake trout predation changed lower trophic levels. We predicted that the structure of lower trophic levels would change in conformance with trophic cascade theory because Yellowstone cutthroat trout consume zooplankton. We compared zooplankton and phytoplankton assemblages between the period when Yellowstone cutthroat trout were abundant and the period after they declined. As predicted by trophic cascade theory, zooplankton biomass shifted from being dominated by copepods before lake trout introduction to being dominated by cladocerans after lake trout introduction, with zooplankton body lengths 17% longer after introduction. Vertical water clarity increased by 1.6 m because of a twofold decrease in chlorophyll a and a three- to sevenfold decrease in phytoplankton biovolume. Thus, the introduction of lake trout and subsequent decline of Yellowstone cutthroat trout likely altered lower trophic levels in Yellowstone Lake. Trophic cascades may be common in western U.S. lakes and reservoirs where native salmonids are present and where lake trout have been introduced.

Feeding Ecology of Native and Nonnative Salmonids During the Expansion of a Nonnative Apex Predator in Yellowstone Lake, Yellowstone National Park

Download Feeding Ecology of Native and Nonnative Salmonids During the Expansion of a Nonnative Apex Predator in Yellowstone Lake, Yellowstone National Park PDF Online Free

Author : John M. Syslo
Publisher :
ISBN 13 :
Total Pages : 14 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Feeding Ecology of Native and Nonnative Salmonids During the Expansion of a Nonnative Apex Predator in Yellowstone Lake, Yellowstone National Park by : John M. Syslo

Download or read book Feeding Ecology of Native and Nonnative Salmonids During the Expansion of a Nonnative Apex Predator in Yellowstone Lake, Yellowstone National Park written by John M. Syslo and published by . This book was released on 2016 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The illegal introduction of Lake Trout Salvelinus namaycush into Yellowstone Lake, Yellowstone National Park, preceded the collapse of the native population of Yellowstone Cutthroat Trout Oncorhynchus clarkii bouvieri, producing a four-level trophic cascade. The Yellowstone Cutthroat Trout population?s collapse and the coinciding increase in Lake Trout abundance provided a rare opportunity to evaluate the feeding ecology of a native prey species and a nonnative piscivore species after the restructuring of a large lentic ecosystem. We assessed diets, stable isotope signatures, and depth-related CPUE patterns for Yellowstone Cutthroat Trout and Lake Trout during 2011?2013 to evaluate trophic overlap. To evaluate diet shifts related to density, we also compared 2011?2013 diets to those from studies conducted during previous periods with contrasting Yellowstone Cutthroat Trout and Lake Trout CPUEs. We illustrate the complex interactions between predator and prey in a simple assemblage and demonstrate how a nonnative apex predator can alter competitive interactions. The diets of Yellowstone Cutthroat Trout were dominated by zooplankton during a period when the Yellowstone Cutthroat Trout CPUE was high and were dominated by amphipods when the CPUE was reduced. Lake Trout shifted from a diet that was dominated by Yellowstone Cutthroat Trout during the early stages of the invasion to a diet that was dominated by amphipods after Lake Trout abundance had increased and after Yellowstone Cutthroat Trout prey had declined. The shifts in Yellowstone Cutthroat Trout and Lake Trout diets resulted in increased trophic similarity of these species through time due to their shared reliance on benthic amphipods. Yellowstone Cutthroat Trout not only face the threat posed by Lake Trout predation but also face the potential threat of competition with Lake Trout if amphipods are limiting. Our results demonstrate the importance of studying the long-term feeding ecology of fishes in invaded ecosystems.

Effects of Lake Trout Suppression Methods on Lower Trophic Levels in Yellowstone Lake, Wyoming

Author : Dominique Raquel Lujan
Publisher :
ISBN 13 :
Total Pages : 56 pages
Book Rating : 4.5/5 (699 download)

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Book Synopsis Effects of Lake Trout Suppression Methods on Lower Trophic Levels in Yellowstone Lake, Wyoming by : Dominique Raquel Lujan

Download or read book Effects of Lake Trout Suppression Methods on Lower Trophic Levels in Yellowstone Lake, Wyoming written by Dominique Raquel Lujan and published by . This book was released on 2020 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lake trout (Salvelinus namaycush) were unintentionally introduced to Yellowstone Lake, Yellowstone National Park, Wyoming, and drastically reduced the native Yellowstone cutthroat trout (Oncorhynchus clarkii bouvieri) population. Gillnetting suppresses adult lake trout since 1995; however, Yellowstone National Park is developing methods to suppress embryos, including adding lake trout carcasses and analog pellets to spawning sites. Decomposing carcasses and analog pellets cause lake trout embryo mortality due to low dissolved oxygen concentrations, but the effects of these methods on lower trophic levels are unknown. We estimated the degree to which adding carcasses or analog pellets to spawning sites altered nutrient limitation, nutrient concentrations, algal biomass, and ammonium uptake. We deployed nutrient diffusing substrates at three sites (control, carcass, and analog pellets) before and after carcasses or analog pellets were added to measure algal biomass in six treatments where nothing (control), nitrogen, phosphorus, nitrogen and phosphorus, carcasses or pellets were added to agar. We measured nutrient concentrations, algal biomass (chlorophyll a concentrations) and ammonium uptake at spawning sites where no carcasses were added (control), site where carcasses were added before lake trout spawned (early season sites), and sites where carcasses were added after lake trout spawned (late season sites) in 2018 and 2019 to investigate the degree to which carcasses caused bottom-up effects in periphyton and phytoplankton. Nutrient diffusing substrates indicated that nitrogen and phosphorus co-limited periphyton before treatments; however, nutrients were not limiting after carcasses or analog pellets were added to spawning sites. Analog pellets appeared to suppress algal biomass and carcasses increased algal biomass ≥2.4x after their addition. Adding carcasses to shallow spawning sites did not alter the concentration of ammonium, algal biomass or uptake compared to the control site. Periphyton had higher biomass and phytoplankton uptake was much higher. Adding carcasses to the littoral zone likely alters small areas but overall had a small effect on algal biomass and nutrient cycling. Estimating how lake trout suppression methods may alter basal resources in the littoral zone of Yellowstone Lake will help managers develop the best plan to control these invasive predators at early life stages.

Effects of Introduced Lake Trout on Native Cutthroat Trout in Yellowstone Lake

Author : James R. Ruzycki
Publisher :
ISBN 13 :
Total Pages : 15 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Effects of Introduced Lake Trout on Native Cutthroat Trout in Yellowstone Lake by : James R. Ruzycki

Download or read book Effects of Introduced Lake Trout on Native Cutthroat Trout in Yellowstone Lake written by James R. Ruzycki and published by . This book was released on 2003 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The establishment of a reproducing population of nonnative lake trout (Salvelinus namaycush) poses a serious threat to the integrity of the Yellowstone Lake ecosystem, particularly to the indigenous cutthroat trout (Oncorhynchus clarki bouvieri). We used standard fisheries techniques to quantify the population-level impact resulting from this introduction, while the U.S. National Park Service (NPS) developed a program to control their numbers. Lake trout diets, thermal history, growth, and size structure were incorporated into a bioenergetics model to estimate the predatory impact of introduced lake trout and to evaluate the effectiveness of the NPS lake trout control program. Population size structures were estimated from catches of fish in gill nets that were corrected for mesh size selectivity. Lake trout abundance was estimated using virtual population (cohort) analysis, and cutthroat trout abundance was estimated using hydroacoustics. Juvenile cutthroat trout were highly vulnerable to predation, and lake trout preyed on cutthroat trout that averaged 27?33% of their body length. Based on our model, an average piscivorous lake trout consumed 41 cutthroat trout each year. During 1996, the piscivorous lake trout population consumed an estimated 15 metric tons of cutthroat trout (129 000 fish) composing 14% of the vulnerable cutthroat trout production. The NPS removed nearly 15 000 lake trout from 1995 to 1999. Had these predators remained in Yellowstone Lake they would have consumed an estimated 23 metric tons of cutthroat trout (200 000 fish) during 1999 alone. If left unchecked, lake trout would clearly pose a serious threat to the long-term existence of the indigenous cutthroat trout. This analysis demonstrates the negative impact of an introduced predator in an ecologically isolated aquatic ecosystem.

Lake Trout-induced Spatial Variation in the Benthic Invertebrates of Yellowstone Lake: Invasive Lake Trout Indirectly Increased Biomass and Body Mass of Amphipods

Download Lake Trout-induced Spatial Variation in the Benthic Invertebrates of Yellowstone Lake: Invasive Lake Trout Indirectly Increased Biomass and Body Mass of Amphipods PDF Online Free

Author : Oliver Wilmot
Publisher :
ISBN 13 :
Total Pages : 11 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Lake Trout-induced Spatial Variation in the Benthic Invertebrates of Yellowstone Lake: Invasive Lake Trout Indirectly Increased Biomass and Body Mass of Amphipods by : Oliver Wilmot

Download or read book Lake Trout-induced Spatial Variation in the Benthic Invertebrates of Yellowstone Lake: Invasive Lake Trout Indirectly Increased Biomass and Body Mass of Amphipods written by Oliver Wilmot and published by . This book was released on 2016 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Invasive predators can induce trophic cascades in the open water of lakes; however, much less is known about their effect on benthic invertebrates, which inhabit the lake bottom, or benthic zone. Lake trout (Salvelinus namaycush) were introduced to Yellowstone Lake, Wyoming, and reduced the Yellowstone cutthroat trout (Oncorhynchus clakrii bouvieri ) population. We predicted that lake trout indirectly reduced predation of benthic invertebrates through cutthroat trout. To estimate how the benthic invertebrate assemblages differed under cutthroat trout? versus lake trout?dominated food webs, we collected benthic invertebrate samples from two areas of Yellowstone Lake in 2004 using a Ponar sampler and compared them with stomach contents from cutthroat trout. Cutthroat trout selectively ate benthic invertebrates with the largest body sizes. The amphipod genus, Gammarus, had the highest biomass of all benthic invertebrates. Gammarus biomass was higher in West Thumb (6,000 mg/m2 [0.02 oz/ft2]) where lake trout dominated and lower in South Arm (3,160 mg/m2 [0.01 oz/ ft2]) where cutthroat trout dominated (p = 0.01). Additionally, individual body mass of Gammarus was greater in West Thumb (1.6 mg/individual [0.000056 oz/individual]) than in South Arm (1.1 mg/individual [0.000039 oz/individual; p = 0.01). Our results suggest that lake trout predation on cutthroat trout indirectly reduced predation on Gammarus in West Thumb, leading to a relative increase in the local Gammarus biomass and body mass. Monitoring the benthos of Yellowstone Lake may allow managers to understand the food web dynamics at higher trophic level.

Yellowstone’s Wildlife in Transition

Author : P. J. White
Publisher : Harvard University Press
ISBN 13 : 0674076435
Total Pages : 321 pages
Book Rating : 4.6/5 (74 download)

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Book Synopsis Yellowstone’s Wildlife in Transition by : P. J. White

Download or read book Yellowstone’s Wildlife in Transition written by P. J. White and published by Harvard University Press. This book was released on 2013-04-15 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world's first national park, Yellowstone is a symbol of nature's enduring majesty and the paradigm of protected areas across the globe. But Yellowstone is constantly changing. How we understand and respond to events that are putting species under stress, say the authors of Yellowstone's Wildlife in Transition, will determine the future of ecosystems that were millions of years in the making. With a foreword by the renowned naturalist E. O. Wilson, this is the most comprehensive survey of research on North America's flagship national park available today. Marshaling the expertise of over thirty contributors, Yellowstone's Wildlife in Transition examines the diverse changes to the park's ecology in recent decades. Since its creation in the 1870s, the priorities governing Yellowstone have evolved, from intensive management designed to protect and propagate depleted large-bodied mammals to an approach focused on restoration and preservation of ecological processes. Recognizing the importance of natural occurrences such as fires and predation, this more ecologically informed oversight has achieved notable successes, including the recovery of threatened native species of wolves, bald eagles, and grizzly bears. Nevertheless, these experts detect worrying signs of a system under strain. They identify three overriding stressors: invasive species, private-sector development of unprotected lands, and a warming climate. Their concluding recommendations will shape the twenty-first-century discussion over how to confront these challenges, not only in American parks but for conservation areas worldwide. Highly readable and fully illustrated, Yellowstone's Wildlife in Transition will be welcomed by ecologists and nature enthusiasts alike.

Dynamics of Yellowstone Cutthroat Trout and Lake Trout in the Yellowstone Lake Ecosystem

Author : John Michael Syslo
Publisher :
ISBN 13 :
Total Pages : 154 pages
Book Rating : 4.:/5 (926 download)

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Book Synopsis Dynamics of Yellowstone Cutthroat Trout and Lake Trout in the Yellowstone Lake Ecosystem by : John Michael Syslo

Download or read book Dynamics of Yellowstone Cutthroat Trout and Lake Trout in the Yellowstone Lake Ecosystem written by John Michael Syslo and published by . This book was released on 2015 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: The introduction of lake trout Salvelinus namaycush into Yellowstone Lake preceded the collapse of the native Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri population. As a system with a simple fish assemblage and several long-term data sets, Yellowstone Lake provided a unique opportunity to evaluate the ecology of a native salmonid in the presence of a non-native salmonid population undergoing suppression in a large natural lake. Diet data for Yellowstone cutthroat trout and lake trout were evaluated at varying densities to determine the effects of density on diet composition. Temporal diet shifts from 1996-1999 to 2011-2013 were likely caused by limitation of prey fish for lake trout. Diets, stable isotopes, and depth-related patterns in CPUE indicated lake trout> 300 mm consumed primarily amphipods, making them trophically similar to Yellowstone cutthroat trout from during 2011-2013. A lake trout removal program was initiated during 1995 to reduce predation on Yellowstone cutthroat trout. Abundance and fishing mortality were estimated for lake trout from 1998 through 2013 and Yellowstone cutthroat trout from 1986 through 2013. Density-dependence was evaluated by examining individual growth, weight, maturity, and pre-recruit survival as a function of abundance. In addition, a simulation model was developed for the lake trout- Yellowstone cutthroat trout system to determine the probability of Yellowstone cutthroat trout abundance persisting at performance metrics given potential reductions in lake trout abundance. Estimates of Yellowstone cutthroat trout abundance varied 5-fold and lake trout abundance varied 6-fold. Yellowstone cutthroat trout weight and pre-recruit survival decreased with increasing Yellowstone cutthroat trout abundance; however, individual growth and maturity were not related to abundance. Lake trout population metrics did not vary with lake trout abundance. Simulation model results were variable because of uncertainty in lake trout pre-recruit survival. Conservative estimates for required lake trout reductions were> 97% of 2013 abundance for a> 70% probability of Yellowstone cutthroat trout persistence at the performance metrics outlined in the Native Fish Conservation Plan. Lake trout removal will likely reduce lake trout abundance and result in Yellowstone cutthroat trout recovery if the amount of fishing effort exerted in 2013 is maintained for at least 15 years.

The Lake Charr Salvelinus namaycush: Biology, Ecology, Distribution, and Management

Author : Andrew M. Muir
Publisher : Springer Nature
ISBN 13 : 3030622592
Total Pages : 526 pages
Book Rating : 4.0/5 (36 download)

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Book Synopsis The Lake Charr Salvelinus namaycush: Biology, Ecology, Distribution, and Management by : Andrew M. Muir

Download or read book The Lake Charr Salvelinus namaycush: Biology, Ecology, Distribution, and Management written by Andrew M. Muir and published by Springer Nature. This book was released on 2021-03-03 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lake charr Salvelinus namaycush is a ubiquitous member of cold-water lake ecosystems in previously glaciated regions of northern continental U.S., Alaska, and Canada that often support important commercial, recreational, and subsistence fisheries. The lake charr differs from other charrs by its large size, longevity, iteroparity, top-predator specialization, reduced sexual dimorphism, prevalence of lacustrine spawning, and use of deepwater habitat. The species is remarkably variable in phenotype, physiology, and life history, some of which is reflected in its ecology and genetics, with as many as four morphs or ecotypes co-occurring in a single lake. The lake charr is often the top predator in these systems, but is highly adaptable trophically, and is frequently planktivorous in small lakes. The lake charr by their name highlights their common habitat, lakes both large and small, but often frequents rivers and occasionally moves into the Arctic Ocean. Movement and behaviour of lake charr are motivated by access to cool, well-oxygenated water, foraging opportunities, predator avoidance, and reproduction. Owing to their broad distribution and trophic level, the lake charr serves as a sentinel of anthropogenic change. This volume will provide an up-to-date summary of what is currently known about lake charr from distribution to genetics to physiology to ecology. The book provides a compilation and synthesis of available information on the lake charr, beginning with an updated distribution and a revised treatment of the paleoecology of the species. Understanding of ecological and genetic diversity and movement and behaviour of the species has advanced remarkably since the last major synthesis on the species over 40 years ago. Mid-sections of the book provide detailed accounts of the biology and life history of the species, and later sections are devoted to threats to conservation and fishery management practices used to ensure sustainability. A new standard lake charr-specific terminology is also presented. The book will be a valuable reference text for biologists around the world, ecologists, and fishery managers, and of interest to the angling public.

Life-history Trait Shifts in Daphnia Pulicaria in Yellowstone Lake Following the Introduction of Lake Trout

Author : Tonya E. Anderson
Publisher :
ISBN 13 : 9781303711916
Total Pages : 26 pages
Book Rating : 4.7/5 (119 download)

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Book Synopsis Life-history Trait Shifts in Daphnia Pulicaria in Yellowstone Lake Following the Introduction of Lake Trout by : Tonya E. Anderson

Download or read book Life-history Trait Shifts in Daphnia Pulicaria in Yellowstone Lake Following the Introduction of Lake Trout written by Tonya E. Anderson and published by . This book was released on 2013 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent invasion (late 1980s) of piscivorous lake trout into Yellowstone Lake, WY, caused large changes in the aquatic community. For example, lake trout added a fourth trophic level to the food web thereby causing large declines in the population size of Yellowstone cutthroat trout, the primary food source of adult lake trout. Daphnia pulicaria is the second most abundant species of zooplankton in the lake, and the main prey item for native Yellowstone cutthroat trout. I compared D. pulicaria body size, clutch size, egg size, and probability of reproducing from archived Yellowstone National Park samples collected prior to lake trout invasion (1977-1981) to zooplankton samples collected post-invasion (2004 and 2008). Before lake trout were introduced, D. pulicaria matured at a smaller body size and carried larger clutches of smaller eggs. With these data, I cannot distinguish among several possible mechanisms for changes in life history traits, including rapid evolution due to reduced size-selective predation by cutthroat trout and adaptive or non-adaptive phenotypic plasticity. However, our results suggest that the introduction of lake trout and the subsequent changes that they caused in Yellowstone Lake have altered the life-history traits of D. pulicaria. While direct effects of invasions are often studied, indirect effects on lower trophic levels may have significant consequences for community composition and ecosystem function, but are rarely studied.

Migrate, Mutate, Or Die

Author : Sarah Gandhi-Besbes
Publisher :
ISBN 13 :
Total Pages : 51 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Migrate, Mutate, Or Die by : Sarah Gandhi-Besbes

Download or read book Migrate, Mutate, Or Die written by Sarah Gandhi-Besbes and published by . This book was released on 2016 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: Yellowstone National Park is a relatively pristine ecosystem preserved through time. The Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri population, inhabiting shallower waters in Yellowstone Lake and spawning in its tributaries, has been declining primarily due to the introduction of a predatory fish. The lake trout Salvelinus namaycush, which rapidly grow to large sizes, feed on the Yellowstone cutthroat trout, breed and spawn in Yellowstone Lake, and dwell in deeper waters out of predatory reach. The Yellowstone cutthroat trout is relied upon both directly and indirectly by more than 40 species within Yellowstone National Park. The grizzly bear Ursus arctos horribilis, bald eagle Haliaeetus leucocephalus, and osprey Pandion halaetus all feed directly on the spawning fish. This study looks at how the declining Yellowstone cutthroat trout populations affect these predatory populations, and what their populations may look like should current trends continue into the year 2030. Conducting a meta-analysis and collecting primary data allowed for statistical projections predicting and comparing estimated future populations. The ecological change in Yellowstone Lake provides insight into how the concerns of one ecosystem affects multiple.

Predatory Fish Invasion Induces Within and Across Ecosystem Effects in Yellowstone National Park

Author : Todd M. Koel
Publisher :
ISBN 13 :
Total Pages : 11 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Predatory Fish Invasion Induces Within and Across Ecosystem Effects in Yellowstone National Park by : Todd M. Koel

Download or read book Predatory Fish Invasion Induces Within and Across Ecosystem Effects in Yellowstone National Park written by Todd M. Koel and published by . This book was released on 2019 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Predatory fish introduction can cause cascading changes within recipient freshwater ecosystems. Linkages to avian and terrestrial food webs may occur, but effects are thought to attenuate across ecosystem boundaries. Using data spanning more than four decades (1972?2017), we demonstrate that lake trout invasion of Yellowstone Lake added a novel, piscivorous trophic level resulting in a precipitous decline of prey fish, including Yellowstone cutthroat trout. Plankton assemblages within the lake were altered, and nutrient transport to tributary streams was reduced. Effects across the aquatic-terrestrial ecosystem boundary remained strong (log response ratio ? 1.07) as grizzly bears and black bears necessarily sought alternative foods. Nest density and success of ospreys greatly declined. Bald eagles shifted their diet to compensate for the cutthroat trout loss. These interactions across multiple trophic levels both within and outside of the invaded lake highlight the potential substantial influence of an introduced predatory fish on otherwise pristine ecosystems.

Relative Contributions of Climate Variation, Lake Trout Predation, and Other Factors to the Decline of Yellowstone Lake Cutthroat Trout During the Three Recent Decades

Download Relative Contributions of Climate Variation, Lake Trout Predation, and Other Factors to the Decline of Yellowstone Lake Cutthroat Trout During the Three Recent Decades PDF Online Free

Author : Lynn Robert Kaeding
Publisher :
ISBN 13 :
Total Pages : 200 pages
Book Rating : 4.:/5 (714 download)

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Book Synopsis Relative Contributions of Climate Variation, Lake Trout Predation, and Other Factors to the Decline of Yellowstone Lake Cutthroat Trout During the Three Recent Decades by : Lynn Robert Kaeding

Download or read book Relative Contributions of Climate Variation, Lake Trout Predation, and Other Factors to the Decline of Yellowstone Lake Cutthroat Trout During the Three Recent Decades written by Lynn Robert Kaeding and published by . This book was released on 2010 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: The relative contributions of climate variation, lake trout Salvelinus namaycush predation, and other factors to the recent, three-decade decline of the lacustrine-adfluvial (i.e., a life-history form consisting of fish that mostly live in a lake but spawn in an inflowing tributary) Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri (YCT) population of Clear Creek, a Yellowstone Lake tributary, were evaluated. Strong growth of that population's storied spawning run between the early 1960s and 1978, when the run peaked at about 70,000 fish, had been considered key evidence of recovery of the lake's YCT population from formerly excessive angler harvest and other adverse factors. Thus the run's subsequent, almost continuous decline to about 500 fish in 2007 was perplexing. Gillnet catches of YCT at established lake locations likewise indicated a concurrent decline in the lake-wide YCT population. Prominent among the factors that may have importantly affected the YCT population during the recent decades was predation by the illegally introduced, reproducing, nonnative lake trout discovered in Yellowstone Lake in 1994. Data mainly taken from YCT in the spawning run (n = 29 years) and gillnet catch (n = 30 years) were examined for information useful to specifying the Leslie matrix of a dynamic, age-structured model that had climate as a covariate. The model, fitted to spawning run size and mean total length (TL) of YCT in the run during 1977-2007 (n = 29 data years), explained 87% of variation in observed run size, 86% of variation in observed mean TL, and strongly suggested that climate (as indexed by total-annual air degree-days> 0°C measured on the lake's north shore) had an important effect on recruitment of age-0 YCT to subsequent spawning runs. Results also suggested that an effect of lake trout predation on survival of age-1 to age-5 YCT became apparent only during the recent decade. The important test of ongoing efforts to control lake trout in Yellowstone Lake and thereby limit their predation on YCT - on the basis of data for YCT - will occur when climatic conditions improve for YCT recruitment to the Clear Creek and other YCT spawning stocks of the lake.

Demography of Lake Trout in Relation to Population Suppression in Yellowstone Lake, Yellowstone National Park

Author : John Michael Syslo
Publisher :
ISBN 13 :
Total Pages : 208 pages
Book Rating : 4.:/5 (651 download)

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Book Synopsis Demography of Lake Trout in Relation to Population Suppression in Yellowstone Lake, Yellowstone National Park by : John Michael Syslo

Download or read book Demography of Lake Trout in Relation to Population Suppression in Yellowstone Lake, Yellowstone National Park written by John Michael Syslo and published by . This book was released on 2010 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduced lake trout Salvelinus namaycush threaten to extirpate native Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri in Yellowstone Lake, Yellowstone National Park. Suppression of the lake trout population is deemed necessary for the conservation of Yellowstone cutthroat trout. A National Park Service gill netting program removed nearly 273,000 lake trout from Yellowstone Lake between 1995 and 2007. Lake trout population size has not been estimated; therefore, it is difficult to determine the efficacy of the program (i.e., proportion of the population that has been removed). My objectives were to (1) examine catch per unit effort (C/f) through time and catch as a function of effort to determine if the suppression program has caused lake trout abundance to decline, (2) determine if length structure, age structure, individual growth, mortality, body condition, length at maturity, age at maturity, and fecundity have changed as a function of harvest, and (3) develop age-structured models to determine the level of mortality required to cause population growth rate to decline below 1.0 (replacement). An increase in lake trout abundance was indicated by increasing C/f over time. Additionally, catch has continued to increase as a function of effort, indicating lake trout abundance is increasing. Population metrics were not clearly indicative of a response to harvest. However, metrics were comparable to North American lake trout populations where harvest has occurred, indicating that lake trout have not reached carrying capacity in Yellowstone Lake. Results from an age-structured matrix model determined the rate of population growth was 1.1 given the current rate of fishing mortality and that population growth rate would be 1.3 in the absence of fishing mortality. The current rate of population growth is positive; however, it is slower than it would be in the absence of lake trout suppression. Fishing mortality needs to increase from the rate of 0.22 estimated in 2007 to at least 0.32 to reduce population growth rate below replacement. Lake trout suppression is becoming an increasingly common management practice throughout the Intermountain West. Thus, Yellowstone Lake provides a case study for evaluating a strategy to remove the apex predator from a large lake.

Yellowstone Fishes

Author : John D. Varley
Publisher : Stackpole Books
ISBN 13 : 9780811727778
Total Pages : 170 pages
Book Rating : 4.7/5 (277 download)

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Book Synopsis Yellowstone Fishes by : John D. Varley

Download or read book Yellowstone Fishes written by John D. Varley and published by Stackpole Books. This book was released on 1998 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: This richly illustrated and thoroughly researched reference covers all the species of fish and every aspect of their existence in one of the most famous sport fisheries in the world. This edition includes new material on the impact of forest fires and the introduction of non-native species; an expanded chapter on angling; and an assessment of recent management policies. Full color plates and historic b&w photos.

Introduced Lake Trout Alter Nitrogen Cycling Beyond Yellowstone Lake

Author : Lusha Marguerite Tronstad
Publisher :
ISBN 13 :
Total Pages : 24 pages
Book Rating : 4.:/5 (13 download)

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Book Synopsis Introduced Lake Trout Alter Nitrogen Cycling Beyond Yellowstone Lake by : Lusha Marguerite Tronstad

Download or read book Introduced Lake Trout Alter Nitrogen Cycling Beyond Yellowstone Lake written by Lusha Marguerite Tronstad and published by . This book was released on 2015 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: Introduced predators can have large effects on the ecosystem in which they were introduced, but how much these effects extend to other ecosystems beyond the invaded one is less known. We compared how lake trout (Salvelinus namaycush) affected nutrient cycling in an invaded and adjacent ecosystem in Yellowstone National Park, Wyoming, USA. Introduced lake trout in Yellowstone Lake caused the native Yellowstone cutthroat trout (Oncoryhynchus clarkii bouvieri) population to decline. Native cutthroat trout are a dominant animal in the lake and may alter nutrient cycling in both Yellowstone Lake where they reside and in tributary streams used for spawning. We estimated changes in nutrient transport and nutrient uptake in both Yellowstone Lake and Clear Creek, a spawning stream, before and after the invasion of lake trout. Annual area-specific excretion fluxes from cutthroat trout were nine times higher in Clear Creek compared to Yellowstone Lake when cutthroat trout were abundant. However, fluxes within the lake and stream were similar after cutthroat trout declined. In Yellowstone Lake, zooplankton excretion supplied 86% of ammonium (NH4+) that was taken up, but cutthroat trout only supplied 0.3% after the introduction of lake trout. Conversely, NH4+ excreted by cutthroat trout was likely a major flux in Clear Creek, because NH4+ fluxes from cutthroat trout exceeded watershed export of NH4+ in years when 3000 cutthroat trout spawned. Furthermore, NH4+ excretion fluxes from spawning cutthroat trout in Clear Creek supplied up to 6.1% of the NH4+ demanded by microbes after the introduction of lake trout. However, based on modeled past NH4+ uptake, we estimated that up to 60% of NH4+ excreted by spawning cutthroat trout may have been taken up by stream microbes when cutthroat trout were abundant. Therefore, transported NH4+ from spawning cutthroat trout was likely an integral part of N cycling in tributary streams in the past. By comparing the effects of declining cutthroat trout on two ecosystems, we show that lake trout had a larger effect on N cycling within an adjacent stream ecosystem than the invaded lake ecosystem itself, because the migratory behavior of cutthroat trout concentrated them in spawning streams increasing their effect.

Ecology of North American Freshwater Fishes

Author : Stephen T. Ross Ph. D.
Publisher : Univ of California Press
ISBN 13 : 0520955196
Total Pages : 473 pages
Book Rating : 4.5/5 (29 download)

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Book Synopsis Ecology of North American Freshwater Fishes by : Stephen T. Ross Ph. D.

Download or read book Ecology of North American Freshwater Fishes written by Stephen T. Ross Ph. D. and published by Univ of California Press. This book was released on 2013-06-01 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: The North American freshwater fish fauna is the most diverse and thoroughly researched temperate fish fauna in the world. Ecology of North American Freshwater Fishes is the only textbook to provide advanced undergraduate and graduate students and researchers with an up-to-date and integrated view of the ecological and evolutionary concepts, principles, and processes involved in the formation and maintenance of this fauna. Ecology of North American Freshwater Fishes provides readers with a broad understanding of why specific species and assemblages occur in particular places. Additionally, the text explores how individuals and species interact with each other and with their environments, how such interactions have been altered by anthropogenic impacts, and the relative success of efforts to restore damaged ecosystems. This book is designed for use in courses related to aquatic and fish ecology, fish biology, ichthyology, and related advanced ecology and conservation courses, and is divided into five sections for ease of use. Chapter summaries, supplemental reading lists, online sources, extensive figures, and color photography are included to guide readers through the material and facilitate student learning. Part 1: Faunal origins, evolution, and diversity Presents a broad picture—both spatially and temporally—of the derivation of the fauna, including global and regional geological and climatological processes and their effects on North American fishes. Part 2: Formation, maintenance, and persistence of local populations and assemblages Focuses on how local fish populations and assemblages are formed and how they persist, or not, through time. Part 3: Form and function Deals with the relationship of body form and life history patterns as they are related to ecological functions. Part 4: Interactions among individuals and species Discusses the numerous interactions among individuals and species through communication, competition, predation, mutualism, and facilitation. Part 5: Issues in conservation Focuses on several primary conservation issues such as flow alterations and the increasing biotic homogenization of faunas.

Marine Ecosystems

Author : Tasman P. Crowe
Publisher : Cambridge University Press
ISBN 13 : 1316368378
Total Pages : 409 pages
Book Rating : 4.3/5 (163 download)

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Book Synopsis Marine Ecosystems by : Tasman P. Crowe

Download or read book Marine Ecosystems written by Tasman P. Crowe and published by Cambridge University Press. This book was released on 2015-06-18 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecosystem services are emerging as a key driver of conservation policy and environmental management. Delivery of ecosystem services depends on the efficient functioning of ecosystems, which in turn depends on biodiversity and environmental conditions. Many marine ecosystems are extremely productive and highly valued, but they are increasingly threatened by human activities. With contributions from leading researchers, this volume synthesises current understanding of the effects on biodiversity and ecosystem functioning caused by a variety of human activities and pressures at play in coastal marine ecosystems. The authors examine the likely consequences for ecosystem service provision, covering key topics including fisheries, aquaculture, physical structures, nutrients, chemical contaminants, marine debris and invasive species. Critically reviewing the latest developments, this is a unique resource both for environmental managers and policy-makers, and for researchers and students in marine ecology and environmental management.