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
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Author : Lusha Marguerite Tronstad
language : en
Publisher:
Release Date : 2010
Introduced Lake Trout Produced A Four Level Trophic Cascade In Yellowstone Lake written by Lusha Marguerite Tronstad and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with Cutthroat trout categories.
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
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Author : John M. Syslo
language : en
Publisher:
Release Date : 2016
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 has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Cutthroat trout categories.
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 Introduced Lake Trout On Native Cutthroat Trout In Yellowstone Lake
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Author : James R. Ruzycki
language : en
Publisher:
Release Date : 2003
Effects Of Introduced Lake Trout On Native Cutthroat Trout In Yellowstone Lake written by James R. Ruzycki and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2003 with Yellowstone Lake (Wyo.) categories.
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.
Effects Of Lake Trout Suppression Methods On Lower Trophic Levels In Yellowstone Lake Wyoming
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Author : Dominique Raquel Lujan
language : en
Publisher:
Release Date : 2020
Effects Of Lake Trout Suppression Methods On Lower Trophic Levels In Yellowstone Lake Wyoming written by Dominique Raquel Lujan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Cutthroat trout categories.
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.
Yellowstone S Wildlife In Transition
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Author : P. J. White
language : en
Publisher: Harvard University Press
Release Date : 2013-04-01
Yellowstone S Wildlife In Transition written by P. J. White and has been published by Harvard University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-04-01 with Nature categories.
The world's first national park is constantly changing. How we understand and respond to recent events putting species under stress will determine the future of ecosystems millions of years in the making. Marshaling expertise from over 30 contributors, Yellowstone's Wildlife in Transition examines three primary challenges to the park's ecology.
The Lake Charr Salvelinus Namaycush Biology Ecology Distribution And Management
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Author : Andrew M. Muir
language : en
Publisher: Springer Nature
Release Date : 2021-03-03
The Lake Charr Salvelinus Namaycush Biology Ecology Distribution And Management written by Andrew M. Muir and has been published by Springer Nature this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-03-03 with Science categories.
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.
Lake Trout Induced Spatial Variation In The Benthic Invertebrates Of Yellowstone Lake Invasive Lake Trout Indirectly Increased Biomass And Body Mass Of Amphipods
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Author : Oliver Wilmot
language : en
Publisher:
Release Date : 2016
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 has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with Diet categories.
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.
Ecology Of North American Freshwater Fishes
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Author : Stephen T. Ross Ph. D.
language : en
Publisher: Univ of California Press
Release Date : 2013-06-01
Ecology Of North American Freshwater Fishes written by Stephen T. Ross Ph. D. and has been published by Univ of California Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-06-01 with Science categories.
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 Macrophytes As Foundation Species
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Author : Emil Olafsson
language : en
Publisher: CRC Press
Release Date : 2016-11-25
Marine Macrophytes As Foundation Species written by Emil Olafsson and has been published by CRC Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016-11-25 with Nature categories.
Marine macrophytes (macroalgae, seagrasses, and mangroves) comprise thousands of species distributed in shallow water areas along the world’s coastlines. They play a key role in marine ecosystems regarding biodiversity and energy flow. A large proportion of macrophyte species can be characterised as ecosystem engineers—organisms that directly or indirectly affect the availability of resources to other species by modifying, maintaining, and creating habitats. This book is divided into three main themes: • Marine macroalgae and seagrasses as sources of biodiversity gives an overview of the diversity of the main organisms associated with macrophytes, and their functional role and interactions within their hosts. • Primary and secondary production of Macrophytes synthesizes research on food web structures derived from/or associated with, macrophytes and the transfer of macrophytic primary and secondary production from one ecosystem to another. • Threats to macrophytic ecosystem engineers addresses human-induced effects including eutrophication, physical destruction, invasive species, and global warming. The book is among the first one to concentrate on the value of macrophytes for the well-being of marine habitats. The book is aimed at academics but may be useful for students, policy makers, and laymen alike.
Dynamics Of Yellowstone Cutthroat Trout And Lake Trout In The Yellowstone Lake Ecosystem
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Author : John Michael Syslo
language : en
Publisher:
Release Date : 2015
Dynamics Of Yellowstone Cutthroat Trout And Lake Trout In The Yellowstone Lake Ecosystem written by John Michael Syslo and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Introduced fishes categories.
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.