Academic literature on the topic 'Large predators'

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Journal articles on the topic "Large predators"

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Omkar, Geetanjali Mishra, Bhupendra Kumar, Neha Singh, and Garima Pandey. "Risks associated with tandem release of large and small ladybirds (Coleoptera: Coccinellidae) in heterospecific aphidophagous guilds." Canadian Entomologist 146, no. 1 (2013): 52–66. http://dx.doi.org/10.4039/tce.2013.56.

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AbstractMultiple interactions occurring within aphidophagous guilds determine their final predation outcomes, i.e., antagonistic, additive, or synergistic. Based on these predatory outcomes, the suitability of guilds in suppressing aphid pests is determined. The present study assesses the efficacy of 11 guilds, formed from both larval and adult stages of four locally abundant aphidophagous coccinellids (Coleoptera: Coccinellidae), while exploiting the pea aphid, Acyrthosiphon pisum Harris (Hemiptera: Aphididae). The observed antagonistic effects within these guilds are resultants of enhanced predator–predator interactions due to the size and diversity of guild predators. Smaller ladybird predators maintained their usual body mass, probably by increasing their conversion efficiencies to compensate for their reduced prey consumption. However, larger ladybirds reported loss in their body mass, owing to their higher energy needs. The overall guild conversion efficiencies and growth rates were reduced. Among the experimental guilds, the observed prey mortalities were relatively higher in two-predator guilds, and within these two-predator combinations, the higher prey mortalities were recorded in those guilds where Coccinella septempunctata was one of the predators.
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Ortiz, Esteban, Rodrigo Ramos-Jiliberto, and Matías Arim. "Prey selection along a predators’ body size gradient evidences the role of different trait-based mechanisms in food web organization." PLOS ONE 18, no. 10 (2023): e0292374. http://dx.doi.org/10.1371/journal.pone.0292374.

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An increase in prey richness, prey size and predator trophic position with predator body size has been consistently reported as prime features of food web organization. These trends have been explained by non-exclusive mechanisms. First, the increase in energy demand with body size determines that larger predators must reduce prey selectivity for achieving the required number of resources, being consumption relationships independent of prey traits. Second, when consumption is restricted by gape limitation, small predators are constrained to select among small prey. However, this selection weakens over large predators, which progressively consume more and larger prey. Finally, the optimal foraging mechanism predicts that larger predators optimize their diet by selecting only large prey with high energy reward. Each one of these mechanisms can individually explain the increase in prey richness, prey size and predator trophic position with predator body size but their relative importance or the direct evidence for their combined role was seldom considered. Here we use the community assembly by trait selection (CATS) theory for evaluating the support for each one of these mechanisms based on the prey selection patterns that they predict. We analyzed how prey body size and trophic guild determine prey selection by predators of increasing body size in a killifish guild from a temporary pond system. Results support the combination of the three mechanisms to explain the structural trends in our food web, although their strength is contingent on prey trophic group. Overall, high energy prey are preferred by larger predators, and small predators select small prey of all trophic status. However, large predators prefer large primary producers and avoid large carnivorous prey, probably because of the inherent risk of consuming other carnivorous. Our study provides a mechanistic understanding of how predator traits determine the selection of prey traits affecting food web assembly.
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Thorp, Corey J., Mhairi E. Alexander, James R. Vonesh, and John Measey. "Size-dependent functional response of Xenopus laevis feeding on mosquito larvae." PeerJ 6 (October 26, 2018): e5813. http://dx.doi.org/10.7717/peerj.5813.

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Predators can play an important role in regulating prey abundance and diversity, determining food web structure and function, and contributing to important ecosystem services, including the regulation of agricultural pests and disease vectors. Thus, the ability to predict predator impact on prey is an important goal in ecology. Often, predators of the same species are assumed to be functionally equivalent, despite considerable individual variation in predator traits known to be important for shaping predator–prey interactions, like body size. This assumption may greatly oversimplify our understanding of within-species functional diversity and undermine our ability to predict predator effects on prey. Here, we examine the degree to which predator–prey interactions are functionally homogenous across a natural range of predator body sizes. Specifically, we quantify the size-dependence of the functional response of African clawed frogs (Xenopus laevis) preying on mosquito larvae (Culex pipiens). Three size classes of predators, small (15–30 mm snout-vent length), medium (50–60 mm) and large (105–120 mm), were presented with five densities of prey to determine functional response type and to estimate search efficiency and handling time parameters generated from the models. The results of mesocosm experiments showed that type of functional response of X. laevis changed with size: small predators exhibited a Type II response, while medium and large predators exhibited Type III responses. Functional response data showed an inversely proportional relationship between predator attack rate and predator size. Small and medium predators had highest and lowest handling time, respectively. The change in functional response with the size of predator suggests that predators with overlapping cohorts may have a dynamic impact on prey populations. Therefore, predicting the functional response of a single size-matched predator in an experiment may misrepresent the predator’s potential impact on a prey population.
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Olson, AM, A. Frid, JBQ dos Santos, and F. Juanes. "Trophic position scales positively with body size within but not among four species of rocky reef predators." Marine Ecology Progress Series 640 (April 23, 2020): 189–200. http://dx.doi.org/10.3354/meps13275.

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Intra- and interspecifically, larger-bodied predators generally occupy higher trophic positions (TPs). With widespread declines in large predators, there is a need to understand their size-based trophic roles to predict ecosystem-level responses. In British Columbia, Canada, we examined size-based trophic interactions between predatory fishes—3 rockfish species (genus Sebastes) and lingcod Ophiodon elongatus—and their prey, converting predator δ15N signatures to TP and analyzing stomach contents. Intraspecifically, TP scaled positively with predator length and gape width, but the rates of change varied by species. Interspecifically, TP did not scale positively with the observed mean sizes or known maximum sizes of species. Lingcod TP was lower than that of yelloweye and quillback rockfishes, which were 51 and 37%, respectively, smaller than lingcod. Yellowtail rockfish had the smallest average size, yet their mean TP did not differ significantly from that of lingcod. Neither species differences in some morphometric traits known to influence body size-TP relationships nor phylogenetic history explained these results. Most prey consumed were <20% of the predator’s size, which might partially explain the lack of a size-based trophic hierarchy among species. Currently, large size classes of rockfishes are being lost due to fisheries and perhaps climate-driven changes. Our findings on intraspecific size-TP relationships indicate that fishery removals of large individuals may diminish trophic structures. Interspecific comparisons of TP suggest that, along with size, species remain an important factor in understanding trophic dynamics. In addition, smaller-bodied predator species may have significant ecological roles to be considered in ecosystem-based fisheries management.
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Mislan, K. A. S., and Russ C. Babcock. "Survival and behaviour of juvenile red rock lobster, Jasus edwardsii, on rocky reefs with varying predation pressure and habitat complexity." Marine and Freshwater Research 59, no. 3 (2008): 246. http://dx.doi.org/10.1071/mf07116.

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The role of large predatory fish in coastal communities is generally unknown because of overfishing. In order to understand the direct and indirect impacts of these increased population sizes on coastal food chains, the effect of areas with more fish predators on the survival and behaviour of potential prey was assessed. Juvenile lobsters, Jasus edwardsii (10–20 mm carapace length), were tethered on rocky reefs inside and outside marine reserves in northeastern New Zealand to assess survival under differing predator densities. Since rocky reef habitats in northeastern New Zealand include zones of kelp forest and barren reef, a two-way factorial design was used to determine the effects of predators, habitat, and the interaction of these two factors on juvenile lobster survival. Overall, the results indicated that neither varying large fish density nor varying kelp density had direct impacts on the survival rate of juvenile lobsters. Laboratory manipulations demonstrated behavioural changes by juvenile lobsters such that when a large predatory fish was present, juvenile lobsters spent significantly less time moving, even when separated from the predator by a porous barrier. Thus areas with more fish predators may increase juvenile lobster survival but potentially at the cost of reduced feeding opportunities.
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Weissburg, Marc, and Jeffrey Beauvais. "The smell of success: the amount of prey consumed by predators determines the strength and range of cascading non-consumptive effects." PeerJ 3 (November 19, 2015): e1426. http://dx.doi.org/10.7717/peerj.1426.

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We examined whether chemically mediated risk perception by prey and the effects of changes in prey behavior on basal resources vary as a function of the amount of prey biomass consumed by the predator. We studied these issues using a tritrophic system composed of blue crabs,Callinectes sapidus(top predator), mud crabsPanopeus herbstii(intermediate prey), and oystersCrassostrea virginica(basal resource). Working in a well characterized field environment where experiments preserve natural patterns of water flow, we found that biomass consumed by a predator determines the range, intensity and nature of prey aversive responses. Predators that consume large amounts of prey flesh more strongly diminish consumption of basal resources by prey and exert effects over a larger range (in space and time) compared to predators that have eaten less. Less well-fed predators produce weaker effects, with the consequence that behaviorally mediated cascades preferentially occur in refuge habitats. Well-fed predators affected prey behavior and increased basal resources up to distances of 1–1.5 m, whereas predators fed restricted diet evoked changes in prey only when they were extremely close, typically 50 cm or less. Thus, consumptive and non-consumptive effects may be coupled; predators that have a greater degree of predatory success will affect prey traits more strongly and non-consumptive and consumptive effects may fluctuate in tandem, with some lag. Moreover, differences among predators in their degree of prey capture will create spatial and temporal variance in risk cue availability in the absence of underlying environmental effects.
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L.A., Escudero-Colomar, Creus E., Chorąży A., and Walzer A. "Intraguild aggressiveness between an alien and a native predatory mite." Systematic and Applied Acarology 24, no. 11 (2019): 2094–105. http://dx.doi.org/10.11158/saa.24.11.5.

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The predatory mite Amblydromalus limonicus, non-native in Europe, can be used legally in several European countries as greenhouse biocontrol agent against thrips species, although this species is also able to feed on whiteflies and gall mites. The first record of the unintended occurrence of A. limonicus in apple orchards in Europe comes from Catalonia (Spain), where A. limonicus is well established in the native predatory mite community since 2011. The dominant species in this community is Amblyseius andersoni, which has a similar life-style as A. limonicus (large, aggressive predator with broad diet range) making intraguild (IG) interactions between the two predators likely. Thus, we tested the IG aggressiveness of native and alien female predators, when provided with IG prey (larvae). Alien females of A. limonicus proved to be highly aggressive IG predators against native larvae of A. andersoni, which were attacked earlier and more frequently than alien larvae by the native predator. Nearly all attacks by the alien predator resulted in the death of native IG prey, whereas about 10% of the alien intraguild prey escaped the attacks of the native predator. Additionally, native IG prey is smaller than alien prey, which should facilitate the overwhelming by the alien predator. We argue that the strong aggressive intraguild behavior of A. limonicus is contributing to its establishment success in the native predatory mite community.
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Vermeij, Geerat J. "Evolution in the Consumer Age: Predators and the History of Life." Paleontological Society Papers 8 (October 2002): 375–94. http://dx.doi.org/10.1017/s1089332600001169.

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Three properties of predation make this form of consumption an important agency of evolution: universality (all species have predators), high frequency (encounters of prey with predators test both parties often), and imperfection (many predatory attacks fail, enabling antipredatory selection to take place). On long time scales, predators have two principal effects: they influence their victims' phenotypes, and prey species that are highly vulnerable to all phases of predatory attacks are evolutionarily restricted to environments where predators are rarely encountered. Although predator and prey can affect each other's behavior and morphology on timescales commensurate with individual lifespans, predators have the evolutionary upper hand over the long run, especially in the expression of sensory capacities, locomotor performance, and the application of force. Only in passive defenses (armor, toxicity, large body size) does escalation favor the prey. In a review of methods for inferring predation in the geological past, I argue against the use of whole assemblages, which combine species of contrasting adaptive type, Instead, I strongly favor species-level and clade-level approaches (including examples of clade replacement) in which comparisons among places and among time intervals are made within the same adaptive types and the same physical environments. The available evidence, much of which comes from studies of shell drilling and shell breakage, points to temporal increases in both predator power and prey defenses. Escalation between species and their enemies, including predators, has proceeded episodically against a backdrop of generally increasing productivity and increasing top-down evolutionary control by high-energy predators during the Phanerozoic, the consumer age.
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Tscholl, Thomas, Gösta Nachman, Bernhard Spangl, Hanna Charlotte Serve, and Andreas Walzer. "Reproducing during Heat Waves: Influence of Juvenile and Adult Environment on Fecundity of a Pest Mite and Its Predator." Biology 12, no. 4 (2023): 554. http://dx.doi.org/10.3390/biology12040554.

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The thermal history of arthropod predators and their prey may affect their reproductive performance during heat waves. Thus, a matching juvenile and adult environment should be beneficial as it enables the individuals to acclimate to extreme conditions. Prey fecundity, however, is also affected by a second stressor, namely predation risk. Here, we assessed the impact of extreme and mild heat waves on the reproductive output of acclimated (juvenile and adult heat wave conditions are matching) and non-acclimated females of the biocontrol agent Phytoseiulus persimilis, a predatory mite, and its herbivorous prey, the two-spotted spider mite Tetranychus urticae, on bean leaves. Their escape and oviposition rates and egg sizes were recorded over 10 days. Additionally, ovipositing prey females were exposed to predator cues and heat waves. Acclimation changed the escape rates and egg sizes of both species, whereas fecundity was only influenced by the adult thermal environment via increased egg numbers under extreme heat waves. Acclimation reduced predator and prey escape rates, which were higher for the predator. Pooled over acclimation, both species deposited more but smaller eggs under extreme heat waves. Acclimation dampened this effect in prey eggs, whereas acclimation resulted in smaller female eggs of the predator. Prey deposited larger male and female eggs. Predator cues reduced prey oviposition, but the effect was small compared to the large increase gained under extreme heat waves. We argue that the success of predators in controlling spider mites during heat waves mainly depends on the fates of escaping predators. A permanent absence of predators may result in the numerical dominance of prey.
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Gallagher, Austin J., Simon J. Brandl, and Adrian C. Stier. "Intraspecific variation in body size does not alter the effects of mesopredators on prey." Royal Society Open Science 3, no. 12 (2016): 160414. http://dx.doi.org/10.1098/rsos.160414.

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As humans continue to alter the species composition and size structure of marine food webs, it is critical to understand size-dependent effects of predators on prey. Yet, how shifts in predator body size mediate the effect of predators is understudied in tropical marine ecosystems, where anthropogenic harvest has indirectly increased the density and size of small-bodied predators. Here, we combine field surveys and a laboratory feeding experiment in coral reef fish communities to show that small and large predators of the same species can have similar effects. Specifically, surveys show that the presence of a small predator ( Paracirrhites arcatus ) was correlated with lower chances of prey fish presence, but these correlations were independent of predator size. Experimental trials corroborated the size-independent effect of the predator; attack rates were indistinguishable between small and large predators, suggesting relatively even effects of hawkfish in various size classes on the same type of prey. Our results indicate that the effects of small predators on coral reefs can be size-independent, suggesting that variation in predator size-structure alone may not always affect the functional role of these predators.
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Dissertations / Theses on the topic "Large predators"

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Lourenço, Rui Nascimento Fazenda. "Predatory interactions among vertebrate top predators superpredation and intraguild predation by large raptors." Doctoral thesis, Universidade de Évora, 2011. http://hdl.handle.net/10174/14789.

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Nesta tese estudaram-se as interacções predatórias entre vertebrados predadores de topo (predação intraguilda e superpredação), utilizando quatro aves de rapina de grande porte como modelos de superpredadores: Bufo-real, Açor, Águia-real, e Águia de Bonelli. A superpredação em aves de rapina é um fenómeno abrangente, que pode variar entre espécies, e mais frequente em paisagens mais humanizadas. Os meso-predadores não são recursos energeticamente relevantes para as aves de rapina, e o seu consumo está associado à diversificação da dieta resultante da diminuição das presas habituais. A eliminação de competidores e potenciais predadores são outros factores que podem aumentar a frequência da superpredação. O aumento da percentagem de meso-predadores na dieta está associado a menor sucesso reprodutor e maiores níveis de acumulação de mercúrio nas aves de rapina. O risco de predação pode levar um meso-predador (Coruja-do-mato) a diminuir a sua actividade vocal de modo a estar menos exposto ao predador intraguilda; ABSTRACT: This thesis analyses predatory interactions among vertebrate top predadores (intraguild predation and superpredation), using four large raptors as superpredator models: eagle owl, goshawk, golden eagle and Bonelli's eagle. Superpredation in raptors is a widespread phenomenon, that can vary between species, and that is more frequent in human-altered landscapes. Mesopredators are not energetically relevant resources for raptors, and their consumption is related to diet diversification as a result of the decline of staple prey. Competitor and predator removal are additional factors that can cause an increase in superpredation rates. The increase of mesopredators in the diet of raptors is associated to lower breeding success and higher levels of mercury contamination. Predation risk can drive a mesopredator (tawny owl) to reduce its vocal activity in order to be less exposed to its intraguild predator.
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Vankeuren, Jody L. "Parasites Predators and Symbionts." Kent State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=kent1619475426952694.

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Shane, Keith Dennis. "Habitat-use and emigration patterns of two top predators stocked in a large flood-control impoundment." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1542722595138777.

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Crobe, Valentina <1989&gt. "Towards the conservation of vulnerable marine large predators: morphometric, molecular and microchemical variation of historical sawfish rostra from Mediterranean collections." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10177/1/PhD_Thesis_VCrobe_def040422.pdf.

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Sawfishes (Chondrichthyes, Pristidae) are considered one of the most endangered families among elasmobranchs. Extensive efforts are required worldwide to gather solid information on historical and recent changes in the composition/range of species. In this study, we have implemented an integrative approach to characterize the species diversity and the abundance of historical rostra of sawfishes from museums and private collections of the Mediterranean area. The identification at the species level of 172 dried rostra was carried out through the integration of both traditional and geometric morphometric techniques with molecular tools, allowing the assessment of a robust methodical approach to discriminate species. In addition, we analysed 35 rostral teeth to clarify the past distribution of sawfish species considering the isotopic composition of oxygen and carbon. The morphometric, molecular, and geographical characterization of samples was accompanied by the preliminary evaluation of growth structures and the inspection of the strontium isotope composition in two teeth to unravel movement patterns of individuals across different salinities of water. Results were integrated with currently available data from public repositories and showed that the historical specimens belonged to four nominal species: Pristis zijsron (81), Anoxypristis cuspidata (39), P. pristis (30), and P. pectinata (22). An identification error of 5.41% emerged in the morphological distinction of rostra between juvenile individuals of P. pectinata and P. zijsron. The new approach of carbon and oxygen isotopes, implemented for the first time in these taxa, permitted the identification of the high-probability habitat preferences of these benthopelagic elasmobranchs in about 50% of the analysed specimens. Using this multidisciplinary approach, we successfully assigned the numerous museum rostra with lacking data to a given species and identified their candidate geographical origin, retrieving novel information and data for understanding the species distribution and ecology of past, sometimes locally/regionally extinct sawfish faunas.
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Tallian, Aimee. "The Behavior and Ecology of Cursorial Predators and Dangerous Prey: Integrating Behavioral Mechanisms with Population-level Patterns in Large Mammal Systems." DigitalCommons@USU, 2017. https://digitalcommons.usu.edu/etd/5629.

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Driving into Yellowstone National Park for the first time is a moving experience. Gazing over the sweeping landscapes, seeing a geyser erupt 80 feet into the air, and having your first ‘wildlife encounter’, whether that be a 2 ton bull bison aggressively wallowing on his dirt mound, snorting and kicking up dust, or watching a pack of 6 wolves move through a valley off in the distance, pausing to howl in search of their companions. Yellowstone staff wishes to manage our park in a way that preserves these remarkable experiences. In order to effectively manage this dynamic ecosystem, it is critical to thoroughly understand how different animal and plant species interact with each other and their environment. Wolves were reintroduced to Yellowstone in 1995-1997 and park researchers and managers are still trying to understand how their presence impacts the ecosystem. In Yellowstone, wolves primarily prey on elk; however, predation on bison has started to increase in recent years. We still know little about how wolves hunt bison and what impacts wolves have had on how bison use their environment. The objective of this study was to better understand the behavioral and ecological interactions of wolves and bison, the most dangerous prey for wolves in North America. Since reintroduction, researchers have collected data on how wolves hunt both elk and bison. I used these data to understand 1) the conditions that allow wolves to capture their most dangerous prey, bison, 2) whether wolves have started preying on bison more often as the bison population increased, and 3) whether wolf reintroduction has limited bison use of Yellowstone’s most extreme high-elevation winter range. Finally, I collaborated with ecologists in Scandinavia to determine how wolf predation was affected by a competitor, the brown bear. My study adds to the current body of work addressing the effects of wolf reintroduction in Yellowstone. This research is unique because it focuses on wolf bison interactions, about which little is known in this system. This research also sheds light on the behavioral relationships at play in a special type of predator-prey interaction: predators that hunt dangerous prey
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Mullan, Rory. "The computational modelling of large scale predator-prey ecosystems." Thesis, Ulster University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.665505.

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Predator-prey modelling involves computationally simulating predator-prey relationships which are observable in nature. Predator species hunt and consume prey species, forming an ecosystem where the population sizes of the various species are interdependent. The models take the form of mathematical equations, where a set of coupled equations model the effect that predator and prey species have upon each other, with the modelling either taking place on a continuous or discrete time basis. Generally to date, the majority of research into the modelling of predator-prey ecosystems has concentrated on a single predator species interacting with a single prey, especially in the case of discrete time implementations. Historically, the modelling of large scale multiple species predator-multiple prey ecosystems would have been too computation ally intensive to be modelled. As computers have increased in power, the execution of these larger ecosystems has become possible. This thesis investigates large discrete time multiple species predator-prey models with the introduction of mutation amongst the various predators and prey species that occupy it. It consists of three main studies. First it was necessary to model and discuss a discrete time multiple species predator-prey model without mutation. This was achieved by the modification and execution of a discrete time single predator- single prey model taken from current literature. A focus here is placed on the number of surviving species when executing the multiple species model for a varying numbers of initial predators and prey species (between 2 and 10,000 species), and the effect of the control parameters varying upon them. Two main studies are undertaken. Firstly the unimodal discrete time map that governs the prey dynamics is varied, with this it was shown that the choice of unimodal map has a great effect on the survival of the predator and prey species. Secondly a study into the effect of predation strategies, which define how the predator hunts the prey species, is presented. Each strategy is outlined and conclusions are drawn comparing each strategy, assessing how effective each of them are in allowing predator and prey species survival in the model. The next step was to detail how mutation could be introduced into the ecosystem, with a Coupled Map Lattice (CML) approach being identified. The second study details the dynamics of this CML without predation. A focus was placed upon a CML where the parameters are linearly scaled across the set of maps. The number of maps in the CML is varied between 10 and 10,000, Comments are made upon how changing the mutation rate affected the dynamics of the CML and conclusions are drawn upon how the number of maps within the CML impacts upon these dynamics. Finally the Finally the two studies are merged, attaining and presenting a multiple species discrete time predator-prey model with CML based mutations amongst the various species that occupy the ecosystem. Again various unimodal maps are usedfor the underlying dynamics of the prey species, and different predation strategies are utilised. The system is first observed in a simple form, with a single predator and multiple mutating preys, and then in more complex form , with both mUltiple mutating predators and multiple mutating prey. Conclusions are drawn on how varying the parameters govern the underlying behaviour and survival of the species within the various models. It is observed, that in such a complex system, with both multiple mutating predators and multiple mutating preys, a large range of non-linear dynamics are possible.
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Gude, Justin Albert. "Applying risk allocation theory in a large mammal predator-prey system." Thesis, Montana State University, 2004. http://etd.lib.montana.edu/etd/2004/gude/GudeJ04.pdf.

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Understanding the behaviorally-mediated indirect effects of predators in ecosystems requires knowledge of predator-prey behavioral interactions, and the risk allocation hypothesis can be used to make predictions about such interactions. In predator-ungulate-plant systems, empirical research quantifying how predators affect ungulate group sizes and distribution, in the context of other influential variables, is particularly needed. We determined non-predation variables that affect elk (Cervus elaphus) group sizes and distribution on a winter range in the Greater Yellowstone Ecosystem (GYE), using regression analyses of 1219 elk groups counted and mapped over 12 years prior to wolf (Canis lupus) recolonization. We next examined the relevance of these non-wolf-predation variables in the presence of wolves using logistic and linear regression on surveys of 513 1-km&Acirc;&sup2; areas conducted over 2 years. Using model selection techniques, we evaluated risk allocation and other a priori hypotheses of elk group size and distributional responses to wolf predation risk while accounting for influential nonwolf- predation variables. We found little evidence that wolves affect elk group sizes, which were strongly influenced by habitat type. Following predictions from the risk allocation hypothesis, wolves likely created a more dynamic elk distribution in areas that they frequently hunted, as elk tended to move during the period of safety following wolf encounters in those areas. We predict that this distributional response to wolf predation risk should decrease the spatial heterogeneity of elk impacts on grasslands in areas that wolves frequently hunt. We also predict that this response should decrease browsing pressure on heavily-browsed woody plant stands in certain areas, which is supported by recent research in the GYE. This research highlights the importance of predator-prey behavioral interactions in large mammal systems.
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Meissner, K. (Kristian). "Consequences of predator-prey interactions in boreal streams:scaling up from processes to large-scale patterns." Doctoral thesis, University of Oulu, 2005. http://urn.fi/urn:isbn:9514278682.

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Abstract In this thesis I studied lotic trout predation and its ecological effects, and investigated invertebrate predator-prey interactions under natural and anthropogenically modified flow conditions. Given the growing concern about the reliability of extrapolations from small-scale studies to larger spatio-temporal scales, results of mechanistic small-scale experiments were scaled up by linking them to large-scale field surveys. An intensive survey assessed changes in diel feeding periodicity, prey selection and daily ration of juvenile brown trout (Salmo trutta L.) over the course of the open water period. This survey provides the first field estimates of juvenile brown trout daily rations and indicates crepuscular feeding peaks. Trout selectively preyed on medium- to large-sized prey, shifting towards epibenthic feeding with increasing availability of suitable prey. In a small-scale field experiment, trout displayed clear size-related predation concentrating on invertebrate predators and cased caddisflies, a pattern that scaled up successfully in large-scale surveys. Further, predation effects on large-sized prey were also repeated in a meta-analysis on lotic salmonid predation. While dense blackfly populations in lake-outlet streams are common, mass outbreaks of blackflies in short-term regulated rivers are poorly studied. In our studies the principal invertebrate predator of vernal benthic communities, the caseless caddisfly Rhyacophila, displayed significant preference for blackflies and was almost unable to capture any other prey, thus resulting in passive selection for larval blackflies. Rhyacophila larvae displayed highest capture success in intermediate current velocities, whereas further increases in current velocities decreased capture success. Short-term regulation releases increased both predator and prey drift but, unlike for Rhyacophila, magnitude of drift was unrelated to substrate for blackflies. Indeed, field observations indicated that blackflies rarely face detrimental effects of short-term regulation due to their fast growing rates and early emergence. Moss was the most preferred habitat of Rhyacophila and provided the best buffer against sudden increases in current velocities. These results suggest that several factors maintain spring-time outbreaks of blackfly populations in short-term regulated rivers: exaptation of the dominant blackfly species to prevailing conditions, degradation of the key habitat of the predator, and recurring annual drift losses and diminished capture success of Rhyacophila during short-term regulation releases.
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Gerber, Kayla M. "Tracking blue catfish: quantifying system-wide distribution of a mobile fish predator throughout a large heterogeneous reservoir." Thesis, Kansas State University, 2015. http://hdl.handle.net/2097/20351.

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Master of Science<br>Division of Biology<br>Martha E. Mather<br>A flexible distribution is an adaptive response that allows animals to take advantage of spatial variation in the fluctuation of resources. Distribution of mobile organisms is complex so multi-metric patterns derived from dynamic distribution trajectories must be deconstructed into simpler components for both individuals and populations. Tagging and tracking fish is a very useful approach for addressing these fisheries research questions, but methodological challenges impede its effectiveness as a research tool. Here, I developed and evaluated a high-retention, high-survival tagging methodology for catfish. Then, I integrated multiple distribution metrics to identify if sites within an ecosystem function differently for mobile predators. Finally, I determined if distinct groups of individuals existed, based on distributional patterns. In the appendices, I test sources of variation in system-wide detections (i.e., season, diel period, size, and release location) and provide additional details on methods and interpretation of the results. To address these objectives, I tracked 123 acoustically tagged (VEMCO V9-V13) Blue Catfish (Ictalurus furcatus mean: 505.3 mm TL; SE: 12.3 mm; range: 300-1090 mm) from June through November, 2012-2013, in Milford Reservoir, KS. Across the five months, 85.4-100.0% of the tagged Blue Catfish were detected at least once a month by an array of 20 stationary receivers (VR2W), a detection rate much higher than rates reported in the literature for catfish (38%). Blue Catfish were consistently aggregated in the northern portion of the middle region of Milford Reservoir. Using three metrics (population proportion, residence time, and movements), I found four types of functional sites that included locations with (i) large, active aggregations, (ii) exploratory/transitory functions, (iii) small, sedentary aggregations, and (iv) low use. I also found that tagged Blue Catfish clustered into three groups of individuals based on distribution. These included (1) seasonal movers, (2) consistent aggregations across seasons, and (3) fish exhibiting site fidelity to Madison Creek. Sites with different functions and groups of individual fish were related but not the same. My approach to looking at multiple responses, functions of sites, and individual groupings provided new insights into fish ecology that can advance fisheries management of mobile predators.
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Leland, Amanda V. "A New Apex Predator in the Gulf of Maine? Large, Mobile Crabs (Cancer borealis) Control Benthic Community Structure." Fogler Library, University of Maine, 2002. http://www.library.umaine.edu/theses/pdf/LelandAV2002.pdf.

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Books on the topic "Large predators"

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Zehra, Nazneen. Large mammalian prey-predators in Gir: Status, ecology and conservation. Authorspress, 2017.

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Cornwell, Patricia Daniels. Predator [large print]. Thorndike Press, 2005.

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Wright, Sally S. Pride & predator. Thorndike Press, 1999.

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Wright, Sally S. Pride & predator. Multnomah Books, 1997.

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Blackstock, Terri. Predator. Thorndike Press, 2010.

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Blackstock, Terri. Predator. Zondervan, 2010.

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Blackstock, Terri. Predator. Thorndike Press, 2010.

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Cornwell, Patricia Daniels. Predator. Putman Publishing Froup, 2005.

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Cornwell, Patricia Daniels. Predator. Berkley Books, 2006.

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Cornwell, Patricia Daniels. Predator. G.P. Putnam's Sons, 2005.

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Book chapters on the topic "Large predators"

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Wakolbinger, Manfred. "Service for Large Predators." In Unter der Oberfläche / Under the Surface. Springer Vienna, 2012. http://dx.doi.org/10.1007/978-3-7091-1075-1_13.

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Bedrosian, Bryan. "Avian Predators in Rangelands." In Rangeland Wildlife Ecology and Conservation. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34037-6_14.

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AbstractManagement of avian predators in western rangelands is uniquely challenging due to differences in managing for/against particular species, management of sensitive prey species, long-standing human/wildlife conflicts, and the unique legal protections within this ecological group. In general, many avian predator species considered rangeland specialists have been declining due to habitat loss, fragmentation, human sensitivity, and direct persecution. Conversely, avian predators that are more human-tolerant and/or are subsidized by human activities are significantly increasing across rangelands. The complicated nature of inter- and intra-species guilds, coupled with human dynamics has created a challenging scenario for both management for avian predators, as well as their prey. Human-mediated population control, both legal and illegal, continues for avian predators to reduce livestock conflict, aid sensitive prey populations, and/or because of general predator persecution. Conversion of rangeland to development for energy, cultivation, and urbanization remains the largest impediment to maintaining viable, historical assemblages of avian predators. Large-scale habitat protections, reduction of invasive plants, and reducing wildfire will continue to enhance at-risk populations of predators and their prey. Further, mediating human-induced mortality risks will also aid at-risk predator populations, such as reducing direct killing (poisoning and shooting), secondary poisoning from varmint control and lead ammunition use, electrocutions, and vehicle strikes, while reducing anthropogenic subsidies can help curtail population expansion of corvids. Additional understanding of long-term, successful predator control efforts for corvids and mitigation options for declining raptors is needed to help balance the avian predator–prey dynamic in western rangelands.
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Mahajan, Prashant, and Afifullah Khan. "Ecological Drivers of Livestock Depredation by Large Predators." In Case Studies of Wildlife Ecology and Conservation in India. Routledge, 2022. http://dx.doi.org/10.4324/9781003321422-13.

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Hayward, Matt W., Cassandra Bugir, Salvador Lyngdoh, and Bilal Habib. "Prey Preferences of the Large Predators of Asia." In Case Studies of Wildlife Ecology and Conservation in India. Routledge, 2022. http://dx.doi.org/10.4324/9781003321422-3.

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Åhman, Birgitta, Sirpa Rasmus, Camilla Risvoll, Svein Morten Eilertsen, and Harri Norberg. "Large predators and their impact on reindeer husbandry." In Reindeer Husbandry and Global Environmental Change. Routledge, 2022. http://dx.doi.org/10.4324/9781003118565-9.

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Thompson, Daniel J., and Thomas J. Ryder. "Large Carnivores." In Rangeland Wildlife Ecology and Conservation. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34037-6_24.

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AbstractFollowing historical efforts to eradicate them, large carnivores including gray wolves (Canis lupus), mountain lions (Puma concolor), black bears (Ursus americanus), and grizzly bears (U. arctos), have demonstrated an ability to recover across rangeland habitats in western North America during the last 50 years. While former distributions of these species were greatly reduced by the early-1960s, all are exhibiting range expansion and population increase across much (e.g., mountain lion and black bear) or portions (e.g., wolf and grizzly bear) of their historical range. This recovery of large carnivores in western landscapes has led to increased conflict with humans and a greater need for science-based management strategies by agencies with statutory responsibility for wildlife conservation. As conflict potential with large carnivores has increased, so have proactive and reactive conflict management programs for those impacted by large carnivores. Imperative to any successful large carnivore conflict mitigation is a focused outreach and education program for those who live, work, and recreate in habitats where wolves, mountain lions, and bears occur. Managers are continually evaluating the challenges and realities of intact large carnivore guilds within rangeland settings. Research and monitoring furthers our understanding and efficacy of management strategies for large carnivores now and into the future, striving to build on knowledge regarding the intricacies of population dynamics among predators and prey, including domestic species and humans.
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Hamer, M. L., and C. C. Appleton. "Life history adaptations of phyllopods in response to predators, vegetation, and habitat duration in north-eastern Natal." In Studies on Large Branchiopod Biology and Aquaculture. Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3366-1_14.

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Christensen-Dalsgaard, Jakob, Paolo Galeotti, Charles R. Knapp, and Nicolas Mathevon. "Reptiles." In Exploring Animal Behavior Through Sound: Volume 2. Springer Nature Switzerland, 2025. https://doi.org/10.1007/978-3-031-83460-8_4.

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Abstract The class reptiles—lizards, snakes, turtles and tortoises, tuataras, and crocodiles—are a large (~11,000 species) and diverse group of animals. Reptiles include a wide variety of both terrestrial and aquatic species, and their sizes vary from a few cm to 10 m. This traditional class consists of all the recent, scaly amniotes that are not mammals or birds, and reptiles have no unique common ancestor. This chapter summarizes the current knowledge about hearing and sound production in the different reptile groups. Many reptiles, especially lizards and crocodilians, have sensitive ears and hearing, and their sensitivity and frequency range of hearing are comparable to those of most birds. The use of sound signals or even clear behavioral responses to sound is not nearly as ubiquitous as in mammals and birds. The chapter discusses the evidence of use and detection of sound for purposes such as conspecific communication, species recognition, territorial defense, proper mate selection, mate attraction, predator detection and avoidance, synchronous hatching of eggs, or warning of intruders or predators. Also, the effects of body size and ambient temperature on acoustic behavior of these cold-blooded vertebrates are discussed.
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Shepherd, Suzanne M. "Large Felid Predators and “Man-Eaters”: Can We Successfully Balance Conservation of Endangered Apex Predators with the Safety and Needs of Rapidly Expanding Human Populations?" In Problematic Wildlife II. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-42335-3_2.

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Wilson, Seth M. "Living with Predators: A 20-Year Case Study in the Blackfoot River Watershed of Montana." In Rangeland Wildlife Ecology and Conservation. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34037-6_28.

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AbstractThis chapter describes 20 years of efforts to live with large carnivores in the Blackfoot watershed located in western Montana with a focus on the processes and projects that were developed to adapt to the presence of grizzly bears (Ursus arctos) and gray wolves (Canis lupus) under the capacity of a non-governmental organization called the Blackfoot Challenge. Initial efforts were focused on generating a shared understanding of the problem, engaging community members in the co-generation of data, and designing an inclusive decision-making process that led to the adoption of a suite of tools that represented the values of stakeholders who represented communities of place and interest. Between 2003 and 2018, damages and livestock depredations by grizzlies tended to remain below 10 conflicts per year. Confirmed and probable livestock depredations show a low level of 1.8 annual livestock losses per year to grizzlies. Between 2007 and 2020, the wolf population increased and eventually leveled off, while livestock losses to wolves remained low. Annual confirmed livestock losses to wolves have been 3.3 livestock per year with less than four wolves removed annually due to depredations in the core project area. The central lesson of this effort is that living with large carnivores requires bringing people together to build trust, to generate a shared understanding of the problem using science, and to develop a participatory and equitable approach for changing practices and adopting tools that foster coexistence with carnivores.
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Conference papers on the topic "Large predators"

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Nguyen, Thanh Thi, Campbell Wilson, and Janis Dalins. "Fine-Tuning Llama 2 Large Language Models for Detecting Online Sexual Predatory Chats and Abusive Texts." In ESANN 2024. Ciaco - i6doc.com, 2024. http://dx.doi.org/10.14428/esann/2024.es2024-222.

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Lazić, Marko, Milutin Đorđević, and Vladimir Drašković. "Pest control at the Palić zoo: Overview of the methodology for implementing pest control in the facility for large parrots." In 36. Savetovanje dezinfekcija, dezinsekcija i deratizacija jedan svet - jedno zdravlje, Vrnjačka Banja, hotel "Vrnjačke Terme", 28-31.maj 2025.godine. Srpsko veterinarsko društvo, 2024. https://doi.org/10.5937/ddd25239l.

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Pest control in zoos represents a great challenge. Easly accessible food, the absence of predators, and favorable living conditions for rodents allow them to multiply and reach a large number in the habitats where animals are kept. The presence of unwanted rodents poses a major biosecurity risk and creates a bad impression among zoo visitors. In the Palic Zoo in the facility for large parrots, a large number of mice were observed. They can be seen during the day. We analyzed the number of mice and they level of activity in order to develop a pest control plan and reduce they number, in a way that will be safe for macaws.
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Chatterjee, Nilanjan, Madhura Davate, Bilal Habib, and Parag Nigam. "CANCELLED: Mesopredator spatial and temporal response to large-predators and anthropogenic activities in a Central Indian Reserve." In 5th European Congress of Conservation Biology. Jyvaskyla University Open Science Centre, 2018. http://dx.doi.org/10.17011/conference/eccb2018/107750.

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Timuş, Asea, and Elena Baban. "Entomofauna speciei Rosa canina l. din zona de centru a Republicii Moldova." In International symposium ”Actual problems of zoology and parasitology: achievements and prospects” dedicated to the 100th anniversary from the birth of academician Alexei Spassky. Institute of Zoology, Republic of Moldova, 2018. http://dx.doi.org/10.53937/9789975665902.79.

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In the work are exposed investigations in 2007-2017 of entomofauna with development on the species Rosa canina L. from various urban and rural biotopes in the center of the Republic of Moldova. In total, were recorded 52 species of insects in 9 orders (Orthoptera, Homoptera, Hemiptera, Thysanoptera, Coleoptera, Neuroptera, Lepidoptera, Hymenoptera, Diptera) and 1 mite (Trombidiformes). Of these, 17 species of insects have developed large populations and impact on the rose, 12 insect species developed annual faunistic populations, 12 solitary and rare individuals, 2 species one individual. At the same time, 4 species have been recorded recently: Harmonia axiridis (predators afidophagus), Polygonia c-album (nectar consumer and pollinator), Blenocampa phyllocopa (phytophagus in the larval stage) and Dasineura rosae (gallicol in the larval stage). The species Epicometis hirta was affected by the calamity of 21-23 April 2017, after which it was not recorded in the center of the republic, including the usual host plants, thus being considered an ecological indicator.
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Самашев, З. "SHIMAILY – A NEW LOCATION OF PETROGLYPHS IN EASTERN KAZAKHSTAN." In Труды Сибирской Ассоциации исследователей первобытного искусства. Crossref, 2019. http://dx.doi.org/10.25681/iaras.2019.978-5-202-01433-8.301-315.

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В статье приводятся сведения о петроглифах урочища Шимайлы на территории Тарбагатайского района Восточно-Казахстанской области Республики Казахстан. Наскальное искусство этого памятника охватывает время от эпохи бронзы до раннего средневековья. Основные мотивы изображений бронзового века антропоморфная фигура, зооморфные изображения, колесница, знаки-символы и предметы вооружения. Основу звериного образа наскальных изображений Шимайлы бронзового века составляет триада рогатых животных: бык, горный козел/архар, олень. В репертуар петроглифов эпохи бронзы входят также и другие травоядные животные, хищные звери и птицы. Последние представлены изображениями дрофы, которые чаще всего включены в состав многофигурных композиций. Хищники представлены фигурами волков, которые преследуют или терзают парнокопытных. К переходному периоду от эпохи бронзы к раннему железному веку в Шимайлы относятся образы птицеголовых или клювастых оленей, идентичные фигурам на так называемых оленных камнях. К раннесакскому и развитому сакскому периодам относятся изображения оленей поджарых, в летящей позе и/или стоящих на кончиках копыт, с большими глазами, ветвистыми откинутыми назад рогами. Зафиксированы тамги средневековых народов. The article includes new information on the petroglyphs of the Shimaily (Tarbagatai district of the East Kazakhstan region of the Republic of Kazakhstan). The imagery of this rock art site is related to the period from the Bronze Age to the Early Middle Ages. The main images of the Bronze Age are an anthropomorphic figure, numerous zoomorphic images, a chariot, depictions of weapons, signs and symbols. Animal images are basically represented by the figures of bulls, mountain goats and deer. Other herbivores are also depicted as well as predators and birds. The latter are represented by images of bustards, which are most often included in the multi-figure compositions. Predators are mostly wolves that shown in the scenes of pursuing or tormenting the artiodactyls. Another series of images in Shimaily refers to the transitional period from the Bronze Age to the Early Iron Age. These are birdheaded or beaked deer, identical to the figures depicted on the so-called deer stones. The Early Saka and developed Saka periods include a series of typical deer figures: theiy are lean, flying and/or standing on the tips of the hoofs, with large eyes, with branchy antlers thrown back. The tamga-signs of the medieval peoples are also recorded in Shimaily.
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Liu, Chenying, Zhong You, and Perla Maiolino. "Kinematics of an Origami Inspired Millipede Robot." In ASME 2022 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/detc2022-88998.

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Abstract A millipede is a worm-like arthropod with a relatively hard exoskeleton, a segmented body, and numerous pairs of legs. Its appendage helps to coordinate the behaviour of multiple body segments to generate a peristaltic wave, so that efficient locomotion can be achieved on uneven surfaces and limited space. When sensing danger or disturbed, the millipede curls up into a coil shape to protect itself against predators. The curling behaviour of a millipede has also been found in some of its close relatives in the arthropod family, such as pill bugs and lobsters. Inspired by its peristaltic and curling behaviours, we propose an origami-based concept for a robot that imitates the motion of a millipede. The mechanism is made with a chain of interlinked modules, mimicking the segments in a millipede. Each module is an assembly of rigid facets with a uniform and finite thickness, reducing the overall degrees of freedom (DoF) to a manageable number. Given its unique geometric design, the assembly can contain any number of modules without an excessively large DoF. Its curling and peristaltic motions are quantified kinematically in the paper, which paves the way for the millipede robot design with actuation and control components integrated. In addition, a few other configurations of the proposed origami mechanism and its geometric variants are presented, thus opening up design space for other possible applications.
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Dedmon, S. "Going Beyond Conventional Problem Solving for Two Railroad Wheel Defects." In 2019 Joint Rail Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/jrc2019-1312.

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Conventional problem solving is a time-honored and accepted methodology for solving many problems we encounter in our daily home and work lives. Thought processes can be linear (like a programmer) or non-linear and still use conventional problem solving skills. Conventional problem solving begins with a statement of the problem, accumulation of data, analysis of data and proposals of solutions to the problem, then testing of the hypotheses. Non-conventional problem solving often skips some of these steps, beginning with a statement of the problem and ending with possible solutions. The tools of conventional problem solving include “critical thinking”, Fool-proofing, “thinking outside the box” and Statistical techniques. Consider the first of our ancestors to figure out that harnessing fire would provide security from large predators, make food safer and easier to eat and make tools such as fire hardened tips on spears. Did all these inventions occur in one moment of genius, or did they take innumerable years to accomplish? Sometime in this process of non-conventional thinking our ancestors brought forth a new technology which ensured the survival of our species. So, how does non-conventional problem solving work? When current theory does not appear to work, then we look to the margins of our science to see if current theory continues to be ineffective. Most theories fail in the margins of the science. A classic example of conventional science failing in the margins is the general and special theory of relativity. Non-conventional problem solving offers greater opportunity for revolutionary rather than incremental, or evolutionary advancements to our science. Other examples are included in this paper. Two wheel related problems are also presented using non-conventional problem solving techniques to provide alternative solutions.
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Tkacheva, Olga, and Victor Utkin. "Control of the Predator-Prey System Based on the Expansion of the State Space." In 2023 16th International Conference Management of large-scale system development (MLSD). IEEE, 2023. http://dx.doi.org/10.1109/mlsd58227.2023.10303935.

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Xu, Jeffrey, Thomas Le Pichon, Isaac Spiegel, Dustin Hauptman, and Shawn Keshmiri. "Bio-Inspired Predator-Prey Large Spacial Search Path Planning." In 2020 IEEE Aerospace Conference. IEEE, 2020. http://dx.doi.org/10.1109/aero47225.2020.9172365.

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Poole, Jason C. "A SCIENTIFICALLY DIRECTED RECONSTRUCTION OF THE LARGE DEVONIAN PREDATORY FISH HYNERIA LINDAE." In GSA Annual Meeting in Indianapolis, Indiana, USA - 2018. Geological Society of America, 2018. http://dx.doi.org/10.1130/abs/2018am-325384.

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Reports on the topic "Large predators"

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Lundgren, Jonathan, Moshe Coll, and James Harwood. Biological control of cereal aphids in wheat: Implications of alternative foods and intraguild predation. United States Department of Agriculture, 2014. http://dx.doi.org/10.32747/2014.7699858.bard.

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The overall objective of this proposal is to understand how realistic strategies for incorporating alternative foods into wheat fields affect the intraguild (IG) interactions of omnivorous and carnivorous predators and their efficacy as biological control agents. Cereal aphids are a primary pest of wheat throughout much of the world. Naturally occurring predator communities consume large quantities of cereal aphids in wheat, and are partitioned into aphid specialists and omnivores. Within wheat fields, the relative abilities of omnivorous and carnivorous predators to reduce cereal aphids depend heavily on the availability, distribution and type of alternative foods (alternative prey, sugar, and pollen), and on the intensity and direction of IG predation events within this community. A series of eight synergistic experiments, carefully crafted to accomplish objectives while accounting for regional production practices, will be conducted to explore how cover crops (US, where large fields preclude effective use of field margins) and field margins (IS, where cover crops are not feasible) as sources of alternative foods affect the IG interactions of predators and their efficacy as biological control agents. These objectives are: 1. Determine the mechanisms whereby the availability of alternative prey and plant-provided resources affect pest suppression by omnivorous and carnivorous generalist predators; 2. Characterize the intensity of IGP within generalist predator communities of wheat systems and assess the impact of these interactions on cereal aphid predation; and 3. Evaluate how spatial patterns in the availability of non-prey resources and IGP affect predation on cereal aphids by generalist predator communities. To accomplish these goals, novel tools, including molecular and biochemical gut content analysis and geospatial analysis, will be coupled with traditional techniques used to monitor and manipulate insect populations and predator efficacy. Our approach will manipulate key alternative foods and IG prey to determine how these individual interactions contribute to the ability of predators to suppress cereal aphids within systems where cover crop and field margin management strategies are evaluated in production scale plots. Using these strategies, the proposed project will not only provide cost-effective and realistic solutions for pest management issues faced by IS and US producers, but also will provide a better understanding of how spatial dispersion, IG predation, and the availability of alternative foods contribute to biological control by omnivores and carnivores within agroecosystems. By reducing the reliance of wheat producers on insecticides, this proposal will address the BARD priorities of increasing the efficiency of agricultural production and protecting plants against biotic sources of stress in an environmentally friendly and sustainable manner.
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Axenrot, Thomas, and Erik Degerman. Ontogenetic variation in lacustrine European smelt (Osmerus eperlanus) populations as a response to ecosystem characteristics : an indicator of population sensitivity to environmental and climate stressors. Department of Aquatic Resources, Swedish University of Agricultural Sciences, 2024. http://dx.doi.org/10.54612/a.5qdiolcgj2.

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Smelts play a key role in the pelagic ecosystem of large lakes in northern Europe and North America. In numbers, they often dominate the open water. In large lakes in Scandinavia (including Finland), European smelt (Osmerus eperlanus L.), a cold-water glacial relict, is commonly the most important prey for piscivorous fish species, but also acts by ontogenetic shifts as a predator on zoo-plankton, small crustaceans, fish larvae, mysids and occasionally – with increasing size - fish. Furthermore, the large numbers of smelt in the open water are important competitors to other planktivorous fish. Due to the diverse life histories and biological interactions of smelt in large lakes, its role in the food-web structure is expected to be variable. Smelt population dynamics, recruitment, size and age structure, growth, life history and mortality were analysed and compared for five Swedish lakes that varied in size, depth, morphology, trophic status and latitude to understand the varying life histories and roles in lake food-webs. The results showed that in shallow, eutrophic lakes smelt stayed small and short-lived, and populations experienced high mortality. In deeper, colder and less nutrient-rich lakes, smelts grew larger and older, and might shift to a piscivorous trophic level. By ontogenetic adaptions smelt seems to uphold high abundance and recruitment over a wide range of ecosystems, but in shallow lakes without cold water refuges smelt populations run the risk of collapsing on the occasion of extremely warm summers with drastic consequences for their predators and lake ecosystems.
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Salcido, Charles, Patrick Wilson, Justin Tweet, Blake McCan, Clint Boyd, and Vincent Santucci. Theodore Roosevelt National Park: Paleontological resource inventory (public version). National Park Service, 2022. http://dx.doi.org/10.36967/nrr-2293509.

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Theodore Roosevelt National Park (THRO) in western North Dakota was established for its historical connections with President Theodore Roosevelt. It contains not only historical and cultural resources, but abundant natural resources as well. Among these is one of the best geological and paleontological records of the Paleocene Epoch (66 to 56 million years ago) of any park in the National Park System. The Paleocene Epoch is of great scientific interest due to the great mass extinction that occurred at its opening (the Cretaceous–Paleogene extinction event), and the unusual climatic event that began at the end of the epoch (the Paleocene–Eocene Thermal Maximum, an anomalous global temperature spike). It is during the Paleocene that mammals began to diversify and move into the large-bodied niches vacated by dinosaurs. The rocks exposed at THRO preserve the latter part of the Paleocene, when mammals were proliferating and crocodiles were the largest predators. Western North Dakota was warmer and wetter with swampy forests; today these are preserved as the “petrified forests” that are one of THRO’s notable features. Despite abundant fossil resources, THRO has not historically been a scene of significant paleontological exploration. For example, the fossil forests have only had one published scientific description, and that report focused on the associated paleosols (“fossil soils”). The widespread petrified wood of the area has been known since at least the 19th century and was considered significant enough to be a tourist draw in the decades leading up to the establishment of THRO in 1947. Paleontologists occasionally collected and described fossil specimens from the park over the next few decades, but the true extent of paleontological resources was not realized until a joint North Dakota Geological Survey–NPS investigation under John Hoganson and Johnathan Campbell between 1994–1996. This survey uncovered 400 paleontological localities within the park representing a variety of plant, invertebrate, vertebrate, and trace fossils. Limited investigation and occasional collection of noteworthy specimens took place over the next two decades. In 2020, a new two-year initiative to further document the park’s paleontological resources began. This inventory, which was the basis for this report, identified another 158 fossil localities, some yielding taxa not recorded by the previous survey. Additional specimens were collected from the surface, among them a partial skeleton of a choristodere (an extinct aquatic reptile), dental material of two mammal taxa not previously recorded at THRO, and the first bird track found at the park. The inventory also provided an assessment of an area scheduled for ground-disturbing maintenance. This inventory is intended to inform future paleontological resource research, management, protection, and interpretation at THRO. THRO’s bedrock geology is dominated by two Paleocene rock formations: the Bullion Creek Formation and the overlying Sentinel Butte Formation of the Fort Union Group. Weathering of these formations has produced the distinctive banded badlands seen in THRO today. These two formations were deposited under very different conditions than the current conditions of western North Dakota. In the Paleocene, the region was warm and wet, with a landscape dominated by swamps, lakes, and rivers. Great forests now represented by petrified wood grew throughout the area. Freshwater mollusks, fish, amphibians (including giant salamanders), turtles, choristoderes, and crocodilians abounded in the ancient wetlands, while a variety of mammals representing either extinct lineages or the early forebearers of modern groups inhabited the land. There is little representation of the next 56 million years at THRO. The only evidence we have of events in the park for most of these millions of years is isolated Neogene lag deposits and terrace gravel. Quaternary surficial deposits have yielded a few fossils...
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4

Tulloch, Olivia, Tamara Roldan de Jong, and Kevin Bardosh. Data Synthesis: COVID-19 Vaccine Perceptions in Sub-Saharan Africa: Social and Behavioural Science Data, March 2020-April 2021. Institute of Development Studies (IDS), 2021. http://dx.doi.org/10.19088/sshap.2028.

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Safe and effective vaccines against COVID-19 are seen as a critical path to ending the pandemic. This synthesis brings together data related to public perceptions about COVID-19 vaccines collected between March 2020 and March 2021 in 22 countries in Africa. It provides an overview of the data (primarily from cross-sectional perception surveys), identifies knowledge and research gaps and presents some limitations of translating the available evidence to inform local operational decisions. The synthesis is intended for those designing and delivering vaccination programmes and COVID-19 risk communication and community engagement (RCCE). 5 large-scale surveys are included with over 12 million respondents in 22 central, eastern, western and southern African countries (note: one major study accounts for more than 10 million participants); data from 14 peer-reviewed questionnaire surveys in 8 countries with n=9,600 participants and 15 social media monitoring, qualitative and community feedback studies. Sample sizes are provided in the first reference for each study and in Table 13 at the end of this document. The data largely predates vaccination campaigns that generally started in the first quarter of 2021. Perceptions will change and further syntheses, that represent the whole continent including North Africa, are planned. This review is part of the Social Science in Humanitarian Action Platform (SSHAP) series on COVID-19 vaccines. It was developed for SSHAP by Anthrologica. It was written by Kevin Bardosh (University of Washington), Tamara Roldan de Jong and Olivia Tulloch (Anthrologica), it was reviewed by colleagues from PERC, LSHTM, IRD, and UNICEF (see acknowledgments) and received coordination support from the RCCE Collective Service. It is the responsibility of SSHAP.
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Tulloch, Olivia, Tamara Roldan de Jong, and Kevin Bardosh. Data Synthesis: COVID-19 Vaccine Perceptions in Africa: Social and Behavioural Science Data, March 2020-March 2021. Institute of Development Studies (IDS), 2021. http://dx.doi.org/10.19088/sshap.2021.030.

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Safe and effective vaccines against COVID-19 are seen as a critical path to ending the pandemic. This synthesis brings together data related to public perceptions about COVID-19 vaccines collected between March 2020 and March 2021 in 22 countries in Africa. It provides an overview of the data (primarily from cross-sectional perception surveys), identifies knowledge and research gaps and presents some limitations of translating the available evidence to inform local operational decisions. The synthesis is intended for those designing and delivering vaccination programmes and COVID-19 risk communication and community engagement (RCCE). 5 large-scale surveys are included with over 12 million respondents in 22 central, eastern, western and southern African countries (note: one major study accounts for more than 10 million participants); data from 14 peer-reviewed questionnaire surveys in 8 countries with n=9,600 participants and 15 social media monitoring, qualitative and community feedback studies. Sample sizes are provided in the first reference for each study and in Table 13 at the end of this document. The data largely predates vaccination campaigns that generally started in the first quarter of 2021. Perceptions will change and further syntheses, that represent the whole continent including North Africa, are planned. This review is part of the Social Science in Humanitarian Action Platform (SSHAP) series on COVID-19 vaccines. It was developed for SSHAP by Anthrologica. It was written by Kevin Bardosh (University of Washington), Tamara Roldan de Jong and Olivia Tulloch (Anthrologica), it was reviewed by colleagues from PERC, LSHTM, IRD, and UNICEF (see acknowledgments) and received coordination support from the RCCE Collective Service. It is the responsibility of SSHAP.
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6

Börjesson, Patrik, Maria Eggertsen, Lachlan Fetterplace, et al. Long-term effects of no-take zones in Swedish waters. Edited by Ulf Bergström, Charlotte Berkström, and Mattias Sköld. Department of Aquatic Resources, Swedish University of Agricultural Sciences, 2023. http://dx.doi.org/10.54612/a.10da2mgf51.

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Marine protected areas (MPAs) are increasingly established worldwide to protect and restore degraded ecosystems. However, the level of protection varies among MPAs and has been found to affect the outcome of the closure. In no-take zones (NTZs), no fishing or extraction of marine organisms is allowed. The EU Commission recently committed to protect 30% of European waters by 2030 through the updated Biodiversity Strategy. Importantly, one third of these 30% should be of strict protection. Exactly what is meant by strict protection is not entirely clear, but fishing would likely have to be fully or largely prohibited in these areas. This new target for strictly protected areas highlights the need to evaluate the ecological effects of NTZs, particularly in regions like northern Europe where such evaluations are scarce. The Swedish NTZs made up approximately two thirds of the total areal extent of NTZs in Europe a decade ago. Given that these areas have been closed for at least 10 years and can provide insights into long-term effects of NTZs on fish and ecosystems, they are of broad interest in light of the new 10% strict protection by 2030 commitment by EU member states. In total, eight NTZs in Swedish coastal and offshore waters were evaluated in the current report, with respect to primarily the responses of focal species for the conservation measure, but in some of the areas also ecosystem responses. Five of the NTZs were established in 2009-2011, as part of a government commission, while the other three had been established earlier. The results of the evaluations are presented in a synthesis and also in separate, more detailed chapters for each of the eight NTZs. Overall, the results suggest that NTZs can increase abundances and biomasses of fish and decapod crustaceans, given that the closed areas are strategically placed and of an appropriate size in relation to the life cycle of the focal species. A meta-regression of the effects on focal species of the NTZs showed that CPUE was on average 2.6 times higher after three years of protection, and 3.8 times higher than in the fished reference areas after six years of protection. The proportion of old and large individuals increased in most NTZs, and thereby also the reproductive potential of populations. The increase in abundance of large predatory fish also likely contributed to restoring ecosystem functions, such as top-down control. These effects appeared after a 5-year period and in many cases remained and continued to increase in the longer term (&gt;10 years). In the two areas where cod was the focal species of the NTZs, positive responses were weak, likely as an effect of long-term past, and in the Kattegat still present, recruitment overfishing. In the Baltic Sea, predation by grey seal and cormorant was in some cases so high that it likely counteracted the positive effects of removing fisheries and led to stock declines in the NTZs. In most cases, the introduction of the NTZs has likely decreased the total fishing effort rather than displacing it to adjacent areas. In the Kattegat NTZ, however, the purpose was explicitly to displace an unselective coastal mixed bottom-trawl fishery targeting Norway lobster and flatfish to areas where the bycatches of mature cod were smaller. In two areas that were reopened to fishing after 5 years, the positive effects of the NTZs on fish stocks eroded quickly to pre-closure levels despite that the areas remained closed during the spawning period, highlighting that permanent closures may be necessary to maintain positive effects. We conclude from the Swedish case studies that NTZs may well function as a complement to other fisheries management measures, such as catch, effort and gear regulations. The experiences from the current evaluation show that NTZs can be an important tool for fisheries management especially for local coastal fish populations and areas with mixed fisheries, as well as in cases where there is a need to counteract adverse ecosystem effects of fishing. NTZs are also needed as reference for marine environmental management, and for understanding the effects of fishing on fish populations and other ecosystem components in relation to other pressures. MPAs where the protection of both fish and their habitats is combined may be an important instrument for ecosystembased management, where the recovery of large predatory fish may lead to a restoration of important ecosystem functions and contribute to improving decayed habitats. With the new Biodiversity Strategy, EUs level of ambition for marine conservation increases significantly, with the goal of 30% of coastal and marine waters protected by 2030, and, importantly, one third of these areas being strictly protected. From a conservation perspective, rare, sensitive and/or charismatic species or habitats are often in focus when designating MPAs, and displacement of fisheries is then considered an unwanted side effect. However, if the establishment of strictly protected areas also aims to rebuild fish stocks, these MPAs should be placed in heavily fished areas and designed to protect depleted populations by accounting for their home ranges to generate positive outcomes. Thus, extensive displacement of fisheries is required to reach benefits for depleted populations, and need to be accounted for e.g. by specific regulations outside the strictly protected areas. These new extensive EU goals for MPA establishment pose a challenge for management, but at the same time offer an opportunity to bridge the current gap between conservation and fisheries management.
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7

Lazonick, William. Investing in Innovation: A Policy Framework for Attaining Sustainable Prosperity in the United States. Institute for New Economic Thinking Working Paper Series, 2022. http://dx.doi.org/10.36687/inetwp182.

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“Sustainable prosperity” denotes an economy that generates stable and equitable growth for a large and growing middle class. From the 1940s into the 1970s, the United States appeared to be on a trajectory of sustainable prosperity, especially for white-male members of the U.S. labor force. Since the 1980s, however, an increasing proportion of the U.S labor force has experienced unstable employment and inequitable income, while growing numbers of the business firms upon which they rely for employment have generated anemic productivity growth. Stable and equitable growth requires innovative enterprise. The essence of innovative enterprise is investment in productive capabilities that can generate higher-quality, lower-cost goods and services than those previously available. The innovative enterprise tends to be a business firm—a unit of strategic control that, by selling products, must make profits over time to survive. In a modern society, however, business firms are not alone in making investments in the productive capabilities required to generate innovative goods and services. Household units and government agencies also make investments in productive capabilities upon which business firms rely for their own investment activities. When they work in a harmonious fashion, these three types of organizations—household units, government agencies, and business firms—constitute “the investment triad.” The Biden administration’s Build Back Better agenda to restore sustainable prosperity in the United States focuses on investment in productive capabilities by two of the three types of organizations in the triad: government agencies, implementing the Infrastructure Investment and Jobs Act, and household units, implementing the yet-to-be-passed American Families Act. Absent, however, is a policy agenda to encourage and enable investment in innovation by business firms. This gaping lacuna is particularly problematic because many of the largest industrial corporations in the United States place a far higher priority on distributing the contents of the corporate treasury to shareholders in the form of cash dividends and stock buybacks for the sake of higher stock yields than on investing in the productive capabilities of their workforces for the sake of innovation. Based on analyzes of the “financialization” of major U.S. business corporations, I argue that, unless Build Back Better includes an effective policy agenda to encourage and enable corporate investment in innovation, the Biden administration’s program for attaining stable and equitable growth will fail. Drawing on the experience of the U.S. economy over the past seven decades, I summarize how the United States moved toward stable and equitable growth from the late 1940s through the 1970s under a “retain-and-reinvest” resource-allocation regime at major U.S. business firms. Companies retained a substantial portion of their profits to reinvest in productive capabilities, including those of career employees. In contrast, since the early 1980s, under a “downsize-and-distribute” corporate resource-allocation regime, unstable employment, inequitable income, and sagging productivity have characterized the U.S. economy. In transition from retain-and-reinvest to downsize-and-distribute, many of the largest, most powerful corporations have adopted a “dominate-and-distribute” resource-allocation regime: Based on the innovative capabilities that they have previously developed, these companies dominate market segments of their industries but prioritize shareholders in corporate resource allocation. The practice of open-market share repurchases—aka stock buybacks—at major U.S. business corporations has been central to the dominate-and-distribute and downsize-and-distribute regimes. Since the mid-1980s, stock buybacks have become the prime mode for the legalized looting of the business corporation. I call this looting process “predatory value extraction” and contend that it is the fundamental cause of the increasing concentration of income among the richest household units and the erosion of middle-class employment opportunities for most other Americans. I conclude the paper by outlining a policy framework that could stop the looting of the business corporation and put in place social institutions that support sustainable prosperity. The agenda includes a ban on stock buybacks done as open-market repurchases, radical changes in incentives for senior corporate executives, representation of workers and taxpayers as directors on corporate boards, reform of the tax system to reward innovation and penalize financialization, and, guided by the investment-triad framework, government programs to support “collective and cumulative careers” of members of the U.S. labor force. Sustained investment in human capabilities by the investment triad, including business firms, would make it possible for an ever-increasing portion of the U.S. labor force to engage in the productive careers that underpin upward socioeconomic mobility, which would be manifested by a growing, robust, and hopeful American middle class.
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8

van Gemert, Rob, Per Holliland, Konrad Karlsson, Niklas Sjöberg, and Torbjörn Säterberg. Assessment of the eel stock in Sweden, spring 2024 : fifth post-evaluation of the Swedish eel management. Department of Aquatic Resources, Swedish University of Agricultural Sciences, 2024. http://dx.doi.org/10.54612/a.4iseib7eup.

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For decades, the population of the European eel has been in severe decline. In 2007, the European Union decided on a Regulation establishing measures for the recovery of the stock, which obliged Member States to implement a national Eel Management Plan by 2009. Sweden submitted its plan in 2008. According to the Regulation, Member States shall report regularly to the EU-Commission, on the implementation of their Eel Management Plans and the progress achieved in protection and restoration. The current report provides an assessment of the eel stock in Sweden as of spring 2024, intending to feed into the national reporting to the EU in August this year. This report updates and extends previous evaluation reports by Dekker (2012, 2015) and Dekker et al. (2018, 2021). In this report, the impacts on the stock - of fishing, restocking and mortality related to hydropower generation - are assessed. Other anthropogenic impacts (climate change, pollution, increased impacts of predators, spread of parasites, disruption of migration due to disorientation after transport, and so forth) probably have an impact on the stock too, but these factors are hardly quantifiable, and no management targets have been set. For that reason, and because most factors were not included in the EU Eel Regulation, these other factors are not included in this report. Our focus is on the quantification of silver eel biomass escaping from continental waters towards the ocean (current, current potential and pristine) and mortality risks endured by those eels during their whole lifetime. The assessment is broken down on a geographical basis, with different impacts dominating in different areas (west coast, inland waters, Baltic coast). In the last decade, a break in the downward trend in glass eel recruitment has been observed, with recruitment no longer declining consistently. Whether that relates to recent protective actions, or is due to other factors, is yet unclear. Nevertheless, recruitment levels remain at historically low levels. This report contributes to the required international assessment, but does not discuss the causing factors behind the recent recruitment trend and the overall status of the stock across Europe. For the different assessment areas, results summarise as follows: On the west coast, a commercial fyke net fishery on yellow eel was exploiting the stock, until this fishery was completely closed in spring 2012. A fishery-based assessment no longer being achievable, we present trends from research surveys (fyke nets). Insufficient information is currently available to assess the recovery of the stock in absolute terms. Obviously, current fishing mortality is zero (disregarding the currently unquantifiable effect of illegal fishing), but none of the other requested stock indicators (current, current potential and pristine biomass) can be presented. The formerly exploited size-classes of the stock show a recovery in abundance after the closure of the commercial fishery, and the smaller size classes show a break in their decline in line with the recent global trend of glass eel recruitment. In order to support the recovery of the stock, or to compensate for anthropogenic mortality in inland waters, young eel has been restocked on the Swedish west coast since 2010. Noting the quantity of restocking involved, the expected effect (ca. 50 t silver eel) is relatively small, and hard to verify – in comparison to the potential natural stock on the west coast (an order of 1000 t). However, for the currently depleted stock, the contribution will likely constitute a larger share of silver eel escapement. For inland waters, this report updates the 2021 assessment, with substantial changes in methodology being the use of a new natural recruitment model, and the full separation of Trap &amp; Transport catches from the fisheries statistics. The assessment for the inland waters relies on a reconstruction of the stock from information on the youngest eels in our waters (natural recruits, assisted migration, restocking). Based on 78 years of data on natural recruitment into 22 rivers, a statistical model is applied which relates the number of immigrating young eel caught in traps to the location and size of each river, the distance from the trap to the river mouth, and the year in which those eels recruited to continental waters as a glass eel (year class). The further into the Baltic, the larger and less numerous recruits generally are. Distance upstream comes with less numerous recruits. Using the results from the above recruitment analysis, in combination with historical data on assisted migration (young eels transported upstream within a drainage area, across barriers) and restocking (young eels imported into a river system), we have a complete overview of how many young eels recruited to Swedish inland waters. From this, the production of fully grown silver eel is estimated for every lake and year separately, based on best estimates of growth and natural mortality rates. Subtracting the catch made by the fishery (as recorded) and down-sizing for the mortality incurred when passing hydropower stations (percentwise, as recorded or using a default percentage), an estimate of the biomass of silver eel escaping from each river towards the sea is derived. Results indicate, that since 1960, the production of silver eel in inland waters has declined from over 700 to below 300 tonnes per year (t/yr). The production of naturally recruited eels is still falling; following the increase in restocking since 2010, an increase in restocking-based production is expected to be starting right around now. Gradually, restocking has replaced natural recruitment (assisted and fully natural), now making up over 90 % of the inland stock. Fisheries have taken 20-30 % of the silver eel (since the mid-1980s), while the impact of hydropower has ranged from 25 % to 60 %, depending on the year. Escapement is estimated to have varied from 72 t in the late 1990s, to 175 t in the early 2000s. The biomass of current escapement (including eels of restocked origin) is approximately 15 % of the pristine level (incl. restocked), or almost 30 % of the current potential biomass (incl. restocked). This is below the 40 % biomass limit of the Eel Regulation, and anthropogenic mortality (70 % over the entire life span in continental waters) exceeds the limit implied in the Eel Regulation (60 % mortality, the complement of 40 % survival). Mortality being that high, Swedish inland waters currently do not contribute to the recovery of the stock. The temporal variation (in production, impacts and escapement) is partly the consequence of a differential spatial distribution of the restocking of eel over the years. The original natural (not assisted) recruits were far less impacted by hydropower, since they could not climb the hydropower dams when immigrating. Since 2010, inland restocking is increasingly concentrated to drainage areas falling to the Kattegat-Skagerrak, also including obstructed lakes (primarily Lake Vänern, and many smaller ones). Even though Trap &amp; Transport of silver eel - from above barriers towards the sea - has contributed to reducing the hydropower impact, hydropower mortality remains the largest estimated contributor to silver eel mortality in inland waters. Without restocking, the biomass affected by fishery and/or hydropower would be only 5-10 % of the currently impacted biomass, but the stock abundance would reduce from 15 % to less than 3 % of the pristine biomass. In summary: the inland eel stock biomass is below the minimum target, anthropogenic impacts exceed the minimum limit that would allow recovery, and those impacts have been increasing. It is therefore recommended to reconsider the current action plans on inland waters, taking into account the results of the current, comprehensive assessment. For the Baltic coast, the 2021 assessment has been updated without major changes in methodology. Results indicate that the impact of the fishery continues to decline over the decades. The current impact of the Swedish silver eel fishery on the escapement of silver eel along the Baltic Sea coast is estimated at 0.3 %. However, this fishery is just one of the anthropogenic impacts (in other areas/countries) affecting the eel stock in the Baltic, including all types of impacts, on all life stages and all habitats anywhere in the Baltic. Integration with the assessments in other countries has not been achieved. Current estimates of the abundance of silver eel (biomass) indicates an order of several thousand tonnes, but those estimates are extremely uncertain, due to the low impact of the fishery (near-zero statistics). Moreover, these do not take into account the origin of those silver eels, from other countries. An integrated assessment for the whole Baltic will be required to ground-truth these estimates. This would also bring the eel assessments in line with the policy to regionalise stock assessments for other (commercial) fish species (see https://ec.europa.eu/oceans-and-fisheries/fisheries/rules/multiannual-plans_en). It is recommended to develop an integrated assessment for the entire Baltic Sea eel stock, and to coordinate protective measures with other range states.
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