Alpine plants are assumed to be in particular danger as the climate changes rapidly worldwide. Specialist alpine species in Norrbotten County, northern Sweden have been surveyed over the last 20 years, providing insight to population dynamics and how the plants might respond to the changing climate. The main current threat to the species is habitat destruction as the climate changes. Variation in the number of plants among populations and years, and correlations with environmental variables were examined. Some species had increased while others had decreased over the years. No uniform relationship for all species and populations were discovered, but some of the species exhibited relationships between population size changes and temperature and precipitation. However, if the future climate in Norrbotten County changes according to the predictions, the habitats of the specialist alpine plants may be severely altered, leaving the species with no alternative places to establish and grow.

This thesis aims to integrate the study of population change with the expectations of foraging models, and to test whether expectations resulting from integrating these two bodies of theory have greater predictive power than foraging models alone. To compare these models, I monitored prey age, butchery practice, and prey desirability in five prehistoric occupations of the Birch Creek rockshelters of Idaho. I modeled hunting pressure with a human population density estimate based on radiocarbon dates from Idaho archaeological sites, and modeled prey abundance with a model of historic effective moisture. Both models predicted younger prey, lower average prey desirability, and more intensive extraction of nutrients from prey when human hunting pressure is high and when prey are scarce. However, unlike the prey model, the Forager-resource Population Ecology (FPE) model predicts that similarly desirable prey with different reproductive rates should show different degrees of resilience to hunting pressure. Contrary to FPE model predictions, statistical analyses of the Birch Creek faunal materials did not indicate that human hunting pressure disproportionately stressed populations of slowly reproducing prey compared to quicker-reproducing prey. While the faunal specimens from Birch Creek provided a limited and flawed dataset, my results did not support the use of the FPE model.

Ages of 213 deer killed during the 1972 hunting season were determined by: (1) eruption-replacement and wear criteria in the field: (2) employing the tooth eruption-replacement and wear criteria under optimum laboratory conditions; and by {3) cementum-annulation counts . Incisors collected for cementum-annulation counts were decalcified in 5 percent nitric acid, sections 16-18 microns were cut on a cryostat and stained in hematoxylin for 18 ± 2 minutes . Age determinations by cementumannulation counts showed 87 percent agreement with the results obtained by eruption-replacement and wear criteria in the laboratory. Survival rates were estimated from the age distribution of 740 teeth aged by cementum-annulation counts . The average adult doe survival rate was 0.55 . Other population parameters were also determined. All five deer herds showed apparent negative rates of population change, averaging -0.14. The adult female survival rate appeared to be the major source of variation between units in rate of population change. The correlation between hunting pressure and the rate of population change was statistically significant .

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21165号 / 農博第2291号 / 新制||農||1060(附属図書館) / 学位論文||H30||N5139(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 縄田 栄治, 教授 舟川 晋也, 教授 松浦 健二 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

We investigate the properties of two distinct disordered systems: the two-species predator-prey Lotka-Volterra model with rate variability, and an elastic line model to simulate vortex lines in type-II superconductors. We study the effects of intrinsic demographic variability with inheritance in the reaction rates of the Lotka-Volterra model via zero-dimensional Monte Carlo simulations as well as two-dimensional lattice simulations. Individuals of each species are assigned inheritable predation efficiencies during their creation, leading to evolutionary dynamics and thus population-level optimization. We derive an effective subspecies mean-field theory and compare its results to our numerical data. Furthermore, we introduce environmental variability via quenched spatial reaction-rate randomness. We investigate the competing effects and relative importance of the two types of variability, and find that both lead to a remarkable enhancement of the species densities, while the aforementioned optimization effects are essentially neutral in the densities. Additionally, we collected extinction time histograms for small systems and find a marked increase in the stability of the populations against extinction due to the presence of variability. We employ an elastic line model to investigate the steady-state properties and non-equilibrium relaxation kinetics of magnetic vortex lines in disordered type-II superconductors. To this end, we developed a versatile and efficient Langevin molecular dynamics simulation code, allowing us to do a careful study of samples with or without vortex-vortex interactions or disorder allows us to disentangle the various complex relaxational features present in this system and investigate their origin. In particular, we compare disordered samples with randomly distributed point defects versus correlated columnar defects. We extract two-time quantities such as the mean-square displacement, the height and density correlations, to investigate the relaxation kinetics of the system of flux lines. Additionally, we compare the steady-state mean velocity and gyration radius as a function of an external driving current in the presence of point-like and columnar disorder. We validate our simulation algorithm by matching our results against a previously-used Monte Carlo algorithm, verifying that these microscopically quite distinct methods yield similar results even in out-of-equilibrium settings. / Ph. D.

Interior Double-crested cormorant reproduction was examined on a large geographical scale to evaluate management actions. Three distinct breeding areas across Ontario were selected. Beginning in 2002, over 11,000 preledged cormorants have been marked. During 2006 and 2007, re-observation of banded birds, colony data such as nest, egg, and chick measurements, and island morphology, were collected. Data revealed no significant regional differences in adult size. However, eggs in eastern Lake Ontario (ELO) were larger than North Channel of Lake Huron (NChan) and Lake of the Woods (LOW). Chicks in ELO throughout development were smaller than NChan and LOW. Number of gulls was correlated inversely to cormorant fledge rate. Survival estimates were <20% for young of the year, but increased to >80% after year 2. Elasticity analysis revealed that a 50% reduction in adult survival combined with 100% fecundity reduction would result in a 42% reduction in population growth.

The Cooperative Alleghany Bear Study (CABS) was a 10-year study conducted on 2 areas and designed to investigate the ecology of a hunted population of American black bears (Ursus americanus) in the Alleghany Mountains of western Virginia. Over the course of our research, we handled 1,041 individual bears >18 months old and gathered reproductive data from females during 424 bear-winters. My analyses of 183 litters indicate that reproductive rates were high with relatively large litters (mean = 2.49 cubs / litter) and younger (3–4-year-old) females having smaller litters than older (> 5 years old) females. Overall cub sex ratios did not differ from 1M:1F; however, female cubs were over-represented in 4-cub litters. Most cubs were born in January (mean = January 17) and younger females had later parturition dates than older females. Bears on our study areas had relatively early ages at primiparity (mean = 3.8 years old) and few missed reproductive opportunities. Hard mast failure apparently resulted in periodic reproductive failures and subsequent reproductive synchrony, which I tracked using 5 indices. The amplitude of oscillations in reproductive synchrony dampened through time after each synchronizing event. The population contained substantially more females than males; however, males were more vulnerable to trapping than were females. Population size was determined using genetic and photographic capture-recapture estimators. Density estimates were relatively high and approached 1 bear / km2. Annual survival rates were high for cubs (0.87) and females (0.91). For males, annual survival rates were lower, particularly for 1–3-year-olds (0.57). Excluding hunting mortality, natural survival rates were high (0.98) for all >1-year-old bears on our study areas. The results of Leslie Matrix and Program RISKMAN models indicated a growing population. A Leslie Matrix model incorporating the effects of a 5-year-cyle of mast-failure-induced reproductive failure yielded a lambda = 1.13. To reach the objective of 0 population growth prescribed for some areas of Virginia, increased levels of hunting mortality on adult (>3-year-old) females would likely be necessary. / Ph. D.

Despite a number of recent studies focused on the issue, patterns of stream insect dispersal in temperate streams of North America remain poorly understood. Movement of benthic invertebrates is notoriously difficult to measure directly using traditional means; however, genetic markers provide an ideal method for estimating stream insect dispersal. In this study, the control region of mitochondrial DNA was used to study gene flow and dispersal among populations of the stonefly <i>Peltoperla tarteri</i> in the Southern Appalachians. The control region of <i>P. tarteri</i> is approximately 1270 base pairs (bp) in length, 81% AT-rich, and contains variable numbers of a 74 bp tandem repeat containing the sequence motif "5'-GGGGGC-3". Many stream insects have long life cycles that result in the simultaneous existence of multiple cohorts throughout the larval development period. If larval development is fixed, genetic isolation among cohorts may confound genetic estimates of dispersal. Although larval head width data indicated that <i>P. tarteri</i> is semivoltine in southwestern Virginia, low levels of genetic differentiation among cohorts suggested that larval development of <i>P. tarteri</i> is not fixed and that some individuals complete development in one or three years rather than two. This 'cohort splitting' would result in individuals from distinct cohorts maturing at the same time and mating with one another. Such developmental plasticity may allow some individuals to avoid adverse environmental conditions. The extent and likely mechanism of dispersal was determined by comparing levels of population genetic differentiation within drainages to that among drainages. While there was no consistent relationship between genetic and geographic distance, genetic differentiation was generally high within and among drainages. Nested clade analysis indicates that historical fragmentation and range expansion coupled with contemporary gene flow explain the present day pattern of genetic variation in <i>P. tarteri.</i> In order for these historical patterns to have such a strong influence on present day genetic structure, both larval and adult dispersal must be restricted. However, the genetic data suggest that larval dispersal is more frequent than adult dispersal. / Ph. D.

We present an investigation of two non-equilibrium systems: spatial many-species predator-prey games and systems of interacting magnetic skyrmions. We numerically study two predator-prey systems characterized by nested pattern formations. We first consider a six species game in which spiral patterns spontaneously form within coarsening domains. Through a systematic investigation of relevant correlation functions, the interface width, and other quantities, we show that the non-trivial in-domain dynamics affect the coarsening process and the interfacial properties. The exponents which govern domain growth, aging, and interface fluctuations differ from those expected from curvature driven coarsening. The response to perturbations of the reaction rates is also studied. Furthermore, we introduce a nine species model characterized by nested spiral pattern formations. Quantitative evidence of the existence of two length and time scales associated to the spiral levels is presented in the form of correlation lengths and a temporal Fourier analysis of the species densities. A generalized interaction scheme is proposed for dynamically generated hierarchies. Magnetic skyrmions are particle-like spin configurations found in certain chiral magnets. We study the effect of the Magnus force on the relaxation dynamics through Langevin molecular dynamics simulations. The Magnus force enhances the disorder of the system at high noise strengths while we observe a dynamic regime with slow decaying correlations at low noise strengths. The different regimes are characterized by changes in the aging exponent. In general, the Magnus force accelerates the approach to the steady state. In the presence of quenched disorder, we find that the relaxation dynamics are more robust in systems with a strong Magnus force. We also examine periodically driven skyrmion systems and show that a transition from reversible to irreversible flow exists in the presence of attractive defects. The Magnus force enhances the irreversible regime in this case. The work on predator-prey systems was supported by the U.S. National Science Foundation through Grant No. DMR-1606814 whereas the work on skyrmions was supported by the US Department of Energy, Office of Basic Energy Sciences (DOE-BES), under Grant No. DE-FG02-09ER46613. / Doctor of Philosophy / We present an investigation of two non-equilibrium systems: spatial many-species predator- prey games and systems of interacting magnetic skyrmions. We numerically study two predator-prey systems characterized by nested pattern formations. We first consider a six species game in which spiral patterns spontaneously form within coarsening domains. Through a systematic investigation of relevant correlation functions, the interface width, and other quantities, we show that the non-trivial in-domain dynamics affect the coarsening process and, to a greater extent, properties at the interface between competing groups of species. The exponents which govern domain growth, aging, and interface fluctuations are shown to differ from those expected in typical games of competition. We also study the change of the system due to a perturbation of the reaction rates, which could represent an abrupt change in the environment. Furthermore, we introduce a nine species model characterized by the emergence of nested spiral pattern formations. Quantitative evidence of the existence of two distinct spiral levels is presented. We also propose a generalized interaction scheme for dynamically generated spiral hierarchies. Magnetic skyrmions are particle-like spin configurations found in certain chiral magnets. We study the effect of the Magnus force on the dynamic properties of skyrmion systems through particle-based simulations. The Magnus force enhances the disorder of the system at high noise strengths while accelerating the formation of the triangular lattice at low noise strengths. We find that, in general, the Magnus force accelerates the approach to the steady state. In the presence of randomly placed attractive pinning sites, we find that a strong Magnus force can prevent caging effects and allow skyrmions to more easily move around pinning sites. We also examine periodically driven skyrmion systems and show that a transition from reversible to irreversible flow exists in the presence of attractive defects. The Magnus force is shown to enhance the irreversible regime in this case. The work on predator-prey systems was supported by the U.S. National Science Foundation through Grant No. DMR-1606814 whereas the work on skyrmions was supported by the US Department of Energy, Office of Basic Energy Sciences (DOE-BES), under Grant No. DE-FG02-09ER46613.

Quantitative population dynamics modeling is needed to evaluate the stock status and fisheries management plans to provide robust model and management strategies. Atlantic Weakfish (Cynoscion regalis), one important commercial and recreational fish species along the west coast of Atlantic Ocean that was found to be declining in recent years, was selected as an example species. My study aimed to explore the possible spatial heterogeneity of CPUE (catch per unit effort) year trend based on three fishery independent surveys and explore the influence of nonstationary natural mortality on the fisheries management through a MSE (Management Strategy Evaluation) algorithm based on the Weakfish stock assessment results. Five models for catch rate standardization were constructed based on the NEAMAP (NorthEast Area Monitoring and Assessment Program) survey data and the ‘best' two models were selected based on the ability to capture nonlinearity and spatial autocorrelation. The selected models were then used to fit the other two survey data to compare the CPUE year trend of Weakfish. Obvious differences in distribution pattern of Weakfish along latitude and longitude were detected from these three surveys as well as the CPUE year trend. To test the influence of the model selection on the MSE, five stock-recruitment models and two forms of statistical catch-at-age models were used to evaluate the fishery management strategies. The current biomass-based reference point tends to be high if the true population dynamics have nonstationary natural mortality. A flexible biomass based reference point to match the nonstationary process is recommended for future fisheries management. / Master of Science