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Anthony R. Ives By: Andrew Flick Biol 7083

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Outline Background Community Interactions Predator-Prey Dynamics Phylogenetic Correlation Population Fluctuations Wrap-up

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Real Background B.A. – University of Rochester M.A. – Princeton University Ph. D. – Princeton

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Family Tree Whose lab he was in – Henry Horn – Robert May Who has been in his lab – Eric Klopfer – John Losey – Derek Johnson

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Getting pretty far from Real Background Why I chose Tony Ives Predator-Prey models Theoretical Ecology Fitting models with data Wisconsin!

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Interesting (to me) Facts Top 5 papers – Phylogenetic Analyses – Stability and Diversity of Ecosystems Too many definitions Stability & press perturbations

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Research Interests Interactions and community structure Pea aphid predators Phylogenetic correlation of traits Population dynamics with orders of magnitude

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Research Interests Interactions and community structure Pea aphid predators Phylogenetic correlation of traits Population dynamics with orders of magnitude Dispersal

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What is dispersal’s role when species extinction is not happening? How does dispersal affect the mean population density of a species?

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Dispersal Same mean densities Daily alternating growth rate of.5 and 2 Introduce dispersal

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Dispersal Same mean densities Daily alternating growth rate of.5 and 2 Introduce dispersal

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Dispersal Without dispersal average growth rate is 1.0 With dispersal the growth rate is 1.25 Time is geometric while space is arithmetic

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Dispersal - Aureobasidium pullulans Yeast-like fungus Epiphytes Dispersers Variability within populations

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Dispersal - Experiment Liquid culture Apple-leaf model Mathematical model Explain the specific and understand the general Pop A Pop B 90% Dilution

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Dispersal - Experiment Liquid culture Apple-leaf model Mathematical model Relative Density Hours 50% 10% 0% Redrawn poorly from Ives, et al. Ecology Letters

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Dispersal - Experiment Liquid culture Apple-leaf model Mathematical model From Ives, et al. Ecology Letters

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Dispersal - Experiment Liquid culture Apple-leaf model Mathematical model From Ives, et al. Ecology Letters

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Research Interests Interactions and community structure Pea aphid predators Phylogenetic correlation of traits Population dynamics with orders of magnitude Stability

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Things affecting stability – Diversity (number of species) – Strength of Interactions – Topology of Food Webs – Sensitivity to environmental change Stable states

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Stability (A)Alternative stable states, the initial densities of four species determine which species persist; pairs of alternatively persisting or non-persisting species are shown with solid and dashed lines.(B)Nonpoint equilibria, stable and chaotic attractor. (C)Pulse perturbations to systems with a stable equilibrium. The left panel shows dynamics of a 2-species system after a single pulse perturbation, with combined densities shown by the heavy line. The right panel gives the same system with repeated pulse perturbations.(D)Press perturbations to systems with a stable equilibrium. The arrows trace the equilibrium densities of species i and j in a six-species ecosystem as the intrinsic rates of increase decline for all species. In the left panel, the equilibrium point collides with the unstable point at which species j goes extinct; in the right panel, the equilibrium point bifurcates into a stable nonpoint attractor. From: Ives, and Carpenter. Science.

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Stability Competition in a single trophic level “All models are wrong, but some are useful.” – George Box Showed how one system can show several diversity-stability relationships Species Richness

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Research Interests Interactions and community structure Pea aphid predators Phylogenetic correlation of traits Population dynamics with orders of magnitude Consumer Diversity

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Increasing Consumers Increases Consumed Resource complementarity Trait dominance How to test our question?

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Consumer Diversity How does feeding environment affect resource use? Complimentary, substitutable, or both?

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Consumer Diversity - Experiment Ladybug and parasitoid wasp Plots without caterpillars – Spatial differences Plots with caterpillars – No spatial differences – No differences in leaf area

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Consumer Diversity - Results Absence – Complimentary Presence – Substitutable This is interesting (at least to me) Number Aphids Number of Predator Species Reduced Caterpillars Normal Caterpillars Redrawn from Gable et al Ecology

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Research Interests Interactions and community structure Pea aphid predators Phylogenetic correlation of traits Population dynamics with orders of magnitude Phylogenetic Dissimilarity

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Two types of community similarity – Beta Diversity – Species Turnover Phylogenetic Community Dissimilarity (PCD) – Sorensen’s similarity metric (Species Turnover) – Evolutionary relationship Identify environmental drivers

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Phylogenetic Dissimilarity Fish are defined by pH in lakes Macrophytes defined by Carbon, conductance, alkalinity, and pH Species sensitivities replaced with phylogenies

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Research Interests Interactions and community structure Pea aphid predators Phylogenetic correlation of traits Population dynamics with orders of magnitude Density Fluctuations

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Alternative stable states – Environmental Perturbation – Irreversible – Not always points Midges are the dominant herbivore/detritivore 2 non-overlapping generations/year

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Density Fluctuations Midges crash when populations get too high Algae have refuge and repopulate With just a few algae recovering Model shows… 10 orders of magnitude! 1980’s and environmental changes

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Research Interests Interactions and community structure Pea aphid predators Phylogenetic correlation of traits Population dynamics with orders of magnitude

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Stability and Diversity of Ecosystems (Science) A synthesis of subdisciplines: predator-prey interactions, and biodiversity and ecosystem functioning. (Ecology Letters) High-amplitude fluctuations and alternative dynamical states of midges in Lake Myvatn. (Nature) Interactions between specialist and generalist natural enemies: parasitoids, predators, and pea aphid biological control. (Ecology) Phylogenetic metrics of community similarity. (American Naturalist) Related Papers

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Pea aphids and some enemies

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