Anthony R. Ives By: Andrew Flick Biol 7083

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Pea aphids and some enemies