Anthony R. Ives

By: Andrew FlickBiol 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

http://www.zoology.wisc.edu/faculty/

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

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

www.mycology.adelaide.edu.au/

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

RelativeDensity

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

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

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)

NumberAphids

Number of Predator Species

ReducedCaterpillars

NormalCaterpillars

Redrawn from Gable et al. 2012 Ecology

Research Interests

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

• Phylogenetic Dissimilarity

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

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

http://www.zoology.wisc.edu/faculty/

Pea aphids and some enemies