Transcript Anthony R. Ives: Theoretical and Empirical Community Ecology

Anthony R. Ives
By: Andrew Flick
Biol 7083
Outline
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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
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Interactions and community structure
Pea aphid predators
Phylogenetic correlation of traits
Population dynamics with orders of magnitude
Research Interests
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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
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Yeast-like fungus
Epiphytes
Dispersers
Variability within populations
www.mycology.adelaide.edu.au/
Dispersal - Experiment
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Liquid culture
Apple-leaf model
Mathematical model
Explain the specific and understand the
general
Pop A
90%
Dilution
Pop B
Dispersal - Experiment
• Liquid culture
• Apple-leaf model
• Mathematical model
Relative
Density
50%
10%
0%
Hours
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
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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
From: Ives, and Carpenter. Science.
(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.
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
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Interactions and community structure
Pea aphid predators
Phylogenetic correlation of traits
Population dynamics with orders of magnitude
• Consumer Diversity
Consumer Diversity
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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)
Normal
Caterpillars
Number
Aphids
Reduced
Caterpillars
Number of Predator Species
Redrawn from
Gable et al.
2012 Ecology
Research Interests
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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
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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
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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
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Interactions and community structure
Pea aphid predators
Phylogenetic correlation of traits
Population dynamics with orders of magnitude
Related Papers
• 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)
Pea aphids and some enemies
http://www.zoology.wisc.edu/faculty/