Interactions between Avian and Insect Herbivore Communities within MOFEP

1
Interactions between Avian and Insect Herbivore
Communities within MOFEP

• John Landosky, Robert J. Marquis, Rick Clawson,
  Wendy Gram, Paul Porneluzi, John Faaborg, Julie
  Ryan, Florence DiTirro, Rebecca Forkner, John
  Lill, and Josiane Le Corff
• University of Missouri St. Louis
• November 8, 2007

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Outline

• What is MOFEP?
• Insect and avian communities interactions?
• Preliminary analysis Something there?
• Refining the analysis

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What is MOFEP?
4
MOFEP
Whats the best way to harvest timber while
conserving healthy ecosystems?
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Design
6
Timeline
1996 Treatment applied
1991-1995
1991
2007

Proposed 2011 treatment
1997-2000 Post-treatment data gathered
(full-scale) Post-treatment
1993-1995 Baseline data gathered (full-scale)
Pre-treatment
1991-1992 Baseline data gathered (preliminary)
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Timeline
1996 Treatment applied
1997-present
1991
2007

Proposed 2011 treatment
1997-2000 Post-treatment data gathered
(full-scale) Post-treatment
1993-1995 Baseline data gathered (full-scale)
Pre-treatment
1991-1992 Baseline data gathered (preliminary)
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Isa textula (Limacodidae)
Ecosystem health?
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Avian/Insect Interactions
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Top-Down/Bottom-Up Interactions

• Do trophic levels interact?
• Top-down?
• Bottom-up?
• How can we test for interactions with our data?

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Bird Project
Hypothetical WOTH Observations

• Crew members cover entire forest using
  birdlines
• Identify singing males and spot-map
• Each line walked 10 times during the month of
  June
• Three independent observations define a bird
  territory

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Bird Census
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Common MOFEP Species
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Insect Project

• Leaf chewing herbivores on
• White oak Quercus alba
• Black oak Quercus velutina
• Four times per year
• Early May, and late June, July, and August
• Over 250 species identified

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Free Feeders vs. Shelter Builders
Free Feeders
Shelter Builders
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Bird Census
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Preliminary Analysis

• Is there something there?

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Preliminary Analysis Model
Bird Census
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Preliminary Analysis Model

• Bird territory size
• 200m from center

Bird Census
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Preliminary Analysis Model

• Bird territory size
• 200m from center
• Bird Effect
• Sum each species
• of territories
• Mating pair weight

Bird Census
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Preliminary Analysis Model

• Bird territory size
• 200m from center
• Bird Effect
• Sum each species
• of territories
• Mating pair weight
• Insect stands
• point in space

Bird Census
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Preliminary Analysis Model

• Bird territory size
• 200m from center
• Bird Effect
• Sum each species
• of territories
• Mating pair weight
• Insect stands
• point in space
• If gt50 coverage
• corrected
• If lt50 coverage
• excluded

Bird Census
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Hypothetical Data Slide
rmANCOVA Unstructured Log-transformed Year p lt
0.0001 Ecotype p0.34 Treatment p0.23 Bird
Density (cov) p0.01
Pre-treatment (1993-1995)
Post-treatment (1997-2000)
rmANCOVA Compound Symmetry Log-transformed Year
p lt 0.0001 Ecotype p0.10 Bird Density (cov)
p0.02
y -0.021x 0.342 r2 0.0312
y -0.012x 0.11 r2 0.0127
0.8
0.8
Herbivore Abundance (residuals)
Herbivore Abundance (residuals)
0
0
-0.8
-0.8
30
0
30
0
15
15
Birds w/in 200m
Birds w/in 200m
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Hypothetical Data Slide
Pre-treatment (1993-1995)
Post-treatment (1997-2000)
rmANCOVA Unstructured Log-transformed Year p lt
0.0001 Ecotype p0.34 Treatment p0.23 Bird
Density (cov) p0.01
rmANCOVA Compound Symmetry Log-transformed Year
p lt 0.0001 Ecotype p0.10 Bird Density (cov)
p0.02
y 0.031x 0.34 r2 0.0332
y 0.023x 0.11 r2 0.0202
0.8
0.8
Herbivore Abundance (residuals)
Herbivore Abundance (residuals)
0
0
-0.8
-0.8
30
0
30
0
15
15
Birds w/in 200m
Birds w/in 200m
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Effect of Bird Density on Herbivore Abundance
rmANCOVA Unstructured Square-root
transformed Year p lt 0.0001 Ecotype
p0.728 Bird Density (cov) p0.430
Pre-treatment (1993-1995)
rmANCOVA First Order Autoregressive Log-transforme
d Year p lt 0.0001 Ecotype p0.056 Treatment
p0.311 Bird Density (cov) p0.061
Post-treatment (1997-2000)
y -0.0015x 0.0134 r2 0.0022
2.0
0.6
Herbivore Abundance (residuals)
Herbivore Abundance (residuals)
0
0
-1.5
-0.5
30
0
30
0
15
15
Birds w/in 200m
Birds w/in 200m
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Effect of Bird Density on Free Feeder Herbivore
Abundance
rmANCOVA First Order Autoregressive Log-transforme
d Year p lt 0.0001 Ecotype p0.001 Bird Density
(cov) p0.067
rmANCOVA Compound Symmetry Log-transformed Year
p lt 0.0001 Ecotype p0.120 Treatment
p0.360 Bird Density (cov) p0.026
Pre-treatment (1993-1995)
Post-treatment (1997-2000)
y -0.0058x 0.0527 r2 0.0210
y -0.0066x 0.0651 r2 0.0223
0.8
0.8
Free Feeder Abundance (residuals)
Free Feeder Abundance (residuals)
0
0
-0.8
-0.8
30
0
30
0
15
15
Birds w/in 200m
Birds w/in 200m
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Effect of Bird Density on Ratio of Free Feeders
to Shelter Builders
rmANCOVA First Order Autoregressive Log-transforme
d Year p 0.708 Ecotype p lt0.0001 Bird Density
(cov) p0.043 Bird Density Year 0.001
Pre-treatment (1993-1995)
y -0.0107x 0.1064 r2 0.0473
0.8
Ratio free feeders to shelter builders (residuals)
0
-0.8
30
0
15
Birds w/in 200m
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Effect of Bird Density on Ratio of Free Feeders
to Shelter Builders
rmANCOVA Compound Symmetry Log-transformed Year
p lt 0.0001 Ecotype p0.015 Treatment
p0.229 Bird Density (cov) p0.011 Bird Density
Year 0.0004
Post-treatment (1997-2000)
y -0.0059x 0.0536 r2 0.0214
0.8
Ratio free feeders to shelter builders (residuals)
0
-0.8
30
0
15
Birds w/in 200m
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Preliminary Conclusions

• All herbivores considered together
• no relationship between insects and birds
• Just free feeders
• Some evidence for negative correlation between
  insects and birds
• Ratio of free feeders to shelter builders
• Birds shift herbivore community structure in some
  years but not others

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Refining the Model

• Under construction

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Territory From Point to Area

• A challenge
• Preliminary analysis crude
• Conspecifics defend territories
• Territory size may depend on
• Bird species
• Topography
• Region (i.e. Ozark highlands)
• Year
• Territories may not be circular

center of territory modeled
territory
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Territory From Point to Area

• Euclidean polygons
• ½ distance to nearest conspecific in 360 degrees
• Maximum
• mean distance to nearest conspecific/2 1 SD
• Limit territory by topography

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Insect Stand From Point to Distribution

• Stands distributed in space
• Stand as point can be
• inaccurate
• misleading
• Abundance best by stand
• Predation pressure
• per tree
• summed across trees to stand

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Diet and Foraging
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Summary

• Preliminary evidence for top-down effects of
  birds on insects
• Working with authors to make the model more
  biologically relevant
• Territory size
• Diet and foraging behaviors

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Acknowledgments
Kathleen Baker Herbivore crews Bird crews Randy
Jensen Missouri Department of Conservation Marquis
Lab