poster
TRANSCRIPT
Effects of agriculture on evolution of native species Scott A. Chamberlain1, Kenneth D. Whitney2, and Jennifer A. Rudgers2
1 Simon Fraser University, Canada – 2 Rice University, USA
The Idea
The Approach
What did we find?
What does it mean?
• Agriculture covers ~50% of vegetated land surface
• Evolution is altered in agricultural landscapes – Gene flow occurs from crops to wild relative plants
– Evolution of resistance occurs in plants to GMOs
– Evolution of plants/insects to herbicides/pesticides
• Yet, we know less of how natural selection is altered in agricultural landscapes through species interactions
• There is much evidence for altered biotic communities
• How do changes in abundance and community structure of mutualists and antagonists near sunflower crops alter natural selection on flower traits in wild sunflowers?
Does proximity to crops alter:
1. Abundance of mutualists and antagonists? 2. Community structure of mutualists and antagonists? 3. Selection on native plant floral traits? 4. Contribution of mutualists and antagonists to selection on native plant floral traits?
Conclusions • Sunflower mutualists more abundant near,
antagonists more abundant far from crops • Beta-diversity of mutualists greater near crops • Natural selection altered by proximity to sunflower
crops • Changes in mutualist/antagonist communities drive
differences in selection near vs. far from crops • This is one of few studies to show agricultural
effects on natural selection across a landscape in a native plant species
Implications • Mutualist-antagonist framework may be useful in
understanding agricultural effects on plant evolution • Natural selection altered in agricultural landscapes,
BUT contrary to expectation
The Questions
Does proximity to sunflower crops alter:
1. …abundance of mutualists and antagonists?
2. …community structure of mutualists and antagonists?
3. …selection on native plant floral traits?
Does proximity to sunflower crops alter:
4. …contribution of mutualists and antagonists to selection on native plant floral traits?
Scott Chamberlain [email protected] t: @recology_ http://schamberlain.github.com/scott
Far Near
Abundance
Visits inflorescence
-1
min
-1
Far Near
Abundance
…what did we find?
No difference for antagonists
Sunflower Crop
Near
Far
Distance ≤ 10 m
Distance ~ 2.5 km
Agricultural landscape
Other Crop [corn/sorghum/wheat/cotton]
Natural habitat
Proximity to sunflowers (2 levels) X
Seed source (2 levels) @ 5 sites in ‘10, @ 2 sites in ‘11
Data Collected • Pollinators: pollinator observations • Seed predators: counted damaged seeds • Folivores: leaf damage
Floral traits Inflor. traits
Iso sp. N. hel. Pollen
Fitness
-‐0.06 0.004 Site 1 2011
Site 2 2011
Far Near Floral traits Inflor. traits
Iso sp. N. hel. Pollen
Fitness
Floral traits Inflor. traits
Iso sp. N. hel. Pollen
Fitness
0.002 -‐0.01
Floral traits Inflor. traits
Iso sp. N. hel. Pollen
Fitness N. Helianthi a
bundance
Mutualists more abundant near, antagonists more abundant far from crops
Silhouettes from phylopic.org
Beta-diversity of mutualists greater near crops
Natural selection altered by proximity to sunflower crops, and more variable near sunflower crops
= the take-home message
Predictions Results
Predictions Results
Changes in mutualist/antagonist communities drive differences in selection near vs. far from crops