Lec 5 - Competition Flashcards
Competition
A reduction in fitness due to shared use of a resource
that is in limited supply.
Generally considered the strongest plant-plant
interaction.
Effect
Ability to deny resources to a neighboring plant.
Competitive strategy
Response
Ability to maintain function in spite of low resource
levels / interference from neighboring plants.
Stress-tolerant strategy
Measuring competition
Target-Neighbour Experiment used to
develop hierarchies of competitive ability.
Measuring competition intensity
Addition series experiment used to measure how much
competition limits the growth of individual plants.
Competition intensity is a community level property.
Light competition
Light comes mainly from one direction. Key Strategy: Intercept light before your neighbor does. Important Traits: Height Leaf position in the canopy Photosynthetic capacity of leaves Adaptability
In low light:
↑ Leaf area
↓ Photosynthetic rate
↓ Respiration rate
Light competition is _________
since a plant has to be only a
little bit taller to intercept the
majority of the light.
asymmetric
Nutrients diffuse down ________ ___________
concentration gradient
Root competition is symmetric because
Unlike light competition, bigger plants don’t have a
disproportionate advantage in soil nutrient capture.
Asymmetric competition
where larger size allows disproportionate
resource capture.
Symmetric competition
Symmetry where resource capture is proportional to
plant size.
Who Does a Plant Compete
With?
Plant neighbourhood “zone of influence”
In light competition neighbourhood
Aboveground zone of influence
measured by shading.
Competition can result in:
Underyielding (net negative effects on total biomass) Overyielding (net positive effects on total biomass)
