Interspecific Competition Superior and inferior competitor Rates of reproduction Rates of growth Tolerance to limiting factors Direct competition

Mechanisms for superior competition Consumption Preemption Overgrowth Chemical interactions (allelopathy) Territoriality Encounter competition

Competitive Exclusion Eastern cottontail New England cottontail

Coexistence of Groton rodents

How can six species of salamander coexist on Groton School lands?

Coexistence Resource Partitioning Resource-based models Spatially based models Temporal Models Changes over time (long-term) Low levels of competition allow for extended persistence Limiting Factor Models Predation Disease Parasitism

Competition and Niche Fundamental Niche Realized Niche Resource Partitioning –Spatial –Resource Selection –Timing?

Spatial heterogeneity and variation Environmental Gradients Disturbance Soil/bedrock Aspect/topography

Temporal Variation Parameters that vary predictably over time –Temperature –Moisture –Seed and nut production –Prey population cycles Response of the inferior competitor –Dispersal –Dormancy –Reduction in density

Predation and Herbivory

Competition and Evolution Short-term changes –Behavioral Long-term changes –Structural Character Displacement Behavioral plasticity

How do so many New England carnivores persist in a small area?

Full Circle Why are the invasive species so successful in this system? How do so many New England carnivores persist in a small area? How can six species of salamander coexist on Groton School lands?

Competition and Conservation Small Whorled Pogonia Isotria medeoloides