Dauphin Island Memories…… Mecha Streisand

Competition (Ch. 10) Ken Jennings: my hero! 74 wins (2004) $2.52 million

DeWit Replacement Series After growing, determine output ratios Ex: # seeds A:# seeds B biomass A:biomass B

DeWit Replacement Series After growing, determine output ratios Ex: # seeds A:# seeds B biomass A:biomass B Graph input & output ratios (log scale) log output A:B log input A:B

DeWit Replacement Series No interaction, input ratio=output ratio Stability line. Slope=1 Ex: 50:50 input & output ratios Stability line 50:50 X log output A:B 50:50 log input A:B

DeWit Replacement Series Area above stability line? Stability line X log output A:B log input A:B

DeWit Replacement Series Area above stability line: “A wins zone” More A output than input Ex: 50:50 input, 75:25 output Stability line 75:25 X log output A:B 50:50 log input A:B

DeWit Replacement Series Area below stability line? Stability line log output A:B X log input A:B

DeWit Replacement Series Area below stability line: “B wins zone” More B output than input Ex: 50:50 input, 25:75 output Stability line log output A:B 25:75 X 50:50 log input A:B

DeWit Replacement Series Movement on graph Suppose take output (X) & plant again Stability line 75:25 X log output A:B 50:50 log input A:B

DeWit Replacement Series Movement on graph Suppose take output (X) & plant again 95:5 Y Stability line 75:25 X log output A:B 75:25 50:50 log input A:B

DeWit Replacement Series Movement along line (experimental line) A better competitor & eliminate B 95:5 Y Stability line 75:25 X log output A:B 75:25 50:50 log input A:B

DeWit Replacement Series If line above stability line, move left to right Stability line log output A:B log input A:B

DeWit Replacement Series If line below stability line, move right to left Stability line log output A:B log input A:B

DeWit Replacement Series Ex results (4 possible): Stability line log output A:B log input A:B

DeWit Replacement Series Ex results: Slope = 1 above stability line A Stability line log output A:B log input A:B

DeWit Replacement Series Ex results: Slope = 1 below stability line B Stability line log output A:B log input A:B

DeWit Replacement Series Ex results: Slope <1 Lo input ratios A wins: Stability line log output A:B log input A:B

DeWit Replacement Series Ex results: Slope >1 Stability line log output A:B log input A:B

DeWit Replacement Series More complicated designs: change ratio and density Replacement Series Partial Additive Series Additive Series Complete Additive Series

DeWit Replacement Series How helpful? Ex, wild oats (Avena) CA annual grassland Mediterranean climate Tule Elk

DeWit Replacement Series Greenhouse results (dotted line): Outcome? A) wild oat wins B) slender wild oat wins C) 1 stable ratio D) either wins (which depends on input ratio)

DeWit Replacement Series Field trials: >

Studying Competition Field approach: removal experiment Remove Ex: target-neighborhood experiment

Target-neighborhood experiment Ex: creosote bush (Larrea tridentata) & burro bush (Ambrosia dumosa) Mojave Desert

Target-neighborhood experiment Remove around “target” shrub Target monitored (water status)

Target-neighborhood experiment Remove around “target” shrub Target monitored (water status) Result: Danger…

Danger for removal experiments: Apparent competition Herbivore effects mimic competition Ex: Herbivore eats A and B

Other points 1) Herbivory influences competition Ex, chalk grassland (England) Lab studies: grass better competitor. How forbs persist? Rabbits (“killer rabbits?”) Plant Ecology Theatre!

Other points Rabbits prefer grass (help forbs) Twist: Myxomatosis decimated The marsh fritillary

Other points 2) Disturbance timing on competition species 1 numbers No disturbance time

Other points Can allow coexistence Frequent disturbances numbers species 1 species 2 time

Other points 3) Phenology can