III) Biotic Interaction limit Distributions (Other species)
1. Predation
2. Parasitism/Disease
3. Competition
1. Predation
a. Example - Mussels Lough Ine, Ireland
b. Explain distributions - transplant experiments
c. Herbivory form predation (urchins on algae marine systems)
d. Herbivory also important tropical reefs
e. Predation from exotics can reduce range native spp. - result extinction
f. 4-Criteria consider before conclude predation mechanism
i. prey survive when transplanted when exclude predators
ii. inverse correlation prey & predator (Algae vs Urchins)
iii. predator able to kill prey in field and lab
iv. prey shown to kill prey in transplant exp. to predator habitat
g. Prey abundance can also influence distribution of predator
-Predator has to very specialized
-Specialist predator = monophagous
-Many insect predators specialists � vertebrate not
-Although specific plant-insect interaction
-No clear evidence of positive correlation distribution plant-animal
2. Disease and Parasitism
a. Pathogens may eliminate species
b. Example:
i. Chestnut blight - Fungus introduced Asia w/ nursery stock
ii. Labyrinthula- Seagrass wasting disease (slime mold; fungal pathogen)
iii. Hawaiian bird extinctions & retreat to highlands
3. Competition
a. Exploitation
i. Plants - Light, water, nutrients, pollinators
b. Interference
i. Allelopathy - chemical defenses-toxic secretions plants & animals
ii. Direct competition - physical battles space, food, nest sites, mates etc.
c. Difficult to determine if distribution is a result of competition (>factors)
i. Checkerboard patterns tend to arrive from competition (fruit pigeons)
d. Competition minimized for niche-overlap by diversification through natural selection