Competition and Facilitation

intraspecific competition

same species, usually greater

interspecific competition

between species, often leads to one species dominating e.g. Paine removing starfish from a rocky shore → mussels dominating

main limiting resources

food and space

exploitative competition

indirect by depletion of a shared resource - scramble and contest

scramble competition

limited resources but nothing to limit spp accessing it. more efficient spp wins

contest competition

spp fight for resources through direct interaction

mechanisms of action to compete

consumption, preemption, overgrowth, allelopathy, territoriality, direct encounter

consumption

spp inhibits another by consuming a shared resource (limpets/barnacles)

preemption

spp inhibits another by arriving first (kelp growing first)

overgrowth

spp inhibits another by growing over another (barnacles)

allelopathy

spp inhibits another by producing toxic chemicals (coral/algae)

territoriality

spp inhibits another by defending a territory (damselfish)

direct encounter

direct interactions between individuals

facilitation

one or both spp benefits and are unharmed

drivers of community structure

predation, competition, abiotic stress, intraspecific facilitation, interspecific facilitation

which model

predator-stress model

which model

intraspecific facilitation

which model

interspecific facilitation

amelioration

improve environmental conditions