Multiple stressors

phase shift

transition from one dominant spp to another. each spp must last for at least 3 years.

impacts of phase shifts

loss of antagonistic and mutualistic interactions, decrease in spp abundance, population decline of a spp and increase of another.

hughes phase shifts study

shift from coral to macroalgae in caribbean after hurricane. large predatory fish wiped out from overfishing → overfishing of herbivorous fish → urchin lose predator and overgrow → urchins killed by pathogen = no fish/coral/urchins = nothing to keep algae in check = algal overgrowth and corals can’t recover

trophic cascade

changes at the top of the trophic pyramid affect all the way down, e.g. in hughes’ study

phase shift due to tropicalization

warmer waters and stronger currents → tropical spp go into temperate waters and overtake native spp