Exploitative Interactions Flashcards
examples of exploitation
herbivores and plants
predators and prey
interactions can be…
direct
indirect
inter- and intraspecific
exploitation and abundance
predators, parasites and pathogens influence distribution, abundance and structure (eg age distribution) of prey and host populations
- parasites can decrease density of populations etc.
enemy release hypothesis
introduced species are released and native pop has no defences
dynamics
predator-prey, host-parasite and host-pathogen relationships are dynamic
- can produce population cycles that are not influenced by outside forces (snow rabbit + big cat go up and down together)
refuges
to persist in the face of exploitation. hosts and prey need refuges
refuges:
- secure places
- safety in numbers
- growing large (size-selective predators)
- fear of predators which can change distribution and create a refuge for plants
lokta-volterra predator-prey model
rate at which predator consumes prey is determined by prey abundance
ratio dependent models of functional response
models incorporating the ratio of prey to predator numbers better predict predator functional responses in many ecological circumstances
- some models suggest both predator and prey abundance can influence predator functional response
complex interactions
exploitative interactions weave populations into a web of relationships that defy easy generalisation
- more exploitative interactions than species
numerical response (component of predation):
increase through reproduction and moving to an area with more prey
functional response (component of predation):
change in numbers of prey eaten per predator
aposematism
colouration to confuse or warn predators
camouflage
cryptic colouration
batsman mimicry
mimic unpalatable species
mullein mimicry
convergence in appearance of unpalatable species reinforces effect on predators and benefits both species
