LECTURE 8 -> comunities Flashcards
What is a metapopulation
group is a metapop when: contains isolated populations connected by immigration/emigration
Characteristic of a meta population
have the SOURCE (Ex// a flour) and then a sink EX// a flower from the seed of main plant
why is determining meta populations important?
- > Is this really extinct or is just one of its sub-populations extinct?
- > Why is it collenizeing? Are there better resourse>
What causes communities to change?
DISTERBENCES drive succession
How to measure a disturbance?
extent [size], severity [intensity] and frequency [how often]
difference between primary and secondary succession
1 } disterbence so suverse, there is no soil --> relies on external colonizers ---> ex// volcanos & glacerars 2 } some species remain, soil ---> likely a gap in a larger zone
Types of disturbance initiated gaps
founder-controll -> First to arrive dominates
dominance controlled-> over time, some other species comes and out competes it
What is the order of succession
weeds, herp perennials, early succession trees, late succession trees (brings more shade)
-> from r dominances to k dominance
Goal of succession
to reach the climax o(shade tolerance species) but there will always be gaps
chronosequences are used for
identifying sites at various ages from disturbance, Helps determined what your looking for
complext food systems lead to
trophic cascades -> predator out competes prey, leading into a pop boom of lower trophic levels
explain the wolves in Yellowstone park saving the rivers
wolves kill the deer that eat the vegetation that stops the erosion of the river (top bottom control)
explain the fox conservation of Santa Cruz islands
decrease in bald egales, more golden eagles came and killed the foxes (and the pigs?)
- Ranchers brought the pigs, after all, and the pigs attracted the golden eagle
