BIOE 20C Lecture Notes - Lecture 17: Dynamic Equilibrium, Primary Succession, Secondary Succession
12 Sep 2016
School
Department
Course
Professor
Lecture 17 12/1/2015 8:56:00 PM
Island Biogeography
• Study of spatially isolated communities
• True islands:
o Chunks of terrestrial habitat surrounded by water
o Study terrestrial animals only, water acts as barrier
• Have distinct species/area relationships with steeper slopes than
comparable mainland
Equilibrium Theory
• MacArthur and Wilson 1967
• Dynamic equilibrium between
o Rates of colonization
o Rates of extinction (local extinctions)
• S=species number; as S increases
o Rates of new spp colonization decrease
o Rates of extinction increase
Experimental Tests of Equilibrium Theory
• Simberloff and Wilson 1969
• Arthropod spp diversity on mangrove islands in Florida
• Did spp removal with insecticide
• Documented return of species
• Result
o Similar # of spp recolonized islands
o Overall spp composition could be very different
Kicking it up a Notch
• Simberloff 1976
• Reduced island habitat size
o Removed portion of mangrove trees
• Compared spp number change to unaltered islands
• Result: smaller islands had fewer species
Community Dynamics
• Two views
• Frederick Clements
find more resources at oneclass.com
find more resources at oneclass.com
o Saw communities as superorganisms
o Spp worked cooperatively
• Henry Gleason
o Communities=collection of individual spp with unique
physiological tolerances
o Individualistic view of communities dynamics
Succession
• Recovery of a community after a disturbance
• Primary succession
o All spp and soil/propagules removed
o Ex. volcano eruption destroys everything nearby
• Secondary succession
o Some or all spp removed but soil/propagules left intact
o Some of the original community left behind to influence new
community
o Ex. fire, strong storm
Sequence of Succession
• Early successional community
o Pioneer species (high dispersal, fast growing, short lived)
▪ r-selected
• Late successional community
o Long lived, slow growing, superior competitors
▪ K-selected
• Climax community—stable persistent community
Two Views of Succession
• Clements:
o Primary succession is like embryology
o Secondary succession like wound healing
o Succession follows order sequence of distinct
communities=seres
• Gleason:
o Succession result of individual spp responses
o Community sequences can vary following disturbance
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
12/1/2015 8:56:00 pm: study of spatially isolated communities, true islands, chunks of terrestrial habitat surrounded by water, study terrestrial animals only, water acts as barrier, have distinct species/area relationships with steeper slopes than comparable mainland. Equilibrium theory: macarthur and wilson 1967, dynamic equilibrium between, rates of colonization, rates of extinction (local extinctions, s=species number; as s increases, rates of new spp colonization decrease, rates of extinction increase. Kicking it up a notch: simberloff 1976, reduced island habitat size, removed portion of mangrove trees, compared spp number change to unaltered islands, result: smaller islands had fewer species. Community dynamics: two views, frederick clements, saw communities as superorganisms, spp worked cooperatively, henry gleason, communities=collection of individual spp with unique physiological tolerances, individualistic view of communities dynamics. Sequence of succession: early successional community, pioneer species (high dispersal, fast growing, short lived, r-selected, late successional community, long lived, slow growing, superior competitors, k-selected, climax community stable persistent community.
