BIS 2B Lecture Notes - Lecture 34: Myrica, Serpentine Soil, Edge Effects

• School: UC-Davis
• Department: Biological Sciences
• Course: BIS 2B
• Professor: Schmitt Johanna

Document Summary

Greenhouse gases, climate warming, sea level rise. Current rates of extinction are ~1000 times the likely background rate of extinction. Trends in population abundance for 14152 populations/ 3706 terrestrial species: avg decline 2%/yr. Stochastic fluctuations (# of offspring individual has) Allee effects - difficulty finding mates, reduced reproduction. Fixation of deleterious alleles by genetic drift. Bigger states, more ecological niches - more endemic species. Ex: furbish lousewort; all populations on one river, risk of flooding. Narrow habitat or resource specialists, specialized niche. Ex: california serpentine soil specialists, mycoparasitic orchids; very specific requirements. Small populations, many endemic species, vulnerable to invasions (e. g. novel predators) Ex: loss of primary forest in costa rica; loss of habitat, fragmentation into. Loss of endemic species roughly proportional with area loss. S = ca^z logs = logc +zloga. Edge effects: circumference/area increases as size goes down. Theory of island biogeography: equilibrium between species arrival/colonization & extinction.