Chapter 18- Species Diversity in Communities

  1. Biofuels
    • liquid or gas fuels made from plant material
    • carbon neutral: amount of CO2 produced by burning matches amount taken up by plants
    • supply limitless as long as crops can be grown to fulfill needs
    • reality is that they reduce fossil fuel modestly
  2. Distribution and abundance factors
    • regional species pools and dispersal ability
    • abiotic conditions
    • species interactions
  3. Species Supply
    regions of higher species richness tend to have communities that have high species richness
  4. Abiotic Conditions
    may be unable to become part of comunity if cannot tolerate physiological coditions
  5. Species Interaction
    • might depend on other species for growth
    • excluded by competition, predation, parasitism, or disease
  6. Biotic Resistance
    native species exclude or slow-down the population growth of non-native species
  7. Resource Partitioning
    competeing species more likely to coexist if they use resources in different ways
  8. Resource Ratio Hypothesis
    species coexist by using resources in different ratios or portions
  9. Intermediate Disturbance Hypothesis
    • the level of disturbance experienced by a community could have drastic effects on its species diversity
    • a balance between distruption of competition and mortality leads to high diversity
  10. Competitive Displacement
    the growth rate of the strongest competitor in a community and its dependent on the productivity of its environment
  11. Dynamic Equilibrium Model
    considers how the frequency or intensity of disturbance and the rate of competitive displacement combine to determine species diversity
  12. recruitment
    • influx of young individuals into a population
    • if increases level of competition increases as well influencing species diversity
  13. Lottery Model
    • emphasis role of chance in maintainance of species diversity
    • assume that resources made available by disturbance, stress, and predation are captured at random by recruits from a larger pool of potential colonists
    • for highly diverse systems (Great Barrier Reef)
  14. Function of Diversity
    • plant productivity
    • soil fertility
    • water quality and availablity
    • atmospheric gas exchange
    • resistance to disturbance
    • resilience
  15. Stability
    tendency of a community to remain the same in structure and function
  16. Complementary Hypothesis
    • as species richness increases will be linear increase in community function
    • with each new species added thier unique function will contribute to increase community function value
  17. Redundancy Hypothesis
    • places upper limit on effect of species richness on community function
    • will reach threshold causing redundancy among species
    • as long as all functional groups are present the actual species composition of the community is of little importance to its overall function
  18. Driver Passenger Hypothesis
    • strength of the effects of species' ecological function vary dramatically among species
    • Driver species have higher impact on function
    • passenger have minimal effect
    • addition of driver/passenger species have unequal effect on community function
    • creates stair step curve
  19. Driver/Passenger with overlap
    produces curvilinear relationship caused by slight overlap in functins of driver and passenger species
Card Set
Chapter 18- Species Diversity in Communities
chapter 18 term