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
Distribution and abundance factors
regional species pools and dispersal ability
abiotic conditions
species interactions
Species Supply
regions of higher species richness tend to have communities that have high species richness
Abiotic Conditions
may be unable to become part of comunity if cannot tolerate physiological coditions
Species Interaction
might depend on other species for growth
excluded by competition, predation, parasitism, or disease
Biotic Resistance
native species exclude or slow-down the population growth of non-native species
Resource Partitioning
competeing species more likely to coexist if they use resources in different ways
Resource Ratio Hypothesis
species coexist by using resources in different ratios or portions
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
Competitive Displacement
the growth rate of the strongest competitor in a community and its dependent on the productivity of its environment
Dynamic Equilibrium Model
considers how the frequency or intensity of disturbance and the rate of competitive displacement combine to determine species diversity
recruitment
influx of young individuals into a population
if increases level of competition increases as well influencing species diversity
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)
Function of Diversity
plant productivity
soil fertility
water quality and availablity
atmospheric gas exchange
resistance to disturbance
resilience
Stability
tendency of a community to remain the same in structure and function
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
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
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
Driver/Passenger with overlap
produces curvilinear relationship caused by slight overlap in functins of driver and passenger species