Card Set Information
community ecosystem ecology
Describe the invasion process
transport and introduction
establishment in the recipient region
What are the characteristic of non-indigenous species?
widespread with high abundance
widespread with low abundance
restricted range with high local abundance
restricted range with low local abundance
What kind of barriers do invasive species have to encounter?
demographic barriers (early effects, biotic interactions)
How are invasive species transported and introduced?
ballast water (unintentional transport)
food, recreation, etc (intentional transport)
In an ecosystem, what is the relationship between native species richness and probability of establishment? Explain.
more diverse ecosystem, more resistance to invasion -> fewer niches and resources available
more diverse ecosystem, less resistant to invasion -> what drives the increase in species richness in native species works the same way for invasive species
Provide an example of how establishment may be naturally facilitated.
Zebra mussels ...
high filtering rate has large impact on native plankton communities
--> increase water clearity, microphytes flourish
--> increase organic matter and provide substrate for benthic macroinvertebrates
allows for both native and non native species to flourish
What does geographic spread depend on?
population growth and dispersal ability
Describe the phosphorus cycle.
largest quantities of P occur in mineral deposits and marine sediments
P is slowly released through the weathering of rock
P is absorbed by plants, moves through the food chain and decay eventually returns P to the environment
Much P ends up dissolved in oceans
P returns to terrestrial system through uplift of marine sedimentary rock
Describe the nitrogen cycle.
atmospheric pool of N in the form of N
N fixation- N
is reduced into NH
by N fixers, lightening, and burning of fossil fuels for human use
ammonification after an organism dies
nitrification by bacteria
What can we say about the relationship between biodiversity and ecosystem functioning?
biodiversity loss reduced efficiency by which communities capture resources, produce biomass, decompose, and recycle nutrients
biodiversity increases stability of ecosystem through time
the impact of biodiversity is non-linear and saturating
diverse communities are more productive because...
...key species with large influence on productivity
...differences in functional traits increase total resource capture
loss of diversity across trophic levels may have stronger influence then within trophic levels
function traits of organisms have large impact on magnitude of ecosystem function
What are the factors that influence biodiversity?
migration of individuals
Describe the carbon cycle.
plants absorb CO
from the atmosphere during photosynthesis
in oceans used by marine
fossil fuels and changing land use also contribute
the ocean sink is growing, but the atmosphere sink is shrinking
carbon in soils, peat, fossil fuels and carbonate rock take a long time to return back to the atmosphere
largest pool of carbon is contained in carbonate rocks
What is the difference between a heterotroph and an autotroph?
: consumes organic molecules from other organisms
: assimilates inorganic resources and produces organic molecules (use energy from sun or other chemical reactions), increases with increasing nutrient addition
What evidence is there for hetertrophy in lakes?
many lakes are supersaturated with CO
bacteria metabolize dissolved organic carbon
What are the different kinds of competition?
: among individuals within a species
: among individuals of different species
: Through a shared limiting resource
interference (contest) competition
: direct interaction among species
exploitative (scramble) competition:
: indirect competition through a shared predator
What is the difference between fundamental niche and realized niche?
: range of biotic and abiotic conditions and resources that a species can persist
in the absence of interactions with other species
realized niche: range of biotic and abiotic conditions and resources that a species can persist
in the presence of interactions with other species
What is environmental heterogeneity? How can it be classified?
the number of species in a given area can often be greater in heterogeneous environments.
: heterogeneity is a feature of the environment
: heterogeneity is caused by the coupled action of environment and the community (eg nutrients)
What is the intermediate disturbance hypothesis?
natural systems often experience disturbance
low disturbance means high competition
high disturbance- few species with the appropriate fundamental niche
intermediate disturbance has greater diversity
Describe the equilibrium model of island biogeography.
on the x axis you have # of species present
on the y axis you have rate of immigration or extinction
the rate of immigration of new species decreases as the number of species on the island increases, the opposite is true for the rate of extinction
higher rate of immigration for islands near a source of colonists
higher rates of extinction on small islands
How might biodiverisity influence ecosystem function?
How might nutrients change as a result of succession?
decrease in soil P
: primary source of P is the weathered bedrock, over time it becomes less accessible and the demand for phosphorus increases so the concentration in the soil decreases
increase in soil N
: more N fixers as succession progresses, and as the soil depth increases, increase in N retention b/c N binds well to soil particles and doesn't get washed away by water
What kind of physiological and life history traits differ from early to late succession?
- EARLY-high LATE-low
- EARLY- many, small, LATE- few seeds, large
- EARLY- high, LATE- low
- EARLY- rapid LATE- slow
- EARLY- small LATE- large
Why do species differ in their elemental ratios?
organic molecules that make them up differ in their elemental composition
species differ in their relative composition of the organic molecules
How do nutrient ratios differ in terrestrial and aquatic organisms?
terrestrial- more variation in C:N ratios
What are the different metacommunity paradigms?
: patches are identical, A is a better competitor, B is a better disperser, coexistence in region
: A is a better competitor in one environment, B is a better disperser in another
: same as above, dispersal very high
: all species are similar, movement is random
What are some important steps in the N cycle?
: the conversion of ammonia to nitrate, generally mediated by bacteria
: the conversion of inorganic ions (eg nitrate) into organic compounds
: the breakdown of organic matter from organic to inorganic for during decomposition
How is the N cycle affected by temperature and moisture?
microbial activity increases with increasing temperature
decomposition increases with increasing moisture
N cycle also affected by...
substrate physical and chemical properties
microbial biomass size
shoot sink strength
What are some effects the tar sands are having on water?
water becomes highly contaminated
migratory waterfowl die by inadvertently landing in the ponds each year
causes deformaties on fish and increases mortality