ecology pt 2 Flashcards
succession
gradual and directional change in community structure through time
describe
early successional species ( pioneer species)
high growth rates, small size, high degree of dispersal: r-strategists
late succesional species
lower rates of dispersal and colonization, slower per capita growth rate, larger, K- strategists
primary succession
occurs on a site previously unoccupied by a community
secondary succession
occurs on a previously occupied sites but after a disturbance
where does primary succession occur?
sites that have never supported a community
rocks, outcrops, cliffs, sand dunes
what are the most successful pioneering plants?
grasses
climax community
assemblage of characteristic plants that define an ecosystem
intermediate disturbance hypothesis
species diversity is at its best when disturbance isn’t too constant or too rare
organismic concept of communities
- transitions between communities are narrow
- communities have few species in common
- common evolutionary history and simialr fundamental responses and tolerances
individualistic/continuum concept of community
- species associate bc of similairties in the tolerance
- species do not cluster along enviornmental gradients
- trasitions are gradual and difficult to identify
landscape
an area that is heterogenous in at least one factor of interest
habitat patches
relatively homogenous community types that differ from their surroundings in physical structure
fragmentation
when large patches of habitat are reudced to small isolated patches
what results in habitat fragmentation
human activity (amongst other things but mainly humans)
mosaic
landscape with different kinds of patches
edges
perimeters of each patch
dynamic and may change through time
types of patches
- narrow and abrupt
- wide with tranistion zone/ecotone
- straight
- concoluted
- perforated
the edge effect
phenomenon where edge communites are often diverse
what are some possible problems with the edge effect?
- attraction of more predators (ecological trap)
- restricts dispersal
corridor
particular strips of landscape differing from adjacent land on both sides
- incr. gene flow, promote reestablishment of locally extinct populations, incr. species diversity
- may provide habitats
ecotone
transitional zone between two communities
ex: fencerows, forest to marshlands transitions, land-water interfaces,
characteristics of ecotones
vegtational sharpness, physiognomic change, occurrence of a spatial community mosaic, many exotics species, species richness higher or lower on either side of the ecotone
matrix
“background ecological system” of a landscape
connectvity
measure of how connected or spatially continuous a corridor, network, or matrix is
what is dispersal important for
- gene flow
- recolonialization of extinct habitat patches
- shifting ranges in response to climate change
what is dispersal between habitat patches affected by
- plants: seed size and dispersal vector (wind, animal, humans)
- animals: dispersal behavior( vagility) and resitance of matrix
theory of island biogeography
number of species on an island represents a dynamic equilibrium between the immigration of new species and extinction of established ones
what are the inputs and outputs of photosynthesis
Carbon dioxide, light energy and water -> oxygen and glucose
inputs and outputs of respiration
glucose + oxygen -> carbon dioxide + energy
gross primary productivity (GPP)
total rate of photosynthesis or the energy assimilated by autotrophs
net primary productivity (NPP)
rate of energy storage as organic matter after respiration
net primary productivity equation
NPP = GPP -R
net primary productity = gross primary producivty - respiration
standing crop biomass
amount of organic matter present at any given time
= mass of organic matter/area= g/m^2
transpiration
- 90% of plant water use
- allows plants to transport water and mineral nutrients from the soil to growth regions
- exhalation of water vapor
evapotranspiration
loss of water from the soil both by evaporation and transpiration from the leaves
factors that influence productivity
- disturbances (herbivory fire)
- seasonal variations ( cold winter= lower productvity)
- nitrogen availability incr. productivty
bioaccumulation
with each trophic level, molecules increase in concentration
DDT
secondary productivity
energy put towards growth and reproduction
how much energy is tranfered in a trophic level
10%
decomposition
breakdown of chemical bonds of organic molecules
nutrient cycle
movement and exchange of organic and inorganic matter into the production of living matter
decomposers
organisms that feed on dead organic matter or detritus
detrius
non-living matter (feces + dead woods, animal tissue etc)
mineralization
transformation of nutrients contained in organic compounds into inorganic forms
net mineralization rate
difference between the rates of mineralization and what is used by the decomposers
retranslocation/resorption
process of recyling nutrients within the plant
main reservoir of hydrologic cycle
oceans (97%)
aquifers
underground reserviors of water
effects of human activities on the water cycle
- withdrawing large amounts of freshwater
- polluting
- contributing to climate change
where is majority of freshwater
glaciers
what percentage of water is freshwater
2.5%
where is most carbon on earth
buried in sedimentary rock, not actively involved
where is the greatest accumulation of organic matter?
where decomposition is inhibited, frozen or waterlogged soils
site of main exchange of carbon dioxide
surface water
greenhouse gases
absorb thermal radiation- warms the earth’s surface and lower atmosphere
FACE Experiment
long term experiment at Duke Experimental forest examining the effect of elevanted CO2
what forms is nitrogen available to plants
ammonium nh4+ and nitrate no3
Haber-Bosch process
making synthetic ammonia from nitrogen gas and hydrogen, led to the green rev.
what can excess nitrogen run off do
eutrophication
eutrophication
stimulates algae blooms that deplete the water of oxygen
how is atmospheric nitrogen fixated
symbiotic bacteria living with plants, cynobacteria
free living bacteria
what is the largest species
Coleopterea (beetles)
latitudinal gradient
increase in biodiversity from the poles to the tropics
largest factor is the greatest mean temp. at the equator compared to the poles
biodiversity hotspots
region with a high level of endemic species that has experienced greaat habitat loss
pleistoncene extinctions
11,000+ years ago many mammals went extinct in North america
human hunting caused/contributed to the extinction of many of the plesitocence large mammal
hypotheses for species diversity & latitude
- spatial heterogeneity of the enviornment
- climate stability
- ecosystem productivity
spatial heterogeneity of the enviornment
habitats with complex physical structures have more niches than habitats with simple physical structures
hypotheses for species diversity
climate stability
seasonal stability- a constant enviornment can allow species to specialize
historical stability- tropical regions have not been glaciated and have had more time for speciation to occur
hypotheses for species diversity and latitude
ecosystem productivity
greater productivity= greater diversity
local (alpha) diverisity
species diversity of individual communities
regional (gamma) diversity
total species diversity across all communities within a geographic area
beta diversity
change in species diversity from one location to another
causes of extinction
overkill, over harvesting
habitat loss
invasive species
climate change
what happened to the passenger pigeon
exinct in 1914, from over hunting
what is the overall greatest threat to biodiversity
deforestation
example of introduced species turned invasive
zebra mussels- cover solld substrates and water intake pipes
asian carp were introduced by catfish farmers to remove alage
what is the first species to be place on the endangered species list due to climate change
polar bear
ecosystem services
services/goods that the enviornment provides to people
kinds of ecosystem services
provisioning
regulating
cultural
supporting
what did the brown tree snake do
eliminated a majority of native bird, lizard and bat species in guam
white-nose syndrome
fungal pathogen that infects cave hibernating bats and threatens extinction
CITES
treaty to protect endangered plants and animals
endangered species act of 1973
provides a program for the conservation of threatened and endangered plants and animals and the habitats
cannot take listed animals
population viabillity analysis (PVA)
species specific method of risk assessment frequency in conservation bio- determines the probabillity that a population will go extinct within a certain amount of years
reintroduction
deliberate release of a species into the wild from captivity where the animal surrvives
translocation
movement of wild caught animals from one natural location to anotther
peregrine falcon
removed from endangered species list after a 30 year recovery program
Aldo Leopold
considered the father of restoration ecology
restoration
improves community composition and ecosystem functions to return to a site to as close a natural system as possible
reclamation
inital goal is detoxification and terrain stabilization
replacement
create a new community entirely different from the orginal, often to replace habitat destroyed nearby
Bubbly Creek
reclamation- garbage pit for waste
