Terrestrial and Wetland environments Flashcards
How many major biomes exist?
8
Major biomes are based on the abundance of 3 major plant types:
- trees
- shrubs
- grasses
Who plotted the biomes across annual temperature and rainfall and found a distinct pattern?
Robert Whittaker
What other factors can determine biomes?
- topography
- soil type
- disturbance
- fire
Biomes are generally a result of _____ and _____ patterns.
temperature and rainfall
What are major determinants of temperature and rainfall?
latitude, elevatioin, and solar exposure
Terrestrial ecosystems reflect adaptations of the _______ plant life forms.
dominant
Grasses
allocate less carbon to support structures; can maintain high % of photosynthetic structures
Shrubs
allocate lower % of biomass to stems
Trees
allocate highest % of biomass to support structures
What determines the abundance of plants on our planet?
availability of water and solar energy
_____ _____ characterize the equatorial zones.
tropical rainforests
Tropical Rainforests
- temperatures remain warm and constant
- rainfall occurs almost daily
- trees dominate but grasses and shrubs exist
- high diversity of plant and animal life
- covers only 6% of Earth’s surface
- highest rate of primary productivity
Tropical Savannas
- characterized by codominance of grasses and woody plants
- region typically has alternating wet and dry seasons
- primary productivity and decomposition is tightly linked with precipitatio-african savanna is dominated by a large and diverse population of ungulates
_______ are partially responsible for maintaining the African savanna
elephants
Temperate Grasslands
- occupy regions where rainfall is 25-80 cm annually
- once very widespread, only a fraction still exists
- tall-grass prairie is the single most endangered ecosystem today (1% remains)
- coevolved with high abundance of grazing species
Today: controlled ______ function to limit the spread of trees
burns
Deserts
- 15% of earth’s land surface
- less than 25 cm rainfall
- largely a result of dry descending air masses
- hot and cold deserts
- strucuturally simple: scattered shrubs, ephemeral plants, stark topography
Shrublands
- plant communities where shrubs are dominant or codominant with other plants
- difficult to classify
- 65% of precipitation occurs in winter months
- summer temp can get high with little rainfall
- trees may take on shrub-like characters to survive
Temperate Forests
- dominanted by broadleaf, deciduous trees
- year round precipitation but seasonal temperatures
- impacted heavily by human activity
- large majority of forests today are “secondary forests” that have regrown from original forest remains
Deciduous
drops leaves annually
Conifer Forests (Boreal)
- dominated by evergreen trees
- low temperatures limit the growing season to only a few months per year
- permafrost is typically maintained by cold temperatures and tree cover
- permafrost strongly influences ground-cover species
- many species are fire tolerant
Tundra
- characterized by low temperatures and low precipitation
- short growing season and permafrost limit plants
- dominant vegetation is cotton grass and sedge
- plants are photosynthetically active 2-3 months per year
The ____ ____ is covered and uncovered daily.
intertidal zone
Salt marshes
- an area of coastal grassland that is regularly flooded by sea water
- resides in the upper intertidal zone
- dominated by dense salt-tolerant plants (herbs and grasses)
- all plants in this ecosystem are terrestrial in origin so they are not impervious to saltwater damage
Mangroves
- function similarly to salt marshes
- replace salt marshes in tropical regions
- covers 60-75% of tropical coasts
- have specialized glands for expelling excess salt
Salt marshes and wetlands __________ and buffer against floods.
protect our coasts; coastal ecosystems absorb a huge amount of kinetic energy
