Lecture 2 - Forest Biomes of the World Flashcards
What factors affect the distribution of vegetation?
- solar radiation (photoperiod)
- water availability
- location
- soil
- disturbances
How does solar radiation affect species distribution?
It has a major control on the climate. The equator gets direct sunlight while the north and south gets the sun an angle - affects which species can grow where. Ex. getting less sunlight due to rotation & angle (shortening photoperiod) causes trees to change colour and lose leaves)
How does water availability affect species distribution?
It is based on the amount of precipitation an area receives and its ability to dry (evaporation). Ex. tropical vs temperate vs boreal are all different.
How does location affect species distribution?
The distance to large bodies of water (coastal areas vs. inland).
How does soil affect species distribution?
- soil fertility: infertile soil hosts gymnos and fertile soil hosts angios
- parent material: type of bedrock influences soil acidity which influences the plants that can grow there
- climate: diff species in areas of high rainfall vs. freeze thaw
- soil weathering & nutrient leaching: ex. tropics have more nutrients in vegetation than in soil
- young vs. old: recent glaciation (new) and nutrient leaching (old)
How do disturbances affect species distribution?
It depends on the intensity, frequency and type of disturbance.
Natural: fire, wind and drought (often influenced by humans through climate change - ex. warm ocean water means harder to suppress hurricanes)
Anthropogenic: land clearing, timber harvesting, fire suppression
How is vegetation classified?
It is based on climate, appearance (physiognomy) and deciduous vs evergreen. The broadest classification is a biome.
What is a biome?
It is a collection of ecosystems that are similar/related to one another based on the types of plants they can support
What are the major global forest biomes?
- Boreal (Taiga)
- Temperate
- Tropical
What are the characteristics of the boreal forest?
It is only found in the N. hemisphere (mainly CAN and RUS) and covers 30% of total global land area. They have harsh climates (long cold winters with permafrost in some areas). There is slow soil development due to poorly drained soils and accumulation of peat moss.
Why is there low species diversity in boreal forest? Give examples of some species.
There is only 9 dominant tree species in taiga b/c of recent glaciation and topography/soil type.
Ex. Spruce/larch do well in poorly drained soils
Ex 2. Pine does well in well drained soils
Ex 3. Poplar, fire, willow do well in upland fine soils
Ex 4. Lots of lichens, mosses, sphagnum, etc.
What are some adaptations of trees in the taiga?
The canopy minimizes snow buildup and maximizes sunlight exposure.
Fire important natural disturbance that some species are dependent on (ex. jack pine)
Why is the taiga the least managed biome?
B/c it has low growth (short growing season) and it is relatively inaccessible. There are lots of underground resources that often causes air pollution (nickel & iron mines)
What are the characteristics of temperate forests?
Located in N. hemisphere and includes mixed forests, broad-leaf forests, and temperate rainforests. It is the second rainiest biome. Typically has 4 seasons with warm summers, cold winters and dominated by angiosperms
What are some animal adaptations to living in temperate forests?
Migration and hibernation
How are temperate forests usually managed?
They usually support rec. activities, have selective logging and prone to invasive species
What are the characteristics of tropical forests?
Tend to be found in S. America, Africa, and Asia and cover 34% of global land area. They have high rainfall and high humidity (usually with a dry period). They occur on highly variable soils with low fertility and are highly leached
Why are there so many species in tropical forests?
It has the highest biodiversity b/c there is a complex canopy that provides habitat for millions of species
What are the disturbances in tropical forests?
Very high disturbance levels occur that receives high pressure from enviro groups
- hurricanes
- wildfires
- volcanoes
- anthropogenic causes of forest loss
What are Canada’s forest ecozones? (know how to label map!!!)
- Acadian
- Deciduous/Carolinian
- Great Lakes/St. Lawrence
- Boreal
- Tundra
- Grasslands
- Columbian
- Coastal
- Subalpine
- Montane
What is the main ecozone of Canada?
It is predominantly boreal (mostly coniferous with mix of deciduous species, like white birch and trembling aspen). It is bordered by tundra in north and grasslands & deciduous in south.
What is the tundra?
It is a treeless area b/w the tree line and the arctic that is has permafrost, making vegetation scarce. It is cold with a short growing season and is quite barren with mainly lichen and few small dispersed trees. This edge of boreal is dominated by spruce and larch.
What is the grasslands (prairies)?
It is not a forest region but supports several tree species (ex. trembling aspen). It is warmer with a longer growing season and this edge of the boreal has many deciduous trees that opens up into the prairies
What is the subalpine region?
It is coniferous forests found in AB to the BC coast
What is the montane region?
It is the interior uplands of BC that has prairie communities with grasses
What is the coastal region?
It is exclusively coniferous on the pacific coast
What is the columbian region?
It it the coniferous forests of BC that merges with other regions
What is the deciduous region?
It is aka carolinian and is temperate forests
What is the great lakes/St. Lawrence region?
found b/w deciduous and boreal and is made of a mix of conifers and deciduous trees
What is the acadian region?
It is in the maritimes and is related to the great lakes. It’s dominated by red spruce trees.
How does altitude affect the environment changes?
As altitude increases:
- changes in temp (decrease 6°C for every 1 km increase in altitude)
- change in humidity/precipitation
- change in soil composition
- change in solar radiation
Why are forests important components of the biosphere?
- they regulate climate
- they sequester C
Why is habitat protection important?
Maintains/improves biodiversity, which is an important ecosystem service
