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