L4 - determinants of ecological variation Flashcards
why does productivity vary temporally and spatially?
- seasons
- environmental variability (temperature, moisture, light, nutrients)
- disturbances
- species composition and age.
What is the association between primary productivity and vegetation structure?
higher productivity = more complex structure
what are biomes based on?
structures of dominant vegetation.
how can biomes be predicted?
precipitation and temperature.
(remember the P&T diagram)
why do we care about variation at a global scale?
- global ecological feedbacks
- human livlihoods
- prediction
- decision making
list all the terrestrial biomes of Canada. (7 listed in class)
- temperate rainforest
- tundra
- temperate deciduous
- desert
- grasslands
- montane forest
- boreal forest
Describe a temperate rainforest
- mild temp
- wet
- structurally complex
- large disturbances uncommon
- conifer dominant
describe a temperate deciduous forest
- warm summers
- moderate precip
- deciduous tree dominant
- restricted range in Canada
Describe a boreal forest (tiaga)
- cold winters, short warm summer
- low precip
- sparse conifers
- high disturbance (bugs, fire)
- more than half of Canada is boreal
Describe a tundra Biome
- cold
- dry
- treeless areas, dominated by dwarfed shrubs
- perennial permafrost
Describe a montane forest biome
- forested area below mountain treeline
- dominated by conifers
- disturbances give it patchy structure
Describe a temperate grasslands biome
- dry
- warm
- soil moisture deficit prevents forest development
- herbaviours suppress tree establishment
- severely impacted by land-use change
describe a desert biome
- very dry
- variety of temperature
- soil moisture deficit limits most vegetation
what are some problems with biome maps?
- oversimplified
- cutoff point is subjective
- missing external factors like:
- proximity to water
- elevation
- land-use change
What is an Ecozone?
a classified region of distinct terrestrial and marine zones in Canada.
- 15 terrestrial
- 5 marines
what are BEC subzones?
subzones are additional divisions based on precipitation.
describe the concept of anthropogenic biomes
Nature is now imbedded within human systems and effective conservation must account for human-ecosystem interactions.
Ellis & Ramankutty (2008)
what determines productivity in the marine realm?
- photosynthesis is light limiting, and rapidly declines with depth
- coastal areas have upwelling, source of nutrients
- river deposit sediment rich water that sparks ocean productivity.
what are the two ocean biomes described in class?
- Open ocean
- Continental shelf.
