Biogeochem: Changing ecosystems - Henrik Flashcards
what drives long term landscape changes
climate change
what drives short term landscape changes
wildfires, landslides etc
What term is used to describe the vegetation development from bare site to climax?
Succession / Seral development
What does a Sere refer to?
a vegetation system in the process of development
What type of forest was Europe dominated by in the Tertiary
Laurel Forests
Where can you find Laurel Forests today?
In higher mountain ranges due to higher moisture and humidity levels
Azores, Canary islands and Micronesia
What was the environment in the Mediterranean during the last ice age?
A Steppe Environment
What is a steppe environment?
A semi-arid low humidity environment. Can have a continental climate (hot summers and cold winters)
Why do Central and Northern Europe show a much lower diversity of forest tree species compared to Southern Europe and North America
This is due to barriers blocking
potential migratory routes including the English Channel and Irish Sea or mountain ranges like the Pyrenees, Alps, Tatra and Carpathians Mountains.
What vegetation can you find on a Steppe Tundra
- Grass
- Shrubs (blueberries and cranberries)
Where would you usually find the plant Pheasants eye during the last ice age?
It was found in the Mediterranean in the continental steppe Belt
What are Pheasants eye species not in the Mediterranean anymore?
The Med species outcompete the Pheasants eye in the winter so don’t grow there
Where can you find the pheasants eye in present day?
In South France over 1000m elevation
Why can you find the species Draba Aizoides in the gower?
- Climatic conditions are suitable (not too warm)
- Relatively little competition (small area, few species)
- Species managed to adapt to changing conditions (speciation)
How many native oak species would be present in the UK if the introduction of 2 other oaks did not occur
2
What is generation time?
The time from seed germination to flower and first seed production to mode of dispersal
What aspects of seed dispersal are considered to determine the speed and distance seeds can spread over?
- Generation time
- Number of seeds produced
- Mechanism of dispersal
What is generation time
how long it takes for a plant to produce fertile seeds
What are Therophytes?
Annual plants that complete their life cycle in a short period when conditions are favourable and survive harsh conditions as seeds
Where do you find Winter Therophytes and whats seasons does their life cycle occur in?
Main area usually in the Mediterranean
They germinate in autumn and photosynthesise during winter. They flower and produce seed in Spring, so that they can persist as robust seed during the Mediterranean dry season.
Where do you find Summer Therophytes and whats seasons does their life cycle occur in?
Are normally found in temperate climates
Usually germinate in Spring, flower in summer and have their seeds produced in Autumn, so that they can survive the winter as a robust seed.
What triggers seed germination?
- moisture
- light (day length)
- temperature (eg after frost)
Which factor triggers which species depends on the species
What are the most common and widespread seed dispersal methods?
1) Anemochory - driven by wind
2) Zoochory - aided by animals
3) Hydrochory - dispersal by water
4) autochory - dispersal by the plant itself