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
what is Anemochory
seed dispersal driven by the wind
What is Zoochory
Seed dispersal aided by animals
What is Hydrochory
Seed dispersal by water
What is autochory?
seed dispersal by the plant itself
What are Archaeophytes
Species that were introduced to an area in ‘ancient times’
what are neophytes?
Species that were introduced to new areas after global travel transport started in 1500AD
How can the wind facilitate seed dispersal?
Seeds ‘flying’ through the use of hair or winged appendicies
Seed capsules shaken by the wind to disperse seeds (ie poppies)
Whole plants driven by wind and dispersing seeds on the way (tumbleweed)
List an example of wind driven seed dispersal by the use of hair or winged appendices
Willows
Dandelions
Sycamore
Maple
How does a tumbleweed form and disperse seeds?
The body of a plant breaks off at the root and rolls over land.
The seeds fall out of the seed pods and disperse fairly well
In Zoochory, how can animals disperse seeds?
Endochory - within the animal… Ingested and spread by faeces (eg berries)
Epichory - stuck to an animal on their skin, fur, hoofs etc
Transporting (carrying) and hiding them - eg squirrels
Zoochory example
Aldrovanda vesiculosa (venus fly trap) seed dispersal
It produced bud like structures which can get stuck in aquatic migratory bird’s feathers
the birds are the vectors transporting it to places like Europe, Asia and Australia when its usually found in East Africa
Zoochory example
Hepatica nobilis (hint: ant burrow)
The seeds of Hepatica nobilis have a nutritious appendage called an elaiosome which is transported to ant burrows and consumed.
Once it has been consumed, the seeds are transported to the ants waste area.
This has favourable conditions for seed growth due to the higher nutrient content
Hydrochory
Water Lily
Its seeds can float on the surface of the water and be transported long distances
Once the seeds have taken up sufficient water, the seeds are become heavier and causes them to sink into the sediment
Hydrochory
Coconut (Cocos nucifera)
Coconuts are transported over distances in sea water
The shell is tight which keeps the fruit afloat and prevents the saline seawater damaging it
Autochory Seed Dispersal
Indian balsam
Seed capsules are under pressure and upon mechanical stimulation (touch or raindrops), the seed pods open and catapult the seeds up to 7m away
This is called ballistic dispersal
Difference between Primary (Sere) and Secondary Succession
Sere
- occurs on vacant land which may have fully developed soils or require the development of soil
- begin with pioneering plants which are adapted to rapidly colonise the habitats
Secondary
- process started by an event such as volcanism, fires, storms, landslides
- occurs on pre-existing soils
Autogenic succession definition
Also ecological succession, driven by abiotic factors like tolerance, inhibition, pollination and seed dispersal
its mainly competition between species
Allogenic succession
driven by the abiotic factors of an ecosystem like climate, rock type and catastrophic events
Where do you get the highest species diversity?
(hint, what stage of a sere)
Intermediate stages
- grass to shrubs and scrubs colonisation
Pioneering Strategy (R strategy) example
Poppy
pioneer species for open ground meaning the seeds face little to no competition for light and nutrients
Established strategy (K strategy) example
Common oak
very few acorns per tree are produced. They reequire 2 or more years to ripen
They contain lots of nutrients which allows the seedling to establish itself in a competitive environment
Description of Pioneering Strategy ( R strategy)
- adapted to new enviornments
- many weeds
- fast reproduction meaning fast colonisation
- often vegetative reproduction (produce clones… eg dandelioins and brambles)
- show minimal variability
Description of Established strategy (K strategy)
- consolidating plants occuring in late seral systems
- slow reproduction
- usually sexual reproduction with many incompatibility systems (forcing mixing of genetic material)
- genetically variable
What plant is an exception to the R, K strategies
and reason
Orchids
produce extremely large number of extremely small seeds that contain no nutrients
they find a fungus species which provides them with the nutrients they need
As a seedling, they are a parasite, but as they grow it becomes a symbiotic relationship as the orchids provide the fungus with photosynthetic products while the fungus helps the orchid take up inorganic nutrients
what is a hydrosere?
plant communities in aquatic environments
What is a psammosere?
plant communities of sandy habitats, dunes
What is a halosere?
plant communities in saline habitats
What is a lithosere?
plant communities of rocky habitats from scree to slopes
What is a sub-climax?
Successional development can be interrupted for a range of reasons (sometimes human activity) and a sub-climax can be reached. It may appear as a stable climax community but will reach climax eventually
What is a plagioclimax
communities that are in a stable state but are not climax communities
how can plagioclimax communities be formed?
- Prevention from further development (subclimax)
- Degradation (eg deforestation… mediterranean or Brecon Beacons)
List examples of plants found in the halosere
Salicornia spp. (glasswort)
Spartina spp. (cord-grass)
What increases or decreases with age in the psammosere
pH decreases
CaCO3 decreases
Organic matter increases
Ground cover increases
List examples of plants found in the psammosere
Sea rocket
- (trap sand and an embryo dune can form on the leeward side)
Sea spurge and Sea holly (foredunes)
Stabilised = Bee orchid
List an example of plants that from in tho lithosere
Welsh poppy
Alpine valerian
What is the Xerosere?
plant communities limited by water availability
- this can include the psammosere, lithosere and others
