L11 Temperate Biomes Flashcards
What is the climax community in the UK
Temperate deciduous forests
Where are temperate deciduous forests found
Are there more in the Northern or Southern hemisphere
Above and below Capricorn and Cancer
More in Northern hemisphere
What are the characteristics of a deciduous forest climate
Cold and wet winters
Warm, slightly drier summers
What is the minimum annual rainfall in a deciduous forest
500-750mm
When did the soils of temperate deciduous forests form
Since last glaciation
Where would Welsh temperate rainforests have dominated
West coast
What trees could you expect to find in temperate deciduous forests
Oak, maple, beech, chesnut, elm, linden, walnut
Why do temperate deciduous forests have species from the dry tropical forest lineage
Frost tolerant bark
What trees are from the dry tropical forest lineage, what is the name for the group
Furgails
Oak, maple and beech
What is the soil of temperate deciduous forests like
Mull soils
High level of organic matter from leaf litter
High decomposition rates
What tree would dominate on shallow chalk soil
European beech (Fagus sylvatica)
What tree would dominate on deeper clay soils
Oak
How does the structural layering of temperate deciduous forests compare to dry tropical, boreal and rainforests
More structural layers than dry tropical and boreal
Less than rainforests
What are the vertical layers of temperate deciduous forests
Canopy layer
Shrub layer / subcanopy
Herbaceous / field layer
Ground layer
What effects can seasonality have
Changes in light availability, resources (food, shelter)
What happens to leaves in autumn
Chlorophyll is broken down
Nutrients are withdrawn
Are yellow and red leaves still photosynthesising
Yes, just using pigments other than chlorophyll
What causes leaves to fall
A change in structure of the petiole
Are the pigments of yellow and red leaves added after chlorophyll breaks down
No, the pigments are already present, but with the chlorophyll green pigment removed, they are now visible
What causes yellow pigment
Carotenoids and flavonoids
What causes orange pigment
Carotenoids - B-carotene
What causes red pigments
Anthocyanins and carotenoids
When is anthocyanin synthesised
Onset of autumn, not actually present the whole time like the carotenoids that produce yellow and orange
What is the season of dormacy
Winter
Why does the herbaceous layer form in Spring
The canopy is open (light availability) and temperatures are warm
What occurs in trees during spring
Sap rises from roots to branches
Some trees flower before leaf flush e.g. Maple, hazel, hawthron
What nutrients are found in young leaves
High in phosphorous and nitrogen
Why do insects appear in spring
Hatching of larvae is coordinated with nutrient rich time of leaves
Explain phenological mismatch in deciduous woodlands
Some plants change their phenology to bloom sooner (plasticity) as a result of climate change
Insects are less plastic so can’t adapt and miss out on nutrient rich period of herbaceous plants
What kind of mismatch is the phenological mismatch occuring in deciduous woodlands as a result of climate change
Temporal
What may arise as a result of this temporal mismatch
Increase in invasive species which then have resource not previously available
What changes occur in summer
Canopy layer becomes denser
What is the negative implication of being a seasonal cyclic tree
Why does it still occur
Expends large amounts of energy
Proccess only beneficial in regions with long growing seasons
Name some animals of temperate forests
Badgers
Bats
Squirrel
Owls
Bears
Birds
Where are boreal forests found
North of temperate deciduous forests
None in Southern hemisphere
What proportion of the Earths surface is covered by boreal forest
8%
What proportion of the Earths surface is covered by boreal forest
8%
What are the climatic conditions in boreal forests
Long cold winters
Short warm summers
Low precipitation
What is species diversity like in boreal forests
Low
What trees are found in boreal forests
Why do they have lower diversity
Coniferous spruce, fir, pine, larch
Gymnosperms - lower diversity than angiosperms due to shorter radiation period
Sometimes an understory of broad-leaved Alder, birch and aspen
What is prodocutivity like in boreal forests and why
Low productivity and slow decomposition as it is cold and dry
What type of soils are in boreal forests
What can accumulate
Acidic soil
Peat accumulation (carbon sinks)
What are the threats to boreal forests
Logging
Oil and gas extraction
Mining
What is the soil in boreal forests like
Young and shallow
Leaf litter composed of conifer needles
What is the mineral content of boreal forest soil like and why
What forms as a result and what can this be called
Acidic water washes away major mineral components
Leaves powdery layer of silicon oxide soils - podzol or spodosol
What colour is the B horizon of boreal forest soil and why
Reddish colour due to iron and lack of humus
What is the fertility of boreal forest soils like and why
Low fertility
Due to leaching from acidic soils and low decomposition rates from leaf litter
What is the vegetation structure in boreal forests
A single layer - the tree canopy
Ground layer of lichen or moss
Can be low shrubs and scattered herbs depending on disturbance regime or successional process
How does succession work in boreal forests
No classic succession
Shifting mosaic of plant comunities existing in response to fire, soil moisture, permafrost depth, organic layer and nutrient depletion
Fires and carbon dioxide in boreal forest
Boreal forests exist as a carbon sink
Fire releases large amounts of carbon dioxide through biomass burning
Charred soils have decreased reflectivity, absorb more solar energy, increase soil temp, depth of thaw and decompostion rate
Regrowth varies, deciduous species may dominate where the organic layer burned
Gradually, evergreen species insulate surface and thaw layer decreases
Fires and carbon dioxide in boreal forest
Boreal forests exist as a carbon sink
Fire releases large amounts of carbon dioxide through biomass burning
Charred soils have decreased reflectivity, absorb more solar energy, increase soil temp, depth of thaw and decompostion rate
Regrowth varies, deciduous species may dominate where the organic layer burned
Gradually, evergreen species insulate surface and thaw layer decreases
What is paludification
What occurs in boreal forests following this
Succession in the abscence of life
Eventually ocygen in the soil becomes too low and the roots starve, killing the trees
Area becomes covered in moss or peat bog
How does evergreen growth benefit boreal trees
Photosynthesis can occur all year, takes advantage of anytime when growing is possible
Adaptations of evergreen plants
Needles are very dark green for maximum absorption of solar radiation
And increases leaf temperature in microclimate which increases photosynthesis rates
Narrow shape and size of lead reduces surface area, minimising water loss
Somata is sunken within leaf - sheltered
What is the drawback of the evergreen stratergy
Constant exposure increases risk of being damaged
Animals found in boreal forests
Wolves
Grazers
Cross-hatch
What are 2 types of tundra
Arctic
Alpine - above 60˚ latitude
What is the climate in tundra biomes
Lack summer warmth entirely
Growth only occurs during breif cool summer
Months of bitter cold
Are there trees, why
Cold temperatures restrict woody growth so treeless
What is the diversity like in tundras
Low
What plants can be found in tundras
Highly specialised, endemics
Grasses and sedges
Shrubs where there is snow
Mosses and lichens
Which tundra has highest diversity
Alpine tundra (mountains)
What is the climate in Arctic tundras
2-6 months of complete darkness
Average winter temperature of -35˚C
What is the climate like in alpine tundra
More variable than Arctic
Intense radiation on mountain tops
-12˚C to 10˚C
Cold and dry
Temperature fluctuations between day and night
Precipitation 300mm per year (low)
What are soils like in alpine tundra
Course, rocky, well drained
Deep moist peats remain wet in summer as drainage is impeded by permafrost = tundra bog
What are the dominant vascular plants in tundras
Perennial herbs and dwarf shrubs
Many semi-evergreen
No pterophytes as they may not get the temperature for germination
What are some adaptations of tundra plants
Grow close to surface in dense mats and cushions
Pubescent (hairy)
Vegetative
What name is given to the wat flowers move in tundras and why is this beneficial
Heliotrophic flower movement
Favours seed maturation
Why are many tundra species vegetative
High metabolic cost of seed production and uncertainty of seedline recruitment
What type of root growth do tundra plants have and why
Lateral root growth due to low soil temperatures and undeveloped soil
Animal life in tundras
Many vertebrates - small rodents, hares, caribou, musk oxen, mountain goats, migratory birds
Alpine marmots, pika and ungulates
