Topic 15 - Grassland formation and their distribution in the Earth (regarding to the major grassland types) Flashcards
Biogeography
Study of the distribution of species and ecosystems in geographic scale
Distribution of species
Not random → biotic and abiotic factors
Biomes of the earth
A type of vegetation that covers a very large area in continents around the world
Environmental factors of grasslands
Rainfall
Temperature → high annual temperature range (> 25C)
Seasonal drought
Rainfall
Regular annual rainfall (200-500mm)
Annual rainfall can be higher for tropical grasslands and tall grass prairies (600-1000m)
Rainfall occurs only late spring or early summer
Importance of grasslands
Provides a number of products including food crops and meat
Contributes to the provision of clean water and flood prevention
Are essential to carbon sequestration, or the storage of carbon in the soil
Types of grasslands
Natural grasslands
Grasslands of europe
Artificial grasslands
Natural grasslands
Precipitation inequality or low precipitation rates
Under tropical climate
Under temperate climate
Grasslands of europe
semi-natural grasslands → after deforestation, maintained with mowing and grazing
Tropical grasslands -
Savanna
Savanna
Mixed woodland grassland ecosystem without closed canopy
Cover 20% of the world’s vegetation
Rainfall limited to a few months
Regular wildfires occurs
Large number of natural grazers
Grasses of the savanna
Common finger grass - most important forage grass
Elephant grass - most important fodder crop of dairy farmers
Thorn trees
Common in savanna
Digestibility of the foliage is poor compared to grasses
Cerrado
Tropical savanna
Grassland occupying the drier regions - largest area is in brazil
Herbaceous layer reaches 60 cm
Soy production, low density cattle grazing
Half the natural vegetation has been lost since the late 1950s
Grasses of the cerrado
Carpet grasses and bluestem grasses → most frequent
Grasses are intermixed with a diverse selection of sedges
Grazing occurs in the open and the marshy habitats
Temperate grasslands
Prairie
Pampas - South American grasslands
Prairie
Tallgrass Shortgrass prarie Prairie hay Velds Steppe
Tallgrass prairie
The annual rainfall averages about 700-1000 mm
Grazed by large mammals (bison, pronghorn)
Grazed during growing season, cut and baled as hay in the fall
Major species of tallgrass prairie
Big bluestem
Indian grass
Switchgrass
can be used as biogfuel
Shortgrass prairie
Drier climate (3-400 mm)
Cattle and sheep ranching
Short grasses (30-40 cm) are drought- and grazing tolerant
Dominant species of shortgrass praire
Buffalo grass
Blue grama
Prairie hay
Harvested once (twice) a year
10% priotein and 65% total digestible nutrients
High quality (early harvested) hay for young livestock, and average quality (late harvested for higher biomass) hay for dry cows
Pampas
Distributed in the lowlands of Argentina and Uruguay
climate generally temperate (29-32C)
Precipitation is seasonal
Wildfires frequently occurs
Dry and humid pampas
Nutrient rich soils
Domestic livestock and farming → endangered habitats
Pampas grass
Most typical species in pampas grasslands
Europe → used as an ornamental plant
Flooding pampas → average yield → 5-30 kg dry matter/ha/year
Overgrazing commonly occurs
Velds
Temperate grasslands of south-Africa
Occurs in plateaus (high veld) and lowlands (low velds)
Sweet velds and sour velds
Supplies most of South africa’s dairy, beef and wool products
Sweet velds
Low rainfall, low fiber, retain nutrients → palatable to livestock
Sour velds
Higher rainfall → more fibers, less palatble
Species of velds
Red oat grass
Wire grass
Bermuda grass
Steppe
Open, grass-covered plains, which are treeless
Low (300-500mm) annual rainfall
Long drought during the summer
Forest and meadow steppes
Extensively grazed by different species, or preserved as hay
Eurasian steppe
Largest temperate grassland in the world
From Hungary to China
Species of steppes
Most characteristic: Feather grasses, fescues and sedges
Small shrubs (brooms) and roses can occur
many herbaceous species with underground bulbs
tumbleweed species
European grassland types
Fresh moist meadows
Fresh moist meadows
Molinia meadows
Mesotrophic wet meadows
Arrhenatherum hay meadows
Molinia meadows
Dominance of Molinia species
Groundwater does not reach the ground surface
Soil is typically rich in humus or peat
grazing is rare
Mowing once a year
Grasses of molinia meadows
Tall-grown grasses, sedges, and rushes dominates
Most species-rich wet grassland type
Mesotrophic wet meadows
widely distributed in Europe
Decreasing tendency in extent in the EU → draining (drying), fertilisers
Moist or sometimes seasonally inundated
Nutrient-rich soils on floodplains and in brook-valleys throughout lowlands
The vegetation is often species rich
Herbage traditionally cut for hay (nutrient rich)
Light grazing in late summer and autumn
Species of mesotrophic wet meadows
Agrostis, alopecurus, and festuca species
Arrhenatherum hay meadows
Meadows of nutrient rich soils developed in areas of valleys, terraces, basins, high floodplains
graxzing is rare, mowing 1-2 times a year
Dominant species in arrhenatherum hay meadows
Tall grown species: arrehnatherum elatius, Dactylis glomerata, phleum pratense, trisetum flavescens
Sedges (less dominant) buttercup (common)
Dry meadows
Loess steppes Open and closed sand steppes Salt meadows Rocky grasslands Mountain hay meadows
Loess steppes
occurs only in middle-east europe
Good quality soils developed on loess (stilt-sized sediment)
Closed steppes occurs especially on plains and foothills
Species rich, many rare and sometimes endangered species
In europe → also have a decreasing tendency (lack of grazing, forestation)
Grazed mainly with sheep
Species of loess steppes
Festuca rupicola
typical herbs are spring pheasants eye, spurge plants and sage species
Open sand steppes
Drought-tolerant low grasslands with maximum 50-60% cover
On loose, humus poor sand soils
vegetation dries out in mid or late summer
Grasses form tussocks and have enrolled leaves
Inappropriate for hay
Grazed with sheeps
Species in open sand steppes
Feather grasses
small sized fescues
grey-hair grass
Closed sans steppes
Higher, but still low amount of biomass → Light grazing with sheep and goats
Heavy treading can damage the grassland → smaller yield
Dominant species are similar to open sand steppes
Salt meadows
The habitat develops on strongly saline soils (e.g. after drainage)
Water cover for a longer period in the year (wet in springtime but sometimes completely dry in summer)
Salt accumulation
Use of salt meadows
Salt meadows are traditionally grazed or cut once a year and later maintained with grazing (sheep, gray cattle)
Poor yeilds
Species of salt meadows
Many succulent species, but low species diversity
Small-sized fescues
alkali (salt) grasses
Glassworts
Rocky grasslands
Developed on dry, warm southern slopes
Occur on calcareous rocks (limestone, dolomite, calcareous sandstone)
Opened grassland with short-growing (5-30 cm) grasses
Use of rocky grasslands
Very small yield, not appropriate for hay or grazing (or just rarely)
Forage for game species (mouflon, deer)
Importance in nature conservation
Mountain hay meadows
Most common type in western and middle europe with economic importance
Meadows of the montane and subalpine levels (mostly above 600 meters)
Fresh and dry types
also in areas of deforestation or wildfires
Uses of mountain hay meadows
High yield, and species-rich composition
For grazing (cattle) and for hay as well
Threats to grasslands
Conversion to forest
Conversion to farmland
Overgrazing and soil erosion
Climate change
Expansion of towns and roads
Conversion to farmland
Only 3% of the former tallgrass prairie area remained
Most of the European steppe was converted to farmland
Nature-friendly grassland management
Production centered agricultural model → multifunctional agricultural policy
Non-material products of grasslands
Sustainable utilisation of natural resources
Nature protective mowing
Mowing carried at a later time, in early july; Only at daytime
Collection of hay possibly when it is still green
Mower equipped with a chain curtain → game alert
Optimal stubble height
Moving without a stem crusher
Slow progress of work of a speed
Proper progress of mowing in space, leaving a coherent pattern of 10% of the space for the hiding strips
Hiding strips
Unmowed areas of the grasslands changed every year
Mowed grasses have no seed production
Species of the hiding strips produce seeds and they can regenerate grasslands
Protection for animals (insects, birds, rodents)
Grassland restoration
Conversion of farmlands back into grasslands
