Grassland Restoration Flashcards
(25 cards)
What type of climate characterizes grasslands?
Hot, dry climates
Typically found in rain shadows
patchy distribution across landscape
What is important about associated ecotypes?
The mosaic of habitats is the one reason BIODIVERSITY is so high in these areas
How has fire suppression been detrimental?
Many species have evolved being adapted to native fire regimes. may require fire for species survival
-without fire, trees and woody shrubs grow unchecked and encroach on grasslands–>forests
What challenged do low, dry valleys face?
Natural grassland ecosystems, also desireable places for development
loss and fragmentation of habitats
What is another threat to grasslands?
intensive grazing alters the vegetation and soils
-contributes to colonization by invasives
What kind of human influences can effect grasslands
Recreational activities- ATV’s spreading invasives and destroy cryptogrammic crust that protects soild from erosion/drying
What methods are used to control the spread of woody trees and shrubs?
Prescribed burns and brushing
What methods are used to control invasives
Herbicides
Best management practices for grazing cattle
Cattle management practices?
Limiting the amount of time cattle spend in one area, productivity of grazing land is maintained benefiting ranchers and native ecosystems
What are grasslands often reffered to as?
praries
What are two broad categories of grasslands
Temperate and tropical savannah. both dominated by grasses and forbs, trees and shrubs growing only in depressions and riparian areas
What two climates are grasslands found in?
- Continental- hot summers, cold winters, frequent droughts
Where precipitation/evaporation is equal to about 1
What is the main factor determining grassland composition?
Precipitation
What are the 3 main types of grassland ecosystems in North America?
- Shortgrass(4-8cm precip/year)
- Mixed grass(8-10cm precip/year)
- Tall grass (>12cm precip/year)
- Short grass:
dominated by high drought resistant plant species such as blue grama and buffalo grass
- Mixed grass
Dominated by plant species such as little bluestem, western wheatgrass, porcupine grass, prarie sandreed.
plants typically up to 1 m in height
- Tall grass
dominated by plant species such as big bluestem, indian grass, and switch grass
plants can be more than 3m in height
What are some adaptations of grasses to drought and extreme temperatures?
- Leaf structure reduces water loss (fewer stomata) narrow, furrowed blades
- Metabolism: rapid response to abiotic changes. increase growth in wet periods, decrease in drough
- Nutrient stores and metabolism occur underground, where abiotic conditions are more moderate.
What do the extensive root systems of native grassland plants result in?
- Soil stability>erosion
- high atmospheric carbon sequestration
- high below ground species diversity (plants, animals, invertebrates, soil microbes)
Grassland structure and composition are naturally patchy.. why?
- Fire- More fuel=more fire
- grazing- ungulates, prarie dogs, domestic cattle
- cattle are non native and graze more and in riparian areas
What is the main stressor for short/mixed grasses and what are apropriate treatments?
Livestock grazing
- Eliminat/manage grazing
- Re-seed disturbed areas
- stabilize soil
What is the main stressor for tall grass. treatments?
Farming
- Eliminate/manage invasives- tillage +herbicide/cover crops
- Re-seed native species, sometimes with cover crops
- during first growing season after re-seeding, mow vegetation at 15cm. eliminates invasives before they seed- invasives grow quicker more energy to seed than root.
How are prescribed burns helpful?
Remove litter accumulation
recycle nutrients
tall grass isnt impacted by grazing as much as short and mixed
When should prescribed burns be done?
Late spring/ early summer. time to grow after
