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RANGELANDS:. GRASSLANDS, DESERT SHRUBLAND, AND SHRUB WOODLAND   Precipitation = 10-30 inches/yr   29% of US is rangeland . TAYLOR GRAZING ACT OF 1934. 1. halt deterioration 2. improve range quality 3. stabilize rangeland economy . IMPORTANT WILDLIFE OF THE GRASSLANDS .

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rangelands
RANGELANDS:
  • GRASSLANDS, DESERT SHRUBLAND, AND SHRUB WOODLAND  
    • Precipitation = 10-30 inches/yr  
    • 29% of US is rangeland
taylor grazing act of 1934
TAYLOR GRAZING ACT OF 1934
  • 1. halt deterioration
  • 2. improve range quality
  • 3. stabilize rangeland economy
important wildlife of the grasslands
IMPORTANT WILDLIFE OF THE GRASSLANDS
  • Waterfowl (prairie potholes and marshes)
  • Large ungulates (deer, elk, pronghorn)
  • Smaller mammals and birds
grazing permit controversy
GRAZING PERMIT CONTROVERSY
  • Nearly 5 million cattle and sheep graze on 80% of public rangelands annually  
  • Permits cost one-fifth that charged by private landowners
  • Federal subsidy = $100 million/yr over the water subsidy they get
  • In 45 National Parks, 150 National Wildlife Refuges, and BLM lands
  • http://www.sagebrushsea.org/pdf/factsheet_Grazing_Economic_Contributions.pdf
grazing permit controversy continued
GRAZING PERMIT CONTROVERSY, continued
  • Current fee doesn\'t even pay for administration of program
  • Ecosystem is being damaged by overgrazing and miss-management: wildlife suffer
  • Ranchers benefit, but land belongs to everyone
  • The paradox persists. Why?
rangelands8
RANGELANDS
  • Grasslands
  • Desert Shrubland
  • Shrub Woodland  
  • Tropical - Savanna, campos, llanos
  • Temperate - prairie, steppes, pampas, veld
  • Arctic - Tundra (mostly wetland too)
ecology of rangelands
ECOLOGY OF RANGELANDS  
  • Metabolic reserve = lower half of grass plant  
  • Decreasers - plants favored by grazing animals; subject to decline when grazed
  • Increasers - avoided by grazers; abundance increases upon grazing
  • Invaders - dominate overgrazed areas
ecology continued
ECOLOGY, continued
  • Overgrazing:
    • Too many animals for too long
    • grasses replaced by woody plants and forbs
    • reduces water and nutrients
    • reduces litter, exposes soil
    • more wind erosion  
  • Undergrazing:  
    • brown leaf and stem left to age (poor food quality)
    • kills off (chokes) grasses and favors woody vegetation
    • reduces water and nutrients
    • reduced root mass leads to soil erosion
management of rangelands
MANAGEMENT OF RANGELANDS:
  • Control amount of grazing
    • periods of grazing and rest (deferred rotation)
    • continuous grazing
    • holistic grazing (6 paddock rotation)
  • Control vegetation
    • fire
    • herbicides
management of rangelands continued
MANAGEMENT OF RANGELANDS, continued 
  • Control rodents and predators
    • Rodent control:
      • Controls don\'t last (temporary relief
      • Ecology gives long-term solution
    • Predator control:
      • controls don\'t work (temporary relief)
      • Ecology gives long-term solution  
    • Coyotes eat Rodents!!!
coyote problems
COYOTE PROBLEMS 
  • The federal government kills coyotes!
    • \'1080\' in collars
    • cyanide in "coyote getter"
    • costs about $1,000 per coyote!
    • ineffective in reducing coyotes
  • Other methods to deal with coyotes:
    • fencing
    • guard dogs
    • good animal husbandry practices
    • Kansas model program only costs 5% of nearby states\' programs
north american grasslands
NORTH AMERICAN GRASSLANDS:
  • tall-grass prairie: southeastern edge
  • mid-grass (mixed-grass) prairie: north and west of tallgrass prairie
  • short-grass prairie: western plains
  • Palouse prairie: great basin country
  • Valley grasslands: California\'s Central Valley
  • Desert grasslands: Arizona and New Mexico and Mexico
more ecology
MORE ECOLOGY
  • Most grasslands are subject to great variability in temperature, precipitation, grazing, and fire, leading to "multiple stable states" rather than one climax community type  
  • Global warming and grasslands:
  • may increase decomposition rate and thus increase CO2 release (positive feedback)  
  • Grassland restoration is in progress  
temperate and tropical deserts
TEMPERATE AND TROPICAL DESERTS  
  • Characteristics
    • Hot vs. Cool deserts:
      • temperatures below freezing may be rare or common
  • What creates the desert environment?
    • Rain shadow - mountains
    • Cold upwelling - oceans  
special features of desert ecosystems
SPECIAL FEATURES OF DESERT ECOSYSTEMS
  • caliche - cement-like subsoil of calcium carbonates  
  • desert pavement - hard, protective surface layer  
  • cryptobiotic crust - algae, fungi, and lichens form a fine organic tissue
    • may take 200 years to reform if disturbed
deserts ecological problems
DESERTS, ecological problems
  • Desertification- drying of arid ecosystems is a global concern
  • Other Problems:
    • Overgrazing by livestock
    • Competition with feral ungulates
    • ORV\'s
    • compact soil, disrupt surface
    • first pass does most of damage  
      • Reptiles, mammals, and birds are all reduced in number of species and number of individuals per species under heavy and very heavy ORV use*  
        • *Even moderate use cuts # species to <11
effects of orv s on desert fauna density per 2 ha plot
Effects of ORV’s on desert fauna(Density per 2 ha plot)
  • *Even moderate use cuts # species to <11
problems continued
Problems, continued
  • Invasion of exotic plants:  
    • Annual grasses of genus Bromus that choke out native plants after a rain, die, and carry fire (native species evolved w/o fire)  
    • Salt cedar - shrub replacing willow and cottonwood in riparian areas
    • Deep-rooted, high transpiration: dries soil
    • Carries fire; resprouts vigorously after fire, outcompeting native species  
    • Beaver and deer do not feed on it
problems continued21
Problems, continued
  • Global warming will increase desertification  
  • Desert soils are a source of carbon in the atmosphere; more desert surface and weaker cryptobiotic crusts will add to the greenhouse effect!
management of arid desert systems
Management of arid/desert systems:
  • Need to limit use of ORV\'s
  • California Desert Protection Act
    • 1994 - upgraded several deserts to National Parks, enlarged areas of protection, and designated more "wilderness"
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