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Ch 13 Rangeland Management

Proposed Schedule Changes: Unit 4: Ch 13, 14 Test on 3/21 Unit 5: Ch 15, 16 Test on 4/4 Unit 6: Ch 17,18,19 Test on 4/28 Unit 7: Ch 22, 23 Test on ??? (Final Exam). Ch 13 Rangeland Management . 13.1 Ecology of Rangelands.

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Ch 13 Rangeland Management

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  1. Proposed Schedule Changes:Unit 4: Ch 13, 14 Test on 3/21Unit 5: Ch 15, 16 Test on 4/4Unit 6: Ch 17,18,19 Test on 4/28Unit 7: Ch 22, 23 Test on ??? (Final Exam)

  2. Ch 13 Rangeland Management

  3. 13.1 Ecology of Rangelands • Rangelands are areas of the world that have forages like grass and shrubs for free-ranging native and domestic animals • Make up about half of the terrestrial land surface (- frozen land) • 99% of rangeland in US is west of Mississippi River • 7 major biomes: grasslands, tropical savannas, tundra, desert shrubs, shrub woodlands, temperate forests, and tropical forests

  4. Grasslands – • Found in temperate regions, mix of grasses and some forbs, usually no trees or shrubs, rainfall 25-75 cm per year

  5. Tropical savannas – • Tropical grasslands, mix of grass, shrubs, and scattered trees, not many crops grown (low water and poor soil) • Tundra – • Arctic and alpine; no crop production • Desert shrublands • Largest portion of rangelands, arid climate, poor soils, sparse vegetation • Shrub woodlands – • Usually in same rainbelt as grasslands, dominant vegetation is low growing trees and dense shrubs

  6. Temperate forests – • Open areas for grasses to grow • Tropical forests • Little herbaceous vegetation • Characteristics of Rangeland Vegetation • Forage – grasses, sedges, rushes, forbs, and shrubs • Ideal forage because leaf tips can be eaten without effecting growth, as long as the basal zone isn’t eaten and the grass has time to recover • Plants are classified into 3 groups

  7. Decreasers – highly nutritious, palatable plants that decrease under moderate grazing pressure • Ex: big bluestem, little bluestem, wheatgrass, buffalo grass • Increasers – less palatable, highly nutritious, increase when grazed • Increase due to decrease in decreasers, if overgrazed or trampled they are replaced with invaders

  8. Invaders – ragweed, cactus, thistle; undesirable weed species, low nutritional value, some poisonous, often are perennials

  9. Rangeland Carrying Capacity • The size of a population of species that can be supported by the habitat • Grazing carrying capacity is the max number of animals that can graze each year on a given area without causing a downward trend in forage production, quality, or soil quality • Animal Unit Months – the amount of forage needed to keep a 1000 lb animal well fed for a month

  10. 3/10/14 HW : pg 369 #1-3

  11. Effects of Human Activities and Overgrazing • Light to moderate grazing of rangelands is necessary for the health of the ecosystem • Overgrazing – heavy grazing that exceeds the carrying capacity of the community, resulting in the deterioration of the range • Can increase erosion • Undergrazing – allows plant material to get old which reduces grass production and increases growth of woody shrubs and forbs

  12. 13.2 A Brief History of Range in US • Before settlement Great Plains were dominated by large herbivores • Overgrazing was uncommon due to competition, predation, and migration • Introduction of Domestic Animals • By 1800s domestic animals dominated rangelands • Land was bought and then overgrazed, killing many native species

  13. Public Land Distribution and Abuse • Homestead Act of 1862 accelerated the development of the west • John Wesley Powell recommended that farmers graze fewer animals on more land; he was ignored • 1905 USFS was formed and began restricting livestock numbers and grazing seasons in national forests • Taylor Grazing Control Act and Other Laws • 1934; 3 major parts • 1. halt overgrazing and soil deterioration • 2. improve and manage ranges • 3. stabilize rangeland economy

  14. 1976 Federal Land Policy and Management Act • Gave BLM the authority to mange all public lands not in national forests or parks • 1976 National Forest Management Act • USFS had to develop an inventory of National Forest Service lands • 1978 Public Rangeland Improvement Act • 1985 Food Security Act (Farm Bill) • Conservation Reserve Program (CRP) – removes highly erodible cropland from production • Land is to be planted back to grassland

  15. Range Condition • The current state of vegetation of a range in relation to the potential • Determined by USFS, BLM, and NRCS – excellent, good, fair, poor • Excellent – existing vegetation closely resembles its natural potential • Poor – existing vegetation is very dissimilar to natural potential • US rangelands are in the best condition in past 100 years

  16. 3/11/14 HW: pg 369 #5, 6, 8, 9

  17. 13.4 Range Management • Requires information from various areas – plant science, soil science, animal and wildlife, forestry, hydrology, and economics • Major goal is to maximize livestock or wild-herbivore productivity while protecting long-term health of rangeland • Best method is prevention- keeping rangelands from deteriorating

  18. Stock Manipulation • Distribute water and salt: this causes animals to move between the two and graze more uniformly • Uniform grazing can also be done by using fences • Grazing Systems: rotational grazing vs. continuous grazing • Continuous – allowing animals to feed in one area the entire growing season or year • Can lead to overgrazing decrease nutritional value • Deferred-rotation grazing – animals are moved to various fields in different years • Allows plants time to recover and reproduce, increases nutrition • Short-duration grazing – intensive grazing, animals confined to small area, eat all plants but only there for short period of time • Season-suitability grazing – ex: warm season vs. cool season grasses

  19. Artificial Seeding • Reseeding helps restore degraded lands and increase carrying capacity • Control of Rangeland Pests • Need to control weeds and woody vegetation that compete with grasses, also control herbivore pests and predators • Control of Plant Pests • Invasion of shrubs is more likely if ground is overgrazed • Mesquite – population was kept in check by periodic fires, since they have stopped and overgrazing began population has boomed • Controlled burning – farmers replicate the natural control of undesirable (or invasive) species through fires • Encourages growth of native grassland species

  20. Control of Herbivores • Insects can be a bigger cause of overgrazing than livestock, mainly grasshoppers • Wet weather helps to keep populations smaller • In severe droughts, density may exceed 30/sq mi • Jackrabbits can also compete for grazing • 75-150 rabbits can eat as much as one cow • Populations of harmful herbivores coincide with decreasing rangeland condition • Control of Predators: Coyote • Other predators include black bears, eagles, bobcats, foxes, mountain lions • Animal Damage Control Act 1931

  21. 3/12/14 HW: pg 369 #12 – 14, 16, 17

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