Rangeland Final

Rangeland

Rangeland is land dominated by native grasses, forbs, and shrubs and used mainly for grazing and wildlife.

Range management

The science and art of optimizing use of rangelands for livestock, wildlife, soil, water, and recreation.

Herbivory

Consumption of plant material by animals.

Habitat

The biotic and abiotic environment where an organism lives.

Edge effect

Greater diversity and density of wildlife where two habitat types meet.

Decreaser

Highly palatable plants that decrease under heavy grazing.

Increaser

Plants that increase when decreasers decline.

Invader

Species that appear after disturbance or overgrazing, often non-native or weedy.

Browsing

Feeding on shrubs and forbs.

Grazing

Feeding primarily on grasses.

Five principles of range management

Rangeland is a renewable resource (support 30-50% biomass without damage); Energy Capture (green plants capture energy from the sun and then consumed by animals); low energy food and fiber (provide low cost food and fiber for animals); range production (determined by specific aspects of the soil, topography, and climate of an area); products (variety of products harvested)

Vegetation drivers

V is a function of climate (warm and cool season plants), organisms (species, limitations), relief (aspect, elevation, topography), soil (sand, silt, clay), disturbance (humans, animals, Mother Nature), and time (linear scale).

Importance of rangelands

Rangelands provide forage, wildlife habitat, water filtration, carbon storage, recreation, biodiversity, and economic value.

Timing of grazing

When grazing occurs; early-season grazing is most harmful.

Intensity of grazing

How much plant material is removed.

Frequency of grazing

How often grazing occurs in a season or over years.

Take half leave half

Only remove 50% of current year's growth to maintain roots and soil cover.

Sagebrush Steppe

Cold desert system with shrubs and cool-season grasses (Wyoming, Great Basin).

Shortgrass Prairie

Semi-arid prairie dominated by blue grama and buffalo grass.

Tallgrass Prairie

Moist prairie dominated by tall C4 grasses like big bluestem.

California Annual Grasslands

Mediterranean climate grassland dominated by non-native annuals like oats and bromes.

Deserts (Mojave, Sonoran, Chihuahuan)

Sparse shrubs, cacti, and warm-season grasses.

Forest–grassland ecotone

Transition zone of conifer forest and grass meadows.

Poisonous plant factors: environmental

Drought, early spring growth, frost, overgrazed pastures.

Poisonous plant factors: livestock

Hunger, age, species differences, inexperience.

Poisonous plant factors: plant

Toxin concentration, palatability changes, abundance near water/shade.

Homestead Acts

Encouraged settlement and contributed to overgrazing.

Taylor Grazing Act

Created grazing districts and permits; reduced degradation.

Multiple Use–Sustained Yield Act

Balances federal land uses: grazing, wildlife, recreation.

NEPA

Requires environmental analysis for federal land decisions.

Endangered Species Act

Protects species; influences grazing management.

Wild Horses & Burros Act

Manages feral horse and burro populations on public lands.

Animal Unit (AU)

One 1000-lb cow equals one AU.

AU formula

AU = animal weight ÷ 1000.

Stocking rate formula

Stocking rate = available forage ÷ forage demand (lbs per AU).

Grass early growth

Uses stored carbohydrates; most sensitive to grazing.

Grass rapid growth

Most resilient; best grazing window.

Grass reproductive stage

High energy demand; grazing lowers seed production.

Grass dormancy

Least sensitive to grazing.

Mechanical weed control

Mowing, chaining, grubbing, root plowing.

Chemical weed control

Use of herbicides.

Biological weed control

Use of insects, pathogens, or grazing animals.

Cultural weed control

Prescribed fire, seeding, improved grazing practices.

Plant avoidance traits

Spines, toxins, hairs, waxy leaves, low growth form, unpalatable seasons.

Sun–soil–plants–grazing

Sun drives photosynthesis; soil provides nutrients; plants store energy; grazing removes biomass and affects regrowth.

Carbohydrates

Primary plant energy source (fiber, sugars).

Protein

Needed for muscle and enzymes; highest in young plants.

Fats

High-energy nutrient in plants.

Minerals

Essential for bones and metabolic processes (Ca, P, Mg).

Vitamins

Needed in small amounts for immune and metabolic functions.

Large wildlife

Bison, elk, pronghorn, mule deer, cattle, bighorn sheep.

Small mammals

Prairie dogs, ground squirrels, jackrabbits.

Insects

Grasshoppers, Mormon crickets, black grass bugs.

Birds

Sage grouse, sharp-tailed grouse, bobwhite quail, Mearns quail, waterfowl.

Leaves nutrition

Highest protein and digestibility.

Stems nutrition

Low protein and digestibility.

Seeds nutrition

High energy.

Dormant forage

Very low nutrition; supplementation required.

Fire benefits

Reduces woody encroachment; stimulates new growth; improves forage; controls some invasives.

Fire negatives

Can cause erosion, smoke issues, promote cheatgrass, escape risk.

State & Transition drivers

Grazing pressure, fire frequency, drought, invasives, soil degradation, management actions.

Meteorological drought

Lack of precipitation.

Hydrological drought

Low water levels in rivers, streams, groundwater.

Agricultural drought

Insufficient soil moisture for plant growth.

Socioeconomic drought

Water demand exceeds supply due to human use.

Livestock challenges (developing countries)

Poor forage, water scarcity, low vet access, land tenure issues, wildlife conflict, poor infrastructure.

Economic terms

Supply, demand, marginal cost, marginal benefit, opportunity cost, externalities, property rights.

Pastoralists

Mobile livestock herders.

Transhumant herders

Move seasonally between elevations.

Nomadic herders

Continuously move following forage.

Ranchers

Fixed base; use private land or grazing allotments.

Mechanical treatments

Chaining, mowing, root plowing, bulldozing; used to reduce woody plants.

Future rangeland trends

Remote sensing, adaptive grazing, wildlife coexistence, climate adaptation, restoration, invasive grass control.