Rangeland Final

What are trophic levels

a) feeding levels with respect to primary source of energy

b) producers consumers each occupy a different trophic level

c) energy is lost at each level

1st Level?

Producers, such as plants and algae, that convert sunlight into energy through photosynthesis.

2nd Level?

Herbivores

3rd Level

Carnivores that eat herbivores.

What is lost at each level?

Heat

What is the biomass pyramid?

a) the total weigh of all living organisms

b) biomass at each trophic level

Not all biomass is consumed from one trophic level to the next

• not all is consumed

• not all consumed is digestible

• nat all that is digested is turned into mass

• part of mass is converted to energy/heat

• last mass is available for decomposition

Shorter food chains = loss of less energy

vegetarianism results in a decrease of human position on food chains

2 Good Reasons Why Vegetarianism Won’t work

• cellulose → most abundant, naturally occurring organic molecule on earth

  • humans can’t digest cellulose

  • ruminants and hind-gut fermentors can

  • we need cows, sheep, goats, horses, etc

• only about 10% of earth’s land surface can be farmed

  • the rest is too rocky, too cold, or too dry

  • we need animals to harvest these lands for us

What is Succession?

the directional change of plant communities over time

What does it begin with?

volcanoes

landslides

floods

What is the pioneer stage?

lichens and mass

Early Seral Stage?

annual plants

herbaceous

invasive characteristics

Late seral?

Perennial Long-Lived Plants

Diverse Community Plants & Animals

PNC=Potential Natural Community

What is PNC of Potential Natural Community?

the end-point of succession

What kinds of plants show the end result of succession?

trees in forests

grasses in prairies

cacti in desert

lichens and shrubs in he tundra

A prescribed fire to reduce juniper trees

Primary or Secondary?

Secondary

An erosion event hat removes all the soil and leaves only bedrock

Primary or Secondary

Primary

Over grazing by elk and cattle on canyon grasslands

Primary or Secondary

Secondary

A restoration practice where the land managers sprayed cheatgrass with herbicide and reseeded with perennial grasses

Primary or Secondary

Secondary

Basic ideas of Succession

• the simple plants dies, adding more organic matter

• the soil layer thickens, and grasses, wildflowers, and other plants begin to grow

• these plants die, and they add more nutrients o soil

• shrubs and trees can then survive

• insects, small birds, and mammals being to inhabit

Forces of ecosystem change

• immigration and establishment of plants

• competition between plants

• site modification (added organic matter, available moisture and nutrients)

• stabilization (reduce yearly variation in kind and amount of plants and animals)

Ecological Sites

the product of all the environmental factors that influence the development of soils and vegetations, including disturbance

Community Resilience

the ability of a plant community to return to prior composition and structure after a disturbance

Community Resistance

the plants communities ability to avoid being changed following disturbance

Forces and Impacts

fire

herbivory

invasion

human uses

climate change

Ecological Services and Resources

forage for livestock

wildlife habitat

watershed management

biodiversity conservation

open space

carbon sequestration

Tools for Stewardship

fire

livestock grazing

weed management

human impacts

restoration/rehabilitation

Demographic Inertia

removal of disturbance may not result in successional progress

Loss of Plant Materials

plant decomposition is dynamic, overgrazing a certain species may eliminate them, species may be outcompeted

Fire Feedbacks

grasses increase fire frequency and are promoted by fires

Soil Feedbacks

erosion, loss of seedbank, loss of nutrients compaction

Problems with Succession

multiple pathways of succession

multiple stable vegetation types

no single and certain end-point

Equating climate composition o range condition confuses evaluation of _______ and their _________

rangelands and potential

Site Potential

precipitation, temp, soil, topography, elevation

State and Transitional Model

hold great potential to aid in understanding rangeland ecosystems response to natural and/or management induced disturbance

Steady State

forces hold a community in suspended succession unless something happens to change it

Transition

disturbance or competition can cause a plant community to shift to a different community within a stable state

Threshold

a transition where a resource is lost so he community cannot go back to the previous steady state without sig source input by humans

Stepwise Degradation

defined by functional integrity and transition limitation

Biotic Transition

vegetation manipulation

Abiotic transition

physical manipulation

Wildfire

started by lightning or by humans

Wildland Fire Use

unintentional ignition, but no suppressed because it meets guidelines in wildland fire plan

Prescribed Fire

intentionally set under specific conditions

The prescription indicates the acceptable ____ and ____ conditions under which a fire should be set so hat the blaze can be controlled

fuel and weather

Fire Triangle

heat, oxygen, fuel

Fire Behavior Triangle

topography, fuel, weather

Red Flag

conditions are high risk is you burn, fire is more likely to get away from you

Temperature

< 32F = grass is hard to ignite

40-60F = fire behavior more or less uniform

> 67F = increased fire band distance

> 80F = red flag

Humidity

< 20% = red flag

20-40% = fire behavior more or less uniform

60% = uniform

> 60% = fire doesn’t carry well

Wind

< 6 mph = glowing fire bands don’t ignite

6 mph = minimum speed for non-contagious fuels

8 mph = consume woody fuels

> 20 mph = fresh supply of oxygen and pushes fire to fuel

Slope

fire moves quickly through grass and brush, further accelerating uphill; surface fuels are closer to flames as steepness increases

Fuel Moisture Content

the moisture content and distribution of. these fuels defines how quickly a fire can spread and how intense or hot a fire may become

live fuel material v. dead fuel material

Fuels and Fuel Loads

density of fuel influences is flammability

fuels particles close together = burn readily

fuel particles too close = fuel will not burn readily

Challenges with Prescribed Fre

NEPA

fire line prep work

timing of weather, personnel availability

caution, safety, trained personnel

flight plans, burn plans, safety plans

scale and risk

Wildland Fires Pros

lowers infestation

lowers disease

provide shelter for animals

lowers fuel loads

nutrients are released

lowers competition

serotinous

mosaic pattern

Wildland Fires Cons

threat to humans

financial loss

loss of habitat

nutrients are released

lowers competition

Positive Ecological Weed Impact

some provide forage

resource for pollinators

some reduce erosion

Negative Ecological Weed Impact

many reduce soil cover and increase erosion

compete with good forage plants

increase fire frequency (cheatgrass)

reduce habitat quality

Positive Socioeconomic Weed Impact

jobs for those who fight weeds

herbicide companies

honey

plant products

Negative Socioeconomic Weed Impact

reduce forage productivity

reduce recreation quality

cause health issues (pollen)

What to do?

prevention - single best way to limit impacts

early detection and rapid response

eradication - ay be feasible early in an invasion

Control:

biological - introducing a natural enemy, predator or parasite

chemical - pesticides, herbicides, and fungicides

mechanical - physically removing the invasive species of changing the habitat conditions

Prevention

consider vectors of introduction

develop plans to minimize introduction

minimize disturbances that may favor weeds

Requirements for biological control to be successful

1) destructive enough to control weeds

2) host specific enough not endanger non-target species

3) able to survive and reproduce in target environments

Targeted grazing is the application of a specific __________ at a _________, duration, and __________ to accomplish defined vegetation or landscape goals

1) kind of livestock

2) determines season

3) intensity

Need to pay attention to:

desired landscape

grazing animal

Negative of livestock on weeds

increase spread of weeds

cause disturbance

transport seeds

reduce competition from native plants

Positive of livestock on weeds

suppress weeds

stress weeds

reduce root biomass

reduce seed production

reduce competitive edge

Cheatgrass. Easy Doable. Difficult

Kudzu. Easy Doable Difficult

Leafy Spurge. Easy Doable Difficult

Yellow Starthistle. Easy Doable Difficult

Knapweeds. Easy Doable Difficult

Juniper. Easy Doable Difficult

Salt Cedar. Easy Doable Difficult

easy

easy

doable

doable

doable

difficult

difficult

Grazing systems

a planned effort to leave some areas unused for at least part of the year

Grazing period

season and number of days when pasture is grazed

Deferment

a period of non-grazing until key forage species set seeds

Rest

a period of non-grazing for a full year

Continuous Grazing

grazing a whole are for the whole grazing season

Pros -

• simple/low input

• animals get maximum choice and have high animal performance

Cons:

• plants and areas that livestock prefer can be excessively used and become degraded

Deferred Rotation

do not graze at least on pasture until after is has set seed (defer), rotates through pastures every year

Pros:

• rangeland condition can improve because pastures are occasionally not grazed when they are most sensitive to grazing

Cons:

• can reduce animal performance a little because animals opportunity to choose among plants and places is restricted

• requires more fencing and management

Rest Rotation

do not graze at least on pasture for a whole year, rotate pastures every year

Pros:

• rangeland condition can improve sa pastures are allowed to be rested and set seed every few years

Cons:

• can reduce animal performance because stocking rate is increased on grazed pastures and animals are always moved into pastures that were not grazed recently and have dormants stems mixed with green growth

Short-Duration

each pasture in the unit is grazed for a short time and animals are rotated through all viable pastures so that each pasture is grazed at least twice per year

Pros:

• stocking rate often higher because animals eat all plants

• forage quality can be higher because animals are always eating fresh green regrowth

• range condition sometimes improves because all plants are grazed, not just favorable ones

Cons:

• animals performance may lower cause animals have to eat all plants not just their favorites

• rangeland condition can be decreased as plants never get rest or deferment

Seasonal-Suitability

moving livestock to different areas of range depending on growth patterns of different vegetation types

Pros:

• animals have green forage most of year = high growth performance

• plants mostly grazed early in season before seed set

Cons:

• high management/herding input

• summer range many not get deferment

Best-pasture system

move livestock to pasture that looks the “best” in terms of forage availability

Complementary system

designed in the central plains where animals rely on

Success of grazing depends on:

type of forage

weather patterns

terrain

skill of manager