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PWS 215 > Exam 1 > Flashcards

Exam 1 Flashcards

1
Q

Describe biotic and abiotic changes that occur when pinyon/juniper trees encroach on a sagebrush ecosystem

A

Biotic- outcompetes sagebrush and understory dies

Abiotic- connecting canopies can lead to megafires

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2
Q

Mean fire intervals for Mountain Big Sagebrush and Wyoming Big Sagebrush

A

Mountain Big- 15 years

Wyoming big- 60-100 yrs

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3
Q

How has decreases in fire attributed to degradation of sagebrush?

A

Too little fire allows woody plants to outcompete sagebrush

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4
Q

How has increases in fire attributed to degradation of sagebrush?

A

Too many fires allows invasive weeds to establish before native ones can

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5
Q

What makes cheatgrass a good fire fuel?

A

1 It is a fine fuel
2 It dries out early in spring
3 It’s a continuous fuel source (no fire breaks)

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6
Q

What can be don to decrease cheatgrass?

A
  • controlled burns
  • seeding native plants
  • grazing
  • introduce bunch grass species
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7
Q

How are perennial bunchgrasses opponents to cheatgrass?

A

Vast root systems occupy bare ground

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8
Q

List 6 sagebrush obligate species

A

Sagebrush lizard, pygmy rabbit, greater sage grouse, sagebrush vole, sagebrush thrasher

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9
Q

List 3 sagebrush obligate species

A

Mule deer, burrowing owls, Merriam’s shrew

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10
Q

Define fragmentation in regards to sagebrush systems

A

Sagebrush communities are not continuous. Sagebrush obligate species isolated

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11
Q

How are pasturelands different from rangelands?

A

Rangelands are not highly cultivated. No plowing, no tilling.

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12
Q

What % of earth’s land surface is covered by rangeland?

A

40-50%

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13
Q

List and explain five basic concepts on which range management is based

A
  1. Rangeland is a renewable resource
  2. Energy captured by green plants can only be harvested by animals
  3. Rangelands supply humans with food at comparatively low energy costs
  4. Productivity varies depending on soils, topography and climate
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14
Q

What are some agencies that manage public land in the United States? (4)

A

Bureau of Land Management
Forest Service
National Park Service
Department of Defense

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15
Q

Describe at least 8 uses for rangelands

A
  1. Grazing cattle
  2. Recreation
  3. Water
  4. Energy
  5. Minerals
  6. Open space
  7. Wildlife habitat
  8. Forage
  9. Native plants
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16
Q

How does occupied bare ground benefit a site?

A

Perennial grasses utilize nutrients and water in that space, making it unsuitable for annual grasses

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17
Q

How have seeding practices changed regarding native and introduced species?

A

We have shifted away from planting introduced species, and towards planting natives

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18
Q

Pros of seeding natives

A

Habitat for wildlife, increased polinators

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19
Q

Cons of seeding natives

A

Doesn’t survive as well, seed is more costly, not strong against weeds

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20
Q

Pros of seeding introduced

A

Better against weeds, quick to establish

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21
Q

Cons of seeding introduced

A

Outcompete natives, leads to monoculture, could spread into non-target areas

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22
Q

How do roots respond to above-ground defoliation?

A

0%- no effect
50%- small effect
70%- less than half of roots remain
90%- very few roots remain

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23
Q

What are non-structural carbohydrates?

A

carbohydrates that are easily transported within plant, good forage, important for recovery of plant

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24
Q

What are structural carbohydrates?

A

Carbohydrates found in the form of cellulose and ligden, not easily digested

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25
Q

How do non-structural carbohydrate levels vary with growth phase of plants?

A

When grass is dormant, NSC recede to roots of plants. When active, NSC found in leaves.

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26
Q

List four ways grazing promotes plant growth

A
  1. Stimulates compensatory photosynthesis
  2. Improves light levels
  3. Disrupts carbon/nitrogen ratio
  4. Reduces influence of apical dominance
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27
Q

List 3 negative impacts of grazing

A
  1. Reduced root mass
  2. Prevent seed propagation
  3. Takes carbohydrate reserves
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28
Q

Name three sources for growth from a grass plant

A
  1. Apical meristem
  2. Intercalary meristem
  3. Axillary bud
29
Q

What is an apical meristem and how does its location change in a grass plant?

A

Apical meristem is the growing point for main upward growth.

In the vegetative stage, the apical meristem is near the ground
In the boot stage, the meristem is high
Once the plant has gone to seed, the meristem is near the ground again

30
Q

Difference between cool and warm season grasses

A

Cool season grasses grow the most in the spring and fall, semi-dormant in summer
Warm season grassed grow in the summer

31
Q

Accordin to Joel Slatin, what is the role of the herbivore in influencing the carbon cycle?

A

They stimulate biomass production by pruning grasses to bring them back to the growth stage and continue carbon sequestration

32
Q

Describe three ways vegetation influence water movement in soil

A
  1. Creates macropores
  2. Strenghtens soil aggragates
  3. Absorbs water and shields ground
33
Q

What is carbon sequestration?

A

Storing carbon from the atmosphere in the soil

34
Q

What does the decomposition of organic matter result in?

A

Humus- stable carbon in soil

35
Q

How can grazing improve soil carbon sequestration?

A

Stimulates bioproduction of grasses

36
Q

How can grazing improve soil carbon sequestration?

A

Stimulates bioproduction of grasses

37
Q

In Rangeland Rehabilitation and Carbon Credits in Kenya, what was done to improve the health of their rangelands?

A

The scattered animals were herded together, and they did planned grazing on pre-determined plots

38
Q

What are the two major motivating factors for landowners to adopt carbon sequestration practices on rangelands?

A
  1. Improved productivity/production of grasses biomass

2. Carbon credits

39
Q

When would be the best time to remove wolf plants through heavy grazing?

A

During dormancy. Plants are less susceptible. Easier to get cattle to eat them.

40
Q

With respect to plant physiological development explain four different strategies strategies land managers could implement to promote/sustain grazing productivity?

A
  1. Change duration of grazing
  2. Change season of grazing
  3. Provide opportunity for leaves to regrow
  4. Avoid annual use during reproduction
  5. Periodic heavy use during dormant to address wolfy plants
41
Q

Explain what factors make some grasses more grazing tolerant than others

A
  1. Height of growing points

2. Ability to perform compensatory photosynthesis

42
Q

How is Green and Brown strategy used to control cheat grass?

A

Graze when perennials are brown. Graze when cheat grass is green.

43
Q

How does the green and brown strategy contribute toward the overall reduction of cheatgrass?

A
  1. Keep annual grasses from flowering (green)

2. Keep perennial species strong and healthy (brown)

44
Q

Give two examples of morphological and biochemical avoidance mechanisms of plants

A

Morphological - Spines, tensile strength

Biochemical - Reduce digestive benefit, Terpenes in sagebrush

45
Q

Give two examples of morphological and biochemical tolerance mechanisms

A

Morphological - Location of meristem, leaf replacement potential
Biochemical - Compensatory photosynthesis

46
Q

Why do warm season grasses grow little above ground in it’s first few years?

A

They focus most of their energy on establishing a root system

47
Q

What are three ways we are losing sagebrush

A
  1. More frequent, larger fires
  2. More trees moving into landscape
  3. Introduction of weeds
48
Q

Describe the 3 functional groups of sagebrush-stepp

A
  1. Forbes - tall flowering plants
  2. Grasses - low plants with many tillers and leaves from ground
  3. Shrubs - sagebrush and other low, woody species
49
Q

Describe 4 purposes native americans used fire for

A
  1. Increase availability of desireable plants
  2. Maintain habitat for animals
  3. Driving game for hunts
  4. Warfare
50
Q

What are fire scars and what do they teach us about fire frequencies?

A

We know what year the fire happened, how often it happened. Dark marks in tree rings left over from fires

51
Q

What is a potential reason for fire frequencies decline in 1900’s

A

Overgrazing took fuel away

52
Q

What did the railroad do for livestock production in the west?

A

It made it easier to transport livestock from Texas

53
Q

Homestead Act

A

160 acres per family

54
Q

1905 Transfer Act

A

Established Forest Service. Permits to use public land to run livestock

55
Q

Who brought cattle to America?

A

Cortez and Coronado

56
Q

Who was John Wesley Powell?

A

The guy that understood native American prescribed burning principles. Soldier, explorer, geologist.

57
Q

Who was Arthur Sampson?

A

Father of range science. Started in Ephraim Canyon.

58
Q

Explain tragedy of the commons

A

Everyone had the opportunity to use the finite resource of the grass growing in the Wasatch Plateau.

59
Q

List consequences from uncontrolled livestock grazing

A

Bad erosion, destructive floods, people became sick from run-off water from grazing areas, fires stopped

60
Q

Enlarged Homestead Act

A

320 acres per family, 1/4 cultivated

61
Q

Stock Raisers Homestead Act

A

640 acres per family

62
Q

Taylor Grazing Act

A

Put remaining public land under BLM management

63
Q

Multiple Use Act

A

You can use lands for more than just livestock

64
Q

Wilderness Act

A

Protected some areas against profit-ventures

65
Q

National Environmental Policy Act (NEPA)

A

Must prepare impact of policy and publish it to the public

66
Q

Federal Land Policy and Mgmt Act

A

Ends homestead act

67
Q

Range Improvement Act

A

Federal grazing fee ($1.35 per AUM)

68
Q

Who was Gifford Pinchot

A

1st chief of Forest Service, against forest fires, from Europe.

69
Q

What are other potential reasons for fire frequency decline?

A

The Smokey the Bear/ Bambi effect
Removed native americans
overgrazing
fire repression policies

PWS 215 (3 decks)

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