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what's in a plant cell?
- ratio of cell contents to cell structure
- cell contents: good stuff
- cell structure: hard to digest
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leaves of nearly all forages have higher _________ and lower ________ than stems
- higher crude protein, phosphorous, cell soluble levels
- lower fiber and lignin
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stems of woody plants are ____ in quality because of _________
- low
- high levels of lignification
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fruits and flowers from _______ generally have higher levels of _________ than leaves
- forbs and shrubs
- cell solubles and protein
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what nutritional compounds do animals need?
- carbohydrates
- fats
- proteins
- minerals
- vitamins
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energy allocation in animals
- 1. maintenance
- 2. reproduction
- 3. growth
- 4. storage
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types of grazers
- grazers
- browsers
- intermediate feeders
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grazers
- consume primarily grasses, bulk feeders
- ex. cattle, elk, bison, bighorn sheep, horses
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browsers
- mostly forbs and shrubs throughout the year, concentrate selectors
- ex. moose, pronghorn, mule deer, domestic goats
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intermediate feeders
- can adjust their diet to whatever is available
- ex. domestic sheep, caribou
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types of digestive systems
- ruminants (microorganisms)
- monogastric with enlarged cecum (hindgut fermenters)
- monograstric without enlarged cecum
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pro and con of ruminants?
- pro: excellent survival under moderate quality forage
- disadvantage: intake limited by passage rate (ie. can't cope with extended exposure to low quality forage)
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pro and con of monogastric with enlarged cecum?
- pro: intake NOT limited by forage quality, can survive under low quality forage conditions
- con: problems with limited forage quantity, esp. with inefficient digestion (need to eat lots)
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factors of forage selection by large ungulates
- 1. body size
- 2. digestive system
- 3. mouth size and shape
- 4. rumen reticular volume
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determinants of vegetational nutritional quality
- phenology
- environmental conditions
- plant growth form/species
- plant species composition
- management
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animal strategies to increase forage quality
- selection of higher quality plants while feeding
- selection of actively growing plant communities
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plans to avoid animals eating poisonous plants?
- identify and avoid high risk areas
- avoid moving livestock when hungry
- provide efficient salt (avoid cravings)
- ensure adequate water and sufficient feed to facilitate passage rates and breakdown of toxins
- control poisonous plants (mowing, targeted herbicides)
- avoid overgrazing and forcing animals to eat plants they wouldn't normally pick
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ecological constraints on animal production
- <1% of solar energy converted to primary production
- <20% of primary production is consumed by herbivores
- conversion efficiency is <10%
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what 3 things does animal production depend on?
- energy capture
- harvest
- conversion efficiencies
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measurements of animal production
- gains per animal
- gains per unit land area
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factors determining animal impact
- animal type
- stocking density
- stocking rate (timing, duration, frequency)
- location of grazing (animal distribution)
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forage available
browse and palatable herbage
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forage demand
daily amount of forage required to meet nutrition requirements
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grazing pressure
forage demand/forage available
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Safe use factor (SUF)
max level of plant defoliation that facilitates continued vigorous growth
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actual SUFs depend on
- plant species available (and grazing tolerance)
- plant phenology
- plant vigor
- susceptibility of the site to erosion
- objectives of the rangeland manager
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carrying capacity
max number of animals that can be supported on a particular rangeland
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grazing (safe) cc (AUM) [what]
number of animals that can be sustainably supported given current management
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absolute CC (AUM)
- max number of animals that an area can support (assumes all forage is consumed, FA=FD)
- no SUF
- no buffer to deal with variability
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supplemental feeding is beneficial if:
forage digestibility (eg. quality) limits intake
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compensatory growth
animals in poorer condition consume greater quantities of moderate to high quality forage
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common-use grazing
dietary difference allow for greater production when multiple sp. are present
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factors of disturbance
- intensity
- frequency
- duration
- extent (spatial)
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disturbance alters:
- plant growth
- biomass
- plant community composition
- plant-plant interactions
- biophysical properties (ex. litter)
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grazing systems
a detailed protocol specifying the type, number, timing, and physical distribution of grazing animals
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objectives of grazing system
- defer or rest key species
- obtain more uniform use of forage
- increase livestock productivity
- provide opportunity for sacrifice areas to recover
- increase wildlife productivity
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grazing season
total period of time during which grazing could sustainably take place given the inherent conditions of the region
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grazing period
actual time period during which grazing takes place within a particular area
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rest period
timer interval bw successive grazing periods
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rest
nonuse for a full year
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deferment
delay of grazing in a pasture until seed maturity for key forage species
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rotation
movement of cattle from one pasture to another on a schedule
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types of no pasture grazing systems
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types of multiple pasture grazin systems
- seasonal suitability
- defered rotation
- rest rotation
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types of complex multiple pasture grazing systems
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considerations for grazing systems
- topography
- climate (variable ppt)
- wildlife
- trees
- water distribution
- vegetation type (ex. grazing resistant)
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zero grazing
livestock not exposed to landscape, food brought to them
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transhumance grazing
- animals migrate bw adjacent land areas on concert with major phenological changes
- reflects grazing history wild animals had with landscape
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single pasture (continuous) grazing (pro and con)
- animals confined to a single pasture at low densities for the entire growing season
- pro: selectivity, max per animal weight gain, least amt fencing
- con: forage use is uneven, retrogression in over-used patches
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seasonal suitability
livestock graze each vegetation type when it is most suitable
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deferred rotation
- animals not allowed on a portion of the range until after growth is well advanced
- allows vegetation to reach maximum growth
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rest rotation (pro and con)
- similar to DRG, except at least one pasture remains ungrazed all year to allow plants to produce seed
- pro: helps with livestock distribution, wildlife
- con: pastures that aren't getting rested get heavier use, reduces livestock performance bc less selectivity
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three herd/four pasture system
- multiple herds, moderate/conservative stocking
- effective where there is year-round potential for regrowth
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"best" pasture system
- designed for localized ppt events
- ex. desert systems where forbs are responsive to rainfall
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high intensity low frequency
- livestock are moved after utilization reaches high levels (~70%)
- long rest periods
- high utilization grazing
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low intensity high frequency
- livestock are moved frequently after light utilization
- shorter rest periods
- high performance grazing
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short duration (SD)
- livestock are kept at higher densities and moved frequently, generally after 1 or 2 days, following the rule of "maximum of 1 bite per plant per grazing period"
- animals move based on plant growth/development
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6 steps for planning for interactions with livestock and wildlife
- 1. establish objectives and priorities in multi-species management
- 2. determine essential requirements for all
- 3. determine habitat potential to meet multiple sp. objectives
- 4. assess species interactions
- 5. monitor impacts of livestock management on associated wildlife
- 6. modify management (adaptive management)
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common use grazing systems
grazing of 2 or more species on the same range to obtain more efficient use of forage
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direct effects of livestock on wildlife
- modification of available forage
- alteration of vegetation structure
- disease transmission
- trampling (exposure time x stocking rate)
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indirect effects of livestock on wildlife
- alteration of plant community species over time
- wildlife injury and altered movement due to infrastructure
- water development may increase in the area of suitable habitat
- range improvements like burning, spraying, etc
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the 4 rangeland wildlife case studies
- 1. wild ungulates and facultative grazing
- 2. horses and wild burros
- 3. waterfowl
- 4. upland avifauna
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facultative grazing
- strategic grazing by livestock of a given area in mid to late summer to stimulate regrowth during fall
- relies on having adequate moisture for regrowth
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4 objectives of facultative grazing
- 1. provide high quality winter forage
- 2. remove mature vegetation (graze later in season)
- 3. provide current year's growth (rest?)
- 4. maintain vigour (all treatments get deferment or rest)
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when does ducks unlimited recommend that you defer grazing of uplands until after?
- July 15
- gives birds time to nest
- minimize trampling damage
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mechanisms for enhancing wildlife habitat/management
- public land (regulation and enforcement)
- private land (paid hunting-fishing, nature camps/retreats, etc)
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benefits of managing for native ungulates
- "common use" grazing increases efficiency of animal production relative to forage available
- native ungulates better adapted to endemic diseases, landscapes, climatic conditions
- lower input costs (vet bills, breeding,etc)
- simultaneous benefits to other wildlife that use the same habitat/resources
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predator management
- controversial today, used to be common practice
- best kind of management is "proactive prevention" - minimize contact with predators (guard dogs, donkeys, know when are where is risky, etc)
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insect management
- can be hard to control, can sometimes be predicted
- regulated by many factors (ex. climate), most importantly can be excasperated by overgrazing
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habitat selection broad factors
- evolutionary factors (increase survival value on habitat selection)
- behavior factors (provide the mechanism by which areas are selected)
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most mammalian species are ________
- generalists
- some specialists tho (pandas, koalas)
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vegetation influences on selection
- biomass regulates foraging (and therefore intake)
- composition and quality of forage
- phenology
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optimal foraging theory
notion that animals "know" what nutrients they ned and actively "select" forage containing these nutrients (~innate ability)
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learning by consequence foraging theory
- notion that animals "learn" what nutrients are beneficial by
- 1. mimicking their parents
- 2. post-ingestive feedback
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animal-regulated influence on selection
- location and availability of water
- topography (steep slopes - avoidance or preference)
- safety (ie. risk of predation)
- time of year (summer vs winter)
- location and availability of shade (forest and riparian)
- insects
- wind (better in summer, bad in winter)
- other behavioral considerations (breeding, calving, etc)
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thermal neutral zone
range of ambient temperatures within which an animal does not need to expend additional energy cooling or heating itself
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both cattle and wildlife...
- strategically use topography (ex. south-facing slopes) and vegetation for thermal and safety cover
- develop a winter coat and fat reserves
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traits more characteristic just to wildlife
- seasonally migrate with forage availability
- estivation (lowering of metabolic rate)
- ungulates experience strong seasonal patterns of weight gain and loss
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primary range
- spatially preferred areas of the landscape
- ex. valley bottoms, riparian areas
- the first choice to livestock
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secondary range
- areas used predominantly after primary areas are depleted
- ex. slopes, forests
- second-choice
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non-use range
areas ungrazed by livestock
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unintentional non-use range
- areas inherently avoided by animals
- excessive slopes
- heavy timber
- lack of water
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intentional non-use range
- avoided through management
- fenced out riparian areas, areas with poisionous plants, critical wildlife habitat
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management factors
- adjustments made to available forage when quantifying grazing capacity to account for uneven use
- not the same as SUFS!
- MFs stress the difference between communities across the landscape
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feeding station
array of plants available when an animal lowers its head to feed
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plant and plant part selection factors
- diet selection
- feeding behavior
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palatability
- characteristics inherent to the individual plant that elicit a selective response by a herbivore
- regulated closely by plant "avoidance" mechanisms
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preference
- proportional choice made by a herbivore in selecting one plant species for consumption over others
- varies by animal species, plant availability, time of year
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factors that go into predator-prey relationships
- density of prey
- search efficiency
- total time spent
- total search time for all prey
- handling time per prey item
- number prey eaten during period of search time
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foraging time
f(x): travel to patch + searching + feeding
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actual intake
= bite rate x bite size
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feeding behavior with good forage conditions (quality and quantity) ?
- travel time is short
- search time is high (more choosey)
- actual foraging time is short (pick the best and fill up quickly)
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bulk feeders feeding behavior
low bite rates, large bites
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concentrate selector feeding behavior
high bite rates, small but quality bites
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feeding behaviour with reduced forage quantity
- travel time decreases
- relative proportion of time spent actually foraging within a feeding station increases
- animal get less choosey, more opportunistic
- dont have luxury of going to higher quality FS
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reduced forage quality
- total foraging time may decrease due to slower passage rates (low digestibility)
- actual nutrient intake may decrease
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strategies to improve animal distribution
- water developments
- disperse salt and mineral supplements
- trail development for access (to get animals into areas like forests)
- riding (forced animal movement)
- specialized grazing systems
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excreta can alter
- soil chemistry
- GHG emissions
- local productivity
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indirect effects of grazing
- microclimate modification (ex. litter loss -> xerification)
- soil changes (ex. soil compaction)
- competition bw plant species
- magnification of non-uniform competition
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defoliation favors either...
the less defoliated plant AND/OR the more grazing tolerant plant
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intermediate disturbance hypothesis
- notion that maximum species diversity is associated with intermediate levels of disturbance (ex. grazing)
- competitive species dominate under low levels of disturbance
- only ruderal species can dominate under high levels of disturbance
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plant competition
the tendency of neighbouring plants to utilize the same quantum of light, ion of mineral nutrient, molecule of water or volume of space
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general fire effects
- retrogression changes to production
- strategy of plant species to cope with fire (ex. colonizers, tolerators)
- nature of fire influences retrogression
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nature of fire that influences retrogression?
- frequency
- intensity
- timing/season
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results of fire suppression?
contributes to increased woody vegetation
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catena
repetitive variation in vegetation, soil, etc with changes in slope, aspect, relief
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recharge areas
source points for the entry of water, nutrients, salts, etc to the soil profile
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discharge areas
points of discharge for water, nutrients, salts, etc (local, regional)
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factors affected by the alteration of effective growing conditions
- salt levels
- nutrient levels
- effective moisture regimes
- length of growing season
- textural differences
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