ENCS 356

  1. rangelands tend to be _____ ecosystems
    low productivity
  2. single most important factor determining type and productivity of vegetation in the area?
  3. after which to soil characteristics become a more important characteristic than precipitation?
    over 500m avg annual precipitation (in north america)
  4. characteristics of ppt that affect vegetation (5)
    • amount
    • distribution
    • humidity
    • form
    • annual variability
  5. best predictor of grassland productivity?
    mean annual precipitation
  6. ANPP
    • annual net primary productivity 
    • usually thought of in plant biomass
  7. coefficient of variation (in terms if ppt)
    • cv = std dev/mean
    • used to describe the patterns of rainfall from one year to the next, gives us a percentage
  8. P:E ratio
    • precipitation to evaporation ratio
    • how much ppt is coming in vs how much is evaporating
  9. P:E = 1
    same rainfall is coming in that is evaporating
  10. P:E > 1
    more rainfall is coming in than is evaporating
  11. P:E < 1
    less rainfall is coming in than is evaporating
  12. orographic influences
    • ppt distribution is impacted by topography and distance from oceans
    • as air moves up and cools it can hold less moisture
    • result rainshadows on the leeward side of mountains
  13. C3 plants
    cool season grasses, more efficient with their carbon
  14. C4 plants
    • warm season plants
    • extra molecule needed in photosynthesis pathway
    • less efficient with carbon
    • more efficient with water, so can do better in dry conditions
    • affects nutritional quality of the plant
  15. latitude and temp relationship?
    latitude influences temp by 0.5°C per 1° latitude
  16. elevation and temp relationship?
    temp decreases by ~2°C per 300m elevation
  17. aspect's effect on local growing conditions?
    • directional orientation of slopes
    • ex. southern slopes may be drier (more sunlight), may have diff plants on diff sides of hill
  18. degree of slope's effect on local growing areas?
    • gradual slope vs. steep
    • affects vegetation productivity and use by range animals
    • increases ppt runoff - as slope increases vegetation productivity decreases
  19. soil factors affecting rangeland productivity (6)
    • texture
    • structure
    • depth
    • pH
    • organic content
    • fertility
  20. ____ soils will be more productive
  21. ______ in soil depth can promote plant species diversity
    • heterogeneity
    • different species adapt to being able to root at different depths
  22. more basic soils tend to get _____
    • less rainfall
    • more calcium carbonate
  23. more acidic soils tend to get _____
    more rainfall
  24. most limiting nutrient in younger systems
  25. most limiting nutrient in older systems
  26. salinity limits.....
    • plants' ability to take in water, nutrients
    • takes a lot of energy for plants to deal with salt
  27. types of vegetation (4)
    • grasses
    • forbs
    • shrubs
    • trees
  28. desert shrublands productivity
    100-500 kg/ha
  29. woodland productivity
    • 100-3500 kg/ha
    • large range, depends on what tree types you are dealing with
  30. Tallgrass prairie
    • very little left
    • ppt ranges from 500-1000mm
    • mostly C4 temps
    • warmer winter temps
  31. coastal prairie
    • up to 1500mm in ppt
    • sandy/well-drained
    • sod-forming/adapted to living on sand dunes
    • very productive
  32. Mixed or shortgrass prairie
    • wide range
    • 260-800mm ppt
    • C4 plants, tillers
  33. fescue prairie
    • 340-460mm ppt
    • colder than shortgrass prairie
    • rough fescue sole dominant?
  34. palouse prairie
    • 200-640 mm ppt
    • sage bush
    • bluebunch wheatgrass
  35. pacific prairie
    • 250-500mm ppt in south
    • 1250mm ppt north
    • parent material is serpentine grassland??
    • very basic
    • shallow soils, therefore unproductive despite high ppt
  36. desert plains grassland
    • very low ppt (~250mm)
    • dry and hot, low productivity
  37. plant classification
    • simplifies diversity of plant communities
    • removes gradients 
    • most classifications are local
  38. phytosociology
    • looking at associations bw diff plant communities
    • based on the presence/absence of diff plants
    • hierarchical with naming system like taxonomy
    • dominantly used in Europe
    • good for areas with high lvls of homogenity
  39. lower foothills
    • comparatively wet and warm
    • high tree diversity
  40. mixed dry grass prairie
    • SE corner of AB
    • dry and warm
    • several million ac were farmed then abandoned -> recovery depends on grazing
  41. parkland
    • cool and wet
    • grasses are v productive?
  42. range site
    • (ecosite)
    • localized, mappable area of relatively uniform physical conditons
  43. plant community
    localized, mappable stand of relatively uniform vegetation
  44. range (plant community) type
    • takes into account land use, cattle presence, etc
    • hypothetical/artificial plant community representing many similar plant communities in reality (ex. grouped for convenience)
  45. forbs
    • dicots with fibrous and/or taproots
    • have elevated apical meristem
    • renew above-ground biomass annually
  46. shrubs and trees
    • dicots that accumulate above-ground woody tissue
    • renew growth from intact, elevated meristems (apical and axillary)
  47. grasses
    • monocots with extensive, fibrous root systems
    • apical meristems generally at the plant base
    • renew above-ground biomass annually
    • have high root turnover (growth and death)
  48. apical meristem
    primary zone of growth at the end of roots and stems (forbs and shrubs)
  49. axillary meristem
    • secondary zone of growth 
    • in dicots: the origin point of branches and leaves)
  50. apical dome
    • region of intense meristematic activity at the base of a grass plant
    • low to the ground, allows grasses to recover better from grazing
  51. axillary bud
    specialized zone of development on a grass apical dome, capable of developing into a "tiller"
  52. intercalary meristem
    • secondary zone of growth on the leaves of grasses 
    • junction of leaf sheath and blade, and sheath and node)
  53. phytomer
    • basic repeating unit of an individual grass tiller
    • incl. node and internode with leaf and sheath at the top and bud at the bottom
    • stack of phytomers form a shoot
  54. tiller
    a group of phytomers, linearly arranged (stacked) and derived from the same apical meristem
  55. rhizome
    • an underground lateral stem used for vegetative reproduction
    • ex. plains roughfescue, kentucky bluegrass
  56. stolon
    • an above ground lateral stem used for vegetative reproduction
    • ex. strawberry, buffalograss
  57. xylem
    • translocation sieve tubes for water and minerals 
    • move material predominantly upwards
  58. phloem
    • translocation sieve tubes for carbohydrates and proteins
    • move material predominantly downwards
  59. seminal roots
    the small root system developed from the cotelydon used to temporarily support a seedling
  60. adventitious roots
    extensive, fibrous rot system developed by the plant, particularly grasses, to support itself
  61. levels of photosynthesis depend on (2 things)
    • leaf area (ex. max surface area to volume ratio for leaf blades)
    • age of leaf (PS slows with age nearing senescence)
  62. source (plants)
    • organs that generate carbohydrates that can export them to other areas in the plant
    • ex. could be roots in the spring for biennials/perennials
  63. sink (plants)
    an organ or tissue within the plant that attracts nutrients (ex. CHOs) for active use
  64. non-labile sink
    • once deposited, nutrients can no longer be re-mobilized
    • ex. respiration, structural plant growth
  65. labile sink
    • nutrients that CAN be remobilized
    • ex. non-structural, not immediately used
  66. TNC
    • total non-structural carbohydrates
    • basic sugars actively translocated within the plant and available for respiration and growth
    • can move through the plant
  67. ranked assimilate partitioning (from most important to least important)
    • 1. maintenance (respiration and basic repair)
    • 2. initiation & growth of new roots (where resources are stored) 
    • 3. initiation and growth of new leaf area (allocates between here and #2 differently depending on what kind of plant/what time of year)
    • 4. CHO storage (ONLY with net positive PS)
    • 5. stem elongation, flowering, seed production
  68. sexual plant reproduction
    via flowering, seed set and establishment
  69. floral induction plant reproduction
    • rapid bolting of apical dome in grasses
    • leading to seed head elevation
    • factilitates pollination and seed dispersal
  70. tillering
    • process of vegetative reproduction in grasses
    • development of axillary buds on the apical dome into new apical meristems and domes
  71. disturbance (to plants)
    • mechanisms that limit plant biomass by causing its partial or total destruction
    • ex. herbivory, wind
  72. stress (to plants)
    • anything that slows or limits plant growth
    • ex. lack of nutrients, water
  73. in situ plant disturbance
    • plants die, then the biomass is removed via decomposition
    • ex. frost, senescence
  74. properties of disturbance
    • intensity
    • frequency (and duration)
    • scale (spatial extent)
  75. LAI
    • leaf area index
    • how much leaf area there is per m2
  76. effects of grazers
    • defoliation
    • trampling
    • nutrient inputs
  77. most plants have evolved with and are adapted to __________ but NOT ______________
    • periodic herbivory
    • frequent, intense defoliation
  78. ongoing plant survival depends on: (3 things)
    • i. continual synthesis and storage of PS (needs leaves to do this)
    • ii. maintenance of a healthy root system
    • iii. periodic reproduction (needs to allocate some energy into sexual or vegetative reproduction)
  79. grazer adaptations to grass and grasslands
    • hypsodonty (thick tooth enamel)
    • ruminating
    • hooves
  80. plant adaptations to herbivory
    • i. avoidance
    • ii. tolerators
  81. types of plant avoidance of grazers (a-d)
    • use physical means to deter herbivory
    • a. mechanical (thorns, awns, bristles)
    • b. chemical (unpalatable or toxic)
    • c. spatial avoidance (reduced access to plants)
    • d. temporal avoidance (reduced exposure to herbivores, ex. rapidly growing ephemerals)

    **plants forsake growth and reproduction to produce these structures**
  82. types of plant tolerating grazers (a-g)
    • plants adapted to survive despite being defoliated
    • a. protect growing points near ground surface (ex. grasses)
    • b. resprout freely following defoliation
    • c. reproduce via rhizomes or stolons 
    • d. store high CHOs in roots and stems to facilitate rapid regrowth (v-shaped or flat CHO cycle)
    • e. high proportion of vegetative tillers
    • f. elevate seed-heads rapidly
    • g. may exhibit 'compensatory growth' (grazing may increase primary production over the ungrazed state)
  83. compensatory growth
    increase of growth in response to defoliation
  84. resistance to grazing: forbs
    • produce many seeds
    • delayed elevation of growing points
    • chemical resistance
  85. resistance to grazing: shrubs
    • mechanical: thorns, spines
    • volatile chemicals (smelly)
    • branches
    • older woody growth generally not palatable
    • removal of apical meristem may stimulate axillary bud
  86. resistance to grazing: grasses
    • fewer shoots
    • longer delay in elevation of apical buds
    • more likely to sprout from apical dome
    • higher ratio of vegetative to reproductive stems
  87. growing points
    • places where cells divide and elongate
    • in a vegetative grass: located near ground and are raised as the stem elongates
  88. 3 major stages of grass growth cycle
    • spring vegetative growth
    • late spring/summer reproductive growth
    • fall/winter
  89. early spring vegetative growth
    • inititally relies on stored CHOs for growth
    • growing point: ground level
    • new leaves begin to PS
    • potential for regrowth?
  90. spring/summer reproductive growth
    • plant produces enough energy to support itself, period of rapid growth begins
    • environmental cues signal change to reproductive growth
    • energy allocated to seed production and storage
    • growing points elevated
    • summer slow down/dormancy
  91. fall/winter growth
    • enter partial dormancy
    • plants never truly dormant as they respire all winter
    • if adequate fall moisture is available new tillers may develop from dormant buds
  92. 3 basic factors we can manage for with respect to grazing
    • frequency (# of times a plant is defoliated during a period of time)
    • intensity (the proportional removal of plant material)
    • opportunity for growth and/or regrowth (determined by environmental factors, season of removal, previous defoliation, frequency, intensity)
  93. ecology
    study of relationships among organisms, and between organisms and their environment
  94. autecology
    population ecology - individual organisms and populations
  95. synecology
    community ecology - deals with complex groups of organisms (ex. plant community) and their relationship to other organisms (ex. herbivores) as well as their environment
  96. population
    group of individuals of the same species living in a given area at a given time
  97. species
    a population or group of populations whose members have the potential in nature to interbreed and produce fertile offspring
  98. environment
    total surroundings of an organisms, including other plants and animals and those of its own kind
  99. habitat
    place where a plant or animal can live
  100. community
    a group of interacting plants and animals inhabiting an area
  101. association
    kind of plant community represented by stands that occur in places where environments are so similar that there is a high degree of floristic uniformity in all layers of the plant community
  102. dominant
    plant species or species groups, which by means of their number, coverage, or size, has considerable influence or control upon the conditions of existence of associated species
  103. ecosystem
    the biotic community and its abiotic environment functioning as a system
  104. 4 characteristics of ecosystems
    • web of interactions and interdependencies
    • synergy
    • stability
    • diffuse boundaries
  105. most definitions of ecosystems include
    • 1. a community of species
    • 2. the physical environment on which these organisms are dependent
    • 3. the physical size of the particular ecosystem being considered
  106. abiotic components of an ecosystem
    • 1. parent material
    • 2. climate
    • 3. topography
    • 4. natural disturbances
  107. biotic components of an ecosystem
    • 1. producers
    • 2. consumers
    • 3. decomposers
    • 4. manipulators
  108. ecological succession
    a directional change in species composition, community structure, and function over time and space
  109. primary succession
    • decsribes the sequence of plant communities on a new site (ex. a site previously devoid of plants)
    • ex. volcanic eruptions, mine waste, sand dunes
  110. secondary succession
    • describes the change in plant communities after a disturbance (ex. a site which already had plants and soil)
    • ex. grazing, fire
    • plant traits and dominance play a key role!
  111. autogenic succession
    • aka biotic succession
    • vegetation changes due to the activities of the organisms themselves
  112. allogenic succession
    vegetation change due to environmental conditions and environmental change or external factors
  113. resistance (succession)
    ability of the system to withstand a perturbation
  114. resilience (succession)
    the speed at which a disturbed system returns to equilibrium after a perturbation
  115. inertia
    the tendency of a community to continue to occupy a specific range site, even after conditions have changed to favor a new community
  116. seres
    intermediate stages in the development of a 'climax' plant community
  117. retrogression
    changes within the plant community away from climax due to a disturbance
  118. progression in succession (6 steps)
    • 1. nudation - disturbance
    • 2. migration - arrival of propagules
    • 3. establishment - initial growth of vegetation
    • 4. competition - species compete for space, light, nutrients
    • 5. reaction - autogenic effects (effects of plants on habitat)
    • 6. stabilization - climax
  119. CSR triangle
    • competition, stress, ruderal 
    • triangle represents habitat space, described by stress and disturbance
  120. relay floristics
    • each seral community relays the site to the next community
    • driving force behind succession is the reaction of the site to the plants living in it
  121. initial floristic competition
    • rearrangement of species that were present during initial stages
    • the proportions of the various species changes during succession
  122. mechanisms of succession - facilitation
    each seral community changes the site for the next community
  123. mechanisms of succession - tolerance
    which species have the ability to survive the longest
  124. mechanisms of succession - inhibition
    • /competition
    • some species will actually inhibit the development of others
  125. states
    distinguished from each other by big differences in plant functional groups (vegetation structure) and ecosystem processes (hydrology, energy capture, nutrient cycling)
  126. transition
    a trajectory of system change away from the current stable state that is triggered by natural events, management actions, both
  127. threshold
    boundary in space and time bw two states, so one or more of the ecological processes has been irreversibly changed
  128. excreta can alter:
    • soil chemistry
    • GHG emissions
    • local productivity
  129. indirect effects of grazing
    • microclimate modification
    • soil changes
    • competition
  130. microclimate modification (grazing affects)
    grazing induced changes to water cycle efficiency, which favours some plants over others
  131. soil changes (grazing affects)
    • grazing induced changes to key range site characteristics 
    • ex. soil compaction
  132. competition (grazing affects)
    • disruption of the competitive balance between 2 or more plant species
    • defoliation favours either the less defoliated plant AND/OR the more grazing tolerant plant
  133. 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
    • under high levels of disturbance only ruderals can tolerate the conditions
  134. plant competition (grime defn)
    "the tendency of neighbouring plants to utilize the same quantum of light, ion of mineral nutrient, molecule of water, or volume of space"
  135. hump-shaped curve
    • common pattern in the relationship bw productivity and plant species richness is a unimodal curve
    • pattern been observed in many taxa
  136. general fire effects
    • retrogression changes to production
    • strategy of plant species to cope with fire
    • nature of the fire influences retrogression
    • fire suppression
  137. strategy of plant species to cope with fire
    • colonizers: migrate into burned areas as early successional plant species (fireweed, lodgepole pine)
    • tolerators: recover slowly to pre-burn levels as mid to late seral species
  138. nature of the fire influences retrogression?
    • frequency (recovery interval)
    • intensity (air temp, humidity, fuel load)
    • timing/season (fall vs summer vs spring)
  139. effects of fire suppression?
    contributes to increased woody vegetation
  140. landscape ecology
    applying basic ecological principles to landscapes, the scale at which most management occurs
  141. catena
    • repetitive variation in vegetation, soil, with changes in slope, aspect, and relief (elevation
    • cyclical changes in vegetation across the landscape
  142. recharge areas
    source points for the entry of water, nutrients, salts, etc to the soil profile
  143. discharge areas
    points of discharge of water, nutrients, salts, etc (local, regional)
  144. factors affected by alteration of effective growing conditions
    • salt levels
    • nutrient levels
    • effective moisture regimes
    • length of growing season
    • textural differences (ex. clay buildup in valleys)
  145. animal behavior and landscape ecology
    • strongly interacts with landscape position
    • safety, food, water, etc
  146. fire interactions with landscape ecology
    drier sites burn more often and intensely, and thus are lower in seral status
  147. rangeland defn (animal centered)
    uncultivated lands that will provide the necessities of life for grazing and browsing animals
  148. rangeland broader defn
    areas of the world that are a source of forage for free-ranging native and domestic animals, as well as a source of wood products, water, wildlife, etc
  149. herbivory
    consumption of plants by animals
  150. grazing
    consumption of standing forage (grass and forbs) by livestock or wildlife
  151. browsing
    consumption of leaves and twigs from woody plants (trees and shrubs) by large-hoofed animals
  152. pasturelands
    lands that are periodically cultivated (highly modified) to maintain agronomic forage species and receive inputs
  153. ecosystem
    biotic community and its abiotic environment functioning as a system
  154. rangeland outputs
    • meat and fibre
    • carbon storage
    • energy
    • water
    • biodiversity
  155. rangelands provide ___ of worldwide feed for livestock
  156. rangelands provide ___ of feed for wild ungulates
  157. range management
    the manipulation of rangeland components to obtain the optimum combination of goods and services for society on a sustained basis
  158. range science
    • the organized body of knowledge upon which range management is based
    • ecology
    • its and art and a science (**experience based**)
  159. activities of range managers (6)
    • surveys and monitering
    • range management planning
    • modifications of landscape to achieve diff outputs
    • landscape planning and management
    • dispute resolution
    • information and education
  160. threats to rangelands
    • agricultural conversion
    • urban sprawl
    • overgrazing/desertification
    • climate change
    • industrial development
    • recreation
    • fire suppression
Card Set
ENCS 356
ENCS 356