ENCS 356

low productivity

precipitation

over 500m avg annual precipitation (in north america)

• amount
• distribution
• humidity
• form
• annual variability

mean annual precipitation

• annual net primary productivity 
• usually thought of in plant biomass

• cv = std dev/mean
• used to describe the patterns of rainfall from one year to the next, gives us a percentage

• precipitation to evaporation ratio
• how much ppt is coming in vs how much is evaporating

same rainfall is coming in that is evaporating

more rainfall is coming in than is evaporating

less rainfall is coming in than is evaporating

• 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

cool season grasses, more efficient with their carbon

• 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

latitude influences temp by 0.5°C per 1° latitude

temp decreases by ~2°C per 300m elevation

• directional orientation of slopes
• ex. southern slopes may be drier (more sunlight), may have diff plants on diff sides of hill

• gradual slope vs. steep
• affects vegetation productivity and use by range animals
• increases ppt runoff - as slope increases vegetation productivity decreases

• texture
• structure
• depth
• pH
• organic content
• fertility

deeper

• heterogeneity
• different species adapt to being able to root at different depths

• less rainfall
• more calcium carbonate

more rainfall

nitrogen

phosphorous

• plants' ability to take in water, nutrients
• takes a lot of energy for plants to deal with salt

• grasses
• forbs
• shrubs
• trees

100-500 kg/ha

• 100-3500 kg/ha
• large range, depends on what tree types you are dealing with

• very little left
• ppt ranges from 500-1000mm
• mostly C4 temps
• warmer winter temps

• up to 1500mm in ppt
• sandy/well-drained
• sod-forming/adapted to living on sand dunes
• very productive

• wide range
• 260-800mm ppt
• C4 plants, tillers

• 340-460mm ppt
• colder than shortgrass prairie
• rough fescue sole dominant?

• 200-640 mm ppt
• sage bush
• bluebunch wheatgrass

• 250-500mm ppt in south
• 1250mm ppt north
• parent material is serpentine grassland??
• very basic
• shallow soils, therefore unproductive despite high ppt

• very low ppt (~250mm)
• dry and hot, low productivity

• simplifies diversity of plant communities
• removes gradients 
• most classifications are local

• 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

• comparatively wet and warm
• high tree diversity

• SE corner of AB
• dry and warm
• several million ac were farmed then abandoned -> recovery depends on grazing

• cool and wet
• grasses are v productive?

• (ecosite)
• localized, mappable area of relatively uniform physical conditons

localized, mappable stand of relatively uniform vegetation

• takes into account land use, cattle presence, etc
• hypothetical/artificial plant community representing many similar plant communities in reality (ex. grouped for convenience)

• dicots with fibrous and/or taproots
• have elevated apical meristem
• renew above-ground biomass annually

• dicots that accumulate above-ground woody tissue
• renew growth from intact, elevated meristems (apical and axillary)

• 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)

primary zone of growth at the end of roots and stems (forbs and shrubs)

• secondary zone of growth 
• in dicots: the origin point of branches and leaves)

• region of intense meristematic activity at the base of a grass plant
• low to the ground, allows grasses to recover better from grazing

specialized zone of development on a grass apical dome, capable of developing into a "tiller"

• secondary zone of growth on the leaves of grasses 
• junction of leaf sheath and blade, and sheath and node)

• 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

a group of phytomers, linearly arranged (stacked) and derived from the same apical meristem

• an underground lateral stem used for vegetative reproduction
• ex. plains roughfescue, kentucky bluegrass

• an above ground lateral stem used for vegetative reproduction
• ex. strawberry, buffalograss

• translocation sieve tubes for water and minerals 
• move material predominantly upwards

• translocation sieve tubes for carbohydrates and proteins
• move material predominantly downwards

the small root system developed from the cotelydon used to temporarily support a seedling

extensive, fibrous rot system developed by the plant, particularly grasses, to support itself

• leaf area (ex. max surface area to volume ratio for leaf blades)
• age of leaf (PS slows with age nearing senescence)

• organs that generate carbohydrates that can export them to other areas in the plant
• ex. could be roots in the spring for biennials/perennials

an organ or tissue within the plant that attracts nutrients (ex. CHOs) for active use

• once deposited, nutrients can no longer be re-mobilized
• ex. respiration, structural plant growth

• nutrients that CAN be remobilized
• ex. non-structural, not immediately used

• total non-structural carbohydrates
• basic sugars actively translocated within the plant and available for respiration and growth
• can move through the plant

• 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

via flowering, seed set and establishment

• rapid bolting of apical dome in grasses
• leading to seed head elevation
• factilitates pollination and seed dispersal

• process of vegetative reproduction in grasses
• development of axillary buds on the apical dome into new apical meristems and domes

• mechanisms that limit plant biomass by causing its partial or total destruction
• ex. herbivory, wind

• anything that slows or limits plant growth
• ex. lack of nutrients, water

• plants die, then the biomass is removed via decomposition
• ex. frost, senescence

• intensity
• frequency (and duration)
• scale (spatial extent)

• leaf area index
• how much leaf area there is per m2

• defoliation
• trampling
• nutrient inputs

• periodic herbivory
• frequent, intense defoliation

• 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)

• hypsodonty (thick tooth enamel)
• ruminating
• hooves

• i. avoidance
• ii. tolerators

• 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**

• 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)

increase of growth in response to defoliation

• produce many seeds
• delayed elevation of growing points
• chemical resistance

• mechanical: thorns, spines
• volatile chemicals (smelly)
• branches
• older woody growth generally not palatable
• removal of apical meristem may stimulate axillary bud

• fewer shoots
• longer delay in elevation of apical buds
• more likely to sprout from apical dome
• higher ratio of vegetative to reproductive stems

• places where cells divide and elongate
• in a vegetative grass: located near ground and are raised as the stem elongates

• spring vegetative growth
• late spring/summer reproductive growth
• fall/winter

• inititally relies on stored CHOs for growth
• growing point: ground level
• new leaves begin to PS
• potential for regrowth?

• 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

• 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

• 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)

study of relationships among organisms, and between organisms and their environment

population ecology - individual organisms and populations

community ecology - deals with complex groups of organisms (ex. plant community) and their relationship to other organisms (ex. herbivores) as well as their environment

group of individuals of the same species living in a given area at a given time

a population or group of populations whose members have the potential in nature to interbreed and produce fertile offspring

total surroundings of an organisms, including other plants and animals and those of its own kind

place where a plant or animal can live

a group of interacting plants and animals inhabiting an area

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

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

the biotic community and its abiotic environment functioning as a system

• web of interactions and interdependencies
• synergy
• stability
• diffuse boundaries

• 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

• 1. parent material
• 2. climate
• 3. topography
• 4. natural disturbances

• 1. producers
• 2. consumers
• 3. decomposers
• 4. manipulators

a directional change in species composition, community structure, and function over time and space

• decsribes the sequence of plant communities on a new site (ex. a site previously devoid of plants)
• ex. volcanic eruptions, mine waste, sand dunes

• 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!

• aka biotic succession
• vegetation changes due to the activities of the organisms themselves

vegetation change due to environmental conditions and environmental change or external factors

ability of the system to withstand a perturbation

the speed at which a disturbed system returns to equilibrium after a perturbation

the tendency of a community to continue to occupy a specific range site, even after conditions have changed to favor a new community

intermediate stages in the development of a 'climax' plant community

changes within the plant community away from climax due to a disturbance

• 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

• competition, stress, ruderal 
• triangle represents habitat space, described by stress and disturbance

• 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

• rearrangement of species that were present during initial stages
• the proportions of the various species changes during succession

each seral community changes the site for the next community

which species have the ability to survive the longest

• /competition
• some species will actually inhibit the development of others

distinguished from each other by big differences in plant functional groups (vegetation structure) and ecosystem processes (hydrology, energy capture, nutrient cycling)

a trajectory of system change away from the current stable state that is triggered by natural events, management actions, both

boundary in space and time bw two states, so one or more of the ecological processes has been irreversibly changed

• soil chemistry
• GHG emissions
• local productivity

• microclimate modification
• soil changes
• competition

grazing induced changes to water cycle efficiency, which favours some plants over others

• grazing induced changes to key range site characteristics 
• ex. soil compaction

• 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

• 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

"the tendency of neighbouring plants to utilize the same quantum of light, ion of mineral nutrient, molecule of water, or volume of space"

• common pattern in the relationship bw productivity and plant species richness is a unimodal curve
• pattern been observed in many taxa

• retrogression changes to production
• strategy of plant species to cope with fire
• nature of the fire influences retrogression
• fire suppression

• 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

• frequency (recovery interval)
• intensity (air temp, humidity, fuel load)
• timing/season (fall vs summer vs spring)

contributes to increased woody vegetation

applying basic ecological principles to landscapes, the scale at which most management occurs

• repetitive variation in vegetation, soil, with changes in slope, aspect, and relief (elevation
• cyclical changes in vegetation across the landscape

source points for the entry of water, nutrients, salts, etc to the soil profile

points of discharge of water, nutrients, salts, etc (local, regional)

• salt levels
• nutrient levels
• effective moisture regimes
• length of growing season
• textural differences (ex. clay buildup in valleys)

• strongly interacts with landscape position
• safety, food, water, etc

drier sites burn more often and intensely, and thus are lower in seral status

uncultivated lands that will provide the necessities of life for grazing and browsing animals

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

consumption of plants by animals

consumption of standing forage (grass and forbs) by livestock or wildlife

consumption of leaves and twigs from woody plants (trees and shrubs) by large-hoofed animals

lands that are periodically cultivated (highly modified) to maintain agronomic forage species and receive inputs

biotic community and its abiotic environment functioning as a system

• meat and fibre
• carbon storage
• energy
• water
• biodiversity

~70%

~95%

the manipulation of rangeland components to obtain the optimum combination of goods and services for society on a sustained basis

• the organized body of knowledge upon which range management is based
• ecology
• its and art and a science (**experience based**)

• surveys and monitering
• range management planning
• modifications of landscape to achieve diff outputs
• landscape planning and management
• dispute resolution
• information and education

• agricultural conversion
• urban sprawl
• overgrazing/desertification
• climate change
• industrial development
• recreation
• fire suppression