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DRAFT
RS300 – PRINCIPLES OF RANGE MANAGEMENTI. Introduction – Why a discipline of Rangeland Ecosystem Science? (3 to 5)
A. Range as a discipline
1. Definitions
a. Rangeland
i. derived from one of many different ways to describe the surface character of the earth
ii. classifications are a way to communicate, both within and across disciplines
iii. a kind of land – historically based on use
b. Range Science – a body of knowledge derived from both inductive and deductive thought, and based on rules of evidence accepted by the discipline.
c. Range Management
i. application of human-derived practices and natural events to control processes that collectively produce an ecosystem state, or dynamic, valued by humans.
ii. Managers
* choose collections of ideas and
paradigms for explaining variability
accepted by the discipline and
cultures involved
* set system boundaries, (i.e.,
managers choose appropriate
temporal and spatial scales) based
on the issues that require human
intervention
* operate within cultural, political and
economics systems
* link biological and human systems
@ resolve disputes among people
and groups that hold traditional
and other cultural values
@ accommodate multiple cultural
values in NR planning and
decision-making
@ facilitate communication among
stakeholders and clientele
B. Value of rangelands, rangeland uses and rangeland products
1. Intrinsic values
a. biological diversity
b. sense of place
c. aesthetics
d. source of germplasm
e. habitat for endemic and transitory fauna
2. Economic values – a source of wealth to privately held land and
a source of revenue for governments
a. wildlife ranching and sale of wildlife products
b. livestock ranching and sale of livestock products
c. sale of recreational access to land
d. minerals
C. Historical context and future contribution
1. prehistoric context, including the evolution of flora and support
of various fauna
2. historic context, including the role of land disposal schemes and
economic development
a. The discipline grew out of a concern for sustainable
uses on grasslands and shrublands.
b. Early experiments and demonstrations showed the
response of systems to management.
c. Formation of a Society in 1948.
d. Relation to other disciplines.
3. Future contribution of the discipline is to continue to build
knowledge of system processes and sustainable uses.
Management will be required for most rangeland uses to be
sustainable. The reason is mostly related to change in scale and
dampening of natural system modifiers like fire and grazing.
II. Characteristics and global distribution of rangelands – Structure of
terrestrial vegetation (4)
A. Habitat factors that determine vegetation structure (based on the Holdredge
Triangle), including lifeform and life histories of vegetation.
1. Temperature, represented by latitude and altitude represent life
zones. Temperature determines the boundary above which
plants adapted to a life zone cannot survive
2. Total available water drives systems within life zones. Total
available water determines the lifeform of plants that dominate a
site.
a. Total precipitation and form
i. total annual precipitation
* frequency of low intensity vs
high intensity events * distribution of events
ii. seasonal distribution
b. coincidence of precipitation and evaporation
i. vegetation use of stored water vs
water from ephemeral events
ii. interaction of water availability and
environmental conditions conducive
to growth or regrowth
* influence of prolonged
periods of reduced water
supply – drought cycles * influence of periods of
above average water
supply * wet and dry intervals under
temperatures too cold for
growth * wet and dry intervals under
temperatures suitable for
plant growth
c. Soils and relief
i. water interception and evaporation
ii. infiltration rate and runoff
iii. water holding capacity and
availability
iv. water transpiration and evaporation
* radiant energy
* wind
B. Distribution of Rangeland types in the US and World
1. Grasslands
a. tallgrass prairie and world homologues
b. midgrass prairie and world homologues
c. shortgrass prairie and world homologues
d. desert grass
i. Palouse
ii. California
e. annual
2. Desert shrub
a. northern
i. sagebrush-steppe
ii. salt desert
b. southern
3. Shrub woodlands
a. mesquite
b. pinon-juniper
c. chaparral
d. mountain brush
4. Temperate forests
a. juniper woodlands
b. ponderosa pine
c. fir, including transitional states
d. aspen
e. hardwood woodlands
5. Tundra
III. Plant Physiology and Morphology in Relation to Defoliation – Rangeland
vegetation is renewable (4 to 6)A. Plant morphogenesis and response to amount and timing of tissue removal
1. review of monocot and dicot anatomy and response to above and below
ground tissue removal (e.g., herbivory or fire)
2. below ground
a. root growth
i. annual growth cycle – time of root growth
ii. mortality and annual turnover, including use by below ground
feeders and decomposition
iii. interaction with above ground tissue removalb. modified stems – rhizomes
i. number
ii. initiation and time of emergence
iii. interaction with above ground tissue removal2. above grounda. plant growth
i. monocots vs dicots
ii. effect of tissue and meristem removalb. reproduction
i. sexual
* seed production
@ dispersal mechanisms in relation colonization of ecological
gaps
@ viability and requirements for germination and survival in
relation to colonization of ecological gaps
– rooting morphology and seedling emergence and root
development
– water availability
– temperature
* interaction of seed production and environment, including
herbivory and fire
ii. asexual
* tillers and the morphology of tillering
* rhizomes and the morphology of rhizome production
* stolons and the morphology of stolon production
* apomixis
* corms or bulbsB. Photosynthesis and Respiration – the organismal level of response
1. Accumulation of above ground and below ground biomass is the difference
between total photosynthesis and respiration. The difference is net primary
productivity.
a. photosynthesis is the process of capturing CO2 from the atmosphere
in the presence of sunlight and incorporation of the carbon into
biomass, structural and nonstructural. In the process, energy is
transformed and captured in various chemical bonds. The process of
photosynthesis is called assimilation.i. photosynthetic pathways – C3 vs C4* photosynthetic efficiency – effect of temperature, water and the interaction of
temperature and available water
– efficiency of N use * form of carbon stored/translocated, i.e., sugars vs starchii. efficiency of energy capture in different leaves and stems
iii. carbon mobilization – timing and units of storage
b. respiration is the amount of energy used (heat lost) in the process of
chemical transformations and support of the living tissue. Tissue must
be supported both during active growth and during periods of
non-growth when no photosynthate is being produced.2. Carbon is either fixed in structural biomass or remains mobilea. allocation above ground and below ground in response to stress
b. storage during periods of quiescence and mobilization to initiate
growth when growing conditions are favorable
i. annual carbon dynamics in monocots vs dicots – “U” and “V”
shaped replenishment and depletion curves in different tissues
ii. modification of carbon dynamics in response to tissue removal,
e.g., mechanical cutting, herbivory or fire3. Individual plant response to defoliation and its ability to maintain equity
position in the plant community is a function of
a. timing of defoliation in relation to morphological development
i. frequency or duration of defoliation
ii. intensity of defoliation (amount of photosynthetically active
tissue removed)
iii. opportunity for plants to compensate for defoliation
* mobility of carbon in different tissues
* ability of different tissues to fix carbon (e.g., old vs young
leaves, flag leaf vs other leaves, stems vs leaves)
* environmental conditions conducive to growth or regrowthb. associated plants and ability to compete for nutrients and water
i. generally, late seral plants have lower nutrient and water
requirements than early seral plants
ii. generally, C4 plants have lower nutrient requirements than C3
plantsIV. Plant Ecology in Relation to Defoliation. Rangeland Vegetation is Dynamic.
(4 to 6) A. Relationship of range management to plant ecology
1. Range management is the application of human-derived practices and natural
events to control processes that collectively produce an ecosystem state or
dynamic valued by humans.
a. Management is goal directed. It implies management can define a
desired future system state.
b. Manipulation of ecosystem processes (i.e., directing energy flow and
controlling nutrient cycling) to control the number and strength of
negative feedbacks in the system to maintain status; or, control the
reinforcing impact of positive feedbacks in the system, i.e., manage the
trajectory of a transition toward a desired future state or prevent
transition to a former state.2. Management is adaptive, that is, it combines managerial experience with
models of vegetation dynamics to predict system response to a human
intervention or natural processes. (See section on monitoring)B. Vegetation dynamics – community and landscape levels of organization
1. Variation in the dynamics of stand composition is explained by various
models of succession. One of the key organizing ideas in range management
is the range site. The range site represents the potential mix of plants that can
occupy a soil/relief/exposure. The site represents a level of potential primary
productivity. Within that range of potential variation can exist a matrix of
plant communities at all stages of development, i.e., early to late seral.
2. Autogenic vs allogenic processes/succession or primary vs secondary
succession.
3. Ecosystem characteristics of developing (early seral) vs mature (late seral)
communities (from Odum 1969).
a. Community energetics
i. Gross production/community respiration (P/R ratio)
a. developmental = Greater or less than 1
b. mature = Approaches 1ii. Gross production/standing crop biomass (P/B ratio)
@ developmental = High
@ mature = Lowiii. Biomass supported/unit energy flow (B/E ratio)
@ developmental = Low
@ mature = Highiv. Net community productivity (yield)
@ developmental = High
@ mature = Lowv. Food chains
@ developmental = Linear, predominately grazing
@ mature = Weblike [Complex], predominately detritusb. Community structure
i. Total organic matter
@ developmental = Small
@. mature = Largeii. Inorganic nutrients
@ developmental = Extrabiotic
@ mature = Intrabioticiii. Species diversity-variety component
@ developmental = Low
@ mature = Highiv. Species diversity-equatability component
@ developmental = Low
@ intermediate = Often highest
@ mature = Highv. Biochemical diversity
@ developmental = Low
@ mature = Highvi. Stratification and spatial heterogeneity (pattern diversity)
@ developmental = Poorly organized
@ mature = Well-organizedc. Life history
i. Niche separation
@ developmental = Broad
@ mature = Narrowii. Size of organism
@ developmental = Small
@ mature = Largeiii. Life cycles
@ developmental = Short, simple
@ mature = Long, complexd. Nutrient cycling
i. Mineral cycles
@ developmental = Open
@ mature = Closedii. Nutrient exchange rate, between organisms and environment
@ developmental = Rapid
@ mature = Slowiii. Role of detritus in nutrient regeneration
@ developmental = Unimportant
@ mature = Importante. Selection pressure
i. Growth form
@ developmental = For rapid growth (“r” selected)
@ mature = For feedback control (“K” selected)ii. Production
@ developmental = Quantity
@ mature = Qualityf. Overall homeostasis
i. Internal symbiosis
@ developmental = Undeveloped
@ mature = Developedii. Nutrient conservation
@ developmental = Poor
@ mature = Goodiii. Stability (resistance to internal perturbations)
@ developmental = Poor
@ mature = Goodiv. Entropy
@ developmental = High
@ mature = Lowv. Information
@ developmental = Low
@ mature = High4. Indicators of ecosystem stress (from Odum 1985)
a. Trends Expected in Stressed Ecosystems
i. Energetics
@ Community respiration increases
@ P/R (production/respiration) becomes unbalanced (<or> 1)
@ P/B and R/B (maintenance:biomass structure) ratios increase
@ Importance of auxiliary energy increases
@ Exported or unused primary production increasesii. Nutrient Cycling
@ Nutrient turnover increases
@ Horizonal transport increases and vertical cycling of nutrients
decreases
@ Nutrient loss increases (system becomes more leaky)iii. Community Structure
@ Proportion of r-strategists increases
@ Size of organisms decreases
@ Lifespans of organisms or parts (leaves, for example)
decrease
@ Food chains shorten because of reduced energy flow at
higher trophic levels and/or greater sensitivity of predators to
stress
@ Species diversity decreases and dominance increases; if
original diversity is low, the reverse may occur; at the
ecosystem level, redundancy of parallel processes
theoretically declines.iv. General System-Level Trends
@. Ecosystem becomes more open (i.e., input and output
environments become more important as internal cycling is
reduced).
@ Autogenic successional trends reverse (succession reverts to
earlier stages)
@ Efficiency of resource use decreases
@ Parasitism and other negative interactions increases, and
mutualism and other positive interactions decreases
@ Functional properties (such as community metabolism) are
more robust (homeostatic-resistant to stressors) than are
species composition and other structural properties5. Models of succession and usefulness of different models to predict
community response to human and natural disturbance (i.e., creation of gaps
or removal of organisms from the system) or system modifiers, like grazing
and fire.C. Application of knowledge of states and transitions to management of rangeland
ecosystems to achieve desired future conditions.
1. control nutrient cycles vis-a-vis disturbance and system modifiers, like fire
and grazing
2. control colonization
a. following creation of a gap
b. within existing stands of vegetation3. modify plant performance and equity position of plants in association with
other plants vis-a-vis system modifiers, like fire and grazing.V. Secondary Productivity – Nutritional characteristics of rangeland forages and
animal requirements to meet components of life cycles. (4)A. Nutritional characteristics of rangeland forages and browse
1. Methods of representing the nutritional value of foods
a. chemical vs nutritional entities
b. analytical methods2. Nutrients of concern (limiting nutrients) vary with different geology, soil
development processes and total precipitation.
3. Influence of plant phenology and environmental factors on nutrient of forages.
B. Nutritional requirements of range animals
1. management objectives
2. kind and class of animal
3. age
4. physiological state
C. feeding ecology
1. spatial choices
i. learning, memory and perception
ii. social interactions2. diet choices
i. avoidance of toxins and animal poisoning; mechanisms to avoid
poisoning.
ii. avoidance of lose situation – quality and quantity
iii. balance of familiar with novel plants, mixes to create optimal nutrient
ingestion and nutrients as toxinsD. Factors influencing rate and extent of ingestion and utilization
1. Physiological
i. Internal feedback mechanisms
* short term
* long termii. Physiological requirements2. Anatomical
i. gut anatomy – simple vs cecal digester vs ruminant
ii. Extent of digestion is an interaction between rate of digestion and rate
of passsage
* total fiber
* lignification of fiber
* limiting nutrients3. Forage availability
i. animal requirement for free water
ii. animal mobility
iii. forage on offer – herbage allowance
iv. landscape heterogeneity
v. variety of plant lifeforms
vi. animal behavior – home range, defense of territory, etcVI. Management for Proper Use – The number and kinds of organisms a site will
support are complex management issues. (4)A. Numbers of animals (stocking rate) or carrying capacity may be either an
ecological issue, an economic issue, or both.
1. Issues of management using natural regulation to control animal numbers. Implies
a closed system.
a. Population is primarily regulated by food availability
b. Population is primarily regulated by predation
c. Population is regulated by both food availability and predation.2. Issues of management using regulated numbers to achieve an ecological or
economic goalB. Proper use is a reflection of societal values and managerial goals. Determination of the
proper numbers of animals is an iterative process.
1. suitability of the resource for use by different animals during different season.
2. mix of animals and feeding ecology
3. scale
C. Communication of land and resource values and comparison to other systems requires
a data base that can be used to derive information about the resource.
1. Assessment. An ecological assessment is a judgement at a point in time of the
status of a system in relation to known functional relationship in the system,
organisms present and human values. Assessments are usually based on a set of
criteria and indicators developed by scientists and interested stakeholders.
Repeated assessments should not be confused with monitoring.
a. Criteria and indicators for assessment of system “health” at scales of
regions to nations.
b. Criteria and indicators for assessment of system “health” at local and site
scales.2. Inventories. Inventory is an enumeration or qualitative description of elements of
the system valued by management or society. It provides a database for further
stratification and investigation of the resource. Repeated inventories may or may
not be a kind of monitoring. Inventories may serve as a database for
classification.
a. peak standing crop
b. cover
c. frequency
d. cover x frequency
e. density
f. species list and rating of abundance
3. Ecological classification. Ecological classification is usually based
on the structure of the vegetation, because that reflects the potential
mix of life forms of plants, composition of the plant matrix, and
potential productivity of the site. Within a land management
resource area, sites with similar soils, relief and exposure can be
expected to have similar production potential and respond in a
similar way to environment and human induced uses. Often
classification is displayed as maps or electronically stored in a GIS
format.
a. General classification based on correlation of
vegetation to soils, relief, exposure, depth to water,
etc. The range site.
b. Classification of vegetation within a range site that
represent different seral states.
4. Measurements. Elements of the system (plants, animals, soil
particles, microbes, water, etc) have attributes (length, width,
density, volume, color, hue, odor, etc) that can be measured or
indexed. Sometimes we want to know if things of value change as
a result of a use or practice. Since it is impossible to measure every
individual of each element of the system, samples that represent the
population of elements are measured at repeated intervals in time.
That is one form of monitoring.
5. Monitoring
a. Changes in elements in the system of value to
societies or management. Measurements made on
temporal scales of years to decades.
b. Monitoring indicators of change based on relationship
between the indicator and element of interest.
Observations/Notes on temporal scales of years.
c. Monitoring indicators of response of the system to a
use or practice. Observation/Notes on temporal
scales of days to seasons.
C. On determining proper numbers.
1. Determining initial stocking rates
a. calculations based on productivity and accessibility,
ingestion rates and harvest efficiency
b. comparison of the managed area to similar areas
managed for similar outputs
c. Historical
i. proper use factors
ii. Forage acre factors
iii. Other
d. numbers based on the empirical relationship between
animal demand (AUM)
and animal response.
i. The known relationship between
stocking rate (demand) and output per
unit area is useful at tactical levels of
decision making (seasonal temporal
scales). Stocking rate is expressed as
demand (AUM) per acre or per ton (or
the reciprocal).
ii. The known relationship between grazing
pressure or herbage allowance is useful
on operational scales of decision making
(daily to weekly temporal scales).
Herbage allowance is expressed as lb
of desirable, available forage per
demand unit (usually AUD).
Grazing pressure is the reciprocal of
herbage allowance.
iii. Harvest efficiency (ecological efficiency)
is the reciprocal of herbage allowance
expressed as multiples of intake.
e. numbers based on vegetation response to grazing
intensity
i. vegetation response to grazing intensity
is site and species specific
ii. vegetation response to grazing intensity
depends on management
inputs, e.g., herding or pasture rotation.
2. Strategies for dealing with environmental uncertainty
a. At the tactical level of decision making, the manager
might make a judgement about desired sex ratios or
the proportion of the population (herd) composed of
producing vs disposable animals.
i. the number of producing animals would
be conservative in relation to “average”
stocking rate.
ii. grazing management would reserve
forage for times when demand
exceeds supply or have available
complimentary forages.
iii. management provides supplemental
feed, i.e., food imported into the system
b. At the operational level of decision making, the
manger adjusts numbers based on projected food
accumulation rates and projected end-of-season use.
VII. Multiple Uses of Rangeland Resources – Decision making in complex biological
and social environments. (3)
A. Review of major uses
B. Review of intrinsic values and cultural traditions
C. Conflict management and other collaborative management processes
VIII. Rangeland ecosystem conversion, restoration, development and improvement – tools
to manage succession.
A. Conversion of natural rangeland ecosystems
1. Many rangeland ecosystems have been converted to production of
monocultures -agronomic crops. Society has deemed that a higher
use of the land in response to food security.
2. Many rangelands have been “improved” by replacing natural
vegetation with introduced plants or mixtures of plants. Or,
non-native plants have been introduced into natural stands, e.g.,
legumes
B. Restoration
1. In some cases the natural vegetation has been removed or
drastically disturbed by agriculture. Re-colonization is facilitated by
preparing a seedbed and mechanically distributing a seed mix that
mimics the potential vegetation on that site.
2. Selective removal of unwanted or non-native plants with herbicides
or biological controls
C. Improvement for a specific use or to provide specific habitat – assume an
ecosystem functioning within the range of natural variability.
1. Change soil nutrient status
a. Planned disturbance, natural or mechanical
b. Fire
c. Grazing
2. Modify species performance and equity position of target species
in the stand by selectively allowing maximum ecological expression.
a. Fire
b. Grazing
3. Modify species performance and equity position of target species in
the stand by selective negative pressure.
a. Fire
b. Grazing
IX. Contemporary Issues. (2)
A. Global change
B. Endangered Species Act
C. Clean Air and Water Acts
D. Coastal Waters Act
X. Integrating topics and Exercises.
A. Restoration Ecology – rocky Mountain Arsenal – incorporated into section VI.
(3)
B. Riparian Management – Sheep Creek (3
C. Grazing Management – Meadow Springs Ranch (incorporated into section 6 &
7) (3)
D. Field Trips
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