Outline

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Outline

• Discuss definitions and components of range and
  forest ecosystems
• Introduction to biological organization
• How and why do we classify organisms?
• What is a species? Why do we need to identify
  them?
• Interaction with environment variability within
  species
• Examples

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Definitions of range
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• Those areas of the world, which by reason of
  physical limitations, low and erratic
  precipitation, rough topography, poor drainage,
  or cold temperatures, are unsuitable for
  cultivation and which are a source of forage for
  free-ranging native and domestic animals, as well
  as a source of wood products, water and forest
  wildlife'. (Stoddart et al. 1975).

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• Society for Range Management
• Vegetation is predominantly grasses, graminoids,
  forbs or shrubs managed as a natural ecosystem.
• If plants are introduced they are managed
  similarly.
• Rangelands include natural grasslands, savannas,
  shrublands, many deserts, tundras, alpine
  communities, marshes, and meadows.

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Forest

• Area of 0.5-1 Ha, 10-30 tree canopy cover, trees
  gt2-5 m at maturity
• 10 stocked by trees, and not subject to uses
  preventing normal tree regeneration (eg. Heavy
  grazing, mowing)
• Area managed for production of timber and other
  forest products, or maintained as wooded
  vegetation for such indirect benefits as
  protection of catchment areas or recreation.
  (Lund 1998)

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Range management

• Rangeland management is the science and art of
  optimizing the returns from rangelands in
  combinations that are most desired by and
  suitable to society through the manipulation of
  the range ecosystem
• (Stoddart et al. 1975)

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Range management

• Applies knowledge from range science and
  practical experience.
• Protection and improvement of resources (ie
  sustainability).
• Optimum production of goods and services.
• The overriding goal is rangeland resource
  rehabilitation, protection, and management for
  multiple objectives including biological
  diversity, preservation, and sustainable
  development for people." (Heady and Child 1994)

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Components of Ecosystems

• Abiotic
• Biotic

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Processes of Ecosystems

• Carbon fixation (productivity)
• Nutrient cycling
• Water cycling
• Energy transfer between trophic levels
• Materials transport (erosion, deposition)
• Decomposition (cycling)

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Forests

• What processes, components, services are
  important in forests?

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Rangeland

• What processes, components, services are
  important in rangelands?

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Classifying Biotic components

• How do we classify organisms?
• Trophic levels (ecosystem roles)
• Life form (e.g. plant growth forms)
• Life history (e.g. length of life)
• Phylogeny (evolutionary relationships)
• Taxonomy

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Classifying Biotic components

• Why do we classify organisms?
• To understand ecosystem functioning
• To understand relationship of organisms to
  environment and each other, and predict
  responses.

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Species

• What is a species?
• Many definitions (25 )
• Some definitions based on characteristics of
  organsims, some based on reproduction, some based
  on phylogenetic descent.
• 3 main ideas
• Morphological
• Biological (BSC)
• Evolutionary/phylogenetic

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Species Concepts

• Morphological group of animals or plants sharing
  one or more distinct characters.
• Biological Similar natural populations that are
  reproductively isolated from other populations.
• Phylogenetic a cluster of individuals with a
  common evolutionary ancestry. Units of
  evolution.

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Species Concepts

• Species definition combines morphology, breeding,
  and habitat.
• Taxonomic species combines mainly morphology and
  BSC. Somewhat arbitrary and distinctions are not
  clear.
• Composed of ecologically important subunits? Or
  is variation continuous? (ecotypes or ecoclines)

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Species Concepts

• A species is a group of individuals, which, in
  the sum total of their attributes, resemble each
  other to a degree usually accepted as specific,
  the exact degree being ultimately determined by
  the more or less arbitrary judgement of
  taxonomists

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Why are species important?
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Why are species important?

• We consider that species respond as units to
  environmental conditions (ecotypes?).
• Considered to be units of evolution stage
  where biological discontinuity takes place.
• Specieshood related to genetic and ecological
  differences (even if not perfectly). Species
  richness simple measure of biological diversity.
• Endangered species populations with distinct
  characteristics (ecological, reproductive, and
  morphological). In danger of extinction, are
  different enough from similar groups to warrant
  salvage.

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Species in range and forest ecology
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Species in range and forest ecology

• May use species-based measures to assess health,
  identify potential land uses, predict habitat
  quality,etc.
• Species composition related to community
  characteristics.
• Economically important species (e.g. timber
  trees, good forage species)

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Species in range and forest ecology summary

• Species difficult to precisely define.
• All definitions are somewhat arbitrary.
• Variation in response to environment within given
  species.
• We need and want to classify organisms, so
  species still used.
• Even though imperfect, taxonomic species ID can
  and is for assessing ecosystem characteristics,
  understanding community dynamics, and making
  management decisions.

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Species in range and forest ecology summary
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Variation in species (ch. 3)

• Substantial variation within taxonomic species
  heritable, adaptive characters (Turesson)
• e.g. hawkweed in Sweden (ecotypes)
• Three habitats (woodland, field, dune)
• Differ in traits habit, leave shape, dormancy
• Traits maintained when grown in greenhouse
• All groups interfertile
• Similar experiment in California (Clausen et al
  1940).

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Variation in species

• common gardens at Stanford, Mather
  (Mid-elevation Sierra Nevada), and Timberline
  (3000m elevation)
• Grew 60 different species collected from a range
  of sites from coast to eastern slopes
• Potentilla glandulosa ecotypes (subspecies)
  differ in growth form, frost and disease and
  survival in different gardens (see textbook Ch. 3)

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Variation in species

• Additional examples readings
• Saltgrass frost tolerance Crop Science
  432142-2147
• Norway Spruce altitudinal ecotypes Functional
  Ecology 12573-590

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Subspecies or different species?

• Pinus contorta three subspecies. Contorta not
  fire adapted (shore pine). Latifolia (rocky
  mountain lodgepole) fire dependent dominance in
  landscape and proportion serotinous cones related
  to fire frequency. Murrayana (sierra lodgepole)
  fire sensitive, but early after-fire coloniser.
  Not serotinous.
• Pinus ponderosa and Pinus jeffreyi. Differ in
  resin chemistry and habitat (elevation). Are
  sympatric at mid-elevation, and hybridize.
• Ords kangaroo rat in Alberta hibernate. Dont
  hibernate anywhere else. Is this peripheral
  population worth saving as a distinct taxon?