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Outline

Outline. Review of scale and hierarchy in biological organization (handout from Monday) Introduction to autecology (ecology of individual) Variation within species; subspecies (examples) Tolerance and limiting factors Niche Introduction to physiological processes and abiotic factors.

medge-gillespie
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Outline

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  1. Outline • Review of scale and hierarchy in biological organization (handout from Monday) • Introduction to autecology (ecology of individual) • Variation within species; subspecies (examples) • Tolerance and limiting factors • Niche • Introduction to physiological processes and abiotic factors

  2. Reading • Related to this lecture • Kolb and Sperry 1999. Ecology 80(7):2373-2384 • Shahba et al. 2003. Crop Science 43:2142-2147 • Text Chapter 3 • Related to next lectures • Monday – Text Chapters 18 & 19 • Wednesday – Text Chapters 14 & 15 • Lab discussion (Tues Feb 3) • Bestelmeyer et al. 2003. Ecological Applications 13(6):1750-1761. • Hull et al. 2002. Conservation Ecology 6(2):#12. • If interested: there are two responses to Hull et al. in Conservation Ecology 7(1).

  3. Organization • Organisms influenced by 4 types of relationships (see handout from Monday) • Physiological (grp 1 on diagram) • Increasing complexity, emergent properties • Phylogenetic (grp 2 on diagram) • Taxonomic/evolutionary • Partitioning of genetic descent • “Coevolutionary”(grp 3 on diagram) • Deme, Population, Community (definitions) • Organisms affect each other’s reproductive success • Traditional “synecology” • Matter-energy (grp 4 on diagram) • Ecosystems ecology

  4. Hierarchy and scale • With increasing spatial scale, temporal scale of processes also tends to increase • Ecologists study across spatial and temporal scales • Observation scale may affect both our interpretation of ecosystem interactions and our management decisions

  5. Organizational level: individual or species • Autecology = Physiological ecology. Ecology of individual organisms • Environment – rainfall, temperature, light, biotic interactions • Resource acquisition – nutrient uptake, photosynthesis • Allocation of resources to growth and reproduction • Effects of environmental changes, stresses

  6. 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).

  7. 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)

  8. Variation in species • Other experiments show two ecotypic extremes with gradient of variation between them (ecocline) • Current usage of “ecotype” = population, not group of populations. Populations have genetic and phenotypic differences, but act as individuals.

  9. Subspecies or different species? • What is a subspecies? • Regional variants in a species; morphological differentiation (not great enough to be considered separate species) occurs in relation to geographic, ecological or temporal separation from other subspecies.

  10. 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. Different enough to be species. • Ord’s kangaroo rat in Alberta – hibernate. Don’t hibernate anywhere else. Is this peripheral population worth saving as a distinct taxon?

  11. Physiological Differences • Kolb & Sperry (1999) – drought adaptation between subspecies of sagebrush. • Three subspecies: wyomingensis (low elevation, arid) tridentata (mid elevation, less arid) vaseyana (high elevation, mesic) • Subspecies differ in stature, inflorescence, and ploidy. Differences maintained in common garden (genetic). • Differ in physiology: pressures at which xylem cavitates and leaves wilt differ among subspecies. Differences maintained in common garden.

  12. Variation in species • Additional examples: • Saltgrass frost tolerance: Crop Science 43:2142-2147 • Norway Spruce altitudinal ecotypes: Functional Ecology 12:573-590 • Sagebrush subspecies: Ecology 80(7):2373-2384

  13. Liebig’s “Law of the Minimum”: crop yield dependent on nutrient most limited in amount. • More general: growth/distribution of species depends on critical environmental factor. • Limitations: upper limit to tolerance factors interact • Shelford’s “Law of Tolerance”: minimum, maximum, and optimum values for all environmental factors

  14. Niche concept = law of tolerance Expanded law of tolerance (Good, 1953): • Plant species exist and reproduce in a definite range of conditions (climatic, edaphic, biotic)

  15. Niche concept = law of tolerance Expanded law of tolerance (Good, 1953): • Plant species exist and reproduce in a definite range of conditions (climatic, edaphic, biotic) • Tolerance ranges related to physiology

  16. Niche concept = law of tolerance Expanded law of tolerance (Good, 1953): • Plant species exist and reproduce in a definite range of conditions (climatic, edaphic, biotic) • Tolerance ranges related to physiology • Habitat is sum total of tolerance for all environmental factors (fundamental niche – Hutchinson 1957)

  17. Niche concept = law of tolerance Expanded law of tolerance (Good, 1953): • Plant species exist and reproduce in a definite range of conditions (climatic, edaphic, biotic) • Tolerance ranges related to physiology • Habitat is sum total of tolerance for all environmental factors (fundamental niche – Hutchinson 1957) • May shift depending on levels of other factors (e.g. N and water)

  18. Niche concept = law of tolerance Expanded law of tolerance (Good, 1953): • Plant species exist and reproduce in a definite range of conditions (climatic, edaphic, biotic) • Tolerance ranges related to physiology • Habitat is sum total of tolerance for all environmental factors (fundamental niche – Hutchinson 1957) • May shift depending on levels of other factors (e.g. N and water) • May vary as a function of life stage (e.g. seedlings narrow range, adults broad)

  19. Niche concept = law of tolerance Expanded law of tolerance (Good, 1953): • Plant species exist and reproduce in a definite range of conditions (climatic, edaphic, biotic) • Tolerance ranges related to physiology • Habitat is sum total of tolerance for all environmental factors (fundamental niche – Hutchinson 1957) • May shift depending on levels of other factors (e.g. N and water) • May vary as a function of life stage (e.g. seedlings narrow range, adults broad) • Natural distribution not always equal to optimum (biotic interactions affect – realized niche)

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