Outline

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 432142-2147
• 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 others 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.
• Ords kangaroo rat in Alberta hibernate. Dont
  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
  432142-2147
• Norway Spruce altitudinal ecotypes Functional
  Ecology 12573-590
• Sagebrush subspecies Ecology 80(7)2373-2384

13

• Liebigs 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
• Shelfords 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)