1. Outline 1.Review of scale and hierarchy in biological organization (handout from Monday) 2.Introduction to autecology (ecology of individual) 3.Variation within species; subspecies (examples) 4.Tolerance and limiting factors 5.Niche 6.Introduction to physiological processes and abiotic factors

2. Reading 1.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 2.Related to next lectures Monday – Text Chapters 18 & 19 Wednesday – Text Chapters 14 & 15 3.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) 1.Physiological (grp 1 on diagram) Increasing complexity, emergent properties 2.Phylogenetic (grp 2 on diagram) Taxonomic/evolutionary Partitioning of genetic descent 3.“Coevolutionary”(grp 3 on diagram) Deme, Population, Community (definitions) Organisms affect each other’s reproductive success Traditional “synecology” 4.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)