Plant Adaptive Tactics

1. Plant Adaptive Tactics

2. External Factors • Stress • phenomena which limit photosynthetic production and growth. • Disturbance • factors causing partial or total destruction of plant

3. Four permutations • High stress - high disturbance • Low stress - low disturbance • High stress - low disturbance • Low stress - high disturbance

4. Low stress - low disturbance • Competitors • Ability: function of area, activity and distribution in space and time of the plant surfaces through which resources are absorbed. • General Features of Competitors: • Phenology • Plasticity

5. Features of a competitor • - Storage organs • - Height • - Lateral spread • - Phenology • - Growth rate • - Response to stress • - Response to damage

6. High stress - Low disturbance • Stress tolerators • Low plasticity • Growth generally occurs intermittently. • Most important responses are physiological, not morphogenetic. • Symbiosis - Ectotrophic mycorrhizas • Slow growth • Resistance to predation

7. High disturbance - Low stress • Ruderals • Tendency toward annual or short lived perennial habit • Capacity for high rates of dry matter production • Flowers at early stage of development - seed ripening may be extremely rapid • Often death follows seed production

8. Relationship to r- and K-selected types • r-selected: • generally considered to have short life expectancy and large reproductive effort. • K-selected: • long life-expectancy and proportion of energy and resources devoted to reproduction is small. Heavy investment in “care of young.”

9. Spectrum

10. Triangular ordination

11. Triangular ordination

12. Examples Annuals biennials Perennial herbs & ferns Annual herbs Biennial herbs Peren. herbs/ferns Trees & Shrubs Lichens Bryophytes Trees & shrubs lichens bryophytes

13. Cacti

14. Birch and Aspen

15. Forest climax

16. Bog plants

18. Tundra truck tracks 1984 1999

19. Agave