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
Peren. herbs/ferns
Biennial herbs
Trees Shrubs
Lichens
Bryophytes
Trees shrubs
lichens
bryophytes
13
Cacti
14
Birch and Aspen
15
Forest climax
16
Bog plants
17
(No Transcript)
18
Tundra truck tracks
1984
1999
19
Agave