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1. Community Ecology

2. Ecological characteristics of
plant community

3. •A community is an assemblage of
plant and animal populations that
live in a particular area or habitat.
•Populations of the various species
in a community interact and form a
system with its own emergent properties.

4. Ecological characteristics of plant community
Or
Phytosociological attributes of the plant community
Classified into three main groups.
1.Analytic characteristics
2.Synthetic characteristics
3.Physiognomic characteristics

5. 1.Analytic characteristics
Includes
a. Qualitative characteristics
b. Quantitativecharacteristics

6. a. Qualitative characteristics
i. Kinds of species or floristic composition
ii.Stratification
iii. Periodicity (Phenology)
iv.Vitality ( Vigour)
v. Sociability

7. i. Kinds of species or floristic composition
A complete list of species is
essential for the study of a stand.
Floristic list is valuable because
each species has its own amplitude
and relation to the environment and
to other species.

8. ii.Stratification
 In a community , plants occurring together having a
similar ecology occurs in definite strata, known as
stratification.
 The size and number of these strata depends upon the
kinds of life form present.
 Most temperate forest communities are composed of
at least 3-4 strata.
 Desert, Alpine and grass land communities may have
fewer strata.
 Tropical rain forests are extremely complex and have
5-7 strata.

9. iii. Periodicity (Phenology)
 Periodicity refer to the phenomena
related to the seasonal changes i.e.
growth, flowering, pollination, ripening .
 Periodicity is controlled by number of
environmental factors, such as light,
temperature etc.
 Phenology refers to the appearance of
various plants at different seasons of
the year.

10. iv.Vitality ( Vigour)
 It relates to the condition of a plant and its capacity to
complete the life cycle.
 There are number of criteria to determine the vigour of
the plants such as the rapidity of growth, rate and amount
of leaves, shoots and roots.
Following are the vitality classes:
Class I. well developed plants, which regularly complete
the life cycle.
Class II. vigours plants which usually do not complete their
life cycle.
Class III. Feeble plants that never complete life cycle.
Class IV. Plants occasionally appearing from seed but do not
increase in numbers.

11. v. Sociability
Sociability refers to the degree to which the
plants are aggregated in nature.it is not a
constant feature.
It is depend upon the life form, mode of
reproduction, Vigour of the plants, habitat
conditions, competition between individuals.

12. Following are the classes of Sociability.
Class I. growing singly
Class II. Plants growing in small groups
Class III. Small scattered patches
Class IV. Large patches
Class V. very large stands.

13. b. Quantitative characteristics
i. Density
ii. Cover
iii. frequency

14. 2. Synthetic characteristics
a.Presence
b. Constancy
c. Fidelity
d. dominance
Includes

15. a.Presence
Presence is used to show more or less
persistent occurrence of a species in all the
stands of a certain plant community.

16. b. Constancy
Constance refer to how uniformly a species
occurs in number of stands of the same
type of community.
Species that occur in 90% or more of the
stands are called constant species.

17. c. Fidelity
Fidelity concerned with occurrence of a
species in different kinds of community types.

18. d. Dominance
Dominance are those species which have high
number and large volume in relation to other
species.
Constant species occurring in more than 80%
of the stands, with the higest cover of
numerical abundance may be designated as
dominance.

19. 3.Physiognomic characteristics
Includes
a. Physiognomy
b. Pattern
c. Life-form

20. a. Physiognomy
It is appearance of a stand.

21. b. Pattern
Pattern is the group of individuals with physiognomic
contrast, such as shrubs in a grassland or vegetational
zone around a lake.
Causes of pattern
i. Vegetative reproductive organs
ii. Association of species
iii. Variation in soil moisture
iv. Concentration of nutrition
v. Soil texture & structure

22. c. Life-form
The characteristic vegetative appearance of the plant
body and its longevity is known as life-form.