Download Vegetation - Succession

Reading Exercise
• Refer to Hong Kong Vegetation Ecology
(Chinese Article) on P.6 and P.7
• Circle all the vegetation mentioned
SUCCESSION IN HONG
KONG
Pioneer species
More diverse
than weed
More diverse
than scrubland
What is ecological succession?
• The repeated replacement by another
usually more diverse community of
organisms over a period of time
Model on Ecological Succession
(Outside Hong Kong)
Types of Succession
Succession
Primary
Succession
Secondary
Succession
succession happens
where no living community existed
suucession happens when an ecosystem
at some stage of succession is removed
Internal Changes during
Succession
• Soil stabilization by pioneer species
– bind soil particles by root action
– prevent the rain splash action and wind erosion
Soil stabilization by pioneer species
• Modification of Climatic Environment
– HOW?
• Improvement of Soil Structure and SOM
– HOW?
Microclimate Modification
• Light intensity
• temperature
• wind speed
• RH
• Interception by rainfall
Improvement of Soil Structure
and SOM
• More litter -> more organic matter
• organic matter can:
– hold more water
– hold more nutrient
– improve soil structure
Refer to P.12 Stages in Succession, complete
the table for the dynamic changes within the
ecosystem in the process of succession.
SUCCESSION IN HONG
KONG
Pioneer species
More diverse
than weed
More diverse
than scrubland
Would reversed succession take
place?
• Yes
• retrogressive succession