Reading Exercise

• Refer to Hong Kong Vegetation Ecology (Chinese Article) on P.6 and P.7

• Circle all the vegetation mentioned

SUCCESSION IN HONG SUCCESSION IN HONG KONGKONG

Pioneer species

More diversethan 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 happenswhere no living com m unity existed

Prim arySuccession

suucession happens when an ecosystemat som e stage of succession is rem oved

SecondarySuccession

Succession

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 SUCCESSION IN HONG KONGKONG

Pioneer species

More diversethan weed

More diverse than scrubland

Would reversed succession take place?

• Yes

• retrogressive succession