Xeroseres旱生演替系列 (1)Invasion by lichens and mosses 地衣、苔藓植物阶段 The first organisms to arrive are usually lichens or mosses,which are called pioneer species They secrete acids that can break down rock 。 Their dead,decaying organic materials,along with bits of sediment from the rock make up soil. .It occurs very slowly at first 11
11 (1) Invasion by lichens and mosses 地衣、苔藓植物阶段 地衣、苔藓植物阶段 The first organisms to arrive are usually lichens or mosses, which are called pioneer species. • They secrete acids that can break down rock • Their dead, decaying organic materials, along with bits of sediment from the rock make up soil. Xeroseres 旱生演替系列 •It occurs very slowly at first
Xeroseres旱生演替系列 (2)Establishment by weedy plants草本植物阶段 Small weedy plants and other organisms become established. -As these organisms die,additional soil is created. 12
12 (2) Establishment by weedy plants 草本植物阶段 – Small weedy plants and other organisms become established. – As these organisms die, additional soil is created. Xeroseres 旱生演替系列
Xeroseres旱生演替系列 (3)Presence of Shrubs and trees灌木、 乔木植物阶段 Seeds brought in by animals,water and wind begin to grow in the soil. Eventually enough soil is present for shrubs and trees to grow
13 • (3) Presence of Shrubs and trees 灌木、 乔木植物阶段 – Seeds brought in by animals, water and wind begin to grow in the soil. – Eventually enough soil is present for shrubs and trees to grow. Xeroseres 旱生演替系列
-The stable,mature community that eventually develops from bare rock is called a climax community. 14
14 – The stable, mature community that eventually develops from bare rock is called a climax community climax community
Estelle Levetin and Karen McMahon,Botany Visual Resource Library 1998 The McGraw-Hill Companies,Inc.All rights reserved. Primary Succession Time Pioneer Intermediate Climax community communities community Exposed rocks Lichens Grasses Aspen White spruce Mosses Herbs Black spruce Balsam fir Shrubs Jack pine Paper birch Tree seedings
15 Primary Terrestrial Succession