环境科学课程 环境科学 第2讲生态系统 北京大学环境科学与工程学院
北京大学环境科学与工程学院 第2讲 生态系统 环境科学课程
提钢 环境科学 Environmental Science ·基本概念：演替与生物群系 ·生态系统类型 -陆地 一水域 生态系统的服务 北京大学环境科学与工程学院
北京大学环境科学与工程学院 提 纲 • 基本概念：演替与生物群系 • 生态系统类型 – 陆地 – 水域 • 生态系统的服务
演替(Succession) 环境科学 Envlronmental Sclence ·演替(Succession) The concept that communities proceed through a series of recognizable,predictable changes in structure over time is called succession. ·J顶级群落(Climax community) The relative stable,long-lasting community that is the result of succession is called a climax community 。 初级演替(Primary succession) Is a successional progression that begins with a total lack of organisms and bare mineral surfaces or water. ·次级演替(Secondary succession) Begins with disturbance of an existing ecosystem. 北京大学环境科学与工程学院
北京大学环境科学与工程学院 演替(Succession) • 演替 (Succession) – The concept that communities proceed through a series of recognizable, predictable changes in structure over time is called succession. • 顶级群落 （Climax community） – The relative stable, long-lasting community that is the result of succession is called a climax community. • 初级演替(Primary succession) – Is a successional progression that begins with a total lack of organisms and bare mineral surfaces or water. • 次级演替(Secondary succession) – Begins with disturbance of an existing ecosystem
Climax Community Characteristics环境科学 Maintain species diversity for extended period.物种多样 Contain multiple specialized ecological niches.多重生态位 Maintain high level of organism interactions.相互关联复杂 Recycle nutrients while maintaining a relatively constant biomass.物质循环并且生物量相对恒定 The general trend in succession is toward increasing complexity and more efficient use of matter and energy. 化方向：复杂与高效 p3 北京大学环境科学与工程学院
北京大学环境科学与工程学院 • Maintain species diversity for extended period.物种多样 • Contain multiple specialized ecological niches.多重生态位 • Maintain high level of organism interactions.相互关联复杂 • Recycle nutrients while maintaining a relatively constant biomass.物质循环并且生物量相对恒定 – The general trend in succession is toward increasing complexity and more efficient use of matter and energy.演 化方向：复杂与高效 Climax Community Characteristics p3
Primary suecession on land Copyright The McGraw-Hill Companies.Inc.Permission required for reproduction or display. Bare rock Lichens Small annual Perennial Grasses,shrubs, Shade-tolerant trees plants,lichens herbs,grasses shade-intolerant trees Pioneer stages Intermediate stages Climax community Hundreds of years
北京大学环境科学与工程学院 Primary succession on land
环境科学 Envlronmental Science 地衣对污染了的空气也 非常敏感。有人做过试 验，当每立方米的空气 中二氧化硫的含量达 0.23毫克时，地衣29天 之内就会全部死亡。 Pioneer Organism先锋植物The lichen growing on this rock is able to accumulate bits of debris,carry on photosynthesis, and aid in breaking down the rock.All of these activities contribute to the formation of a thin layer of soil,which is necessary for plant growth in the early stages of succession. 地衣依靠它自己分泌出的地衣酸，使岩石破裂，分解成为细微的土壤 粒子，而自己被腐解的遗体，变成肥沃的土地。 北京大学环境科学与工程学院
北京大学环境科学与工程学院 Pioneer Organism先锋植物The lichen growing on this rock is able to accumulate bits of debris, carry on photosynthesis, and aid in breaking down the rock. All of these activities contribute to the formation of a thin layer of soil, which is necessary for plant growth in the early stages of succession. 地衣依靠它自己分泌出的地衣酸，使岩石破裂，分解成为细微的土壤 粒子，而自己被腐解的遗体，变成肥沃的土地。 地衣对污染了的空气也 非常敏感。有人做过试 验，当每立方米的空气 中二氧化硫的含量达 0.23毫克时，地衣29天 之内就会全部死亡
Aquatie Primary Succession 环境科学 CopyrightThe McGraw-Hill Companies.Inc.Permission required for reproduction or display. Tens to hundreds of years Primary succession from a pond to a wet meadow Most aquatic ecosystems are considered temporary.In the above figure,a shallow pond will fill slowly with organic matter from producers in the pond.Eventually,a wet soil will form and grasses will become established.In many areas,this will be succeeded by a climax forest. 北京大学环境科学与工p3院
北京大学环境科学与工程学院 Primary succession from a pond to a wet meadow Most aquatic ecosystems are considered temporary. In the above figure, a shallow pond will fill slowly with organic matter from producers in the pond. Eventually, a wet soil will form and grasses will become established. In many areas, this will be succeeded by a climax forest. Aquatic Primary Succession p3
Seeendary-sueeession on land 环境科学 Envlronmental Science CopyrightThe McGraw-Hill Companies,Inc.Permission required for reproduction or display. Mature Farmland Annual Grasses Perennial Pines begin to Young oak and Pines die and Mature oak/hickory abandoned plants and herbs replace shrubs hickory trees begin are replaced oak/hickory forest biennial and to grow by mature oak forest destroyed herbs shrubs and hickory begin to trees replace grasses and biennials 1-2 3-4 4-15 5-15 10-30 50-75 years years years years years years Occurs when an existing community is disturbed or destroyed. -With most disturbances,most of the soil remains,and many nutrients necessary for plant growth may be available for reestablishment of previous ecosystem.自然或者 人为干扰，但是大量的营养成分得以保留 Nearby undamaged communities can serve as sources of seeds and animals. ,Tends to be more rapid than primary growth.速度较快 北京大学环境科学与工程学院
北京大学环境科学与工程学院 Secondary succession on land •Occurs when an existing community is disturbed or destroyed. –With most disturbances, most of the soil remains, and many nutrients necessary for plant growth may be available for reestablishment of previous ecosystem.自然或者 人为干扰，但是大量的营养成分得以保留 ❖Nearby undamaged communities can serve as sources of seeds and animals. ➢Tends to be more rapid than primary growth.速度较快
Seeendary sueeession from a Beaver Pond 环境科学 Copyright The McGraw-Hill Companies.Inc.Permission required for reproduction or display. 4 5 6 A colony of beavers can dam up streams and kill trees by the flooding that occurs and by using trees for food.Once the site is abandoned,it will slowly return to the original forest community by a process of succession. 北京大学环境科学与工程学院
北京大学环境科学与工程学院 A colony of beavers can dam up streams and kill trees by the flooding that occurs and by using trees for food. Once the site is abandoned, it will slowly return to the original forest community by a process of succession. Secondary succession from a Beaver Pond
环境科学 entnl Science 北京大学环境科学与工程学院
北京大学环境科学与工程学院