This presentation offers a bird's eye view about community dynamics in general and ecological succession in particular with special reference to Climax vegetation.
Ecological succession is the process of change in the species structure of an ecological community over time. It occurs as the newly unoccupied habitat is colonized by pioneering species which are later replaced by other species. There are two main types of succession - primary on newly created habitats and secondary on previously inhabited lands disturbed by events like fire or flooding. Succession progresses through predictable stages until a climax community develops that remains stable unless further disturbed.
Ecological Succession&Ecological PyramidsNiladri Roy
introduction, description, examples and explanation of ecological succession and ecological pyramids.
Lots of images and diagrams to make it easy to understand for you
This document discusses several key concepts related to communities and succession in ecology. It defines a community as a group of interacting species living together in a shared habitat. Succession is introduced as the process of community changes over time, with species composition shifting as environmental conditions change. Several models of succession are described, including Clements' idea of orderly stages leading to a climax community and Gleason's more individualistic view. The roles of dispersal, biotic interactions, and environment in driving successional changes are also noted. Major global biomes like deserts and tundra are briefly outlined.
Ecological succession refers to predictable changes in the species composition of a community over time. There are two main types - primary succession, which occurs on new substrates like bare rock, and secondary succession, which occurs after a disturbed community. Succession proceeds through a series of seral stages until reaching a climax community, where species composition is stable. The climax is determined by climate and can be a monoclimax with one community type or a polyclimax with multiple community types depending on local habitat factors. Community resilience refers to the ability to withstand or recover from disturbance and change over time.
This presentation offers a bird's eye view about community dynamics in general and ecological succession in particular with special reference to Climax vegetation.
Ecological succession is the process of change in the species structure of an ecological community over time. It occurs as the newly unoccupied habitat is colonized by pioneering species which are later replaced by other species. There are two main types of succession - primary on newly created habitats and secondary on previously inhabited lands disturbed by events like fire or flooding. Succession progresses through predictable stages until a climax community develops that remains stable unless further disturbed.
Ecological Succession&Ecological PyramidsNiladri Roy
introduction, description, examples and explanation of ecological succession and ecological pyramids.
Lots of images and diagrams to make it easy to understand for you
This document discusses several key concepts related to communities and succession in ecology. It defines a community as a group of interacting species living together in a shared habitat. Succession is introduced as the process of community changes over time, with species composition shifting as environmental conditions change. Several models of succession are described, including Clements' idea of orderly stages leading to a climax community and Gleason's more individualistic view. The roles of dispersal, biotic interactions, and environment in driving successional changes are also noted. Major global biomes like deserts and tundra are briefly outlined.
Ecological succession refers to predictable changes in the species composition of a community over time. There are two main types - primary succession, which occurs on new substrates like bare rock, and secondary succession, which occurs after a disturbed community. Succession proceeds through a series of seral stages until reaching a climax community, where species composition is stable. The climax is determined by climate and can be a monoclimax with one community type or a polyclimax with multiple community types depending on local habitat factors. Community resilience refers to the ability to withstand or recover from disturbance and change over time.
This document discusses ecological succession, which is the process of change in species composition of a community over time. It defines primary and secondary succession, and describes different types of succession including autogenic, allogenic, autotrophic, heterotrophic, progressive, and retrogressive succession. It also discusses Clements' model of succession involving nudation, invasion, ecesis, aggregation, competition, reaction, and stabilization. Finally, it outlines three major theories of climax communities - monoclimax, polyclimax, and climax pattern theory - and three models of succession - facilitation, tolerance, and inhibition.
1) Ecological succession is the process by which the species in a community change over time following a disturbance.
2) Primary succession occurs in areas without previous communities, like after volcanic eruptions, while secondary succession follows less severe disturbances where soil remains.
3) Early pioneer species like lichens and grasses establish first, gradually changing the environment and allowing more species to colonize over time.
The main causes of ecological succession include the biotic and climatic factors that can destroy the populations of an area. Wind, fire, soil erosion and natural disasters include the climatic factors. Ecological succession is important for the growth and development of an ecosystem. It initiates colonization of new areas and recolonization of the areas that had been destroyed due to certain biotic and climatic factors. Thus, the organisms can adapt to the changes and learn to survive in a changing environment.
The document discusses ecological succession, which refers to predictable changes that occur in a community over time after disturbances. It describes primary succession, which begins in areas with no remnants of older communities, such as those affected by volcanic eruptions. Pioneer species like lichens are the first to colonize these areas. Their growth adds organic matter and forms soil to allow other plants to grow. Secondary succession occurs in areas where communities are partially destroyed, allowing faster regrowth from surviving vegetation and soil. Over time, more species are able to survive as the environment changes. Succession may lead to a stable climax community, though human activities can prevent regrowth of the original community. Studies of areas like Mount St. Helens show primary
The document summarizes key concepts in community ecology:
1. Community structure is described by physical appearance, species diversity, and niche structure.
2. Species diversity is influenced by factors like latitude and pollution.
3. The number of species on an island is determined by immigration and extinction rates, island size, and distance from mainland.
4. Species play roles like native, non-native, indicator, keystone, and foundation species that impact community ecology.
The document summarizes key topics in environmental science including energy flow, ecological succession, food chains, and nutrient cycles. It discusses how energy and nutrients move through ecosystems, from primary producers like plants up the food chain to higher trophic levels. It also describes different types of ecological succession, including primary, secondary, and cyclic succession, and how communities change over time after a disturbance. Finally, it explains how food chains connect to form food webs and ecological pyramids that depict the transfer of energy between trophic levels in an ecosystem.
Ecological succession is the process of change in species composition of an ecological community over time. There are two main types: primary succession, which occurs in areas without previous life, and secondary succession, which occurs after a disturbance in an existing ecosystem. Succession will continue through different stages as species colonize an area and change the environment, eventually reaching a climax community that is stable and able to reproduce itself until the next disturbance. Humans can impact ecological succession through activities like agriculture that clear land and disrupt existing ecosystems.
Ecological succession is the gradual replacement of one community by another until a stable climax community is established. The document describes the process of ecological succession, including primary and secondary succession. It provides examples of hydrosere succession, which begins in a body of water and progresses through stages from phytoplankton to forest. The stages include submerged plants, floating plants, reed swamp, sedge meadow, woodland, and climax forest community as the habitat becomes increasingly dry over time due to soil accumulation.
- Insect ecological succession is the natural gradual change in insect species that live in a given area over time. It involves the replacement of one insect community by another through natural processes.
- There are two main types of succession: primary succession, which occurs on newly exposed substrates like lava flows, and secondary succession, which occurs when a previous community is disturbed.
- Succession progresses based on various factors like substrate conditions, composition of initial colonists, sequence of disturbances, and presence of granivores, herbivores, and predators.
Ecological Succession is the process of change in the species structure of an ecological community over a period of time.
But, over a long period of time, the climate conditions of an ecosystem is bound to change.
No ecosystem has existed or will remain unchanged over a Geological Time Scale.
Ecological succession is the gradual and continuous change in species composition and community structure over time in an area. It occurs through two main types - primary succession, which establishes communities on new areas like bare rock, and secondary succession, which occurs in previously inhabited areas affected by disturbances. Succession proceeds through stages from pioneer to climax communities as conditions change. Deforestation in the Amazon has led to large-scale land use changes and succession, with many secondary forest bird species colonizing but few displacing original forest birds over time. Roads may facilitate some species invasions but succession appears reversible through forest regrowth.
Succession is the gradual process by which the species composition of a biological community changes over time due to ecological disturbances. Primary succession occurs in new areas where soil needs to develop, like sand dunes or volcanic islands. Secondary succession happens in areas damaged by events like fires or deforestation, which allows faster recolonization because soil and some species remain. As succession progresses, communities gain biomass and species diversity but productivity decreases, and specialized and nutrient-recycling species become more common. Biodiversity refers to genetic, species, and ecosystem diversity and is essential for communities to survive, with different reproductive strategies adapted to early or stable succession stages.
This document discusses various environmental cycles and ecological concepts. It describes the energy cycle, water cycle, carbon cycle, and oxygen cycle. It also discusses ecological succession, including primary, secondary, and cyclic succession. Additionally, it covers food chains, food webs, and ecological pyramids. Food chains represent the transfer of energy as organisms eat and are eaten. Multiple interconnected food chains form a complex food web. Ecological pyramids show the trophic levels in an ecosystem, with plants at the base and apex predators at the top.
This document discusses various environmental cycles and ecological concepts. It describes the energy cycle, water cycle, carbon cycle, and oxygen cycle. It also discusses ecological succession, including primary, secondary, and cyclic succession. Additionally, it covers food chains, food webs, and ecological pyramids. Food chains represent the transfer of energy as organisms eat and are eaten. Multiple interconnected food chains form a complex food web. Ecological pyramids show the trophic levels in an ecosystem, with plants at the base and apex predators at the top.
Ecosystems are dynamic communities of living organisms that interact with each other and their non-living environment. Primary succession occurs when organisms first colonize an area that previously had no ecosystem, such as new volcanic land, and gradually establish equilibrium over hundreds of years through pioneer species that establish soil. Secondary succession more rapidly restores an existing ecosystem after a disturbance like fire or logging by taking advantage of existing soil and seeds. Both types of succession help maintain equilibrium in ecosystems over time.
An ecosystem is defined as a system consisting of all living organisms in an area interacting with each other and the non-living components of their environment. The key components of an ecosystem include producers, consumers, and decomposers as the living or biotic components, which interact with abiotic or non-living factors like physical and chemical conditions. Ecosystems transfer energy through food chains and food webs, and can be modeled using ecological pyramids that show the biomass or numbers of organisms at different trophic levels. Ecosystems are dynamic systems that undergo succession over time towards a climax community.
A community is a complex group of individuals interacting and sharing an environment.
Communities can be characterized by their structure (the types and numbers of species present) and dynamics (how communities change over time).
This document discusses ecological succession, which is the process of change in species composition of a community over time. It defines primary and secondary succession, and describes different types of succession including autogenic, allogenic, autotrophic, heterotrophic, progressive, and retrogressive succession. It also discusses Clements' model of succession involving nudation, invasion, ecesis, aggregation, competition, reaction, and stabilization. Finally, it outlines three major theories of climax communities - monoclimax, polyclimax, and climax pattern theory - and three models of succession - facilitation, tolerance, and inhibition.
1) Ecological succession is the process by which the species in a community change over time following a disturbance.
2) Primary succession occurs in areas without previous communities, like after volcanic eruptions, while secondary succession follows less severe disturbances where soil remains.
3) Early pioneer species like lichens and grasses establish first, gradually changing the environment and allowing more species to colonize over time.
The main causes of ecological succession include the biotic and climatic factors that can destroy the populations of an area. Wind, fire, soil erosion and natural disasters include the climatic factors. Ecological succession is important for the growth and development of an ecosystem. It initiates colonization of new areas and recolonization of the areas that had been destroyed due to certain biotic and climatic factors. Thus, the organisms can adapt to the changes and learn to survive in a changing environment.
The document discusses ecological succession, which refers to predictable changes that occur in a community over time after disturbances. It describes primary succession, which begins in areas with no remnants of older communities, such as those affected by volcanic eruptions. Pioneer species like lichens are the first to colonize these areas. Their growth adds organic matter and forms soil to allow other plants to grow. Secondary succession occurs in areas where communities are partially destroyed, allowing faster regrowth from surviving vegetation and soil. Over time, more species are able to survive as the environment changes. Succession may lead to a stable climax community, though human activities can prevent regrowth of the original community. Studies of areas like Mount St. Helens show primary
The document summarizes key concepts in community ecology:
1. Community structure is described by physical appearance, species diversity, and niche structure.
2. Species diversity is influenced by factors like latitude and pollution.
3. The number of species on an island is determined by immigration and extinction rates, island size, and distance from mainland.
4. Species play roles like native, non-native, indicator, keystone, and foundation species that impact community ecology.
The document summarizes key topics in environmental science including energy flow, ecological succession, food chains, and nutrient cycles. It discusses how energy and nutrients move through ecosystems, from primary producers like plants up the food chain to higher trophic levels. It also describes different types of ecological succession, including primary, secondary, and cyclic succession, and how communities change over time after a disturbance. Finally, it explains how food chains connect to form food webs and ecological pyramids that depict the transfer of energy between trophic levels in an ecosystem.
Ecological succession is the process of change in species composition of an ecological community over time. There are two main types: primary succession, which occurs in areas without previous life, and secondary succession, which occurs after a disturbance in an existing ecosystem. Succession will continue through different stages as species colonize an area and change the environment, eventually reaching a climax community that is stable and able to reproduce itself until the next disturbance. Humans can impact ecological succession through activities like agriculture that clear land and disrupt existing ecosystems.
Ecological succession is the gradual replacement of one community by another until a stable climax community is established. The document describes the process of ecological succession, including primary and secondary succession. It provides examples of hydrosere succession, which begins in a body of water and progresses through stages from phytoplankton to forest. The stages include submerged plants, floating plants, reed swamp, sedge meadow, woodland, and climax forest community as the habitat becomes increasingly dry over time due to soil accumulation.
- Insect ecological succession is the natural gradual change in insect species that live in a given area over time. It involves the replacement of one insect community by another through natural processes.
- There are two main types of succession: primary succession, which occurs on newly exposed substrates like lava flows, and secondary succession, which occurs when a previous community is disturbed.
- Succession progresses based on various factors like substrate conditions, composition of initial colonists, sequence of disturbances, and presence of granivores, herbivores, and predators.
Ecological Succession is the process of change in the species structure of an ecological community over a period of time.
But, over a long period of time, the climate conditions of an ecosystem is bound to change.
No ecosystem has existed or will remain unchanged over a Geological Time Scale.
Ecological succession is the gradual and continuous change in species composition and community structure over time in an area. It occurs through two main types - primary succession, which establishes communities on new areas like bare rock, and secondary succession, which occurs in previously inhabited areas affected by disturbances. Succession proceeds through stages from pioneer to climax communities as conditions change. Deforestation in the Amazon has led to large-scale land use changes and succession, with many secondary forest bird species colonizing but few displacing original forest birds over time. Roads may facilitate some species invasions but succession appears reversible through forest regrowth.
Succession is the gradual process by which the species composition of a biological community changes over time due to ecological disturbances. Primary succession occurs in new areas where soil needs to develop, like sand dunes or volcanic islands. Secondary succession happens in areas damaged by events like fires or deforestation, which allows faster recolonization because soil and some species remain. As succession progresses, communities gain biomass and species diversity but productivity decreases, and specialized and nutrient-recycling species become more common. Biodiversity refers to genetic, species, and ecosystem diversity and is essential for communities to survive, with different reproductive strategies adapted to early or stable succession stages.
This document discusses various environmental cycles and ecological concepts. It describes the energy cycle, water cycle, carbon cycle, and oxygen cycle. It also discusses ecological succession, including primary, secondary, and cyclic succession. Additionally, it covers food chains, food webs, and ecological pyramids. Food chains represent the transfer of energy as organisms eat and are eaten. Multiple interconnected food chains form a complex food web. Ecological pyramids show the trophic levels in an ecosystem, with plants at the base and apex predators at the top.
This document discusses various environmental cycles and ecological concepts. It describes the energy cycle, water cycle, carbon cycle, and oxygen cycle. It also discusses ecological succession, including primary, secondary, and cyclic succession. Additionally, it covers food chains, food webs, and ecological pyramids. Food chains represent the transfer of energy as organisms eat and are eaten. Multiple interconnected food chains form a complex food web. Ecological pyramids show the trophic levels in an ecosystem, with plants at the base and apex predators at the top.
Ecosystems are dynamic communities of living organisms that interact with each other and their non-living environment. Primary succession occurs when organisms first colonize an area that previously had no ecosystem, such as new volcanic land, and gradually establish equilibrium over hundreds of years through pioneer species that establish soil. Secondary succession more rapidly restores an existing ecosystem after a disturbance like fire or logging by taking advantage of existing soil and seeds. Both types of succession help maintain equilibrium in ecosystems over time.
An ecosystem is defined as a system consisting of all living organisms in an area interacting with each other and the non-living components of their environment. The key components of an ecosystem include producers, consumers, and decomposers as the living or biotic components, which interact with abiotic or non-living factors like physical and chemical conditions. Ecosystems transfer energy through food chains and food webs, and can be modeled using ecological pyramids that show the biomass or numbers of organisms at different trophic levels. Ecosystems are dynamic systems that undergo succession over time towards a climax community.
A community is a complex group of individuals interacting and sharing an environment.
Communities can be characterized by their structure (the types and numbers of species present) and dynamics (how communities change over time).
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COMMUNITY DYNAMICS CHARACTERISTICS- CYCLIC AND NON-CYCLIC REPLACEMENT CHANGES.pptx
1. COMMUNITY DYNAMICS CHARACTERISTICS- CYCLIC AND NON-
CYCLIC REPLACEMENT CHANGES
SUBMITTED TO, SUBMITTED BY
DR. AGHIL SOORYA KRISHNAPRIYA M
DEPARTMENT OF BOTANY ROLL NO: 10
ST.TERESA’S COLLEGE II M.Sc BOTANY
1
2. COMMUNITY DYNAMICS
Communities are complex systems characterized by community structure (number and size of populations
and their interactions) and community dynamics (how members and their interactions change over time).
Understanding community structure and dynamics allow us to minimize impacts on ecosystem and manage
ecological communities we benefit from.
Changes in community structure and composition over time, often following environmental disturbances
such as earthquakes, volcanoes, storms, fires and climate change is called Community Dynamics.
2
3. Community dynamics cont…
Communities with a relatively constant number of species are said to be at equilibrium.
Equilibrium is dynamic with species identities and relationships changing over time.
But it maintains relatively constant numbers.
Following a disturbance, communities may or may not return to equilibrium state.
Succession- sequential appearance and disappearance of species in a community over time after a severe
disturbance.
In Primary Succession, newly exposed or newly formed rock is colonized by living organisms.
3
4. Community dynamics cont…
In Secondary Succession, a part of ecosystem is disturbed and remnants of previous community remains.
In both cases, there is a sequential change in species until a more-or-less permanent community develops.
4
5. CYCLIC REPLACEMENT CHANGES
Cyclic replacement changes involves a series of vegetation and habitat changes through which community
maintains and regenerates itself.
It is also a pattern of vegetation change in which small number of species tend to replace each other over
time unless there is large-scale disturbance.
It is one of several types of ecological succession and is a concept of community ecology.
Cyclic succession refers to processes not initiated by wholesale exogenous disturbances or long term
physical changes in environment.
5
6. Cyclic replacement changes cont…
Cyclic mode of succession was proposed by British ecologist Alexander Watt in 1947 in his seminal paper
on vegetation patterns in grass, heath and bog communities.
He described plant community as a regenerating entity.
He explains that community can either be in an upgrade phase toward late successional shrubs or downward
phase toward grasses.
These phases occur in a predictable cycle.
6
7. Cyclic replacement changes cont…
Cyclic model of succession can be explained in a transition matrix.
The three states in the cyclic model are open substrate (usually a bare patch of land), Species A dominance
and Species B dominance.
It explains that Species A and Species B are not autosuccessional- they do not facilitate their own growth.
Species A will either facilitate succession of Species B or be eliminated (through mortality) such that patch
occupied becomes open substrate.
Species B will either facilitate succession of Species A or be eliminated.
Open substrate can remain open or become occupied by either Species A or B.
This results in cyclic scheme of species dominance.
7
8. Cyclic replacement changes cont…
Cyclic succession usually involves a series of stages, with different dominating at each stage.
These stages often occur due to disturbances or environmental changes.
a) Pioneer species:
Cyclic succession often begins with pioneer species, which are first to colonize a disturbed or barren
environment.
These species are adapted to harsh conditions.
b) Intermediate species:
As environment stabilizes, intermediate species with different ecological characteristics may replace pioneer
species. This lead to increased biodiversity.
8
9. Cyclic replacement changes cont…
c) Climax species:
Eventually, a stable and mature community dominated by climax species may develop.
These species are well suited to prevailing environmental conditions and are typically more competitive.
d) Disturbance and Reversal:
Cyclic succession may not always lead to a climax community.
Disturbances or changes in environmental conditions can restart the cycle, returning community to earlier
stages.
9
10. Cyclic replacement changes cont…
Example 1: Calluna vulgaris
When Calluna dies in a patch, Cladonia sylvatica grows and become dominant on dead stems of Calluna
stems, if protection is provided.
Disintegration of Cladonia and creation of bare patches of exposed soil follow this and is the termination of
downgrade series.
Upgrade series is initiated on bare patches with appearance and subsequent occupation of Arctostaphylos
uva-ursi.
This stage is subsequently invaded by Calluna, which becomes dominant again completing upgrade series.
10
12. Cyclic replacement changes cont…
Example 2: Two species plant community in Sonoran Desert.
Creosote bush (Larrea tridentata)- cholla cactus (Opuntia leptocaulis) replacement cycles from plants to
people.
12
14. Cyclic replacement changes cont…
Example 3: Repeated fire cycles of coastal chaparral ecosystem in California
This type of ecosystem has a climax community of shrub-sized deciduous and evergreen vegetation.
Fires are major source of disturbance in this ecosystem.
Fires come through in cycles of between 10 and 15 years or sometimes longer.
Plants and animals must be adapted to long periods of dryness and mild, winter time precipitation.
When fires occur, plant life can recover relatively rapidly and return to similar climax community in less
than several years.
14
16. NON-CYCLIC REPLACEMENT CHANGES
Also known as directional succession.
It involves a continuous and one-way sequence of species replacement within a community.
This type of succession occurs when a community transitions through a series of distinct stages, each
characterised by different dominant species.
Community ultimately reaches a climax state in which species composition remains relatively stable, as long
as environmental conditions remain constant.
They are often observed in environments with more gradual or continuous changes, such as changes in soil
conditions or climate.
16
17. Non-cyclic replacement changes cont…
As environmental conditions shifts, species that are better adapted to new conditions gradually replaces
previous dominant species.
This process continues until a climax community is reached where species composition is relatively stable.
Eg: If a field is left abandoned, it may undergo directional succession from grasses to shrubs and eventually to
trees over course of many years as soil and environmental conditions change.
17
18. reference
1) Dash. M. C. (2001). Fundamentals of Ecology. Tata McGraw-Hill Education.
2) Mishra, D. D. (2008). Fundamental Concepts in Environmental Studies. S. Chand & Company Pvt Ltd.
3) Sharma, P. D., & Sharma, P. D. (2012). Ecology and Environment. Rastogi Publications.
18