EcologicalSuccesion

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Ecological Succession:

(THE SUCCESSFUL SUCCESSIONISTS):

Justin, Sheena, Jenny, & Amanda

(THE SUCCESSFUL SUCCESSIONISTS):

Justin, Sheena, Jenny, & Amanda

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(PRIMARY SUCCESSION):



The process by which ecosystems are established in

previously unvegetated surroundings



Complete succession to an advanced community

can take 100-1000’s of years

(SECONDARY SUCCESSION):



Disturbance wipes out existing community

• Leaves soil intact



Allows community to return to its former state

• Forest repopulate after forest fires

What is Succession?

(PRIMARY VS. SECONDARY):

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Primary Succession

: Nudation

_{: Nudation}

(EXPLANATION):



Emergence of barren environment, free of vegetation e.g.

sand



Results from volcanic action or remnants of glacier

movement.



Virtually lifeless substrate



Only able to sustain autotrophic (organism capable of

creating its own food from inorganic substances) bacteria



Establishes abiotic environment suitable for future

colonization.

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Primary Succession

: Nudation

_{: Nudation}

(AT INDIANA DUNES):



The melting of glaciers spawned the formation of

Lake Michigan, and more importantly its shore line.



The receding of lake waters contributed organic

matter to the lifeless sand.



Sand and other debris from the glacier movement

became the primary substrate for the ecological

development of the dunes.



As depicted in the background picture, sand

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

Without any pre-existing seeds or root systems

in the soil, organisms must

migrate

into the

environment from other areas.



Migration, also known as dispersal, involves

arrival of the early colonizers (rapidly

dispersing species) to the new habitat



Migration occurs at different rates

• Species differ in dispersal (migration) ability.

Primary Succession

: Migration

_{: Migration}

(EXPLANATION):

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

Early colonizing species (lichens and certain

mosses) such as the moss shown in this picture

were introduced into the environment through

dispersion.



The decomposition of these colonizing species

aids in soil development, adding organic matter.



The formation of many plants is retarded until soil

_{The formation of many plants is retarded until soil}

development has occurred (sand, silt, clay,

organic matter)



R-Selected Species such as moss, lichens, etc. are

often the early colonizers.



They have great dispersal mechanisms and high

reproductive rates.

Primary Succession

: Migration

(AT INDIANA DUNES):

Primary Succession

: Migration

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Lichens (such as this Cladonia Cristatella) and bacteria first

colonize the barren environment. Acids secreted by the lichens help break rocks to form soil.

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

Migration continually occurs, but the establishment of

plant species is dependent upon soil.



Allogenic

mechanisms- changes in ecosystem from only

abiotic influences

• Ecesis occurs as a result of these abiotic influences such as erosion and gradual removal of harmful substances from soil by natural processes.



After dispersal, the early colonizers establish themselves

at the site, undergoing maturation and reproduction.



The Ecesis stage consists of proliferation of early

colonizers through germination, growth, and reproduction.



Stage is also known as “colonization”

Primary Succession

: Ecesis

_{: Ecesis}

(EXPLANATION):

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

Ecesis marks the point in succession during which

early colonizers (pioneer species) survive their

dispersal.



At the dunes, early colonizers such as the marram

grass (

ammophila breviligulata

) fully develop, thriving

on the dry soil.



Different maturation rates among colonizers allow for

the gradual ecesis of different species to temporarily

gain an advantage over other organisms.



Allows certain species to thrive while others establish

themselves

Primary Succession

: Ecesis

_{: Ecesis}

(AT INDIANA DUNES):

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Once sufficient soil is established within the

community, more advanced species (like this maram grass) are able to develop and thrive in the new

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Eventually the nutrient level in the soil level increases to the point where the shrub community replaces the grass community. With the introduction of shrubs

comes the development of another food source (such as berries) for future

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

Competition- protection or use of a limiting resource that

decreases the accessibility of that same resources for another

individual



arises between both intra- and interspecific organisms in the

community.



intraspecific competition

-when individuals of the same

species compete



interspecific competition

-when individuals of 2 or more

species in a community rely on compete for the same/similar

limiting resources.

Primary Succession

: Competition

_{: Competition}

(EXPLANATION):

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Primary Succession

: Competition

_{: Competition}

(AT INDIANA DUNES):



R Selected species compete with K-Selected species

(interspecific competition)

• R-selected species have a higher fecundity and a faster growth rater,

but a lower ability to compete.

• Consists of early colonizers such as herbaceous species

• Eventually overtaken by the K-selected species.

• Consists of more mature plants such as trees

• Slower growth rate, longer growth period, and lower fecundity,



While exploring the Indiana Dunes, we witnessed the

competition between species first hand.

• We first saw grasses overtaken by herbaceous species, which were

subsequently overtaken by shrubs, then coniferous and deciduous

trees.

r-selected species

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

The adjustment of the environment by

the organism.



Autogenic succession



Transformation of environment is

caused by the plants themselves.



Facilitation

-often early colonizers

clears the way for the later more mature

species.

Primary Succession

: Reaction

_{: Reaction}

(EXPLANATION):

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

Abundance of pioneer species affects

abiotic environment by changing local

conditions.



ex: when the leaves of alders (deciduous

shrub or tree) decompose, the pH of soil

drops



Change in pH allows the entry of conifer

trees, which require acidic soil.

Primary Succession

: Reaction

_{: Reaction}

(AT INDIANA DUNES):

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

Mature communities achieve equilibrium



A generally stable and productive population in

which biological potential is reached and one form

of vegetation dominates



Marked by both deciduous and coniferous forests

with mosses, herbaceous species and shrubs on

the under story.



Climax Community:

a stable community where

two or more plant species predominate

Primary Succession

: Stabilization

_{: Stabilization}

(EXPLANATION):

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

During our hike through the forest, we

witnessed first hand the characteristics of a

climax community.



Mature species pervading over the more

primitive pioneer species



As we explored the dunes farther inland, we

saw more coniferous and deciduous trees in

contrast to the rocks, sand, and marram grass

of the less developed communities closer to the

shore.

Primary Succession

: Stabilization

_{: Stabilization}

(AT INDIANA DUNES):

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Over time the build up of acidic soil due to

decomposition of the

earliest pioneers changes the abiotic factors of the environment (in this case Ph) resulting in the

introduction of conifers (which only grow in slightly acidic soil) into the

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Stabilization is marked by the introduction of mature species (such as this

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Succession is an ongoing process in which certain communities are developing while new ones are

beginning. As pictured here, the new communities develop near the waters edge on the barren sand whereas the

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The species coexisting with the mature pines and deciduous trees are forced into shade. Only shade-tolerant seedlings are able to

survive within the dense forest of the mature community. Within the mature community, the trees

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Secondary Succession

:

_:

(INTRODUCTION):

o

Initiated by disturbance (biotic or abiotic)

•Ex. Fire, Hurricane, Flood, Pollution, etc.

•The process of secondary succession is much faster as

fertile soil is already present.

o

Interferes with existing community and may favor new

ones

•Disturbances influence the course of secondary

succession

•If the abiotic conditions change significantly, the

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Secondary succession begins with a disturbance such as scorched remains of a

developed community as seen here. The fertile soil (which is left largely undisturbed by the disturbance) allows for the

secondary succession process to proceed much faster than from the primary succession which begins with barren rocks/ sand. Also,some species are actually prompted by the heat of such disturbances to reproduce (release their seeds). One

example Serotiny releases its seeds when a resin surrounding its pine cone melts in the

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Secondary Succession

:

(EARLY COLONIZERS):



Often R selected species due to high rates of

reproduction and efficient methods of dispersal



Often change abiotic conditions



Paves the way for K select species



Herbaceous species



Shorter generation period & faster growth rate

• Gives initial prominence over K selected species

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Secondary Succession

:

_:

(HERBACEOUS SPECIES):

With nutrient-rich soil already present, the first stage of

secondary succession is

characterized by herbaceous species that predominate the community. These herbaceous species (including annuals and perennials) sprout up after fires from root crowns and

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Secondary Succession

Secondary Succession:

(WOODY SHRUBS):

Woody shrubs, which succeed the herbaceous species, have good dispersal methods, and have fast rates of reproduction. These factors, accompanied by relatively short

growth periods allows woody shrubs to predominate in a developing

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Secondary Succession

Secondary Succession:

(FOREST TREES):

Like in the final stage of primary

succession, the K-selcted species of secondary succession predominate the community, after developing over significant periods of time (due to their slow rate of growth). Compared to the r-selected species they are better competitors and come to

consume much of the sunlight of the community (the limiting factor).

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Works Cited

 _{Dinnin, Mark. Lecture 10: Ecological Succession. 25 Sep. 2005}

<http://www.ex.ac.uk/geography/modules/GEO1201/biog5web. html>.

 _{Toft, Catherine A. Evolution and Ecology 101--Introduction to} Ecology. 26 Sep. 2005 <http://64.233.167.104/search? q=cache:Dmz0_BEkX_UJ:trc.u cdavis.edu/catoft/eve101/

W03SectionHO.pdf+nudation+migra tion+ecesis&hl=en>.  _{Sheley, Roger L., Tony J. Svejcar, Bruce D. Maxwell, and}

James S. Jacobs. Healthy Plant Communities. 27 Sep. 2005 <http://64.233.167.104/search?q=cache:ez2HLKBvvZUJ:www.m ontana.edu/wwwpb/pubs/mt9909.html+random+dispersal+succe ssion&hl=en>.

 _{Pidwirny, Michael . CHAPTER 9: Introduction to the Biosphere} . 10 Nov 2004. 27 Sep. 2005

<http://www.physicalgeography.net/fundamentals/9i.html>.

 _{Kimball, John W. Plant Succession. 8 Aug 2004. 27 Sep. 2005} <http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/ S/ Succession.html>.

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