Ecological Restoration

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Ecological Restoration
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The Balance of Nature

• An environmental myth that states that the
  natural environment, when not influenced by human
  activity, will reach a constant status,
  unchanging over time.

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Ecological Succession

• Succession occurs as a series of plants, animals
  and microbes colonize a site over time.
• May occur on sites that have not been previously
  occupied or on sites that have been disturbed
  causing the existing biotic community to be
  removed.
• Disturbances may be anthropogenic or natural.

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Role of Disturbances in Succession

• Disturbance creates ecological opportunities for
  organisms that would usually be absent to become
  established.
• Species diversity can be strongly influenced by
  disturbance.
• Intermediate Disturbance Hypothesis
• Highest diversity found in areas where
  disturbance is neither too rare or too frequent.

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When Nature Restores Itself The Process of
Ecological Succession

• Ecological Succession
• The process of the development of an ecological
  community or ecosystem.
• Two Types
• Primary Succession The initial establishment and
  development of an ecosystem
• Secondary Succession The reestablishment of an
  ecosystem where there are remnants of a previous
  biological community

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Secondary Succession
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Stages of Succession

• Biologic communities change over time.
• The complete sequence of change is called a sere.
• Recognizable seral stages make up a sere.
• Species that appear in early succession stages
  are called pioneer species.
• Pioneer species
• Fast growing, short-lived with wide and rapid
  dispersal.
• The process continues until the climax
  community (late successional species) is
  established.

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Patterns in Succession

• An initial kind of vegetation specially adapted
  to the unstable conditions
• Small plants and other early-successional species
  grow and seeds spread rapidly.
• Larger plants and other late successional species
  enter and begin to dominate the site.
• A mature forest develops.
• Examples of Succession
• Dune Succession, Bog Succession, Old-Field
  Succession

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Bog Succession Illustration.
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Changes in Biomass and Diversity During
Succession.
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Succession and Chemical Cycling

• Biomass, production, diversity and chemical
  cycling change during succession
• Biomass and diversity peak in mid-succession,
  increasing at first to a maximum, then declining
  and varying over time.

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Nitrogen and Phosphorus Changes in Soils During
Development.
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Species Change in Succession

• Earlier and later species in succession may
  interact in three ways
• Facilitation
• Interference
• Life history differences
• If they do not interact, the result is termed
  chronic patchiness

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Facilitation

• During succession, one species prepares the way
  for the next (and may even be necessary for the
  occurrence of the next)

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Interference

• During succession, one species prevents the
  entrance of a later species into an ecosystem.
• Ex) Some grasses produce dense and thick mats so
  the seeds of trees cannot reach the soil to
  germinate

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Life History Difference

• The difference in the life histories of the
  species allow some time to arrive first and grow
  quickly, while others arrive late and grow more
  slowly
• Ex) seed disbursal

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Illustration of Facilitation, Interference and
Chronic Patchiness.
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What needs to be restored?

• Wetlands, Rivers and Streams
• (Ex Kissimmee River, Everglades National Park)
• Prairie Restoration
• (Ex Allwine Prairie)

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Environmental Factors Affecting Succession

• Resilience ability of a system to recover after
  some disturbance.
• Depends on
• Type of system
• Extent of disturbance
• Presence of species to recolonize
• Health of the system
• Reduction in biodiversity/pollution/deforestation
  can all reduce the ability of an ecosystem to
  recover.