Transcript Chapter 10 - Planet Earth

Chapter 10
Ecological Restoration
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.
– Major Tenets:
• Nature undisturbed achieves a permanency
• If disturbed momentarily, returns to exact permanent
state
• Place for each creature and each creature in its place
What is “Natural”?
• Restoring an ecosystem to its historical range of
variation and to an ability to sustain itself and its
crucial functions, including the cycling of
chemical elements, the flow of energy, and the
maintenance of the biological diversity that
existed previously.
– Examine populations that have decline and ecosystems
that have been damaged and learn what is lacking.
– Science and nature
What needs to be restored?
1. Wetlands, Rivers and Streams
(Ex: Kissimmee River, Everglades National Park)
2. Prairie Restoration
(Ex: Allwine Prairie)
*Roads and railroads
When Nature Restores Itself: The
Process of Ecological Succession
Ecological Succession:
The process of the development of an ecological
community or ecosystem.
Two Types:
1. Primary Succession: The initial establishment
and development of an ecosystem
2. Secondary Succession: The reestablishment of
an ecosystem where there are remnants of a
previous biological community
Patterns in Succession
1.
2.
3.
4.
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
Dune Succession
• Shores of Lake
Michigan
• Dune Grass
– Runners stabilize soil
• Other plants
• Eastern Red Cedar,
White Pine
• Beech and Maple
Bog Succession
Old-Field Succession
• Farm-land
• Abandoned and
allowed to grow back
to forest
• Small plants, larger
plants, to trees (Sugar
Maple, Beech, Yellow
Birch, White Pine)
Biomass and Diversity with
Succession
• Biomass, production, diversity and
chemical cycling change during succession
• Biomass and diversity peak in midsuccession, increasing at first to a
maximum, then declining and varying over
time.
Succession and Chemical
Cycling
• Storage of chemical elements (nitrogen,
phosphorus, potassium..) increases from early to
mid-succession
– Organic matter stores chemical elements
– Live and dead organic matter retards soil erosion
• Greater amounts of organic matter, greater
amounts of chemicals elements retained
• Soils store more elements than does live tissue but
cycle them at a slower rate.
Species Change in Succession
Earlier and later species in succession may
interact in three ways:
1. Facilitation
2. Interference
3. Life history differences
If they do not interact, the result is termed
chronic patchiness
Facilitation
• During succession, one species prepares the
way for the next (and may even be
necessary for the occurrence of the next)
• Can be useful in the restoration of damaged
areas.
• Ex) Tropical Rain Forest
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
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
• Early vs. Late-Successional Species
• Ex) seed disbursal
Chronic Patchiness
• Species don’t interact
• Harsh Environments
– Limited chemical elements or energy; frequent
disturbances
• Deserts
– Patches of mature shrubs (few seedlings)
– Persist for a long period of time
Applying Knowledge for
Restoration
• Great Britain and lead
mining
• 55,000 hectares
• 1st: heavy fertilizers and
fast-growing grasses
• 2nd: slow growing nativegrasses, adapted to
minerally deficient soils