Download CB098-008.37_Plant_Ecology_B

More Ecosystems
Red Spruce – Fraser Fir Forest in the
Appalachian Mountains of North Carolina
Grassland on rolling hills in
North Dakota
Mid-montane conifer
forest, Yosemite National
Park, CA, about 2,000 m
in elevation.
Biomes
Biomes are groupings of similar ecosystems or landscapes.
Biomes are at a much larger scale.
Our text uses “Major Vegetation Types of North America.” These terms are used
for biomes as well.
Ecological Succession
Ecosystems are dynamic systems always changing. This
section deals with the changing of vegetation communities
or ecosystems through time.
Ecological Succession
- Biotic communities giving way to other biotic
communities.
- The Ecosystem is changing during succession.
- Changing conditions pave the way for other species.
- Pioneer species start Ecological Succession.
Note: Humans can put back succession and manage for
certain successional stages.
- Climax Ecosystem – The last stage in ecological succession.
This is an ecosystem in which populations of all organisms
are in balance with each other and with all existing abiotic
factors. A climax ecosystem can change sometimes if climate
changes or the introduction of introduced species.
Primary Succession – Occurs when an area has not been previously occupied. This
starts with bare rock. Examples: Bare rock exposed by retreating glaciers,
earthquakes, landslides, and volcanic eruptions.
Bare Rock
Moss
Weeds
Annual Grasses
Perennial Grasses
Shrubs
Coniferous Trees (Pines)
Hardwood Trees (Oak-Hickory)
Hardwood Trees (Beech-Maple)
Bare rock gives way to moss. Moss gives
way to weeds. Weeds give way to annual
grass, etc. The ecosystem is changing.
Primary Succession on Bare Rock.
(Moss invades
bare rock and acts as a collector, accumulating a layer of
soil sufficient for additional plants to become established.)
Secondary Succession – Starts with preexisting soil. This is when a biotic community
is reinvading or an ecosystem succession is set back. Examples: Abandoned
agriculture fields slowly succeed to deciduous forests.
Abandoned Field
Annual Grasses
Perennial Grasses
Shrubs
Coniferous Trees (Pines)
Hardwood Trees (Oak-Hickory)
Hardwood Trees (Beech-Maple)
Grass grows fast and is a good invader but
is easily shaded out by other vegetation.
Other vegetation changes the conditions
and the conditions are no longer beneficial
for grass.
Secondary Succession
Introduced Species
Introduced or Exotic Species are species from foreign
ecosystems. They are brought to new ecosystems by
people accidentally or on purpose.
Introduced or Exotic is the opposite of native. A native
species is originally found in the ecosystem of interest.
Introduced species cost the USA 138 billion dollars a year.
A Few Exotic Plants Found in North America:
Tree-of- Heaven, Kudzu, Chinese Chestnut
Introduced species can be problematic because they have
no natural predators or parasites in the newly invaded
ecosystem. When introduced or exotic species
numbers greatly increase, they are termed invasive or
invasive exotics. Invasive exotics can greatly degrade
ecosystems.
How do you control invasive exotic plants? Encourage
herbivores (if possible and those herbivore are native),
herbicides, physical control such as cutting and pulling.
- The American Chestnut is native to Eastern North America.
- The Chinese Chestnut originally from China and was
brought to Eastern North America in the early 1900s. The
Chinese Chestnut carried a disease (a fungal blight) which
decimated the American chestnut population.
Chinese
Chestnut
American
Chestnut
Historic Range of American Chestnut
American Chestnut
By 1950, the fungal
blight killed nearly
every living American
chestnut tree.
However, there is hope
of bringing the
American Chestnut
back by using
biotechnology
techniques.
Conservation Biology
Conservation Biology is a relatively new science that
studies the impact of human societies on the nonhuman
landscape. Conservation biology is interested in
conserving genetic diversity, species diversity and
ecosystem diversity.
When studying conservation biology, endangered species,
minimum populations, human sustainable development,
land management and ecosystem restoration, are
important topics.
Ecosystem Restoration – the process of modifying the
environment and the vegetation of an ecosystem that
has been degraded by human-caused disturbances.
Ecosystem restoration strives to return that degraded
ecosystem to its pre-disturbed state.
Ecosystem Restoration in Action
Paired photographs taken before and after 64 years of firesuppression management near Ebbetts Pass in the Sierra
Nevada of California.
1929
1993
Thinning, followed by
prescribed fire, has restored a
similar forest back to a
condition that resembles the
natural vegetation.
Today
BIO 141 Botany with Laboratory
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