Transcript What effects do plants have on the landscape?

What effects do plants have on the
landscape?
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What caused the grey/green
discoloration on these rocks?
How did that tree get there?
Is the action of plants primarily
chemical, primarily physical, or
both chemical and physical?
How do plants first appear after the
glaciers retreat?
• What plants are first on the
scene?
• How does the development of
soil impact the arrival of plants?
• How do plants impact
development of soil?
• What is the sequence
(succession) of plant life?
deciduous trees
coniferous trees
herbaceous shrubs that tolerate some shade
grasses that prefer sunshine to shade
An additional notions for exploration ….
Questions
Additional food for future thought/research
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What is soil? How does it form? How did it get to Devils Lake?
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The rock cycle is here - - - weathering and erosion factors.
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pH – a chemical refresher (0-14 scale). Types of rocks and their impact (chemical) on the types of soil formed.
Biotic and Abiotic factors in soil. – abiotic are the mineral and the biotic are the organics, the plant and animal debris
Impact of invasive species on the landscape / habitat. We are dealing with Buckthorn and phragmites crowding out
desirable species.
Impact of animals on seed dispersal. Bird droppings and animal waste.
Impact of animals (tooting / belching cows) on global climate change (greenhouse gas emissions) there is a
marvelous Mythbusters episode (Discovery Education) on how it’s actually the burp that adds more methane to the
atmosphere that the toot.
Teacher background - The
big questions
How have plants shaped the landscape?
Why do living things in the environment look the way they do?
* Sun energy rules: photosynthesis in green plants
wind erosion the uneven heating and cooling of the earth’s
surface
freeze and thaw of water
* All living things, flora and fauna, have the same basic needs in order to
remain living: Sufficient quantities of (clean) Air, Water, Food, and Shelter.
* Rocks are broken down into soil by two basic processes of weathering.
1.Mechanical - such as the freezing (expansion) and
thawing (contraction) of water in cracks.
2.Chemical - such as the breakdown caused by weak acids in plant roots.
* Plant life follows a fairly predictable arrival pattern called succession
Teacher background -
Lichens
The splotches in the photograph are actually a form of plant life called lichens. Lichens are often called ‘Pioneer
Plants” because they are the first to grow on barren surfaces such as the Devils Lake rocks.
Lichens are composed of two different organisms living together for the benefit of both. This is called symbiosis. In
each type of lichen the two organisms are a one-celled algae living inside of a partner fungus.
The green algae provides nutrients for the fungus though photosynthesis. Algae need a film of moisture or water in
which to grow. The fungus provides insulation to keep the algae moist. Weak acids produced by the lichen’s
hyphae (root-like structure but not a true root) physically penetrate crevices between mineral grains and allow the lichen
to grow on almost any surface. Together the algae feeds the fungus and the fungus protects and anchors the
algae. This symbiosis is essential for survival since neither partner can survive without the other.
Soil formation
Over time the acids in the hyphae also breakdown the rock surface creating the first mineral particles of soil.
Lichen become dormant during extreme conditions and then rehydrate when conditions improve. This change in
size (shrink when dormant and swell when rehydrated) can break apart solid rock by making small cracks into larger
cracks.
After the glaciers left the Devils Lake area the exposed rock was likely barren of plant life. The lichen pioneers were
the first to take hold on the newly exposed rock. Browsing animals followed
food source and also added their
Funthis
Facts?
waste to enrich the soil.
Colonies may be 9,000 years old
Web Resources:
Lichens of North America: http://www.lichen.com/biology.html
New York Botanical Gardens: http://www.nybg.org/bsci/lichens/
Arizona State U Lichen Herbarium: http://nhc.asu.edu/lherbarium/
United Kingdom: http://www.countrysideinfo.co.uk/fungi/lichens.htm
Colorful dyes for clothes
Packing for ancient Egyptian mummies!
Pollution indicators
High mountain dwellers and Arctic
survivors
Article: Role of Lichens in Weathering and Soil Formation by Frank Bungartz
http://nhc.asu.edu/lherbarium/lichen_info/weathering_soil_formation.pdf
Teacher background –
Plant Succession
Plant succession refers to the sequence in which plant life first appears in an area. The Devils Lake area is an
example of Primary succession. This happens when the first plants to colonize a region have no prior soil or plant
material upon which to begin.
Succession is dependent upon the amount, if there is any, of available soils, climate, and the presence of any
existing plant species to start the process. If there is no soil then generally the lichens are first on the scene.
After the passage of time the variety of plant life changes due to the changing conditions. For example, first plants
to arrive in an exposed area must be sun tolerant species. When these species reach sufficient height or quantify
they create shade. In the shade of taller species the shortest of the sun tolerant plants may be eliminated due to
lack of sun. Eventually a balance is reached between the tallest of the sun lovers and the shade tolerant species
below. Throughout the whole process dead organic materials are dropped to the surface creating humus to enrich
the soil.
The clearing of an area can be caused by human actions such as logging or mining. In these examples there is
likely to be some type of soil already present. A landscape can also be cleared by natural events like the action of
slow moving glaciers which scrape away existing soil and might leave behind deposits of sediments when they
retreat or rapid volcanic eruptions which recycle rock into ash and can leave behind very fertile soils.
However the clearing is achieved nature will soon begin to cover the exposed landscape with plant life. That
process is called succession.
When the glaciers left Devils Rock there was likely runoff erosion of some sediments when the glacier retreated.
However, it’s unlikely that the exposed rock surface held any soil so lichens were probable first on the scene.
Web Resources:
http://www.countrysideinfo.co.uk/successn/summary.htm
Teacher background –
Squaw Root
Add some info, but it’s a non-photosynthetic plant
Web Resources:
http://www.countrysideinfo.co.uk/successn/summary.htm
Ideas that haven’t been worked
in as yet...
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What would this place look like if an
invasive plant species (such as phragmites)
was introduced?
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What would this place look like if an
invasive insect species (such as pine borer)
was introduced?
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What would be the impact on plant
and or animal life if there were no
more:
tall trees? algae? deciduous trees? pine
trees? lichens?
Need a more general photo of landscape