Download Catastrophic Events File

and their effects on Texas
Ecosystems
What’s Happening?
Video 1
Video 2
1. What is happening in each video?
2. How do these videos relate to weathering,
erosion & deposition?
Catastrophic Events
• Catastrophic events are
natural occurrences that
generally have a negative
effect on people and/or
the environment.
• These changes are so
great they may cause
damage to the shape of
the land or to the lives of
people and other living
organisms.
Catastrophic events include, but are
not limited to:
• Those caused by weather
floods
hurricanes
tornadoes
drought
• Those caused by geological forces
volcanoes
earthquakes (tsunami)
• fires
Geological forces are related to or based upon Earth’s structure or composition.
Severe Texas Weather
Weather includes conditions in the atmosphere, including
humidity, cloud cover, temperature, wind, and precipitation
Hurricane
a huge, slowly-spinning
tropical storm that
forms over water and
has winds of at least 74
mph
Severe Texas Weather
Hurricane Statistics
• 1900: Known as "the Galveston Hurricane,"
the deadliest hurricane disaster in U.S. history
• Over 8,000 people died when hurricane storm
tides of 8-15 feet flooded the entire island city
of Galveston, Texas.
• More than half the homes and buildings were
destroyed.
Hurricane Effects
• Discoveries have been
made that could help
coastal ecosystems
recover, depending on
human interaction.
• When comparing before
and after 2008
Hurricane Ike, marshes
lost elevation, which is
contrary to what most
would expect to happen
in a hurricane.
Hurricane Katrina video
Hurricane Effects
• Sand dunes in the area hit by Hurricanes are eroding
at a rate of several feet per year.
• The natural repair of washed-out beaches is delayed
due to man-made landscape and structures which
slows the rebuilding of dunes.
Floods
Floods are an overflow of water onto land that is normally dry
• The benefits of natural
floods almost certainly
outweigh the negative
aspects.
• In areas largely
inhabited by people,
there are both positive
and negative
environmental effects
of flooding.
Flood Benefits
Floods can distribute large amounts of water and
suspended river sediment over vast areas. In many
areas, this sediment helps replenish valuable topsoil
components to agricultural lands and can keep the
elevation of a land mass above sea level.
Negative Flood Effects
• The larger a flood is, the more of the
ecosystem it wipes out.
• It could simply wipe out the producer in the
food chain (plant) which would mean the rest
of the food chain would collapse and destroy
other food chains.
• Predator and prey of food chains and food
webs could also be destroyed by floods
Flood Effects
Floods affect the bays
and estuaries in many
ways. These rainfall
events bring nutrients
that cycle through the
food chain for years to
come. They can also
flush certain toxicants
out of the system.
Flash Flood Video Footage
Flood Effects
Floods improve the water habitats required by
some species and increase in their
populations. Floods also decrease habitat
availability and populations of other species.
However, almost all life in the bays is adapted
to these periodic events.
Tornadoes
small, destructive, whirling, fast-moving storm that forms over land
• Tornadoes are the most violent storms on Earth
of violently rotating air exceeding 100 mph
• Tornados are a symbol of the North American
Great Plains; however, their influence on
communities of animals rarely has been studied.
• Lack of information on influence of tornados may
be due in part to their unpredictable and
localized occurrence.
• It is estimated that in the United States tornados
impact 450,000 habitats each year
Tornados
• Tornados affect
structure and
composition of plant
communities in forested
areas
• Tornadoes kill large
trees which changes the
topography of Texas
ecoregions.
Tornado destruction
Tornado Effects
• Tornadoes destroy the
shelter and food
source of many animal
habitats.
• This process could be
responsible for the
spread of certain types
of small animals and
plants across portions
of the U.S.
Drought
a prolonged period of dryness
The Davis Mountains
suffered a severe
drought for eight
years. Evidence of
this drought could
be seen in the Gray
Oaks that have
turned brown,
dropped their leaves,
and stopped growing.
Drought Effects
Historical Texas Droughts
• Record-high heat and record-low rainfall
caused south and central Texas to experience
the region's deepest drought in 2009
• As a result, there were large losses of crop and
livestock
• In late 2009, 70 Texas counties were
designated natural-disaster areas because of
drought, above-normal temperatures, and
associated wildfires.
Drought Effects
• At Lake Travis near
Austin, TX, officials
closed public boat
ramps in 2009 because
of the lake's receding
waters.
• Area residents
experienced loss of
income due to closed
recreational facilities
Drought Effects
• During droughts, trees and landscape plants
often show the effects of the hot, dry weather.
• Droughts often contribute to forest and range
fires.
Drought Effects
• Lack of water effects tree
health. Stressed trees are
more vulnerable to insect
and disease pests when
compared to a healthy
tree.
• Drought has an effect on
wildlife populations when
food and water is scarce.
• Food chains eventually
lose predators as the prey
base decreases.
Volcanoes
hills or mountains formed by material that erupts onto Earth’s surface; caused by
action of magma below Earth’s surface
Extinct volcanoes found in Davis Mountains
of West Texas
• There are at least
two extinct
volcanoes in the
Davis mountains of
West Texas.
• There is one extinct
volcano in Travis
County, southeast of
Austin, named "Pilot
Knob”
Volcano Effects
• The Davis Mountains of Texas, were formed
by volcanic activity approximately 65 million
years ago.
• The mild climate and volcanic soils support a
diverse selection of mountain plants and
animals.
Volcanic Eruption Video
Eruptions up close
Volcano Effects
• The immediate effect of
volcanoes on plant life is
death ):
• The long term effect
positive. Magma brings
nutrients from the core to
Earth’s surface. When
volcanoes erupt, ash
spreads and ultimately
acts as a fertilizer.
• Soil near volcanoes is
among the richest and
most fertile on Earth.
Mount Capulin,
part of Davis Mountain Range
Fire
Historically, fire has played an important role
in shaping East Texas as a pine community by
controlling hardwood competition.
Fire Effects
• In coastal Texas regions, damage caused by
fire has been minimal because fire is often
used as a tool for range, cattle, and wildlife
control.
• Controlled fires in open areas have benefited
the area by clearing up surface fuels.
Fire Effects
• Many Texas fires are
started by lightning strikes,
common during the
summer storms.
• These fires result in large
areas of grassland that
burn.
Fire Effects
In many Texas regions, fire has been used
to improve nutrients of the soil. Because of
this periodic burning, wildlife (mainly
buffalo), did not have to leave the area to
search for more nutrient-rich lands. The fire
ecosystem has always played a vital role in
the panhandle.
Forest Fire Effects
Smoke from fires can reduce photosynthesis
activity and can be harmful to the health of
humans and animals.
Earthquakes
energy travelling as waves passing through Earth, caused by a sudden shift along a
fault line, or by volcanic activity
• Earthquakes are rare in
Texas
• Some Texas earthquakes
were large enough to be
felt over a wide area and
created significant
damage
Earthquake footage
Earthquake Effects
In south-central Texas the hazard is low, but
residents should be aware that small
earthquakes can occur there, including some
which are triggered by oil or gas production.
Tsunami
a giant, dangerous ocean wave triggered by an earthquake, landslide, or volcanic
eruption; sometimes called a tidal wave, but it has nothing to do with tides
• Texas has never
experienced a tsunami.
• When the series of
waves occurs close to a
shoreline, the effects
can demolish coastal
communities within
minutes.
Tsunami from balcony
Tsunami - Another View