What effects do catastrophic events have on TEXAS ecosystems?

1
What effects do catastrophic events have on
TEXAS ecosystems?
2
What is a catastrophic event?

• 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.

3
Catastrophic events

• Those caused by weather
• floods
• hurricanes
• tornadoes
• drought
• Fires
• Those caused by geological forces
• volcanoes
• earthquakes
• tsunami

4
HURRICANES
Effect on Texas coastal ecosystems

• Research over the years has yielded
• discoveries that could help the tender
• coastal ecosystem recover, depending
• on human interaction.
• Among findings, when comparing
• before and after 2008 Hurricane Ike,
• is that the marshes lost elevation,
• which is contrary to what most would
• expect to happen in a hurricane.

5
HURRICANES
Effect on Texas coastal ecosystems

• Sand dunes in the area hit by
• Hurricanes are already eroding
• at a rate of several feet per year.
• The natural mending of
• washed-out beaches might
• not be possible because of the
• many structures and non-native
• landscapes maintained there,
• blocking dune re-establishment.

6
Floods

• Part of the natural order of things
• The benefits of natural floods almost
• certainly outweigh the negative aspects.
• The problems start when flooding occurs
• in areas of large-scale human development.
• In areas largely inhabited by people,
• there are both positive and negative
• environmental effects of flooding.

7
Floods

• 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.

8
Floods

• The larger a flood is, the more
• of the ecosystem it wipes out.
• A flood could destroy the producer
• in the food chain (plants) which
• could cause the rest of the food
• chain to collapsewhich would
• kill other food chains.
• A flood could also wipe out prey or
• predators, which would impact
• food chains and webs.

9
Floods

• Floods affect the bays and estuaries in many
  ways.
• These rainfall events bring pulses of
  nutrients which
• will cycle through the food chain for years
  to come.
• They can also flush certain toxicants out
  of the system.

10
Floods

• Since many inshore life forms are dependent on
  either
• the lower salinity waters during part of
  their life, or the
• habitats sustained by intermediate
  salinities, the net
• effect of floods on estuaries is very
  positive.
• Floods ensure that the necessary salinity
  balances will
• be in place for many months following the
  event.

11
Tornadoes

• Tornadoes are the most
• violent storms on Earth
• intense rotating columns
• of air exceed 100 mph and
• can reach up to 300 mph.
• Tornados are an iconic symbol of the North
  American
• Great Plains.

12
Tornadoes

• Tornados and other catastrophic wind storms
  affect
• structure and composition of plant
  communities in
• forested areas, particularly in the
  Midwest.
• Tornados increase coarse woody debris and the
  number
• of snags, and they kill larger trees.

13

• Tornadoes kill larger trees, which opens the
  canopy,
• increases woody debris, and adds distance
  between
• patches of forest.
• In the area impacted by tornadoes,
• habitat for forest-edge species such
• as field sparrows and brown-headed
• cowbirds was enhanced however,
• impacted forests still support species
• dependent on dense forested habitats.

14

• Tornadoes destroy animal habitats, take away
• their food, or kill them right away, so
  they either
• dont have a place to live, dont have
  food, or die.
• Trees can fall and destroy their home.

15
Drought

• A combination of record-high heat and record-low
• rainfall caused south and central Texas to
  the region's
• deepest drought in a half century in 2009,
  with
• 3.6 billion of crop and livestock losses
  piling up
• during the nine months.
• In late April 2009, the USDA
• designated 70 Texas counties
• as primary natural-disaster areas
• because of drought, above-normal
• temperatures and associated wildfires.

16
Drought

• At Lake Travis, a popular boating and fishing
  spot,
• officials closed the last of the lake's 12
  public boat
• ramps in 2009 because of the lake's receding
  waters.

17
Drought

• During times of drought, trees and landscape
  plants
• often show the effects of the hot, dry
  weather.
• The 1999 and 2000 drought had an impact on plants
  
• in Texas.
• Drought is very harmful to trees,
• and it contributes to extreme
• conditions for forest and range fires.

18
Drought

• Water deficits in trees have an adverse effect on
  
• many of the tree's growth processes. Severe
  water
• stress will injure trees and may kill them.
  
• In addition, stressed trees are more vulnerable
  to
• insect and disease pests -- such as pine
  bark beetles
• than a healthy tree.
• Immediate effects of drought
• on hardwood trees are usually
• obvious, but delayed effects also
• occur growth for the coming
• year is often affected.

19
Drought

• Drought has a tremendous effect on wildlife
• populations as the food and water is
  nonexistent
• during the time that many species are
  breeding
• to provide next years crop of youngsters.
• The losses are not just in big game but affect
• turkeys, quail, dove and other animals.
• This continues up the food chain, with
• losses in the predators as the prey base
  decreases.

20
Volcanoes

• There are at least two extinct volcanoes in the
• Davis mountains of West Texas.
• There is an extinct volcano
• southeast of Austin "Pilot Knob.
• The University Of Texas at El Paso
• sits on a volcano.
• Ash deposits from eruptions of the
• Yellowstone Caldera have been
• mapped in Iowa, Missouri, Texas,
• and northern Mexico.

21
Volcanoes

• As lava, heat, and ash cover the landscape, trees
  
• and other plants are burned, buried, and
  destroyed
• so volcanoes and plants dont mix.
• Short-term impact on plant life is
• death the long term effect is positive.
• Eruptions bring magma from the
• Earths core containing rich nutrients
• that plants need to survive.
• When volcanoes explode, the ash
• acts as a fertilizer, enriching the soil.

22
Fire

• Pine forests are fire climax systems, meaning
• that fire is necessary in order for pines to
  maintain
• dominance in the presence of hardwood
  competition.
• Historically, fire has
• played an important
• role in shaping East
• Texas as a pine
• community by
• controlling hardwood
• competition.

23
Fire

• Damage caused by fire in the Gulf Coast Area has
• been minimal because prescribed fire is used
  as a
• tool for range management for cattle
  operations and
• wildlife management.
• Controlled fires in open areas
• have benefited the area by
• clearing up surface fuels.
• Tree mortality after a wildfire is
• minimal because fires in this
• region are mostly wind-driven
• with rapid rates of spread.

24
Fire

• Many fires are started by lightning strikes,
• which are common during the summer
• storms, and may burn large areas of
• grassland.
• These fires have helped
• control juniper and oak
• trees in the higher, wet
• and cool areas, and keep
• desert shrubs controlled
• in the lower, dry and hot
• areas.

25
Fire

• Early Native Americans used fire
• to improve the grass lands of the
• panhandle.
• This periodic burning of the plains
• meant that wildlife (mainly buffalo),
• did not have to leave the area to
• search for more nutrient-rich lands.
• Fire kept invader species of trees
• limited and enriched the grass lands.

26
Fire

• Due to human population growth in the High
  Plains,
• fire is no longer allowed to burn. As a
  result, the
• panhandle has seen a dramatic increase in
  the
• number of juniper and mesquite trees.
• Fires that occur today are much harder to
  control,
• because of overgrowth of grass fuel types.

27
Fire

• Fire serves an important function in maintaining
• the health of certain ecosystems, but as a
  result
• of changes in climate and in human use (and
  misuse)
• of fire, fires are now a threat to many
  forests and their
• biodiversity.

28
Fire

• Forest fires have many implications
• for biological diversity
• On the global scale, they are a
• significant source of emitted carbon,
• contributing to global warming.
• At the regional and local level, they
• lead to change in biomass levels
• alter the hydrological cycle with
• subsequent effects for marine systems such
  as
• coral reefs and impact the functioning of
  plant
• and animal species.
• Smoke from fires can significantly reduce
• photosynthetic activity and can be
  detrimental
• to health of humans and animals.

29
Earthquakes

• Earthquakes do occur in Texas. 
• During the twentieth century, there
• were more than 100 earthquakes
• large enough to be felt their
• epicenters occur in 40 of the
• States 257 counties.
• Four of these earthquakes have
• had magnitudes between 5 and 6,
• making them large enough to be
• felt over a wide area, and produce
• significant damage near their epicenters.

30
Earthquakes

• There are four regions within Texas where
• earthquakes have occurred
• Two regions, near El Paso and in the
• Panhandle, should expect earthquakes
• with magnitudes of about 5.5-6.0 to occur
• every 50-100 years, and even larger
• earthquakes are possible.
• In northeastern Texas the greatest
• hazard is from very large earthquakes
• (magnitude 7 or above) which might
• occur outside of Texas, particularly in
• Oklahoma or Missouri-Tennessee.

31
Earthquakes

• In south-central Texas the hazard is generally
  low,
• but residents should be aware that small
  earthquakes
• can occur there, including some which are
  triggered
• by oil or gas production.
• Elsewhere in Texas, earthquakes are exceedingly
• rare. However, the hazard level is not zero
  anywhere
• in Texas small earthquakes are
• possible almost anywhere, and all
• regions face possible ill effects from
• very large, distant earthquakes.

32
Catastrophic Events