and their effects on Texas Ecosystems Catastrophic Events, part 1 and their effects on Texas Ecosystems

What’s Happening? Video 1 Video 2 What is happening in each video? 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.

Extinct volcanoes found in Davis Mountains Volcanoes hills or mountains formed by material that erupts onto Earth’s surface; caused by action of magma below Earth’s surface 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” Extinct volcanoes found in Davis Mountains of West Texas

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

part of Davis Mountain Range 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