What effects do What effects do catastrophic events catastrophic events

have on TEXAS have on TEXAS ecosystems?ecosystems?

What is a catastrophic event?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.

Catastrophic events…Catastrophic events…

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

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.

HURRICANES…HURRICANES…

Effect on Texas coastal ecosystems:Effect on Texas coastal ecosystems:

Sand dunes 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.

HURRICANES…HURRICANES…

Effect on Texas coastal ecosystems:Effect on Texas coastal ecosystems:

Floods…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.

Floods…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.

Floods…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 collapse…which would kill other food chains. A flood could also wipe out prey or predators, which would impact food chains and webs.

Floods…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.

Floods…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.

Tornadoes…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.

Tornadoes…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.

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.

Tornadoes destroy animal habitats, take away their food, or kill them right away, so they either don’t have a place to live, don’t have food, or die. Trees can fall and destroy their home.

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.

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.

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.

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.

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 year’s 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.

Drought…

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.

Volcanoes…

As lava, heat, and ash cover the landscape, trees and other plants are burned, buried, and destroyed; so volcanoes and plants don’t mix. Short-term impact on plant life is death; the long term effect is positive. Eruptions bring magma from the Earth’s core containing rich nutrients that plants need to survive. When volcanoes explode, the ash acts as a fertilizer, enriching the soil.

Volcanoes…

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.

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.

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.

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.

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.

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.

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.

Fire…

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 State’s 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.

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.

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.

Earthquakes…

Catastrophic EventsCatastrophic Events