How do environments change?

Ecological Disturbances

Invasive Species

What makes a species "invasive"?

• Defined as non-native species that cause:• environmental harm• economic harm

• They are:• Able to tolerate/adapt to a variety of habitat conditions so

they can jump habitats/ecosystems • Affect/disrupt the habitat of other species• Can cause native species to decline in population or

disappear

Brandon Tiu

Snakehead

How do invasive species get there?• Ornamental planting

• People bring in/plant exotic flora for beautification purposes • Transportation

• Flora & fauna hitch a ride during human movement or transport of goods

• Black rat that caused the plague got into shipping crates• Brought to be eaten

• People like to eat exotic flora and fauna, particularly immigrant groups who crave their native cuisine

• Used as pets• Exotic pets are bred or become burdensome& are released into the

wild • Pathways

• Human-follow human migration/movement as hitchhikers• Natural-climate change alters migration paths

• Rising & falling sea levels cover & expose land• Species migrate when climate change makes other habitats habitable

Isabel

                                                                               i

How do invasive species affect the ecosystem?

• Grow and reproduce quickly• Often r-selected species• Lack of natural enemies/predators in new ecosystem allows

for rapid population growth• Compete for resources

• Usurp the natural resources of native flora and fauna • Can alter the genetic makeup of native

species• Interbreed with native species causing hybridization

which becomes dominant displacing the native species

Carlos

How do invasive species affect the ecosystem? (cont’d)

• Capable of changing an entire habitat by disrupting the food chain• Invasive flora can clog waterways or lakes• Transport and carry diseases 

• May bring diseases with them for which native flora and fauna have no resistance/immunity

Any and all of these cause disruptions in the food chain that stress native populations and can lead to extinctions

David Kent

How can we address the problem of Invasive Species?

• Eradication to control & prevent spread to un-infested areas • Chemical• Mechanical• biological

• Maintain healthy natural communities• Better health = better resistance to invaders 

• Restoring previously impacted areas• After eliminating the invasive species humans can reintroduce

native species• Limiting human disturbance

• Human contact with an invasive species, particularly flora, often increases the rate of invasion due to human pathways

Eradication of Invasive SpeciesChemical method = use of pesticides, herbicides & poisons:

 Pros:• Very effective initially

Cons:• Expensive• Pests may develop

resistance to them• Can be toxic to

environment• May kill native species as

well 

sabel

Mechanical method = physical human removal/cullingPros: • Not very expensive

(ex: hunting/pulling weeds)

Cons: • Some habitats are

inaccessible/hostile to humans

• Manual labor can be time consuming & difficult

• Difficult for large populations

Biological method = introducing natural pest/predator Pros: • Most “natural” method• Highly effective if

predator/pest is exclusive to native invader

• inexpensive Cons:• Predators/pests may

attack native species as well

• Difficult to remove enemy once introduced

The Invader: Salt Cedar in South Texas   

o introduced to North America in 1823 by nurserymen.o Escaped human cultivation & became a serious problem.

o Ecological Threato Deep tap roots alter ecosystem.

o Robs 200 gallons of water a day from native specieso Lowers ground water levels and drains marshes

o Degrade native habitats.o Leaves a layer of salt above and below soil degrading its fertilityo Crowds out native plants that offer food and resources to fauna

o seeds have no little to no protein/nutritious valueo Little vegetation on salt cedars for forage

o Increase the frequency, intensity, and effect of floods and fires. o Choke streambeds = floodingo Easily flammable creating fuel for fire

o Ecological Benefitso Provide nesting areas

o whitewing & mourning doveso Provides nector

o honey bees.Laiba

Pollution

Types of Pollution1. Land pollution- (a.k.a. soil pollution)

o contamination of soil by harmful substanceso Caused by:

Industrial wastes  Litter & garbage dumps

As trash degrades it leeches chemicals into the soil Agricultural toxins like pesticides

2. Water pollution-o contamination of water by toxic substance released into watero Caused by: 

o Agricultural run-offo Pesticides, fertilizers etc. contaminate groundwater & aquifers as well as

rivers & lakes when rain causes run-offo Household chemicals & cleansers poured down drainso Industrial & radioactive waste dumped into water sources o Oils spillso Sewageo Heavy metals as run-off from mining

Types of Pollution3. Air pollution-

o Direct release of chemicals into the environmento Caused by:

the burning of fossil fuels large factories/industrial pollution emissions from vehicles burning of wood

Forest fires Household chimneys

Volcanic gases Evaporation of contaminated waters

Affect on Environment• Soil Pollution-

o Directly harms animals/food chains through toxicityo Often poisons or destroys producers disrupting food chainso Certain animals absorb toxins through their skin such as frogs

o Can cause disease, birth defects, or early death o Loss of 6 million hectares of land per yearo Loss of 24 billion tons of topsoil per year 

o Due to erosion caused by overuse of land or stripping of vegetation• Water Pollution-

o Release of toxins particularly affects organisms living in aquatic biomeso Often poisons or destroys producers disrupting food chainso Certain animals absorb toxins through their skin such as frogs

o Can cause disease, birth defects, or early deatho Heat released by industrial pipes changes water temperature

affecting the oxygen level available to organisms

Affect on Environment• Air Pollution:

o Causes global warming, its affects: melts ice glaciers

Creates rise in sea levels Crates inundation of terrestrial biomes due to flooding Causes mixing of freshwater and saltwater

brings heat wave threatens polar animals brings storms & droughts

o Affects the respiration of biological life-forms

Reducing Pollution• Water Pollution:

o Organic farmingo Creating alternative ways to keep rodents and pests

away o Industries should dispose of chemicals safely

NOT in the ocean

•  Soil Pollution:o Organic farmingo Recycling to reduce leeching from garbage dumpso Proper waste disposalo Farming techniques that hold top soil such as planting

perimeter of trees

Reducing Pollution• Air Pollution:

o Different methods of transportation riding a bike Public transit Hybrid autos

o Enforcing a rule in your town to: switch bulbs to fluorescent light bulbs

o Reduce the burning of fossil fuels through the development of alternative energy sources

o Planting more treeso Legislation to reduce/regulate greenhouse gas

emissions & industrial pollutants

Pollution in TexasWater Pollution – Texas freshwater endangered by the runoff from chemicals used by

farmers. – The pollution accounts for 64% of pollution in Texas's freshwater

supplies; the chemicals contain nitrates.Land Pollution – Pilgrims Pride Co. raises 99 million chickens each year

• produces 31 billion lbs. of manure in total each year. – This pollutes the land in Titus and Camp Counties (in Texas).

Air Pollution– In Texas, the pollutants that are most concerned about are nitrogen

oxides, volatine organic compounds, and ground-level•  Many areas in Texas are facing the challenge of improving the air quality

around them.  

Aaron

Natural Disasters

Tsunamis• Tsunamis are caused by underwater landslides,

volcanic eruptions, and earthquakes.  • Tectonic collisions transforming vertically displaces

water above it forming enormous waves. 

Positive and Negative Effects of Tsunamis

Positive-• Sand on beaches are

replenished with finer and cleaner sand

• The quality of coastal waters are improved as nutrients are washed into the water

Negative -• coastal ecosystems are

disrupted and damaged• physical removal of flora

and fauna• kills sediment sensitive

coral and sea grass  • Water polluted by

debris & sewage swept to sea

Causes of Volcanic Activity

• Volcanic eruptions result from – Divergent boundaries

• Spreading allows lava to rise through

– Convergent subduction• Denser plate forced downward toward the matle

– Causes plate to melt and magma to pool» Leads to increased pressure & eventual rupture

– Hotspots• Columns of magma born through weak spots on

plates as they pass over

Positive and Negative Effects of Volcanic Activity

Positive - • Underwater volcanoes support

life• Undersea volcanoes produces

nutrients enriching the water.• Volcanic lava produces

nutrient rich soil• Becomes area of primary

succession• Leads to birth of a new

ecosystem/habitat

Negative - • Can produce

destructive tsunamis• Lava flows, pyroclastic

gasses, & lahars kill flora & fauna

• Can ignite wildfires (positive & negative)

Causes of Wildfires

• Wildfires may form through:– Drought

• Dry flora ignites easily– Heat– Sparks from rockfalls– Human carelessness

• Undoused camp fires• Cigarette butts• Garbage burning

– Lightning strikes– Volcanic activity

• Lava flows 

Effects of Wildfires

• Positive• stimulate growth of plants

that use atmospheric nitrogen and return it to the ground improving the soil.

• "clean" the affected land by removing diseased trees and rotting flora.

• Some seed depends on fires to be able to open and grow.

• The burnt vegetation turns into nutrients for the soil

• Negative– Destroys plants

• herbivores suffer as they struggle to find other plants to eat.

– Disrupts food chain

Prevention of Wildfires• Education

o Smoky, the bear, is used to educate the children o "Only you can prevent wildfires."

o News media is enlisted to help inform the public.

o Governments issue burn bans during dangerous conditions

o Government officials kept informed so they can make the right decisions about fire use and restrictions.

Controlling Wild Fires• To elimate wildfires, firefighters need to remove either

oxygen, fuel, or heat from the fire.• Firefighters continue to put out wildfires with a variety of

ways, such as:1. Traditional methods: adding water or phosphate fertilizer (fire

retardant).2. Firebreaks: land stripped of possible fuel.3. Controlled Burning: Burning fires near the fire or burning dead

organic matter before it accumulates & creates fuel

 1 2 3

2011 Texas Forest FiresCauses

• Careless debris burning• Sparks from welding• Grinding equipment• Carelessly discarding

smoking materials• Drought

Effects• 230 of the 254 Texas counties

reported burn bans• September/October 2011- fires

consumed tens of thousands of acres of drought- stricken areas• 21,000 fires

• 1,500 domestic and wild animals perished

• 3,768,453 acres destroyed

Climate Change

What is climate change?"Climate change is a significant and lasting change in the statistical distribution of weather patterns over [long periods of time].”

Because so many systems are tied to climate, a change in climate can affect:• Loss of icebergs and polar icecaps • Accelerated sea level rise.• Longer, more intense heat waves.• One-fourth of Earth’s species could be headed

for extinction by 2050.• Extinction of species would cause less bio-

diversity

•Climate change is the change in temperature and precipitation in a given area.

What causes climate change?

Natural Causes:    i. Continental Drift• Climate changed due to plate

movement• Separation altered flow of ocean

currents & therefore wind currents & precipitation

• Changes the latitude zone in which a region lies

    ii.Volcanoes• Eruptions release large volumes of

gas and ash that have influenced climatic patterns • Ex: Sulfur Dioxide cools

atmospheric temperatures)   

iii. Changes in Earth's Tilt• Precession (gradual change in

direction of Earth's axis)• More tilt = more extreme

temperatures• Less tilt = more moderate

temperatures

iiii. Shifting Ocean Currents• Water vapor = most abundant

greenhouse gas • El Nino & La Nina

• Alters the distribution of heat and precipitation worldwide

What causes climate change?

Human Causes:Consumerism -> Want for material things -> Increase in wastei.Fossil Fuels• Oil, coal, & natural gases supply vehicles and generate

electricity• Produce Nitrogen Oxide and Carbon Monoxide which produce

greenhouse gasesii.Greenhouse Gases• Sources: Deforestation for agriculture, changes in land use

pattern, use of fossil fuels• Methane gas released from landfills/waste dumps & domesticated

animals                     

Climate Change in Earth's Biomes & Ecosystems

Climate change all over the globe has caused some severe and almost irreversible changes through out the world's ecosystems

-Melting Ice caps - Arctic fauna have less surface area for habitat- Sea levels will continue to rise

- Could alter climate patterns - Could inundate terrestrial biomes- Could flood into freshwater destroying/altering the existing biome

- Changing Water Content and Quality (Marine ecosystems)• Ocean water is increasing in acidity - more carbon dioxide is absorbed, laboring

some fishes' respiration• Temperature is not suitable for plankton, if producer is wiped out, the rest of the food

chain is altered in an domino effect•General disturbance of ecosystems.

• Shifting temperatures & precipitation affect what flora survive in a biome• Flora affect the fauna• Entire biomes may change

• Ex: forest biomes that become drier will turn into grasslands• Migration patterns of fauna will change to adapt to the changing environment

• Unpredictability in precipitation which can lead to drought or floods

Addressing Climate ChangeReduce the consumption of natural resources and

emission of greenhouse gasses Making an impact individually:     i. Reduce resource consumption by:        - unplugging machines when not in use        - turning off lights    ii. Smarter shopping        - use reusable bags    iii. Recycle        - save paper and water by reusing materials Making an impact nationally:      - energy efficiency and conservation      - alternative energy sources        

Addressing Climate Change

Climate Change in Texas

How:Natural• rise in temperature evaporates more water and leave areas dry and

more prone to igniting• lightning strikes, sparks from rockfall, and spontaneous combustion

Human• cigarette butts ignite dry plants

Negative & Positive Effects:• Releases toxins in to the atmosphere contributing to poor airs

quality/atmospheric pollution• kills animals and limits food sources of survivors

• Forces animal migration• Causes destruction of million of acres of forest and grassland• Will eventually lead to enriched soil and secondary succession

Climate changes in Texas cause changes or natural occurrences such as wildfires.

Climate Change in Texas (Contin.)

some plants are stimulated by wildfires to germinate

many wildfires occurred near Austin, Texas this year