What is the #1 threat to biodiversity? Habitat Destruction! The process by which natural habitat is damaged or destroyed to such an extent that it no longer.

What is the #1 threat to biodiversity?Habitat Destruction!

The process by which natural habitat is damaged or destroyed to such an extent that it no longer is capable of supporting the species and ecological communities that naturally occur there. It often results in the extinction of species and, as a result, the loss of biodiversity.

Habitat can be destroyed directly by many human activities, most of which involve the clearing of land for other uses such as agriculture, mining, logging, hydroelectric dams and urbanization. Habitat can also be destroyed indirectly by human activities such as pollution, climate change and the introduction of invasive species.

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Deforestation is among the primary causes of habitat destruction

Although much habitat destruction can be attributed to human activity, it is not an exclusively man-made phenomenon. Habitat loss also occurs as a result of natural events such as floods, volcanic eruptions, earthquakes, and climate fluctuations.

What is an INVASIVE SPECIES?A species is invasive when it is both non-native to the ecosystem in which it is found and capable of causing environmental, economic, or human harm.

Invasive species often compete so successfully in new ecosystems that they displace native species and disrupt important ecosystem processes. Plants, fish, insects, mammals, birds, and diseases all can be invasive.

Invasive species are recognized as one of the leading threats to biodiversity and impose enormous costs to agriculture, forestry, fisheries, and other human enterprises, as well as to human health.

In 2007 and 2008, more than 659,600 acres of trees were defoliated by invasive gypsy moth caterpillars in New Jersey, resulting in the death of about 31,000 acres’ worth of trees. The state spent $1.8 million to control gypsy moths in 2009.

Often, invasive species owe their success in colonizing new ecosystems to one or more of the following characteristics:• They tolerate a variety of habitat conditions• They grow and reproduce rapidly• They compete aggressively for resources (like food, water,

and nesting sites)• They lack natural enemies or pests in the new ecosystem

Invasive species can negatively impact ecosystems in a variety of ways. They can:• Displace native species• Reduce native wildlife habitat• Reduce forest health and

productivity• Alter ecosystem processes

THE GREENHOUSE EFFECTIf it were not for greenhouse gases trapping heat in the atmosphere, the Earth would be a very cold place. Greenhouse gases keep the Earth warm through a process called the greenhouse effect.

The Earth gets energy from the sun in the form of sunlight. The Earth's surface absorbs some of this energy and heats up. The Earth cools down by giving off a different form of energy, called infrared radiation. Before all this radiation can escape to outer space, greenhouse gases in the atmosphere absorb some of it, which makes the atmosphere warmer. As the atmosphere gets warmer, it makes the Earth's surface warmer, too.

The Greenhouse GasesThose gas molecules in the Earth's atmosphere with three or more atoms are called "greenhouse gases" because they can capture outgoing infrared energy from the Earth, thereby warming the planet. The greenhouse gases include water vapor (H2O), ozone (O3), carbon dioxide (CO2), and methane (CH4). Also, trace quantities of chloro-fluoro-carbons (CFC's) can have a disproportionately large effect.

Global Warming is issue of major concern is the possible effect of the burning of fossil fuels and other contributors to the increase of carbon dioxide in the atmosphere. The action of carbon dioxide and other greenhouse gases in trapping infrared radiation is called the greenhouse effect. It may measurably increase the overall average temperature of the Earth, which could have disastrous consequences.

Carbon Dioxide (54.7%) (Stays in the atmosphere anywhere from 50 to thousands of years)

Comes from: • Burning fossil fuels to produce electricity and heat for buildings• Burning gasoline & other fossil fuels to run vehicles• DEFORESTATION – the cutting down and burning trees (that would

otherwise USE the carbon dioxide for photosynthesis)

Methane(30%) (Stays in the atmosphere for 12 years – but traps more than 20 times the amount of heat as carbon dioxide)

Comes from:• Farming raising livestock, especially cows and sheep produce

methane as they digest food. Manure also releases methane as it decays.

• Landfills decaying trash releases methane• Producing and transporting natural gas – even small leaks release

methane

The Main Greenhouse GasesPeople produce more carbon dioxide than any other greenhouse gas, and it's responsible for most of the warming.

Chlorofluorocarbons (CFCs) time in atmosphere varies up to thousands of years and amount of heat trapped varies from a few hundred to 23,000 times the amount of trapped heatIt is used as a propellant in aerosol cans, creating foam plastics, cooling refrigerators and air conditioners, as a solvent in cleaners, and as an ingredient in fire extinguisher materials. These also destroy the ozone layer. Nitrous Oxide stays in the atmosphere 114 years and traps almost 300 times more heat than carbon dioxideFarming practices that add nitrogen to the soil (such as fertilizers), bacteria turns it into nitrous oxide

What will be the effects of Global Warming?

• When we talk about global warming, we're not talking about how this summer's temperatures were hotter than last year's. Instead, we're talking about climate change, changes that happen to our environment, atmosphere and weather over time. Think decades, not seasons. The term global warming itself is a bit deceptive because it implies we should expect things to get hotter -- not necessarily stormier, drier and even, in some instances, colder.

What can we expect from a planet undergoing climate changes?

Rising Sea Level & Shrinking GlaciersHotter temperatures mean ice – glaciers, sea ice and polar ice sheets -- is melting, increasing the amount of water in the world's seas and oceans. Such levels would submerge many of Indonesia's tropical islands and flood low-lying areas such as Miami, New York City's Lower Manhattan and Bangladesh.Tundra once covered with thick permafrost is melting with rising surface temperatures and is now coated with plant life. Heat WavesExtreme heat waves are happening two to four times more often now, steadily rising over the last 50 to 100 years, and are projected to be 100 times more likely over the next 40 years Experts suggest continued heat waves may mean future increases in wildfires, heat-related illness and a general rise in the planet's mean temperature.

Storms and FloodsIn just 30 years the occurrence of the strongest hurricanes -- categories 4 and 5 -- has nearly doubled.

DroughtWhile some parts of the world may find themselves deluged by increasing storms and rising waters, other areas may find themselves suffering from drought. As the climate warms, an increase in drought conditions leads quickly to a shrinking water supply and a decrease in quality agricultural conditions. This puts global food production and supply in danger and leaves populations at risk for starvation.

Worldwide droughts, like that in a village northeast of Nairobi, expose rural communities to food shortages.

DiseaseWarmer temperatures along with associated floods and droughts are encouraging worldwide health threats by creating an environment where mosquitoes, ticks, mice and other disease-carrying creatures thrive. The World Health Organization (WHO) reports that outbreaks of new or resurgent diseases are on the rise and in more disparate countries than ever before, including tropical illnesses in once cold climates -- such as mosquitoes infecting Canadians with West Nile virus.Cases of allergies and asthma are also increasing. Global warming fosters increased smog -- which is linked to mounting instances of asthma attacks -- and also advances weed growth, a bane for allergy sufferers.

A field sample of mosquitoes that could carry West Nile virus pictured in California. Image Credit: David McNew/Getty Images

Economic ConsequencesThe costs associated with climate change rise along with the temperatures. Severe storms and floods combined with agricultural losses cause billions of dollars in damages, and money is needed to treat and control the spread of disease. Extreme weather can create extreme financial setbacks. For example, during the record-breaking hurricane year of 2005, Louisiana saw a 15 percent drop in income during the months following the storms, while property damage was estimated at $135 billion Economic considerations reach into nearly every facet of our lives. Consumers face rising food and energy costs along with increased insurance premiums for health and home. Governments suffer the consequences of diminished tourism and industrial profits, soaring energy, food and water demands, disaster cleanup and border tensions.

Conflicts and WarScientists and military analysts alike are theorizing climate change and its consequences such as food and water instability pose threats for war and conflict, suggesting that violence and ecological crises are entangled. Countries suffering from water shortages and crop loss become vulnerable to security trouble, including regional instability, panic and aggression.

Loss of BiodiversitySpecies loss and endangerment is rising along with global temperatures. As many as 30 percent of plant and animal species alive today risk extinction by 2050 if average temperatures rise more than 2 to 11.5 degrees F (1.1 to 6.4 degrees C). Such extinctions will be due to loss of habitat through desertification, deforestation and ocean warming, as well as the inability to adapt to climate warming. Humans also aren't immune to the threat. Desertification and rising sea levels threaten human habitats. And when plants and animals are lost to climate change, human food, fuel and income are lost as well.

Destruction of EcosystemsChanging climatic conditions and dramatic increases in carbon dioxide will put our ecosystems to the test, threatening supplies of fresh water, clean air, fuel and energy resources, food, medicine and other matters we depend upon not just for our lifestyles but for our survival.Forecasts of famine, war and death paint a dire picture of climate change on our planet. Scientists are researching the causes of these changes the vulnerability of Earth not to predict the end of days but rather to help us mitigate or reduce changes that may be caused by humans. If we know and understand the problems and take action through adaptation, the use of more energy-efficient and sustainable resources and the adoption of other green ways of living, we may be able to make some impact on the climate change process.

Again…HOW CAN WE ALL HELP TO REDUCE OUR CARBON FOOTPRINT?!

These greenhouse gases don't just stay in one place after they're added to the atmosphere. As air moves around the world, greenhouse gases become globally mixed, which means the concentration of a greenhouse gas like carbon dioxide is roughly the same no matter where you measure it. Even though some countries produce more greenhouse gases than others, emissions from every country contribute to the problem. That's one reason why climate change requires global action.

• Turn it off Turn off lights, televisions, videos, stereos and computers when not in use - they can use 10 to 40% of the power when on standby. Also, unplug chargers as soon as they have finished charging.

• Be exact Use only as much water as you need. • Close it Don't leave fridge doors open for longer

than necessary.

• Use no plastic Use cloth bags when going shopping and avoid buying products which use too much plastic.

• Fan up Instead of using air conditioners in the summer, wear cool clothes, and use a fan.

• Drive less Do your weekly errands in a single trip or pay your bills online. Walk, bike, ride the bus or carpool.

• Optimize your speed You will consume up to 25% less fuel if you drive no more than 50 mi/hr.

• Drive hybrid A hybrid or other fuel-efficient car emits less carbon dioxide. • Replace them Replace your incandescent bulb with a compact fluorescent

light bulb (CFL). CFLs cost 3 to 5 times as much but use less than a third of the power. Also, replace old fridge and other appliances with energy-efficient ones

• Recycle Consume less, and re-use old products.

Effects of habitat loss:DEFORESTATIONThe cutting down of trees causes several ecological effects:1 – Without the trees to absorb the water, much of the minerals (particularly nitrogen) is lost in the soils from the runoff.2- With the loss of plant life, less carbon dioxide is absorbed (through photosynthesis) making higher levels of CO2 in the atmosphere, contributing to global warming!

Net losses of water were 3040% greater in the deforested site than the undisturbed (control) site.

Also, nitrate levels increased 60 times in the outflow of the deforested site.

Restoration ecologists help return degraded ecosystems to a more natural state

• Given enough time, biological communities can recover from many types of disturbances

• Restoration ecology seeks to initiate or speed up the recovery of degraded ecosystems

• Two key strategies are bioremediation and augmentation of ecosystem processes

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Bioremediation

• Bioremediation is the use of living organisms to detoxify ecosystems

• The organisms most often used are prokaryotes, fungi, or plants

• These organisms can take up, and sometimes metabolize, toxic molecules

– For example, the bacterium Shewanella oneidensis can metabolize uranium and other elements to insoluble forms that are less likely to leach into streams and groundwater

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Figure 55.18a

Biological Augmentation

• Biological augmentation uses organisms to add essential materials to a degraded ecosystem

– For example, nitrogen-fixing plants can increase the available nitrogen in soil or adding mycorrhizal fungi can help plants to access nutrients from soil

However, addition of nutrients to an ecosystem does NOT always have a positive ef….

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The addition of large amounts of nutrients to lakes has a wide range of ecological impacts not always for the better! In some areas, sewage runoff containing fertilizers has caused eutrophication of lakes, which can lead to loss of most fish species

EutrophicationThe process by which a body of water acquires a high concentration of nutrients, especially phosphates and nitrates. These typically promote excessive growth of algae which depletes the water of oxygen and nutrients for other organisms.

Eutrophication often comes from runoff, containing phosphorous and nitrogen from fertilized soils & contaminated water .

This has led to the use of phosphate-free detergents!

An algal bloom or a “red tide”

An algal bloom or a “red tide” is a rapid increase or accumulation in the population of algae (typically microscopic) in an aquatic system. These deplete oxygen and nutrients for other organisms to survive! Some algal blooms add toxins to the environment.

BIOMAGNIFICATION

The increasing concentration of a substance, such as a toxic chemical, in the tissues of organisms at successively higher levels in a food chain. As a result of biomagnification, organisms at the top of the food chain generally suffer greater harm from a persistent toxin or pollutant than those at lower levels

The Swiss chemist Paul Hermann Muller was awarded the Nobel Prize in Physiology or Medicine in 1948 "for his discovery of the high efficiency of DDT as a contact poison against several arthropods.“ After the war, DDT was made available for use as an agricultural insecticide, and soon its production and use skyrocketed.

DDT (dichlorodiphenyltrichloroethane) is an organochlorine insecticide which is a colorless, crystalline solid, tasteless and almost odorless chemical compound.

First synthesized in 1874, DDT's insecticidal properties were not discovered until 1939, and it was used with great success in the second half of World War II to control malaria and typhus among civilians and troops.

In 1962, Silent Spring by American biologist Rachel Carson was published. The book catalogued the environmental impacts of the indiscriminate spraying of DDT in the US and questioned the logic of releasing large amounts of chemicals into the environment without fully understanding their effects on ecology or human health.

The book suggested that DDT and other pesticides may cause cancer and that their agricultural use was a threat to wildlife, particularly birds. Its publication was one of the signature events in the birth of the environmental movement, and resulted in a large public outcry that eventually led to DDT being banned in the US in 1972.

Along with the passage of the Endangered Species Act, the US ban on DDT is cited by scientists as a major factor in the comeback of the bald eagle, the national bird of the United States, from near-extinction in the US.