Environmental Engineering Reference
In-Depth Information
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Habitat alteration
results from any human activity that changes an ecosystem. Deforestation, farming,
mining, development, and dams are examples of activities that affect habitats. Habitat alteration is the
largest contributor to biodiversity loss and population declines.
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Pollution
can affect the water, air, and soil, all of which have an impact on not only the local ecosystem
and its organisms but also those in distant areas as well because pollution can be transported far from its
source. Pollution also has a detrimental effect on human health (see Chapter 6).
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Overharvesting
results from hunting and fishing species beyond their ability to recover the numbers of
their population. Species are overharvested for food and for economic benefit. Poaching is still an issue
in some regions of the world, where animals are hunted for their uniqueness (such as for elephant tusks
and tiger claws) despite laws to protect them.
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Climate alteration
is occurring partly because of the excessive burning of fossil fuels, which is increas-
ing global temperatures, altering weather patterns, and increasing dramatic weather, ultimately changing
the climate globally for species of all kinds.
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Invasive species
are nonnative organisms introduced to an area by humans. These species are so numer-
ous and widespread that it's sometimes difficult to distinguish between a native and invasive species in
an area. When a species is brought into a new area, most often it will not survive. In the case of invasive
species though, they are able to proliferate in a new environment because of a lack of predators and dis-
ease as well as the availability of a useable food source. Well-known examples of successful invasive
species include zebra mussels, European starlings, Asian long-horned beetles, and cheatgrass. Because
of the global economy and ease with which goods are transported throughout the world, invasive species
are continually being introduced and are an ongoing problem.
For more information on biodiversity loss, see Chapter 7.
Conservation
Conservation biology
studies the environment and biodiversity in an effort to protect species and their habit-
ats. Through these studies, solutions are developed to address habitat loss and species loss.
People are trying to protect and conserve our natural world in many ways. Nonprofit organizations, communit-
ies, and individuals bring awareness and take initiative to protect habitats and wildlife, and laws and policies
are put in place to support conservation efforts.
Many laws and initiatives have been established to support conservation efforts on local, regional, national,
and global scales. For example, in the United States the
Endangered Species Act
(ESA) does not allow gov-
ernments or private citizens to perform actions that would affect endangered species and their habitats. Interna-
tionally, the
Convention on International Trade in Endangered Species of Wild Fauna and Flora
(CITES)
bans the transporting of body parts of endangered species internationally.
Extinction
Without human efforts to conserve and protect the environment, the reality of extinction can come to fruition.
Throughout Earth's history, most species have disappeared over time and gone
extinct.
On average, species
spend between 1 million and 10 million years on this planet, depending on a variety of factors. Because the
process of natural selection doesn't happen rapidly—it takes a multitude of generations to occur—if an envir-
onmental change occurs abruptly, species do not have time to adapt and may go extinct. Environmental change
can take place for many reasons, such as a rise in sea level, climate fluctuations, arrival of invasive species,
and natural disasters.
