Download Factors that May Make Species More or Less Prone to

Factors that May Make
Species More or Less
Prone to Extinction
Javier Chewning
Victoria Huertematte
Cristina Rivera
Pedro Icaza
Sebastian Icaza
An “endangered” specie is one that is in danger of extinction throughout all or a
significant portion of its range. A “threatened” species is one that is likely
to become endangered in the foreseeable future.
Factors that make species more prone to extinction:
• the present or threatened destruction, modification, or curtailment of its
habitat or range (habitat loss caused by human development)
• over utilization for commercial, recreational, scientific, or educational
purposes
• disease or predation
• the inadequacy of existing regulatory mechanisms
• pesticides can runoff or drift, which may harm the environment and wildlife.
• the multi-billion dollar illegal trade in wildlife driven by consumer demand
for animals and plants used as luxury foods, medicines, trophies and tourist
souvenirs.
• species displacement, competition for food resources, and hunting
• pollution
• deaths caused by the propellers of outboard motors
Species that have become extinct and the causes:
Blue Pike
The blue pike was an endemic fish of the Great Lakes region in the
United States and Canada. The fishing industry, increased habitat
degradation, introduction of non-native species and pollution caused
the population to crash in 1958. The species lingered on until it
became extinct in 1970.
Bourbon Crested Starling
This Starling once inhabited the Island of Reunion, Africa. Written
accounts note that it was extremely tame and easy to kill and was
used as a source of meat for the islanders.
 The Heath Hen
A small wild fowl, was abundant in the eastern U.S. By 1870s the only
50 Heath Hens left occupied the tiny island, Martha's Vineyard in
Massachusetts, the population grew from 50 to 2,000. But fire,
predatory birds, and disease wiped out most of the remaining
species. The last living heath hen, the final survivor of his species,
was seen on March 11, 1932.
Endangered Species (Case Studies)
Tiger (panthera tigris)
Range & Background information:
The tiger formerly occurred from Turkey across southern Asia and most of China, to
the Soviet Far East. The Southeast Asian range included peninsular Malaysia,
Singapore, Sumatra, Java and Bali. But the abundance and distribution of tigers has
diminished substantially since the beginning of the 20th century. 3 of the 8
subspecies of tiger, the Bali, Caspian and Javan tigers, have become extinct since
the 1950's. As of 1996, the tiger occurred only in scattered populations from India
to Vietnam and in Sumatra (Indonesia), China and the Russian Far East. The tiger is
extinct in most of its former range.
The range of the tiger has undergone a drastic reduction. Tigers were plentiful in
the past when tropical rain forests and grasslands, full of wildlife, covered vast
areas of Asia. In the early 1900's there were in excess of 100,000 tigers in their
native Asia, including about 40,00 in India. By the early 1970's the world population
of these cats had been reduced to as few as 4,000 individuals. Fossil evidence
suggests that tigers evolved in Siberia, migrating to the tropical lands of southern
Asia and the Indian subcontinent, passing north of the Tibetan plateau to the
Caspian region and eastern Turkey.
Threats/Reasons for Decline:
Perhaps the greatest threat to the survival of the tiger is destruction of its habitat. With the
expansion of human populations, the logging of forests, the elimination of natural prey, and the
spread of agriculture, there is continuous conflict between humans and the tiger.
Commercial poaching is mostly due to the use of tiger parts in traditional healing remedies has
been traced back to more than 1,000 years in Chinese culture. The practices have now spread to
Korea, japan, India and other areas where significant Asian populations exist. Renewed interest in
traditional cures, particularly among the Asian cultures, has accelerated consumption of tiger
parts and poaching to fill the demand for this trade has pushed three of the remaining species of
tiger close to extinction. Nearly every part of the tiger has been reported to have healing
properties by Chinese medical practitioners and in Chinese folklore. It has been estimated that
an entire tiger, when being utilized in traditional medicines, is valued in excess of $20,000 at the
retail level. The Amur tiger in Russia has come under increased poaching pressure in recent years
due to the political and economic changes that have occurred subsequent to the breakup of the
Soviet Union. In India, thousands of villagers enter forests around their homes, including tiger
reserves, to shoot and trap the tigers' prey. This can reduce the prey densities to levels below
what is needed to support viable tiger populations. The extirpation of tigers on Bali and Java was
attributed to extensive habitat fragmentation, widespread loss of critical ungulate prey through
disease and direct mortality by man, partly as a result of civil unrest in the 1960's (armed groups
seeking the sanctuary provided by tiger reserves killed the tigers) (Seidensticker 1986).
More so in the past than at present, tigers were killed because they were considered to be a
threat to human life and domestic livestock. They were also valued as a big game trophy by sport
hunters. Some European hunters and Indian maharajahs each killed hundreds of tigers.
Conservation:
One of the lessons learned from India's Project Tiger was that the management goals of
protected areas will not be realized unless the needs of local people are taken into account.
In January 1998, the Tiger Conservation Program of World Wildlife Fund launched a cattle
compensation program in India to counter a major threat to the Bengal tiger - poisoning of
tigers that kill cattle. Up to the end of September, not a single tiger had been reported
poisoned in the states of Uttar Pradesh, Bihar and Andhra Pradesh where the program is in
operation. (Aziz 1998) This is significant because increased numbers of tigers and leopards
were being poisoned in India by farmers because of loss, or fears of potential loss of
wildlife (Cat News 1998e).
Innovative methods have been used to reduce the number of people killed by tigers in the
Sundarbans forest reserve in Bangladesh, thereby reducing the retaliation against tigers.
Woodcutters and honey collectors who entered the forest ran the risk of being killed by
one of the estimated 250 tigers in the area. Measures to reduce the human kill have
included alternative water and food for the tigers (including farm-bred wild pigs released
in the buffer zone), removal of known man-eaters, reduction of permits for collecting in
high-risk areas (e.g. near tiger dens), the use of human face masks on the back of the head,
and aversive conditioning of the tigers by electrified dummies. The measures are
apparently successful as fewer people were killed, although the number of people entering
the reserve doubled between 1983 and 1985. (Caughley & Gunn 1996)
World Population
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1900: 100,000 (Nowell & Jackson 1996)
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1920: 100,000 (Nowak & Paradiso 1983)
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1970: About 5000 (Mountfort 1983)
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1978: As low as 4000 (Nowak & Paradiso 1983)
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1978: 5000 - 7500 (Humphrey & Bain 1990)
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1986: At least 7690 - 7790 (Luoma 1987)
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1994: 5080 - 7380 (Jackson 1994)
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1996: 4792 - 7300 (Jackson 1996)
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1998: 5166 - 7436 (Jackson 1998)
Current range of the tiger as of1998: Occurs in Bangladesh,
Bhutan, Cambodia, China, India, Indonesia (Sumatra), Laos,
Malaysia, Myanmar, Nepal, North Korea, Russia, Thailand,
and Vietnam. (Jackson 1998)
Tiger (Panthera tigris)
Source: http://www.primenet.com/~brendel/tiger.html
Red Wolf (Canis Rufus)
RANGE AND POPULATION LEVEL: The red wolf was once found throughout the
southeastern United States, from the Atlantic coast to central Texas and from the
Gulf Coast to central Missouri and southern Illinois. Between the period of 19OO to
192O, red wolves were extirpated from most of the eastern portion of their range. A
small number persisted in the wild in southeastern Texas and southwestern Louisiana
until the late 197Os. By 198O, the species was determined to be extinct in the wild.
The present red wolf population of at least 249 animals exists primarily in captivity. Two
hundred (2OO) animals are located in 22 captive breeding facilities in the United
States. The U.S. Fish and Wildlife Service has a major captive breeding project at
Graham, Washington. This project is administered by contract with the Point Defiance
Zoo in Tacoma, Washington. To date, there are 26 to 3O adult and yearling red wolves
in the wild at the Fish and Wildlife Service's Alligator River National Wildlife Refuge
in North Carolina; there are 16 animals in the wild at the Great Smoky Mountains
National Park in Tennessee. Also, there are seven animals in the wild on three islands
managed as propagation projects.
HABITAT: The last red wolves were found in coastal prairie and marsh habitat because
this was the last area in which the animals were allowed to remain. Any habitat area in
the southeastern United States of sufficient size, which provides adequate food,
water, and the basic cover requirement of heavy vegetation, should be suitable habitat
for the red wolf. Telemetry studies indicate that red wolf home range requirements
vary from about 25 to 5O square miles.
REASONS FOR CURRENT STATUS: Expanding human populations and extensive land
clearing initially affected the red wolf in two ways. First and probably foremost, these
animals, along with other large predators, were killed in great numbers. Second, the
extensive clearing of forest and hardwood river bottoms eliminated much of the prime red
wolf habitat. The disappearance of the last red wolves from the wild is attributed to two
factors: habitat changes which favored expansion of the historic coyote range into red
wolf territory, and the local breakdown of red wolf social structure (caused by extensive
trapping, poisoning, and shooting). The resulting situation of unmated red wolves in close
proximity to coyotes apparently encouraged interbreeding. Competition with the more
adaptable coyote and parasitic infections such as mange, hookworms, and heartworms, are
of secondary importance in the final decline of the species.
THREATS/REASONS FOR DECLINE:
Reasons for its decline included heavy hunting, poisoning and trapping (because it was
perceived as a threat to livestock, and possibly to people), habitat disruption, and
competition and hybridization with the coyote.
Population Estimates:

WORLD (USA)
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First half of the 1900's: Perhaps numbering in
the hundreds of thousands (Brownlow 1996)
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1973: 100 (Brownlow 1996)
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1980: 0 (Oryx 1989f)
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1989: 4 (Oryx 1989f)
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1990: 8 (Ginsberg & Macdonald 1990)
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1991: At least 10 (Oryx 1991e)
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1993: 46 - 60 (Brownlow 1996)
Red Wolf (Canis Rufus)
(Source: http://www.nczooredwolf.org/)
Endangered Species Organizations (Groups organized
to help the prevention of extinction of animals)
World Wildlife Fund (WWF): Known worldwide by its
panda logo, World Wildlife Fund is dedicated to
protecting the world's wildlife and wild lands. The largest
privately
supported
international
conservation
organization in the world; WWF has more than 1 million
members in the U.S. alone. Since its inception in 1961,
WWF has invested in over 13,100 projects in 157
countries. WWF directs its conservation efforts toward
three global goals: protecting endangered spaces, saving
endangered species and addressing global threats. From
working to save the giant panda, tiger, and rhino to helping
establish and manage parks and reserves worldwide, WWF
has been a conservation leader for 40 years.
Turner Endangered Species Fund (TESF): In response to the endangered
species crisis, Ted Turner and his family launched in June 1997 the Turner
Endangered Species Fund. This private, non-profit charity dedicates itself
to conserving biodiversity by ensuring the persistence of imperiled species
and their habitats. The Turner Endangered Species Fund concentrates its
efforts on carnivores, grasslands, plant-pollinator complexes, and species
that historically ranged onto properties owned by Ted Turner. They support
the distribution of reliable scientific and policy information on biodiversity
conservation and their activities rest upon the principles of conservation
biology.
TESF also works closely with state and federal agencies, universities,
and private organizations. They operate on the belief that many minds
wrapped around a problem will build a certain route to success. Whether
endeavoring to manage an existing population or restore an extinct one, their
goal is population persistence with little or no human intervention. TESF
concentrates on the belief that self-sustaining populations of native species
indicate that the landscapes are healthy or at least recovering.
National Endangered Species Act Reform Coalition (NESARC): is the United
States’ only broad-based, national coalition dedicated solely to achieving
legislative improvements to the Endangered Species Act. The Coalition includes
rural irrigators, municipalities, farmers, electric utilities, and many other
individuals, organizations, and businesses that are directly affected by the ESA.
Since its inception in 1991, NESARC consistently has proven that it is possible to
carve out a balanced middle-ground on the issue of ESA reform – an issue that
has long been characterized by extremists on all sides. The diverse membership
of the Coalition, its single-issue focus, and its emphasis on grassroots activities
have attracted a growing number of major, and geographically diverse industries
to support our efforts.
Their strong advocacy program has been instrumental in pushing regulators
to improve how it implements the Act. They supported and worked with
numerous Members of Congress – of both parties – as they have developed their
proposals to improve the Act.
We seek an open debate so that the ESA will work better both for the species it
was designed to protect and the communities that have to live and work with the
law.
National Wildlife Federation (NWF): The mission of the National Wildlife Federation is to educate,
inspire and assist individuals and organizations of diverse cultures to conserve wildlife and other
natural resources and to protect the Earth's environment in order to achieve a peaceful, equitable
and sustainable future. National Wildlife Federation's main goal is to raise awareness and involve
people of all ages in their fight to conserve and protect the environment.
The Animal Welfare Institute (AWI): is a non-profit charitable organization founded in 1951 to
reduce the sum total of pain and fear inflicted on animals by humans.
Their specific goals are:
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Humane treatment of laboratory animals and the development and use of nonanimal testing methods.
Preservation of species threatened by extinction and protection for wildlife
in international trade.
Prevention of trade in wild-caught exotic birds, and regulation of transport
conditions for all animals.
Reform of cruel treatment of farm animals, such as intensive confinement in
animal factories. AWI has been a leading opponent of cruel slaughter methods
since the 1950s.
Regulation of transport conditions for all animals.
Encouragement of humane science teaching and prevention of painful
experiments on animals by high school students.
Ban on steel jaw leg hold traps and reform of other cruel methods for controlling
wildlife populations.
Convention on International Trade in Endangered Species of Wildlife Fauna and
Flora (CITES): CITES is an international agreement between governments. Its aim is
to ensure that international trade in specimens of wild animals and plants does not
threaten their survival.
Because the trade in wild animals and plants crosses borders between
countries, the effort to regulate it requires international cooperation to safeguard
certain species from over-exploitation. CITES was conceived in the spirit of such
cooperation. Today, it accords varying degrees of protection to more than 30,000
species of animals and plants, whether they are traded as live specimens, fur coats
or dried herbs
CITES was drafted as a result of a resolution adopted in 1963 at a meeting of
members of IUCN (The World Conservation Union). The text of the Convention was
finally agreed at a meeting of representatives of 80 countries in Washington DC.,
United States of America, on 3 March 1973, and on 1 July 1975 CITES entered in
force.
It is important to note that not one specie protected by CITES has become
extinct as a result of trade since the Convention entered into force and, for many
years, CITES has been among the largest conservation agreements in existence,
with now over 150 Parties.
The Giant Panda (Ailuropoda melanoleuca)
The Giant Panda bear is found only in China and restricted to definite habitats. The Giant
Panda lives in Bamboo forests, temperate broadleaf forests, and temperate mixed
forests. It has been placed in the Endangered category for some time now, and even
though several organizations have attempted to restore this species to a Low Risk
category it doesn’t seem to help improve its situation. The Giant Panda is one of the
hardest mammals to bring back to a stable existence for the following reasons:
Causes for endangerment:
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Two may be born, but usually only one survives. They require great care by the
mothers, and losses of the young are a serious problem in recovery and management of
these endangered animals.
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The feeding habits of the giant panda are another serious problem in recovery and
management, since they feed almost exclusively on bamboo, which is not highly
nutritious. They have to spend 16 to 24 hours feeding each day. Also, bamboo species
flower periodically en masse, and die shortly afterwards, which sometimes leads to
starvation. The giant panda's broken-up range has created six isolated populations,
with the total number in the wild estimated at about 1,500. Only very intense
management and care will assure the survival of the species, but recent efforts have
at best been barely adequate
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The Giant Panda population has also been affected by hunting and collecting, shifting
agriculture, livestock ranching, deforestation, human settlement, trapping.
Details of its endangerment:
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The extent of the Giant Panda bear’s area of occupancy is less than 500km2, and the
locations at which they inhabit are greatly fragmented; basically there are no more
than five locations where Giant Panda bears are known to exist (in the wild).
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It is predicted that the area, extent and/or quality of the Giant Panda’s habitat will
continue to decline, as well as its area of occupancy and its territorial areas.
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The population of pandas of 1500 matured individuals, is expected to continue
declining. This is due mainly to the above mentioned facts as well as because of the
large population fragmentation.
Humans involved with Giant Panda conservation have attempted to increase the population
mainly by recruitment, reproduction in safe isolated habitats, and by conserving the
panda’s natural habitat. The main reason that these methods are so unsuccessful is
because:
1) Panda’s are animals that base their diet almost entirely on Bamboo, which is low in
nutritional content, and which demands the panda to eat between 16 to 24 hours a day. Any
scarcity of bamboo could cause starvation easily.
2) Newborn pandas require the full dedication of parents (mother), and with one out of
each two newborn dying, any change in the panda’s environment will make it even harder for
the adult panda to feed and at the same time take care of the cub.
3) Inhabitants around pandas are not all educated and some trap the pandas and either
poach them or sent them to places where they will be caged attractions.
4) There is a great amount of deforestation/destruction of the panda habitat, caused by
overpopulation and agriculture.
5) Poaching for the high priced Panda furs, which can even range from $100,000 to
$200,000!
The Giant Panda (Ailuropoda melanoleuca)
(Source:www.giantpandabear.com)
Bibliography
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www.awionline.org
www.tesf.org
www.nesarc.org
www.ewt.org.za
www.cites.org
http://www.animalinfo.org/species/carnivor/panttigr.htm
http://www.primenet.com/~brendel/tiger.html
http://www.nczooredwolf.org/
http://eelink.net/EndSpp/
http://www.nceet.snre.umich.edu/EndSpp/Endangered.html
http://www.eswr.com/
http://www.stopextinction.org/org/members.html
http://www.endangeredspecie.com