Factors that May Make Species More or Less Prone to Extinction

Javier ChewningVictoria Huertematte

Cristina RiveraPedro 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 I sland of Reunion, Af rica. Written accounts note that it was extremely tame and easy to kill and was used as a source of meat f or the islanders.

The Heath Hen A small wild f owl, was abundant in the eastern U.S. By 1870s the only 50 Heath Hens lef t occupied the tiny island, Martha's Vineyard in Massachusetts, the population grew f rom 50 to 2,000. But fi re, 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 f rom Turkey across southern Asia and most of China, to the Soviet Far East. The Southeast Asian range included peninsular Malaysia, Singapore, Sumatra, J ava 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 J avan tigers, have become extinct since the 1950's. As of 1996, the tiger occurred only in scattered populations f rom I ndia to Vietnam and in Sumatra (I ndonesia), China and the Russian Far East. The tiger is extinct in most of its f ormer 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 wildlif e, covered vast areas of Asia. I n the early 1900's there were in excess of 100,000 tigers in their native Asia, including about 40,00 in I ndia. 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 I ndian 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 f orests, the elimination of natural prey, and the spread of agriculture, there is continuous confl ict 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, I ndia 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 fi ll 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. I t 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. I n I ndia, 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 J ava was attributed to extensive habitat f ragmentation, 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 lif e and domestic livestock. They were also valued as a big game trophy by sport hunters. Some European hunters and I ndian maharajahs each killed hundreds of tigers.

Conservation: One of the lessons learned f rom I ndia'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. I n J anuary 1998, the Tiger Conservation Program of World Wildlif e Fund launched a cattle compensation program in I ndia 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 I ndia by farmers because of loss, or f ears of potential loss of wildlif e (Cat News 1998e). I nnovative 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 buff er 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

• · 1900: 100,000 (Nowell & Jackson 1996)

• · 1920: 100,000 (Nowak & Paradiso 1983) • · 1970: About 5000 (Mountfort 1983) • · 1978: As low as 4000 (Nowak & Paradiso 1983) • · 1978: 5000 - 7500 (Humphrey & Bain 1990) • · 1986: At least 7690 - 7790 (Luoma 1987) • · 1994: 5080 - 7380 (Jackson 1994) • · 1996: 4792 - 7300 (Jackson 1996) • · 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 aff ected 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 f orest and hardwood river bottoms eliminated much of the prime red wolf habitat. The disappearance of the last red wolves f rom 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 DECLI NE: 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)

o First half of the 1900's: Perhaps numbering in the hundreds of thousands (Brownlow 1996)

o 1973: 100 (Brownlow 1996)

o 1980: 0 (Oryx 1989f )

o 1989: 4 (Oryx 1989f )

o 1990: 8 (Ginsberg & Macdonald 1990)

o 1991: At least 10 (Oryx 1991e)

o 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 Wildlif e Fund (WWF): Known worldwide by its panda logo, World Wildlif e Fund is dedicated to protecting the world's wildlif e 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 eff orts 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 f or 40 years.

Turner Endangered Species Fund (TESF): I n response to the endangered species crisis, Ted Turner and his f amily launched in J une 1997 the Turner Endangered Species Fund. This private, non-profi t charity dedicates itself to conserving biodiversity by ensuring the persistence of imperiled species and their habitats. The Turner Endangered Species Fund concentrates its eff orts on carnivores, grasslands, plant-pollinator complexes, and species that historically ranged onto properties owned by Ted Turner. They support the distribution of reliable scientifi c and policy inf ormation on biodiversity conservation and their activities rest upon the principles of conservation biology.

TESF also works closely with state and f ederal 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, f armers, electric utilities, and many other individuals, organizations, and businesses that are directly aff ected 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 f ocus, and its emphasis on grassroots activities have attracted a growing number of major, and geographically diverse industries to support our eff orts.

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 f or the species it was designed to protect and the communities that have to live and work with the law.

National Wildlif e Federation (NWF): The mission of the National Wildlif e Federation is to educate, inspire and assist individuals and organizations of diverse cultures to conserve wildlif e and other natural resources and to protect the Earth's environment in order to achieve a peaceful, equitable and sustainable future. National Wildlif e 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 I nstitute (AWI ): is a non-profi t charitable organization founded in 1951 to reduce the sum total of pain and fear infl icted on animals by humans. Their specific goals are:

Humane treatment of laboratory animals and the development and use of non-animal testing methods.

Preservation of species threatened by extinction and protection for wildlif e in international trade.

Prevention of trade in wild-caught exotic birds, and regulation of transport conditions for all animals.

Reform of cruel treatment of f arm animals, such as intensive confinement in animal f actories. 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

wildlif e populations.

Convention on I nternational Trade in Endangered Species of Wildlif e Fauna and Flora (CI TES): CI TES is an international agreement between governments. I ts 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 eff ort to regulate it requires international cooperation to safeguard certain species f rom over-exploitation. CI TES 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, f ur coats or dried herbs CI TES was draf ted as a result of a resolution adopted in 1963 at a meeting of members of I UCN (The World Conservation Union). The text of the Convention was fi nally agreed at a meeting of representatives of 80 countries in Washington DC., United States of America, on 3 March 1973, and on 1 J uly 1975 CI TES entered in f orce.

I t is important to note that not one specie protected by CI TES has become extinct as a result of trade since the Convention entered into f orce and, f or many years, CI TES 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:• 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.

• 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

• The Giant Panda population has also been affected by hunting and collecting, shifting agriculture, livestock ranching, deforestation, human settlement, trapping.

Details of its endangerment:• 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).

• 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.

• 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 innutritional 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

• 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