These summarised case studies are mostly taken from the Global Species Assessment. They illustrate some of the threats to species, species that have gone extinct, or species that have been brought back from the brink of extinction through effective conservation action.

- Threats
- Extinctions
- Conservation success

Threats

Pushed to the brink of extinction by over-exploitation – the southern right whale

Hunting of the southern right whale began in the 1770s, when whalers moved into the South Atlantic. By 1850, the population had been reduced to less than one-tenth of its original size. Despite this, the southern right whale only received protection in 1935, by which time there may have been as few as 300 individuals left in the Southern Hemisphere. Signs of a recovery were not noticed until the 1970s and by 1997 there were an estimated 7,000 right whales in the Southern Hemisphere. For full story on southern right whales, see the Global Species Assessment (page 120). Visit the Dave Watts Photography site to obtain permission to use this photo.

Over-fishing – a menace to the marine realm

Marine fishes are among the poorest represented groups on the IUCN Red List (only 487 of a potential 15,000 have been assessed to date). Although Red List data are not yet complete enough to infer trends in the overall status of marine fishes, data from marine fish groups that are relatively well assessed (sharks, rays, chimaeras, seahorses, groupers, wrasses) do indicate clearly that exploitation is an important and significant threat to marine species. For example, fishery-dependent and trade-related data for the humphead wrasse (Cheilinus undulates) indicate population declines of more than 50% over the last 10–15 years. For more on declines in marine fish populations, see the Global Species Assessment (pages 61–62; 89–90).

Over-harvesting of turtles and tortoises

Almost all species of tortoises and freshwater turtles in east and Southeast Asia are in serious decline as a result of harvesting for human consumption and medicine. Since 1996, the number of Critically Endangered turtles has increased from 10 to 25, and the number of those Endangered has risen from 28 to 47. This near doubling of the number of seriously threatened turtle species in less than 10 years is almost entirely due to over-use. As populations are disappearing in Southeast Asia, there are disturbing signs that the focus of the harvest will shift to the Indian subcontinent, and perhaps even further afield to the Americas and Africa. In addition, collection for the pet trade has a serious impact on tortoise populations. For more on the decline of turtles and tortoises, see the Global Species Assessment (pages 19-20).

Unintentional poisoning decimates Indian vultures

In South Asia, vultures in the genus Gyps have declined by more than 95% in recent years owing to the toxic effects of a veterinary drug, Diclofenac, which is consumed when the birds feed on carcasses of animals treated with the drug. Diclofenac is widely used in human medicine globally, but was introduced to the veterinary market on the Indian subcontinent during the early 1990s. Vultures have traditionally disposed of animal carcasses, reducing the risk of disease and helping with sanitation. With the vultures gone, carcasses are taking much longer to be disposed of, increasing the risk to human health. Feral dogs are filling the scavenging void, and their growing numbers also increase health and safety risks as they carry rabies. There is an urgent need to control the veterinary use of the drug, and to establish captive breeding populations of the three vulture species concerned. Visit the ARKive website for images of the Gyps here.

Early days in the global assessment of sharks, rays and chimaeras show 18% as threatened

The slow life histories and low population growth rates of chondrichthyans (sharks, skates, rays and chimaeras) limits their capacity to withstand over-fishing and habitat destruction. To date, the Shark Specialist Group of IUCN’s Species Survival Commission has assessed one third of the world’s chondrichthyans (373 out of a total of approximately 1,100 species) and of these, 17.7% are listed as threatened (Critically Endangered, Endangered or Vulnerable), 18.8% Near Threatened, 37.5% Data Deficient and 25.7% Least Concern. For more on declining sharks, rays, and chimaeras, see the Global Species Assessment (pages 21-22), and the Shark Specialist Group.

By-catch – a major threat to many marine species

Sawfishes inhabit coastal tropical, subtropical and warm-temperate regions, often in estuaries and freshwater. Their unique ‘saw’ – a long rostrum studded with ‘teeth’ – makes them extremely vulnerable to capture in nets, and difficult to remove alive. With highly prized fins and ‘saws’, targeting occurs – but most deaths are through by-catch in other fisheries. For more on sawfishes and by-catch, see the Global Species Assessment (page 22).

 Extinction risk exacerbated by climate change

Extreme weather events, which are likely to result from climate change, have been linked with amphibian declines in a few areas. In highland Costa Rica, 20 species of frogs and toads, including the golden toad (Bufo periglenes), declined or disappeared abruptly in 1988, with subsequent sharp declines of survivors in 1994 and 1998. Each of these declines occurred during unusual dry periods when typical spells of cloud-borne mist failed to occur. Andean Ecuador was home to the spectacular jambato toad (Atelopus ignescens), which abruptly disappeared from 47 sites from where it was known in the 1980s, just after the two driest years recorded during 1962-1998. For more information on declines in amphibians and other species linked to climate change, see the Global Species Assessment (pages 37 and 98). Visit the ARKive website for images of the golden toad here.

Extinctions

“Possibly extinct”

The IUCN Red List Programme is developing criteria for identifying Critically Endangered species that may already be Extinct: Critically Endangered (Possibly Extinct) species. For amphibians and birds this has provided a good indication of the number of extinctions that may be confirmed in the not too distant future. In total, 208 species have been identified as Critically Endangered (Possibly Extinct). 122 of these are amphibians, many having disappeared recently. Eighteen bird species are Critically Endangered (Possibly Extinct), including the nukupu'u (Hemignathus lucidus) last seen in Hawaii in 1996 and Spix's macaw (Cyanopsitta spixii), last seen in Brazil in 2000. Incomplete assessments of other groups such as mammals, reptiles, fishes, molluscs and plants account for the remaining Possibly Extinct species. Visit the ARKive website for images of the Spix's macaw here.

Disappearing amphibians

A total of 122 amphibian species are listed as Critically Endangered (Possibly Extinct), and 113 of these may have disappeared since 1980. Most of these took place in Central and South America. Other possible extinctions have been noted in Australia, Indonesia, China, Kenya and Tanzania. Dramatic declines appear to be spreading, with recent reports from Dominica, Spain, and New Zealand. Most of the disappearances happened very suddenly, and it seems increasingly likely that chytridiomycosis (a highly infectious fungal disease), exacerbated by climate change, is the main cause.

The current catastrophic wave of amphibian extinctions is removing major evolutionary lineages. Already, one entire family, the gastric-brooding frogs from Australia (Rheobatrachidae), has been lost, and another, the Darwin’s frogs from Chile and Argentina (Rhinodermatidae) is at severe risk, as are the primitive New Zealand frogs (Leiopelmatidae). Among the larger families, the toads (Bufonidae) have been hit particularly hard, most notably the beautiful harlequin toads (Atelopus species). Amphibian extinctions are happening so rapidly, and so few scientists are monitoring them that it is hard to gain a clear, current picture of their status. But the indications are that this is the most serious wave of all extinctions currently taking place. For more information on amphibian declines and extinctions, see the Global Species Assessment (pages 37-38), and the Global Amphibian Assessment.

Extinction of US freshwater molluscs – an overlooked catastrophe

Freshwater extinctions have been best documented in the United States, where 107 such species are known to have been lost. Molluscs (mussels and snails) in particular have been seriously affected: 78 of the 107 freshwater species extinctions in the US are molluscs. The leading cause for these extinctions is thought to be habitat destruction and alteration due to dam construction, which has turned most large free-flowing rivers in the US into a series of impoundments. However, pollution and invasive alien species (e.g., zebra mussels) have also already affected mollusc populations and continue to threaten many species. For full story on North American freshwater species extinctions, see the Global Species Assessment (page 43).

 The demise of Polynesian Partula snails – not at a snail’s pace

Over the last 30 years, French Polynesia has seen one of the most dramatic examples of extinction caused by an invasive species. Seventy-two percent of the Partula snail species native to the Society Islands have gone extinct as a result of the introduced predatory wolf snail (Euglandina rosea). The wolf snail was originally introduced to Tahiti in 1975 as a biological control agent with the aim of halting the spread of the giant African snail (Achatina fulica). However, it instead developed a taste for the smaller Partulid snails and their rapid decline began. Only five Partula species remain. For the full story on the Polynesian Partula snails and work to conserve the few remaining species there, see the Global Species Assessment (page 93).

The St. Helena olive

The St. Helena olive (Nesiota elliptica) was a small tree that grew on the highest parts of the island’s eastern central ridge. In the 19th century, it became rare, probably as a result of habitat loss, and by 1875 only 12–15 trees were recorded. It was then believed to have become Extinct until a single tree was discovered in August 1977. Sadly, the tree was highly susceptible to fungal infections, which may have been exacerbated by damage sustained during attempts to conserve it. On 11 October 1994, the last wild tree was found dead and the species was classified as “Extinct in the Wild”. The St. Helena olive continued to survive in cultivation, but it proved extremely difficult to propagate. The last remaining seedling showed signs of ill health and in 2003 deteriorated extremely quickly following a dry winter. In December 2003, despite extensive efforts to rejuvenate the species, the St. Helena olive was declared Extinct. For the full story on the demise of the St. Helena olive, see the Global Species Assessment (page 36). Visit the ARKive website for images of the St. Helena olive here.

Conservation success

Re-introductions can be successful, but are not always an option

Currently, there are 36 species of animals and 24 species of plants assessed as Extinct in the Wild. For these species, future re-introduction of captive-bred or artificially propagated individuals to their original habitat is their only chance of recovery. However, this can only be successful if sufficient habitat remains to support the re-introduced populations, and if the factors which caused the initial extinction in the wild have been addressed. The Taiwanese endemic Rhododendron kanehirai, for example, cannot be re-introduced to its native habitat because the site of its only known location was entirely destroyed by the construction of a dam. Conversely, although sufficient habitat remains on Guam to allow the re-introduction of the Guam rail (Gallirallus owstoni) into its native habitat, it will always require protection due to the continued presence of the introduced predatory brown tree snake (Boiga irrelgularis). However, not all re-introduction programmes are doomed to failure. The recent re-introduction of the scimitar-horned oryx (Oryx dammah) to Tunisia has so far run smoothly and once two generations of the re-introduced animals have bred successfully, this species will be downlisted. Other promising re-introductions include the black-footed ferret (Mustela nigripes), the red wolf (Canis rufus), california condor (Gymnogyps californianus), Mallorcan midwife toad (Alytes muletensis) and the St. Helena redwood (Trochetiopsis erythroxylon). For more information on species re-introductions, see the Global Species Assessment (pages 130-133). Visit the ARKive website for images of the scimitar-horned oryx and the red wolf.

Local action – saves globally threatened parrot

Community education and awareness plays an important role in conservation. A good example of this is the case of the Critically Endangered yellow-eared parrot (Ognorhynchus icterotis) and the Vulnerable wax palm (Ceroxylon quindiuense) on which the parrot depends for nesting and roosting. Wax palms are traditionally cut down to adorn processions and churches throughout the Colombian Andes each Palm Sunday. Fundación ProAves has been working with the Catholic Church to support alternatives to cutting down wax palms, in addition to running an intensive environmental awareness campaign nation-wide. ProAves also provided incentives for the creation of an ecological group, "Friends of Nature", who distributed palm and parrot posters, held concerts and theatre productions, and worked on capacity-building of the local police. For further information, see the Global Species Assessment (page 117).

Protected areas provide a critical refuge

Many species are now confined to protected areas and would become Extinct without them, having lost their habitat elsewhere. A typical example is the Critically Endangered pygmy hog (Sus salvanius). Previously, this species had an extensive range in the Himalayan foothills; it is now restricted to the Manas Sanctuary in India.

Although protected areas now cover 12% of the globe, 1,486 “gap” species (species not yet covered by any protected area) exist, including 846 threatened mammals, birds, amphibians, tortoises and freshwater turtles. This shows that the existing global protected area network is not yet complete and needs to be developed further. For more information on protected areas and site-based conservation actions, see the Global Species Assessment (pages 121–129). Visit the ARKive website for images of the pygmy hog here.

Habitat restoration to safeguard threatened island bird – the Rarotonga monarch

The Rarotonga monarch (Pomarea dimidiate) is a bird which is endemic to the Pacific island of Rarotonga in the Cook Islands. Although common in the mid-1800s, the species rapidly declined after the arrival of predators, such as the black rat (Rattus rattus). A few birds were recorded in the early 1900s, but the species was not seen again until 1973. A survey in 1987 estimated the population at 38 individuals, but declining. In 1988 a recovery plan was implemented, involving intensive control of predators, particularly black rats. This reduced adult mortality and increased nesting success and by 2000, the population had reached 221 individuals. Subsequently, 30 young birds were transferred to the rat-free island of Atiu in an apparently successful attempt to establish a second 'insurance' population. For more information on the Raratonga monarch, see the Global Species Assessment (page 124).

Active habitat management to save a threatened species - Kirtland’s warbler

Kirtland’s warbler (Dendroica kirtlandii) has very specific requirements for breeding habitat (stands of young (5–23 years old) jack pine growing on well-drained soils). This confined it to a small area in Michigan’s Lower Peninsula, US. After the population declined from counts of 502 singing males in 1961 to 201 in 1971, a programme was implemented to increase the area of suitable nesting habitat and control the brown-headed cowbird (Molothrus ater), which lays its eggs in the warbler’s nest to improve its own nesting success. This resulted in the population recovering to over 600 birds in 2000. For the full story on Kirtland’s warbler, see the Global Species Assessment (page 123).

Successful re-introductions – the southern white rhinoceros

Formerly widespread in southern Africa, the southern white rhinoceros (Ceratotherium simum simum) was reduced to only 20-50 rhinos by the end of the 19th century. Afforded protection by the Umfolozi Game Reserve, numbers began to increase, and the population grew to at least 700 by 1960. Shortly after, it became possible and necessary to capture animals for translocation to other reserves within their former range, and “Operation Rhino” was launched. Over the next 30 years, more than 4,500 white rhinos were moved to other reserves and to conservation authorities in former range States, and since 1986 more than 1,000 have been sold to the private sector. By 2002, the numbers of free-ranging southern white rhinos in Africa had increased to over 11,500 distributed between 250 populations in seven countries. A quarter of Africa’s southern white rhino population is privately owned and this plays an important role in the economic viability of the wildlife industry. For the full story on the southern white rhino, see the Global Species Assessment (page 125).

Harvest management – sustainable use of the whiskery shark fishery

The whiskery shark (Furgaleus mack) has been targeted by commercial fisheries in Western Australia since the 1940s. In the late 1970s and early 1980s catches rose dramatically and the whiskery shark population plummeted to approximately 30% of original levels. In response to this, Western Australia introduced sustainable use management measures. Since then, whiskery shark abundance has remained relatively stable at 30-40% of original levels over a period of 12 years (approximately two generations). To ensure the continued recovery of this stock, two-month closures of significant portions of the species’ range within the target fishery are being considered to further reduce adult mortality and boost numbers. Continued fishery management has maintained whiskery shark abundance at this lower level and should generate a gradual recovery. For more on recovery of the whiskery shark population, see the Global Species Assessment (page 134).

The black robin (Petroica traversi) is found only on the Chatham Islands, New Zealand, and is one of the most remarkable conservation success stories. Following human settlement of the islands, black robins declined rapidly as their forest habitat was lost and degraded, and they were eaten by introduced rats and cats. In 1976, when the population had declined to just seven birds, the remaining individuals were relocated to Mangere Island, where 120,000 trees had been planted to provide suitable habitat. Nevertheless, by 1980, numbers had fallen to five birds. Nest protection, supplementary feeding, and a breeding programme were then established, and the population began to recover steadily. Individuals were later introduced to South East Island, and by 1989 the population had topped 100 individuals. The population continued to rise throughout the 1990s and it is now stable at around 250 birds. For the full story on the recovery of the black robin, see the Global Species Assessment (page 133). Visit the ARKive website for images of the black robin here.

Captive breeding successfully rebuilds the Mallorcan midwife toad population

The Mallorcan midwife toad (Alytes muletensis) is found only on the island of Mallorca, in the Balearic Islands of Spain. Fossil evidence suggests that the toad was probably widespread over much of Mallorca until about 2,000 years ago, when it declined steeply following the introduction of the predatory viperine snake (Natrix maura) and the competitive green frog (Rana perezi). More recently, further declines occurred due to habitat loss through over-extraction of water from the streams in which it breeds and it was listed as Critically Endangered. In 1985, a captive-breeding programme was initiated for the toad and the first reintroductions took place in 1989. Conservation measures were undertaken to help the recovery of the existing wild populations, and a combination of re-introduction and habitat creation and management has resulted in an increase in both the range and number of populations of the species. While the recovery programme will probably need to be continued indefinitely, the conservation status of the species has now improved so much that it has been downlisted to Vulnerable. For the full story on the Mallorcan midwife toad, see the Global Species Assessment (page 131). Visit the ARKive website for images of the Mallorcan midwife toad here.

The black-footed ferret (Mustela nigripes), one of North America’s rarest mammals, depends on an endangered ecosystem for survival. Prairie dogs, the ferrets’ main prey and an important species for maintaining the ecosystem, were decimated by prairie dog control campaigns. In 1985, the last known free-ranging black-footed ferret population collapsed due to an outbreak of canine distemper, combined with an epidemic of sylvatic plague, and the species was considered Extinct in the Wild. In an effort to save the species, the remaining 18 free-ranging ferrets were brought into captivity. Through effective captive breeding and re-introduction programmes, black-footed ferrets are making a come-back. Since 1987, almost 5,000 kits have been born in captivity and more than 1,800 ferrets have been released in the wild steppes of North America. The Red List still lists the species as Extinct in the Wild, however it is expected to be reassessed in the near future. For the full black-footed ferret story, see the Global Species Assessment (page 132). Visit the ARKive website for images of the black-footed ferret here.

Control of introduced predators to secure successful re-introduction of the great spotted kiwi

The great spotted kiwi (Apteryx haastii) has unfortunately disappeared from large parts of its former range in New Zealand, primarily because of habitat loss and predation by introduced animals, notably rats, feral cats, stoats and weasels. An important step to reverse this decline and return the species to its former range has been taken at the Nelson Lakes National Park, North Island as part of the Rotoiti Nature Recovery Project.

A programme of predator control has been developed to cover 5,000 hectares of mixed honeydew beech forest in the reserve, which supported great spotted kiwis in historical times. Conditions are now considered to be suitable and nine captured wild birds were released in May this year, as the first part of the re-introduction programme. It is hoped that they will establish a core breeding population and the success with other threatened birds, such as the kaka, in the area indicates that the project has every chance of being successful. For further information, please contact Paul Gasson at pgasson@doc.govt.nz.

Re-introduction of the swift fox – an act of ecosystem and cultural restoration

The swift fox (Vulpes velox) is the smallest North American fox and is unique to the plains of North America. It is an important spiritual and cultural icon for the indigenous tribes that share its historic range, but has declined dramatically because of persecution by farmers and ranchers. It was declared extinct in Canada in 1978 and by 1993 it had been reduced to only 10% of its original range in the USA.

Today, the outlook for the swift fox is a lot brighter, thanks to the Cochrane Ecological Institute, which began a swift fox breeding programme in 1972, producing animals solely for re-introduction. Swift foxes have already been re-introduced into Canada where the wild population is now estimated to be over 655 animals. Thanks to this initiative, it has been downlisted in Canada from Extinct to Endangered.

In 1998, the Blackfoot nation of Montana, USA, requested a re-introduction programme on their tribal lands because they consider the return of the swift fox to be an integral part of their spiritual and cultural identity. The swift fox had been exterminated from Montana in the 1950s. A wild breeding population has now been successfully established, restoring not only a key species to the prairie ecosystem, but has been an important part of indigenous culture.

Building on the positive results of the Blackfoot introductions, the Blood tribe of south-western Alberta, Canada, who are members of the Blackfoot confederacy, have also requested the re-introduction of the swift fox to their land and the first releases took place on 11 September this year. For further information, please contact Clio Smeeton at cei@nucleus.com.

Going up? Going down? The Vulnerable humpback whales of eastern Australia

Having their population severely depleted during the late 1950s and early 1960s to a level where their recovery seemed more a dream than a reality, the humpback whales (Megaptera novaeangliae) of eastern Australia have slowly crept back to a level of at least growing hope for their successful turnaround from potential extinction. Of the six populations in the southern hemisphere that migrate annually to the tropics from Antarctica to give birth, PhD researcher Dan Burns and Associate Professor Peter Harrison, Director of Southern Cross University’s Whale Research Centre (SCUWRC) are particularly focused on the recovery of Group V that migrate along the east coast of Australia.

“This population is thought originally to number somewhere between 15,000 – 30,000 individuals, but because of intense whaling pressure, especially south of New Zealand in 1959/61 where at least 25,000 whales were killed for their meat and other body products, numbers fell to only a few hundred in the early 1960s,” says Burns. In Byron Bay, Australia’s most easterly mainland point and location of a whaling station that operated 1954-1962, the Cape Byron Whale Research Project (CBWRP) has been working for 10 years on these animals, contributing a significant amount of knowledge in the jigsaw puzzle of recovery efforts by various groups along the east coast. Photographic identification and genetic assessment are the core of the project, and have helped establish that the population is about 5,000 - 6000.

Listed as Vulnerable (VU) on the IUCN Red List of Threatened Species™, according to Associate Professor Harrison, it is crucial to recognise that the Group V humpbacks are by no means recovered completely. “The establishment of the SCUWRC means projects such as the CBWRP can continue research into these globally threatened species, and the picture is becoming more precise about the status of this population. Threats facing this population may not be as immediately intense or drastic as they were in the 1950s and 60s, but other threats such as entanglement in nets, increased vessel traffic, and boat strike are still very real, as is continuing pressure from some nations to resume commercial whaling – the future looks good for these whales, but is by no means secure.”

For further information, please contact: Multimedia Environment (Andrew Nichols) and Southern Cross University Whale Research Centre (Associate Professor Peter Harrison, PhD researcher Dan Burns), Southern Cross University Whale Research Centre; Tel: +61 (0)266203815; Email: dburns12@scu.edu.au