Conservation

The current rate of species extinction is 100-1,000 times the natural background rate — the planet is in its sixth mass extinction, this time human-caused. The 2019 IPBES Global Assessment estimated that around 1 million species face extinction within decades.

The major drivers (sometimes summarised by the mnemonic HIPPO or HIPPCO):

(1) Habitat loss and degradation (the largest driver).

• Deforestation for agriculture, ranching and timber — 10 million hectares lost annually.
• Urbanisation and infrastructure (roads, dams).
• Wetland drainage for agriculture.
• Habitat fragmentation — even where habitat remains, dividing it into small patches isolates populations and reduces effective population size.

(2) Invasive (alien) species.

• Non-native species introduced deliberately or accidentally (in ballast water, on imported timber, as pets) outcompete or prey on natives.
• Particularly devastating on islands: rats and cats have wiped out countless island bird species. New Zealand's flightless birds (kakapo, takahe) were decimated by introduced rats, stoats and possums.
• Cane toads introduced to Australia for pest control are themselves now a major invasive species.
• Grey squirrels introduced to the UK have largely replaced native red squirrels.

(3) Pollution.

• Chemical pollution: pesticides (DDT bioaccumulation famously thinned eggshells of birds of prey), fertiliser run-off causing eutrophication, heavy metals, pharmaceuticals in waterways.
• Plastic pollution: 8+ million tonnes enter oceans annually; entangles and is ingested by marine wildlife.
• Light and noise pollution: disrupts nocturnal animals' behaviour.
• Air pollution: acid rain damages forests and lakes.

(4) Population growth and overexploitation.

• Overfishing: a third of global fish stocks are overfished. Iconic example — collapse of North Atlantic cod stocks in the 1990s, still not recovered.
• Hunting and poaching: ivory poaching has reduced African elephant populations; tiger and rhino populations are crushed by demand from black markets.
• Bushmeat hunting threatens large mammals in central Africa.
• Overcollection for the pet trade (parrots, reptiles, ornamental fish).

(5) Climate change.

• Rising temperatures shift species ranges; cold-adapted species lose their habitat (polar bears, mountain species).
• Coral bleaching: warm seas eject symbiotic algae, killing coral reefs (Great Barrier Reef has lost ~50% of its coral cover since 1995).
• Phenological mismatches: spring events (flowering, breeding) shift, decoupling pollinator-plant and predator-prey timing.
• Ocean acidification from CO₂ absorption threatens shell-forming organisms.

(6) Introduced diseases.

• Chytrid fungus (Batrachochytrium) has devastated amphibian populations globally, contributing to dozens of extinctions.
• White-nose syndrome has killed millions of North American bats.
• Avian malaria introduced by humans wiped out many Hawaiian birds.

These drivers act synergistically — habitat loss makes populations small and isolated, increasing vulnerability to climate change, disease and invasive species.

In-situ conservation (Latin "in place") protects species in their natural habitats. This is the gold-standard approach: it maintains complete ecosystems, allows natural selection to continue, and supports large populations with full genetic diversity.

Main methods.

(1) National parks and nature reserves.

Large protected areas where habitat conversion (logging, mining, agriculture, settlement) is restricted. Public access regulated. Examples:

• Serengeti National Park (Tanzania, 14,750 km²) — savannah ecosystem with annual migration of 1.5 million wildebeest.
• Yellowstone National Park (USA) — first national park (1872); reintroduced wolves transformed the ecosystem.
• Galapagos National Park (Ecuador) — protects the Galapagos archipelago and its endemic species.
• Great Smoky Mountains National Park (USA) — most-visited US park.

(2) Marine Protected Areas (MPAs).

Sections of ocean where fishing, mining and development are restricted to allow marine biodiversity to recover. Examples:

• Great Barrier Reef Marine Park (Australia) — world's largest MPA.
• Galapagos Marine Reserve.
• Studies show fish biomass in well-enforced MPAs can be 5-10× higher than surrounding fished areas.

(3) Sites of Special Scientific Interest (SSSIs).

UK designation for sites of biological or geological importance. Land owners must follow management plans to maintain the special features (e.g. preserving a chalk grassland's rare orchids).

(4) Agri-environment schemes.

Payments to farmers to maintain features beneficial to biodiversity — hedgerows, wildflower margins, ponds, ungrazed buffer strips. Examples: UK Environmental Stewardship; EU agri-environment payments under the Common Agricultural Policy.

(5) Community conservancies and indigenous-protected areas.

Land managed by local or indigenous communities for biodiversity conservation, often combining conservation with traditional resource use. Examples: Maasai Mara conservancies in Kenya; indigenous-managed lands in the Amazon basin.

Advantages of in-situ.

• Maintains complete ecosystems — species, habitat, and ecological interactions all together.
• Natural selection continues — populations remain adapted to their environment.
• Can sustain large populations with full genetic diversity.
• Most cost-effective per species protected (one park protects thousands of species).
• Supports ecosystem services simultaneously (carbon storage, water filtration, climate regulation).

Disadvantages of in-situ.

• Vulnerable to external threats that don't respect park boundaries: climate change, pollution, invasive species.
• Poaching remains a problem despite ranger patrols, especially for high-value species (ivory, rhino horn).
• May be insufficient for critically endangered species whose populations are already too small to recover, or whose habitat is degraded.
• Conflicts with local communities over land use (grazing rights, traditional hunting) can undermine enforcement; community engagement is essential.
• Enforcement is expensive over large areas.

In-situ is the foundation of biodiversity conservation — it is the only approach that scales to whole ecosystems and all their species.

Ex-situ conservation (Latin "out of place") protects species outside their natural habitats. It is essential for species whose wild populations are too small to recover, or whose habitats are destroyed.

Main methods.

(1) Zoos and aquaria.

Modern conservation zoos (very different from old-fashioned menageries) run captive breeding programmes, conduct research, educate the public, and fund in-situ conservation.

• Successful captive breeding examples: Arabian oryx, California condor, golden lion tamarin, red wolf, Père David's deer, Mauritius kestrel.
• Studbooks: international databases track pedigrees of every individual to pair unrelated animals and preserve genetic diversity.
• Cooperative programmes: EAZA (Europe) and AZA (Americas) coordinate breeding across many institutions.

(2) Botanic gardens.

Living collections of plants, often with associated seed banks and tissue culture facilities. Examples:

• Royal Botanic Gardens, Kew (UK).
• Missouri Botanical Garden (USA).
• Singapore Botanic Gardens.

(3) Seed banks.

Dried, frozen seeds preserved as insurance against extinction. Most cost-effective form of ex-situ conservation for plants — a single facility can hold hundreds of thousands of species.

• Millennium Seed Bank at Kew, UK — over 2.4 billion seeds from 40,000+ species, stored at −20 °C.
• Svalbard Global Seed Vault in Norway — over 1 million crop seed samples in deep-freeze inside a mountain, designed as a global "doomsday vault" against catastrophe.

Limitation: some plants have "recalcitrant" seeds that don't survive drying and freezing (mostly tropical species). For these, tissue culture or living collections are needed.

(4) Captive breeding programmes.

Carefully managed breeding to maintain genetic diversity in small populations. Studbooks track every individual's pedigree; mate selection pairs the most unrelated individuals; some programmes use artificial insemination or embryo transfer to maximise diversity.

Iconic successes:

• Arabian oryx (extinct in the wild 1972; reintroduced from captive populations beginning 1982; several thousand wild today).
• California condor (down to 22 birds in 1987; ~500 birds today, half in the wild — thanks to captive breeding plus lead ammunition bans).
• Black-footed ferret (declared extinct 1979; rediscovered 1981; captive bred from 18 individuals; ~600 wild today).
• Giant panda captive breeding programme.

Advantages of ex-situ.

• Can save species whose wild populations are too small to recover.
• Controlled breeding preserves genetic diversity (studbooks, AI, embryo transfer).
• Allows research, veterinary care, public education.
• Insurance populations against catastrophic loss in the wild.
• Public exhibits raise awareness and funding for in-situ conservation.

Disadvantages of ex-situ.

• Expensive per individual — keeping one elephant in a zoo can cost more than protecting many hectares of wild habitat.
• Small populations suffer inbreeding and genetic drift; even with managed studbooks, ~1% heterozygosity is lost per generation.
• Animals may lose natural behaviours in captivity, making reintroduction difficult.
• Ecosystem interactions are lost.
• Can only cover a tiny fraction of the world's biodiversity — most invertebrates, microbes, fungi cannot be kept ex-situ.

Ex-situ is essential but complementary to in-situ, not a substitute.

Two major international initiatives work together to coordinate global conservation: CITES for trade and the IUCN Red List for threat assessment.

CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora).

• What it is: an international treaty regulating cross-border trade in wild plants and animals. Signed 1973; in force from 1975. Currently 184+ member countries.
• Headquartered: Geneva, Switzerland (under the UN Environment Programme, UNEP).
• Aim: ensure international trade does not threaten species' survival.

Three appendices classify species by threat level:

Appendix	Threat level	Trade rules	Examples
I	Threatened with extinction	Commercial trade banned	African elephant (ivory), tiger, rhinos, great apes, pangolin, many orchids and cacti
II	Not yet endangered, but at risk if unregulated	Trade by permit only	Most commercial corals, mahogany, many parrots
III	Protected in at least one country	Country-specific controls	Various species nominated by individual countries

How CITES works.

• Each member country passes domestic laws to implement CITES rules.
• Export permits required for shipments of listed species.
• Customs officials inspect shipments; fines, imprisonment and seizure for violations.
• The CITES Secretariat coordinates between countries; the Conference of the Parties (CoP) meets every 2-3 years to decide listings.

Successes.

• 1989 ivory ban: African elephant moved to Appendix I; commercial ivory trade banned globally. Poaching declined dramatically in many countries; elephant populations recovered.
• Tiger and rhino: trade in body parts globally banned.
• Sea turtles, primates and many other species receive significant protection.

Limitations.

• Depends on national enforcement, which varies hugely.
• Illegal wildlife trade is estimated at US$15-20 billion/year — among the world's largest illegal industries.
• CITES regulates trade only — does not address habitat loss, climate change, pollution.
• Some controversial decisions (e.g. 1997 and 2008 one-off ivory stockpile sales may have inadvertently fuelled poaching).
• Demand from black markets persists, especially for rhino horn (traditional medicine), ivory, pangolin scales.

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IUCN Red List of Threatened Species.

• What it is: the world's most comprehensive scientific assessment of species' extinction risk. Maintained by the International Union for Conservation of Nature (IUCN), founded 1948.
• Over 150,000 species currently assessed; goal: 160,000+.

Categories (from low to high risk):

Category	Code	Description
Least Concern	LC	Widespread and abundant
Near Threatened	NT	Close to qualifying for VU
Vulnerable	VU	High risk of extinction in the wild
Endangered	EN	Very high risk of extinction
Critically Endangered	CR	Extremely high risk of extinction
Extinct in the Wild	EW	Survives only in captivity (e.g. Père David's deer, formerly Arabian oryx)
Extinct	EX	Last individual died
Data Deficient	DD	Not enough information to assess

The 'threatened' categories — Vulnerable, Endangered, Critically Endangered — are the ones requiring conservation action.

How IUCN classifies species.

Quantitative criteria: population size, rate of decline, geographic range, number of subpopulations, probability of extinction within a time frame.

Examples of classifications:

• Critically Endangered: Amur leopard, Sumatran orangutan, vaquita porpoise, Yangtze finless porpoise.
• Endangered: Asian elephant, blue whale, Bornean orangutan.
• Vulnerable (downgraded from EN): giant panda (after Chinese conservation efforts).
• Extinct in the Wild: Père David's deer (now reintroduced; status changing).
• Extinct: Yangtze river dolphin (last seen 2007).

Role of the Red List.

• Informs governments and conservation organisations about which species need action.
• Underpins CITES Appendix decisions.
• Guides funding allocations (e.g. IUCN's species-specific Action Plans).
• Public awareness and media coverage of "endangered" status drives political pressure.

CITES vs IUCN — easy mix-up. CITES regulates trade; IUCN assesses risk. The two work hand-in-hand but have different remits.

Cambridge 9700 expects you to discuss named conservation programmes — generic answers cap at low marks. Here is a portfolio of case studies to memorise.

(1) Arabian oryx (Oryx leucoryx).

• Decline: hunted relentlessly across Arabia; declared extinct in the wild in 1972.
• Conservation action: a "World Herd" of 9 surviving founders established the captive breeding programme at Phoenix Zoo (USA), later expanded to many zoos worldwide.
• Reintroduction: 1982 onwards in Oman; later Saudi Arabia, UAE, Jordan, Israel.
• Outcome: several thousand wild oryx today; IUCN downgraded from EW to Vulnerable in 2011.
• Key success factors: enough genetic diversity in founders; suitable habitat protected by Gulf states; threats (hunting) reduced.

(2) California condor (Gymnogyps californianus).

• Decline: New World vultures shot by ranchers and poisoned by lead ammunition (in carrion). Down to 22 individuals in 1987.
• Conservation action: all 22 remaining condors captured; captive breeding at Los Angeles Zoo and San Diego Wild Animal Park. Lead ammunition progressively banned in condor range.
• Reintroduction: 1992 onwards in California, Arizona, Mexico.
• Outcome: ~500 birds today, half in the wild.
• Key success factors: captive breeding plus addressing the underlying threat (lead poisoning).

(3) Red kite (Milvus milvus) reintroduction to the UK.

• Decline: persecuted for centuries in Britain; reduced to a handful of pairs in mid-Wales by the 1930s-1980s.
• Conservation action: from 1989, kite chicks taken from healthy continental populations (Spain, Sweden) and released in England and Scotland.
• Outcome: thousands of red kites now breeding across Britain; population still expanding.
• Key success factors: suitable habitat existed; UK Wildlife and Countryside Act protected kites from persecution; public enthusiasm.

(4) Mountain gorilla (Gorilla beringei beringei) — community-based recovery.

• Decline: numbers down to 254 in 1981 due to poaching, habitat loss and disease (some accidentally transmitted from humans).
• Conservation action: in-situ protection in Volcanoes National Park (Rwanda), Virunga National Park (DRC) and Bwindi Impenetrable National Park (Uganda); habituation of some groups for tourism; strict anti-poaching patrols; vet care for snared individuals.
• Outcome: over 1,000 gorillas today; IUCN downgraded from Critically Endangered to Endangered in 2018.
• Key success factors: community engagement (tourism revenue ~US$20M/year for Rwanda); habitat protection; addressing all threats including disease.

(5) Giant panda (Ailuropoda melanoleuca).

• Decline: habitat loss in Chinese bamboo forests; population once below 1,000.
• Conservation action: dozens of nature reserves protect bamboo forests; captive breeding overcame initial reproductive challenges; "panda diplomacy" funds conservation via international zoo loans.
• Outcome: wild population ~1,800; IUCN downgraded from Endangered to Vulnerable in 2016.
• Key success factors: massive Chinese government funding over decades; habitat protection; public profile.

(6) Grey wolf reintroduction to Yellowstone, USA.

• Background: wolves extirpated from Yellowstone by 1926.
• Conservation action: 31 wolves from Canada reintroduced 1995-1996.
• Outcome: wolves restored ecosystem function via a trophic cascade — elk populations regulated, willow and aspen regenerated along riverbanks, beaver populations recovered, watercourses changed. Iconic case study of why top predators matter.
• Key success factors: suitable habitat (large protected park); compensation paid to ranchers for livestock losses.

Reasons for success — generalisable lessons.

1. Sufficient genetic diversity in the founder population.
2. Suitable habitat still available for reintroduction.
3. Original threats removed (lead bans, hunting bans, anti-poaching).
4. Long-term funding and political will (decades, not years).
5. Community engagement — local people benefit economically.

Failures and unresolved cases.

• Yangtze river dolphin (baiji): functionally extinct by 2007; pollution, fishing nets, dam construction overwhelmed conservation efforts.
• Northern white rhinoceros: only 2 individuals remain (both female); genetic line essentially gone.
• Spix's macaw: extinct in the wild; only captive populations remain.

These failures share common themes: habitat too degraded; population reduced below recovery threshold; threats not addressed in time.