outline the roles of zoos, botanic gardens, conserved areas (including national parks and marine parks), ‘frozen zoos’ and seed banks, in the conservation of endangered species

Conservation of Endangered Species – Cambridge AS & A Level Biology (9700)

1. Classification Basics

• Three Domains: Archaea, Bacteria, Eukarya.
• Kingdoms within Eukarya (most relevant to the syllabus): Protista, Fungi, Plantae, Animalia.
• Taxonomic hierarchy (from broad to specific): Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species.
• Binomial nomenclature: Genus name (capitalised) + specific epithet (lower‑case), e.g. Panthera tigris. The name is italicised or underlined.
• Species concepts:

  • Biological species concept – groups of actually or potentially inter‑breeding natural populations which are reproductively isolated from other such groups.
  • Morphological (phenetic) species concept – based on overall similarity of form and structure.
  • Phylogenetic species concept – the smallest monophyletic group distinguished by a unique combination of character states.

2. Levels of Biodiversity

• Species diversity – number of different species in an ecosystem.
• Genetic diversity – variation in genes within and between populations of a species.
• Ecosystem diversity – variety of habitats, ecological processes and biotic communities.

Loss at any level can cascade to the others; therefore integrated conservation is essential.

3. Measuring Biodiversity

• Species richness – simple count of species present.
• Diversity indices:

  • Simpson’s Index (D): \(D = \sum (ni/N)^2\) where \(ni\) is the number of individuals of species *i* and *N* the total number of individuals. Lower D = higher diversity.
  • Shannon–Wiener Index (H'): \(H' = -\sum (pi \ln pi)\) where \(pi = ni/N\). Higher H' = higher diversity.

• Phylogenetic diversity – incorporates evolutionary distances between species (e.g., Faith’s PD).

Worked example (Shannon index) – a pond contains 40 % Rana temporaria, 30 % Bufo bufo, 20 % Lepomis macrochirus and 10 % Gasterosteus aculeatus:

p₁=0.40, p₂=0.30, p₃=0.20, p₄=0.10  
H' = –[0.40 ln 0.40 + 0.30 ln 0.30 + 0.20 ln 0.20 + 0.10 ln 0.10] ≈ 1.28

4. Threats to Biodiversity

5. Conservation Status – IUCN Red List

6. Conservation Strategies

Both in‑situ (within natural habitats) and ex‑situ (outside natural habitats) approaches are required. The syllabus expects the following sub‑strategies:

6.1 In‑situ Strategies

• Protected areas (national parks, marine parks, nature reserves).
• Ecological corridors and landscape‑scale management to maintain connectivity.
• Community‑based conservation and sustainable‑use programmes.
• Legal protection (CITES, national wildlife acts, IUCN Red List).
• Restoration ecology – re‑vegetation, reef rehabilitation, wetland creation.
• Species re‑introduction – soft‑release, hard‑release, post‑release monitoring.
• Genetic rescue – translocating individuals to increase genetic diversity and reduce inbreeding depression.

6.2 Ex‑situ Strategies

• Captive breeding and genetic management in zoos and botanic gardens.
• Cryopreservation of gametes, embryos and somatic cells (“frozen zoos”).
• Seed banks and living plant collections.
• Research on reproductive technologies, disease control and species biology.
• Education, public‑engagement and advocacy to generate support for in‑situ actions.

7. Roles of Specific Facilities in Species Conservation

7.1 Zoos (Ex‑situ Animal Conservation)

• Captive‑breeding programmes for species extinct in the wild (e.g., California condor) or with critically low numbers.
• Genetic management using studbooks, pedigree analysis and molecular markers to minimise inbreeding.
• Re‑introduction & soft‑release – acclimatisation enclosures, gradual exposure to natural conditions.
• Education & advocacy – visitor centres, school outreach, media campaigns highlighting threats.
• Research on physiology, behaviour, nutrition and disease that informs wild‑population management.

7.2 Botanic Gardens (Ex‑situ Plant Conservation)

• Living collections of threatened taxa (e.g., Encephalartos woodii at Kew).
• Propagation techniques – seed germination, tissue culture, micropropagation for large‑scale planting.
• Seed banking as a backup for wild seed collections.
• Public education through themed gardens, exhibitions and citizen‑science projects.
• Scientific research on plant genetics, climate‑change responses and secondary metabolites.

7.3 Conserved Areas

National Parks (Terrestrial In‑situ Conservation)

• Provide extensive, legally protected habitats that support viable population sizes.
• Regulate activities such as tourism, logging and mining to reduce habitat loss.
• Serve as reference sites for long‑term ecological monitoring (e.g., Yellowstone).
• Facilitate community‑based stewardship and eco‑tourism that generate income for local people.

Marine Parks (Marine In‑situ Conservation)

• Safeguard critical habitats – coral reefs, seagrass beds, spawning aggregations.
• Implement fishing quotas, no‑take zones and gear restrictions to curb over‑exploitation.
• Support reef‑restoration projects (e.g., coral gardening in the Great Barrier Reef).
• Monitor water quality and climate impacts to adapt management plans.

7.4 “Frozen Zoos” – Genetic Resource Banks

• Cryopreserve sperm, eggs, embryos and somatic cells at –196 °C (liquid nitrogen).
• Maintain a genetic “insurance policy” for species with few remaining individuals (e.g., black‑footed ferret).
• Provide material for assisted reproductive technologies – IVF, cloning, genome editing.
• Enable future re‑creation of populations after catastrophic loss.

7.5 Seed Banks (Plant Genetic Resource Preservation)

• Collect, dry and store seeds at –18 °C to maintain viability for decades.
• Global facilities such as the Svalbard Global Seed Vault act as a safety net for crop and wild‑plant diversity.
• Supply locally adapted seed lots for habitat restoration and re‑forestation projects.
• Contribute to food security by safeguarding agricultural landraces and wild relatives.

8. Legal & Ethical Frameworks

• CITES – regulates international trade in listed species.
• IUCN Red List – global assessment of extinction risk; guides priority setting.
• National legislation – e.g., Wildlife and Countryside Act (UK), Endangered Species Act (USA).
• Ethical considerations – animal welfare in captivity, rights of indigenous peoples, allocation of limited conservation resources.

9. Evaluating Conservation Effectiveness

10. Summary Table – Key Conservation Facilities