4.2.3 Strategies of Biodiversity Conservation (Cambridge International AS Environmental Management)

Evolutionarily Distinct and Globally Endangered species (EDGE) programme

Spec point — 4.2.3

• There are so many species that need protection that it can seem like an impossible task to decide where to allocate the limited resources available

• The EDGE programme is an initiative developed by the Zoological Society of London (ZSL):

  • It aims to prioritise and conserve evolutionarily distinct and globally endangered species
  • These species are considered to be relatively unique in terms of their evolutionary history, and face the highest risk of extinction

Selection Criteria

• EDGE species are selected based on their evolutionary distinctiveness, which measures how genetically different a species is from its closest relatives:

  • Species that have few close evolutionary relatives
  • Species that are unusual in appearance, behaviour and DNA
  • Species that represent a part of Earth's evolutionary tree that is not represented anywhere else

• They are also selected based on their conservation status, with a focus on species that are critically endangered or those facing imminent extinction:

  • The IUCN red list is used to provide information about the threat level of an evolutionarily distinct species
  • A species must be globally threatened, not just threatened on a local level

• Examples of priority EDGE species include:

  • Largetooth sawfish
  • Chinese giant salamander
  • Purple frog

The platypus (species "A") can be considered to be an EDGE species as it is evolutionarily distinct from rabbits (species 'E') and rats (species 'F'), which have a more recent common ancestor — the platypus is a unique and iconic egg laying mammal that is the only living representative of its family and genus

Conservation Prioritisation

• The EDGE programme prioritises species with high EDGE scores, indicating their evolutionary distinctiveness, and develops conservation strategies tailored to their specific needs:

  • This may include habitat protection, anti-poaching measures, community engagement and captive breeding programmes

Community Involvement

• The EDGE programme encourages community involvement and collaboration with local stakeholders to ensure the success of conservation efforts:

  • By engaging communities living near EDGE species habitats, the programme aims to address human-wildlife conflicts, promote sustainable resource management and raise awareness about the importance of biodiversity conservation

Impact

• The EDGE programme has contributed to the conservation of numerous species worldwide, including the Hainan gibbon, Philippine eagle, and Yangtze giant softshell turtle:

  • It has achieved this by providing funding, technical support and capacity building to conservation projects focused on these species

The Chinese giant salamander is both evolutionarily distinct and globally endangered, and is a focal species for the EDGE programme (CC BY-SA 4.0, via Wikimedia Commons)

Captive Breeding

Spec point — 4.2.3

• Captive breeding is the process of ensuring that endangered species reproduce in captivity, often in zoos, aquariums, or specialised breeding facilities:

  • The goal is to increase their population size and genetic diversity
  • Once bred, individuals may be released into their natural habitat to boost wild populations

Advantages

• Population recovery:

  • Captive breeding programmes can help recover populations of endangered species that are declining in the wild due to habitat loss, poaching or other threats

• Genetic Diversity:

  • By carefully managing breeding pairs and avoiding inbreeding, captive breeding programmes can maintain or increase the genetic diversity of endangered species
  • This reduces the risk of genetic diseases and enhances their long-term survival prospects

• Education and Awareness:

  • Zoos and aquariums with captive breeding programmes play a crucial role in educating the public about endangered species and the importance of biodiversity conservation

Challenges

• Habitat Suitability:

  • Reintroducing captive-bred individuals into the wild requires suitable habitat and conditions for their survival, including access to food, shelter and mates
  • Ensuring that release sites meet these requirements can be challenging

• Adaptation:

  • Captive-bred individuals may lack the necessary skills and behaviours to survive and reproduce in the wild, such as foraging, predator avoidance, or social interactions e.g. attracting a mate
  • This can reduce their chances of successful reintroduction

• Cost and Resources:

  • Captive breeding programmes require significant financial investment and expertise to manage breeding populations, provide appropriate care and monitor released individuals
  • This makes captive breeding a very resource-intensive process, requiring a lot of money, time and highly qualified people

Evaluation

• While captive breeding and release can be an effective conservation tool for certain species, it is not without limitations and risks:

  • Success depends on careful planning, ongoing monitoring and adaptive management to address challenges and maximise the effectiveness of conservation efforts
  • Additionally, captive breeding must be used alongside broader conservation strategies, such as habitat protection and restoration, rather than a standalone solution to biodiversity loss