What is the primary difference between in-situ and ex-situ conservation?

In-situ conservation occurs within the species' natural habitat (e.g., nature reserves), while ex-situ conservation takes place outside the natural habitat (e.g., zoos or seed banks). In-situ focuses on ecosystem preservation, whereas ex-situ is often a targeted rescue mission for specific species.

How does the EDGE programme differ from traditional conservation prioritization?

Traditional methods often focus solely on extinction risk, whereas the EDGE programme prioritizes species based on both extinction risk and evolutionary distinctiveness. This ensures that unique genetic lineages with no close relatives are protected from total loss.

When should captive breeding be used instead of habitat protection alone?

Captive breeding is used when a wild population has reached such low numbers that it can no longer recover naturally, even if its habitat is protected. It serves as an emergency intervention to boost numbers before reintroduction is possible.

What is a common misconception about the success of captive breeding programs?

A common error is assuming that increasing the number of individuals in captivity automatically saves the species. Success actually depends on the ability of those individuals to survive, hunt, and reproduce successfully once they are released back into the wild.

Why is it a mistake to ignore the 'original threat' during a reintroduction program?

If the factors that caused the decline (such as invasive predators or pollution) are still present in the habitat, any reintroduced individuals will likely face the same fate as the original population, leading to program failure.

What error occurs if genetic diversity is not managed in captive populations?

Failure to manage genetics leads to inbreeding depression, where harmful recessive traits become more common. This reduces the overall health, fertility, and survival chances of the population when released.

Define 'Evolutionary Distinctiveness' (ED).

ED is a measure of how genetically unique a species is based on its position on the evolutionary tree. Species with high ED have few close living relatives and represent a significant amount of unique evolutionary history.

What is 'Cryopreservation' in the context of conservation?

Cryopreservation is an ex-situ strategy involving the storage of seeds, pollen, embryos, or DNA at extremely low temperatures (usually in liquid nitrogen). This preserves genetic material for decades or centuries as a backup against extinction.

Define 'Reintroduction'.

Reintroduction is the deliberate release of individuals (often from captive breeding programs) into an area where the species was indigenous but has since declined or disappeared, with the goal of establishing a self-sustaining population.

Why are 'studbooks' used in captive breeding?

Studbooks are detailed records of the pedigree and breeding history of every individual in a captive population. They are used to plan matings that maximize genetic diversity and minimize the risk of inbreeding.

4.2.3 Strategies of Biodiversity Conservation | Cambridge International Examinations AS-Level Environmental Management

Revision Notes

AS-Level

Cambridge International Examinations

Environmental Management

4. Managing Ecosystems & Biodiversity

4.2.3 Strategies of Biodiversity Conservation

Summary

Biodiversity conservation strategies involve systematic approaches to prioritize and protect species at risk. These range from identifying evolutionarily unique organisms through the EDGE programme to intensive intervention methods like captive breeding and reintroduction, balancing the need for immediate rescue with long-term ecological stability.

1. The EDGE Programme: Prioritization Strategy

Evolutionarily Distinct and Globally Endangered (EDGE) is a conservation strategy designed to prioritize species that are both genetically unique and at high risk of extinction.
Evolutionary Distinctiveness (ED): This metric identifies species with few close relatives, representing unique branches of the 'tree of life' that carry distinct genetic information not found elsewhere.
Global Endangerment (GE): This utilizes the IUCN Red List status to identify species facing the highest probability of extinction in the near future.
The strategy ensures that limited conservation resources are allocated to prevent the loss of entire evolutionary lineages rather than just individual species.

2. Captive Breeding: Ex-situ Intervention

Captive breeding involves the management and reproduction of endangered species in controlled environments such as zoological parks, botanical gardens, or specialized research facilities.
The primary goal is to increase the population size of a species that has declined to a level where it can no longer sustain itself in the wild.
This method acts as a 'biological insurance policy,' maintaining a gene pool that can be used to bolster wild populations or restart them if they become extinct in their natural habitat.
Successful programs require meticulous record-keeping (studbooks) to prevent inbreeding and maintain the highest possible levels of genetic diversity.

A diagram showing the cycle between captive populations and wild populations, highlighting the reintroduction process.

3. Reintroduction and Release Programs

Reintroduction is the process of releasing captive-bred individuals back into their native habitats to establish a self-sustaining population.
This phase is highly complex and requires that the original causes of the species' decline (e.g., habitat loss, overhunting, invasive species) have been addressed or mitigated.
Released individuals often require 'soft release' techniques, where they are provided with supplemental food and protection while they acclimate to the wild environment.
Post-release monitoring is essential to track survival rates, reproductive success, and the integration of individuals into the existing ecosystem.

4. Key Distinctions: In-situ vs. Ex-situ Strategies

5. Evaluation of Conservation Strategies

6. Exam Strategy & Tips