Worked example 1
A rare species of endemic orchid, Orchidaceae rara, is facing extinction due to deforestation in its native rainforest habitat. Discuss the relative advantages and disadvantages of using in situ and ex situ conservation methods for this plant species. [6 marks]
Show solution outline
In Situ Conservation:
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Advantages:
- Preserves natural habitat and ecosystem: This maintains the orchid's ecological relationships with pollinators, fungi, and other species crucial for its survival and evolution. (1 mark)
- Maintains genetic diversity: Allows for natural selection and adaptation to changing environmental conditions within a larger population. (1 mark)
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Disadvantages:
- Threats may persist: If the cause of habitat loss (e.g., illegal logging) is not effectively controlled, the protected area may still be vulnerable. (1 mark)
- Vulnerability to disasters: The entire population could be wiped out by a single event like a fire, disease outbreak, or extreme weather if confined to one location. (1 mark)
Ex Situ Conservation:
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Advantages:
- Protection from immediate threats: Removes individuals (as plants, seeds, or tissue cultures) from the endangered habitat, safeguarding them from deforestation. (1 mark)
- Controlled environment for propagation: Allows for rapid multiplication of the species under optimal conditions in botanic gardens or via tissue culture, and facilitates research. (1 mark)
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Disadvantages:
- Limited genetic diversity: Collections may be founded from a small number of individuals, leading to a reduced gene pool and potential inbreeding depression. (1 mark)
- Loss of ecological interactions: Plants grown ex situ lose their co-evolved relationships with natural pollinators and symbionts, which can make reintroduction difficult. (1 mark)
(Maximum 6 marks. Credit any valid, distinct point for an advantage/disadvantage of each method. Points should be clearly linked to the context of the orchid.)