Managing Ecosystems and Resources

Free Managing Ecosystems and Resources OCR A Level Biology revision notes – covering specification points 6.3.2(d) and 6.3.2(e).

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Human population growth has made human exploitation of ecosystems for resources increasingly unsustainable and damaging to habitats.

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Controlling the Effects of Human Activities

As awareness increased about the impact of human activity on the environment over time, so have efforts to reduce it through conservation increased.

The table below outlines some examples of measures used to control the effects of human activity:

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Managing Conflict Between Human Populations and Conservation Efforts

Conflict arises when conservation efforts to protect an ecosystem interfere with the local human population’s needs to acquire resources.

Conservation projects that do not take into account the needs of the local population are likely to encounter resistance or create conflict between humans and wildlife.

Examples of successful conservation measures that balance the needs of the local population include:

• Regulated use: Local people continue using natural resources but at a sustainable rate (e.g. coppicing, quotas).
• Investment: Encourage ecotourism to create local jobs, compensate owners for ending environmentally destructive activities or set aside land for conservation.
• Community involvement: Involve and educate local people so that they know of, have a voice in, and have responsibility for conservation decisions that can affect and benefit them.

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Sustainable Management of Ecosystems: Timber

Trees are harvested to produce timber, which is used in construction, manufacturing, and for energy.

Sustainable timber production considers:

• Harvest rate: Trees are replaced as fast as they are harvested, either by regrowth from the cut stem (e.g. coppicing) or by replanting.
• Ecological integrity: Forest ecosystems are managed so that the nutrient content (e.g. mineral ions) of the soil is not degraded, and a range of habitats are available to support species biodiversity.
• Local benefit: Timber production provides local jobs.

Examples of some sustainable management techniques used in timber production include:

• Coppicing: The stem of a deciduous tree is cut down to just above the ground, so that the remaining stump produces many individual stems.
• Pollarding: The stem of a deciduous tree is cut higher up the tree, so that many individual stems are produced above the height a grazing herbivore (e.g. deer) can reach.
• Rotational coppicing/pollarding: The wood is divided into areas, and only one area is coppiced each year.
• Standards: Full-sized trees are left uncut and allowed to grow larger, with smaller trees managed by coppicing growing under the canopy.

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Sustainable Management of Ecosystems: Fishing

Overfishing has reduced many fish populations faster than their rate of reproduction.

Fish are harvested from marine ecosystems to provide food for millions of people.

Sustainable fishing considers:

• Harvest rate: Fish are caught at a rate that ensures the population will be able to return to its original size.
• Ecological integrity: Fishing is regulated so that marine ecosystems are not damaged by indiscriminate fishing techniques (e.g. bottom trawling).
• Local benefit: Fishing provides local jobs.

Sustainable management of wild fish populations involves the regulation of fishing in ecosystems to avoid irreversible harm to habitats and/or ocean populations.

Sustainable fishing regulations consider:

• Quantity caught: The mass of fish that is and could be caught by fishing vessels.
• Species and size caught: Which fish are removed by fishing vessels.
• Time and place: When and where fishing may occur.

The table below outlines how wild capture is managed sustainably: