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Difficulty: MediumConservation of Natural Resources and Environmental Management

An abandoned open-cast mining area dominated by bare rock surfaces is selected for ecological reclamation. Which of the following biological processes represents the initial step required to rebuild soil and restore this degraded ecosystem?

  1. Primary succession initiated by pioneer organisms such as lichens that weather the rock surfaceAnswer
  2. B
    Secondary succession initiated by planting fast-growing leguminous shrubs directly onto the bare rock
  3. C
    Conversion of soil nitrates to nitrogen gas by denitrifying bacteria to enrich rock minerals
  4. D
    Inversion of the pyramid of energy by introducing primary consumers to build up organic matter

Answer

Primary succession initiated by pioneer organisms such as lichens that weather the rock surface
On completely bare rock surfaces created by activities like open-cast mining, no soil exists. Ecological reclamation must begin with primary succession, where pioneer organisms like lichens and mosses colonize the rock, secrete organic acids to accelerate weathering, and trap windblown particles to form the initial layer of organic soil.

Step-by-Step Solution

1
Identify the environmental condition of the degraded mining site
The substrate consists of bare rock with no pre-existing organic soil or seed bank.
Reclamation on bare abiotic surfaces requires building soil from scratch.
2
Determine the ecological process appropriate for bare rock substrates
Primary succession is the process that begins on newly exposed rock surfaces.
Pioneer species like lichens produce acids that break down rock, creating initial soil particles for subsequent plant species.

Key Concept

Role of primary ecological succession in land reclamation and soil conservation
Estimated Time:1m 15s
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Topics

Conservation of Natural Resources and Environmental Management

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