Biodiversity Survey in a River Segment
Rationale
Links environmental conditions (hydraulics, light, nutrients, salinity, DO) to community structure and function; enables standardized indices for status assessment.
Materials Needed
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Sampling nets (kick-net; small seine or dip net)
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Camera
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Quadrat frame and measuring tape
Step 1: Survey Design
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Define a segment length (100–500 m) with relatively uniform habitat.
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Choose seasons (e.g., spring and late summer) and plan at least two visits.
Step 2: Target Groups and Methods
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Benthic macroinvertebrates
• Conduct survey in a standardize area or time using kick-net.
• Sort and take photos of the specimens; identify to family/genus; count abundances. -
Fishes
• Conduct survey in a standardize area or time using dip net. -
Record species, counts, lengths, native/non-native; mark-release as appropriate.
Step 3: Data Handling and Indices
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Use standardized datasheets; document effort and gear.
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Compute richness, diversity, and biotic indices (e.g., Shannon diversity index).
Simon F.S. Li Marine Science Laboratory
The Chinese University of Hong Kong
Hong Kong SAR, China