THE RIVER CONTINUUM CONCEPT

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THE RIVER CONTINUUM CONCEPT VANNOTE ET AL. (1980)
A synthetic framework to describe the biological
function of streams from the headwaters to the
mouth.
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THE RIVER CONTINUUM CONCEPT VANNOTE ET AL. (1980)

• Physical changes along the stream continuum
• Alter the nature of organic matter inputs
• Which causes changes in the trophic structure of
  stream communities
• And consequently, river ecosystems are
  longitudinally linked i.e., changes upstream
  have measurable effects downstream.

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• PHYSICAL
• Narrow Shallow
• Riparian Vegetation
• CPOM inputs
• Shading
• LWD
• Low Discharge
• Highly Retentive
• Close link to groundwater DOC
• Organic Matter Dynamics
• Low Primary Productivity
• High rates of microbial activity
• Strongly Heterotrophic
• P/R ltlt 1 (0.01 0.3)
• NDM ltlt 0
• High CPOM FPOM ratio
• Biological Community

HEADWATER STREAMS (1ST-3RD ORDER)
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Heterotrophic Headwater Stream
Unnamed Trib of Crooked Run of Elk
River Pocahontas County, WV
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• PHYSICAL
• Wider but still Shallow
• Reduced link to riparian vegetation
• Increased light (radiant energy and heat)
• Higher Discharge
• Low Retention
• Reduced link to groundwater DOC
• Organic Matter Dynamics
• Increased rates of Primary Productivity
• Autotrophic Pathway of Increased Importance
• P/R gt 1 (0.7-3)
• NDM gt 0
• Low CPOM FPOM ratio (FPOM import from US)
• Diverse Energy Sources (CPOM, FPOM, Light)
• Biological Community
• Increased Diversity
• Reduced shredders

MID-ORDER STREAMS (3RD 6TH ORDER)
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Autotrophic Mid-Order Stream
Upper Shavers Fork Randolph County, WV
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LARGE RIVERS (6TH 12TH ORDER)

• PHYSICAL
• Wide and Deep
• Almost no link to riparian vegetation
• High Light but High Turbidity
• High Discharge but Low Gradient
• High Retention
• Organic Matter Dynamics
• Low Primary Productivity (turbidity)
• Heterotrophic Pathway Dominates
• P/R lt 1 (0.3-1)
• NDM lt 0
• Low CPOM FPOM ratio (FPOM import from US)
• Biological Community
• Increased filterers and collector gatherers
• Increased pelagic community
• Fishes (warmwater, piscivores and omnivores)

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Heterotrophic Large River
Ohio River near Parkersburg, WV
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Autotrophic Headwater Stream
Upper Odey Run, Pocahontas County, WV
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