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Rapid Bioassessment Protocol (RBP)
Background to RBP
• changes in community/assemblage composition used to evaluate existence and degree of impact on an ecosystem
• Can infer functional changes by evaluating structural changes
• Not designed to provide definitive answer, id systems needing in-depth evaluation
• Base on two assessments– Biological assessment– Habitat assessment
Biological Assessment
• Evaluates overall biological condition from a few samples (must keep seasonality in mind)
• Assumes composition of benthic community will reflect an integrated response to environmental effects over time
• Can be performed at many levels
• 1st level is Functional Feeding Groups of benthic macroinvertebrates (mostly larval stages of aquatic insects)
Advantages of Using Benthic Macroinvertebrates
• Limited migration = good for upstream/downstream evaluation
• Usually have complex life cycle > 1 year can integrate long-term impact
• Very quick and easy to determine degraded condition by experienced sampler
• Sampling easy with few people, inexpensive, no detrimental effect on resident biota (no rotenone)
• Benthic inverts usually abundant (and serve as food source)
• State agencies often keep data bases on benthic mac. to be used for comparisons
Habitat Assessment
• Evaluate habitat, then predict what stream organisms should be there
• Is “poor” bioassessment due to poor habitat or ecosystem stress (or combination)?
Stream Habitat Assessment
Bottom substrate
Embeddedness
Flow
Channel alteration
Bottom scouring/ deposition
• >50% rubble, gravel, logs, other stable habitat
• < 25% surrounded by fine sediments
• Cold >0.05 cms (2 cfs); warm >0.15 cms (5 cfs)
• No enlargement of islands /bars, no channelization
• <5% of bottom affected by scouring and deposition
Variable Excellent Habitat
Stream Habitat Assessment
Pool/rifle, run/bend ratio(distance between riffles/stream
width)
Bank stability
Bank vegetation
Streamside cover
• 5 – 7 (>25 is poor)
• Stable (no evidence of erosion or bank failure
• > 80% of bank surfaces covered by vegetation, boulders or cobble
• Dominant vegetation is shrub, secondarily trees
Variable Excellent Habitat
PSU students collecting