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