Transcript Rapid Bioassessment Protocol (RBP)

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
Variable
Bottom substrate
Embeddedness
Flow
Channel alteration
Bottom scouring/
deposition
Excellent Habitat
• >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
Stream Habitat Assessment
Variable
Excellent Habitat
Pool/rifle, run/bend ratio
• 5 – 7 (>25 is poor)
(distance between riffles/stream
width)
Bank stability
Bank vegetation
Streamside cover
• Stable (no evidence of
erosion or bank failure
• > 80% of bank surfaces
covered by vegetation,
boulders or cobble
• Dominant vegetation is
shrub, secondarily trees
PSU students collecting