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Benthic Macro-Invertebrate Monitoring Protocols
Transcript of Benthic Macro-Invertebrate Monitoring Protocols
Setting up a Site
Identify the riffles and pools
Measure 40m upstream from a downstream crossover
A "cross over" is a point in the stream where the current travels parallel with the banks.
There should be a riffle and a pool within the 40m length (if not, extend the length beyond 40m
Mark the transects
Transects are lines which cut accross the stream/river perpendicular to the bank.
The number of transects depends upon the width of the stream....so measure the narrowest width of the stream.
Stream length = 40m
Narrowest Width = 3.5m
10m between transects
distance = site length / (# transects -1)
Collecting Your Sample
Collect a sample from all of the transects
To collect a sample use the "Travelling Kick Method"
Start at the Downstream Limit
Travel accross all the transects all the way to the upstream limit
This is a standard BMI monitoring methodology
Two people will enter the water downstream of the transect
One person will hold the D-net facing upstream so the current flows into the net.
With the D-net firmly on the stream bottom, the other person will "kick and dance" in front of the net.
Work your way accross the transect - moving a net-width at a time. Start with the net touching one bank and finish with it touching the opposite bank.
Pick-up any rocks and rub their surfaces to dislodge any attached bugs and collect them in the net.
As you go, be careful not to lose your sample from your net. When you pick up the net, bring the net out of the water face-first.
Emptying your D-net
Empty your net after you have completed each transect.
You will need:
a waste bucket
a sample bucket
one 500-micron sieve
Carefully empty your D-net into your sieve over a bucket - your "waste bucket".
Use the squirt bottles to rinse the net into the sieve.
Remove large debris from the sieve - rinsing it before returning it to the stream.
Pour your waste water through the sieve.
Transfer the contents of the sieve to the "sample bucket". Use squirt bottles to ensure you get all of the bugs.
Sub-Sampling and Sorting
Scoop a sub-sample into a sorting tray
First agitate the sample bucket to mix the sample
Use the scoop to give sub-samples to the sorting groups
Pick out the bugs from the sub-sample
Look carefully at the tray and pick-out anything that moves. The rule is: if it moves, pick it out!
Use the pipettes to pick-out the smaller bugs and use the tweezers to pick-out larger bugs.
Transfer bugs into ice-cube trays and try to sort them according to groups.
If you have gone at least 2 minutes without spotting anything, and have not yet found 100 bugs, put the sub-sample back into the sample bucket and get a new sub-sample.
Once you have 100 bugs, you can stop but only after you finish the sub-samples being worked upon.
Try not to agitate the sub-sample - it will be easier to locate the bugs
Do not count dead bugs
Do not count empty shells
Identify the bugs
See identifying presentation
During the study fill-out the data sheets.
"Riparian Vegetation" is the vegetation on the banks of the stream - 10m from the water.
None = the absence of any vegetation
Cultivated = agricultural (incl. lawns
Meadow = unmanaged stand of tall grass
Scrub = sparsely spaced trees and mixed shrubs and grasses
Forest = mature trees with significant canopy cover
Indicate which vegetation form is on the left and right bank (facing upstream) at each transect.
The "wetted width" is the width of the surface of the water.
"Dominant Substrate" is the main form of the stream's bottom surface. That is, the type of rock, etc.
Indicate at each transect the substrate form by placing a check mark inthe appropriate box
Indicate the wetted width at each transect
Indicate with a check mark the estimated overhead forest cover from the middle of the stream at each transect.
Write any observations about the site including: temperature; problems with the study proceedings; unusual conditions; etc.
Take photos of the first and last transects to help future identification and list the file names.
Draw an "overhead" sketch of the site noting all features.
Use sheet 3 to tally the numbers of each bug type when identifying.
Let's get in the water!
For more information contact:
EcoSpark's Changing Currents
phone: 647-258-3280 ext. 2011