|
Hi Tom and John and everyone, Interesting start of a discussion!
Here are my 2 cents on the MiCorps score… 1) It is very difficult to compare the macro community in two stream
sites without an extensive analysis. This is because the biological
community can differ very much just due to the natural characteristics of the
stream, like John was saying. For example, two very healthy streams may have
very different macro communities and thus different score, simply because one
stream is large and the other is small. The small stream would probably
have a lower score because smaller streams have, in general, less biological diversity
because of less diversity in habitat. The difference in score doesn’t
tell you that one site is better than another. 2) In the 3) Long term monitoring!!!! As John mentions, these scores are useful
for looking for trends at a particular site, and less useful for comparing
sites. --Paul Steen From:
owner-micorps@great-lakes.net [mailto:owner-micorps@great-lakes.net] On Behalf Of John Hayes Hi, You're numbers
mean you have a fantastic trout stream! On a more serious note,
they won't mean that much until you have a nice stockpile of data. Looking
at the data over time, you can appreciate changes that are happening (if
there are any). I.E, climate change, habitat destruction/improvement,
etc. Now, if the numbers change from 50+ to <20, I would be
really concerned. There could be some contamination that is severely
impacting the macros. Though, lots depends on when you
sample. January, on average, is when macros are at
their highest density. Additionally, the numbers you're
generating are really not hard data points. You're getting a qualitative
understanding. Quantifying a qualitative test is trouble. My group samples
a really small creek (Hatlem Creek) that has no where near the biomass as the
Au Sable. Our scores range rom mid 30's to high teens. It's really
inappropriate to compare the two. That doesn't mean the Hatlem is in bad
shape. It's just different water. Hope this helps. John Hayes We
recently had a discussion of the Stream Quality Scores for our September
sampling event. It was our first sampling event and thus the scores are our
first set of scores. For 6 sampling sites in the Upper AuSable River Watershed,
we had scores of 52.4, 56.9, 50.3, 50.4, 55.3, & 51.2. Our discussion was
lively, but basically boiled down to the question of what do those numbers
really mean. We had a couple very accomplished statisticians in our midst and
that made the discussion even more worrisome that casual observers might
misunderstand what our numbers really mean. It's like the school district MEAP
scores that get published in newspapers. What conclusions can be drawn from
MiCorps' brand of Stream Quality Scores. On Apr 22,
2009, at 7:48 AM, Ric Lawson wrote:
By the
way, if you are wondering how to comment to the list, simply "reply
all" or send an e-mail to micorps@great-lakes.net and it will go to the entire MiCorps discussion list.
If you keep the subject as above, then list members can track the discussion
string by topic. Ric
Lawson Watershed
Planner p: 734.769.5123 x13 f: 734.998.0163 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ More info: www.hrwc.org
Ric
Lawson Watershed
Planner MiCorps
Staff p: 734.769.5123 x13 f: 734.998.0163 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ More info: www.hrwc.org
********************************************************** |