Saturday, July 2, 2011

How to Ruin a River: A Summer Trip to the Lynch

Dam it up.  Someone has taken it upon themselves to ruin the Lynch River, or rather, to ruin the riffles that I like to sample.   Kids?  Teens?  The landowner?  Can't really tell you.  But they've stacked up the rocks at the head of what used to be very good riffles, creating pools out of nice, cascading runs.  Were this to create pools where someone could swim, I guess I could understand it -- but the water isn't that deep.  It's a shame.  And I'm not sure I see any reason to return to the Lynch -- at least to this particular site -- to look for bugs.  Alas!

But I looked in the few riffles that still remain, and I found pretty much the same thing I found yesterday at Buck Mt. Creek: flatheaded mayflies (genus Maccaffertium and genus Leucrocuta), and small minnow mayflies -- both Acentrella and Baetis.  The two biggest Maccaffertium nymphs that I kept for photos appeared to me to be different species.  Look at the square-shaped head in the nymph at the top of the page  (I think it's Maccaffertium ithaca -- the "Light Cahill") -- then look at the one in the photo below.

The head is more rounded off.  Here's a neat shot of both nymphs together, and the different shapes of the heads seems pretty clear.  Can't help you out with names for the species.

The Acentrella nymphs that I photographed might also be different species -- at least the colors were not the same.  Still, the darker one might simply be a more mature nymph of the same species.  Neither of these had the reddish/orange neck and spots that we found on the nymphs yesterday.  Still, the colors are stunning.  I'll simply post two photos of both of the nymphs I picked out.  On the last photo, one of the two small Baetis nymphs that I found is in the upper part of the photo.

I didn't see any stoneflies today.  Water pennies, netspinners, fingernets, and a few small brushlegged mayflies -- but the dominant taxa were the flatheads and the small minnow mayflies.

Next week I'll be off to the Rivanna River where I expect to see a good number of "dragons and damsels."

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