Showing posts with label sampling. Show all posts
Showing posts with label sampling. Show all posts

Thursday, August 11, 2011

Lord High Executioner

Flood detention basin BMP

Several years ago, I joined a group of investigators who were establishing and testing five different stormwater best management practices (known as BMPs).  These installations included a porous pavement parking lot underlain with huge voids that could retain a significant amount of stormwater; a set of infiltration beds filled with sand and/or gravel that allowed water running off a driveway to percolate slowly into the ground; two ponds that collected and detained stormwater draining overland from a 60-acre meadow during periods of heavy, prolonged rainfall; a riparian forest planting; and a basin connected to a small stream that was designed to fill when the stream overflowed with floodwater and then to gradually discharge back into the stream as flood levels subsided.

With my background in aquatic entomology, my responsibility in this group has been to sample the aquatic invertebrate community that has established itself in the vegetation ringing the fifth of the BMPs (i.e., the basin connected to the stream during periods of flooding) to show that the BMP provides valuable aquatic habitat in addition to hydrologic benefits in the watershed.  So, for the last three years I've ventured to the basin in the summer and sampled aquatic invertebrates like dragonfly and damselfly nymphs, beetles, and anything else that gets trapped in the dip nets.

My assistant and I spent about an hour running our dip nets through the the cattails, bulrushes, and nut sedges at the margin of the basin this morning.  We emptied our "catches" into gallon-size ziplock bags, then poured in a healthy dollop of 70% denatured ethyl alcohol to preserve the samples until we get a chance to clean, sort and process them.  And there's the rub.

In graduate school and during my early professional years, I collected and killed many thousands of aquatic insects.  But I just hate doing this work any more.  Three days ago, as I was making preparations for our foray this morning, I had already begun thinking about the insects in this pond, and that some of them--even three days ago--were the living dead.  Their halcyon summer would be invaded by this monstrous creature who would scoop them up, dump them unceremoniously into a plastic bag, and then immerse them in a fluid so noxious that it's offensive just to smell it.  Some of the larger and better armored organisms like the dragonfly nymphs and beetles don't die immediately, either.
Lord High Executioner

I vaguely remember seeing a movie about Roman slaves many, many years ago.  I think it was Spartacus, but I'm not sure, and I haven't seen the movie I have in mind (or Spartacus) again since.  At the beginning of the movie, some slaves are encased in a translucent tent lit luridly purple.  The slaves are writing in agony as they expire slowly for the schadenfreude of their captors.  Collecting these insects makes me feel like I'm in the film.

I'm not so naive to think that these insects live an idyllic life, that they don't face daily peril.  Many are relentless predators, and many more are prey.  In addition, most will die from the cold within the next few months.  Nevertheless, I have a hard time reconciling myself to what I'm inflicting on them.

Monday, August 10, 2009

Back to My Roots


I was professionally trained as an aquatic ecologist. I earned my professional degree studying the aquatic invertebrate communities inhabiting a series of six parallel streams draining off a ridge in the central Appalachian Mountains. At that time, I was especially interested in stoneflies (Plectoperans), but the position I accepted after graduate school took me to the Coastal Plain in the deep South where stoneflies are few and far between. Then, I took my current position in the urbanized Piedmont on the East Coast, and our streams are too damaged to have much of an interesting Plecopteran fauna. In short, I lost my stonefly mojo. And, because I'm basically an administrator, I lost most of the rest of my invertebrate mojo, too.

However, recently I was enlisted to help with a multifaceted stormwater research project, and the team leader knew of my background. So, I agreed to sample and identify macroinvertebrates in a stormwater treatment wetland. Last Friday, I pulled on a pair of hip waders and I ventured out into the field after years of being bound to my desk.

As I collected the samples, I noticed that I had netted some dragonfly and damselfly nymphs, micro waterstriders, backswimmers, snails, water measurers, and water boatmen, but I'll have to sort through the samples more carefully over the next few weeks and pick the bugs from the detritus--tedious work!

It was good to be back in the field, though.

When I looked at the images that my assistant took of me, I noticed that (1) I desperately needed a haircut (which I got over the weekend), and (2) my Carhart work dungarees are cut too generously to flatter my butt. Vanity.

Green Heron (Butorides virescens)

While we were sampling, a Green Heron (
Butorides virescens) alighted in a dead tree adjacent to the wetland. I'm sure it wanted to come down to eat, and we were delaying its lunch.