Stream Safari

Stewardship Assistant Kevin with a handful of Asiatic clam shells

Despite the threat of thunderstorms, our annual Stream Safari came off without a hitch.  Our Stewardship Assistant Kevin who just earned his undergraduate degree in education, led about a dozen participants to the creek to comb the streambed cobbles for critters.

What ya' got there?

We billed this year's safari as an event for children more than we have in previous years (when we advertised it as a family activity), and four families with lots of kids came for the event.

Most invertebrates cling to the bottom of rocks

Our creek is "impaired" according to the state's official classification.  How could it not be?  We're in the center of the watershed, and the upper half of the drainage is fully overwhelmed by suburban sprawl.  So, our creek suffers from torrential flooding, sediment deposition, erosion, and nutrient enrichment.  In fact, it's amazing the creek is in as good a condition as it is.

Mom was really getting into the hunt

We found plenty of caddisfly larvae and mayfly nymphs that are tolerant of moderate pollution.  The invertebrates indicative of really high purity streams were, of course, completely absent.

Kevin even set up a field laboratory so that the participants could examine their finds with microscopes.  Everyone seemed to enjoy the cool water on a hot, humid evening as well as the cool animals hidden in the creek's nooks and crannies.

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.