I’m on Vacation
In grad school there are two types of “vacations.” There are conferences, which you hope are in desirable cities that you can explore at night after you’ve turned your brain to mush hearing about cool research and talking to collaborators all day. And then there’s volunteer field work, where you are probably working harder than you would had you not gone on “vacation,” but are just happy to be seeing a different system and learning about a different project for a little bit.
Right now, I’m on the later form of vacation. I traveled six hours south to my alma mater in Ashland, Virginia to help put another year of Mechumps Creek post-restoration monitoring into the books. Some of you may recall Mechumps Creek from my post last year, where I described the need to rebuild this urban stream to restore and protect habitat from stormwater runoff. And, no, there are no trout in central Virginia. But, had it not been for a class on stream restoration featuring this tiny creek, I would have never pursued a career in fisheries. So, Mechumps Creek will always hold a special place in my heart and I’ll gladly “vacation” here anytime (but ask me again when vacation loses those quotation marks).
But, this year’s sampling was a bit different than past. Per the usual, we picked the hottest day of the year for fieldwork. With heat indices once again soaring to 110°F, I swear the Farmer’s Almanac could start using us for their long-term forecasts. And, there was no lack of poison ivy, dense thorns, and interesting animals. As it turns out, beavers don’t much appreciate 250 volts rolling through bodies.
The difference this year was that we got to do twice the work. Lucky us! Normally, our sampling is focused on one section of stream that was restored in 2010 and is now being monitored to determine the long-term response of fish populations (among other things) to restoration. Though there are still a few years left in monitoring, restoration of the first section went so well that a grant was recently received to restore the next reach located just downstream. Woohoo! But, before restoration can start, there needs to be baseline measurements of what the stream and fish community look like now so that later they can determine if restoration was successful. So, after sampling the post-restoration section, we headed downstream to complete the pre-restoration assessment of the fish community.
I was part of pre-restoration sampling of the original section seven years ago, but I’ve long forgotten what fish we caught way back then. So, it was interesting to see, back-to-back, the difference in habitat and fish diversity between pre- and post-restoration sites. Post-restoration, the stream is, on average, only a couple feet wide with maybe five pools in the entire 1,200-foot section, the deepest of which about three feet. Compare that to the pre-restoration reach, which was much wider, much siltier, and was pool after pool, with some too deep to wade through.
On the surface, the shift from many deep pools to mostly small riffles with restoration may seem a little undesirable, especially for all you trout enthusiasts out there. After all, big fish need big pools. But, not all streams are created equal, and management goals are not the same for all streams. While we may want to increase pool size and depth in a coldwater trout stream, Mechumps Creek is a tiny, warmwater system. We don’t necessarily care about the size structure of fish because no one is hoping to catch a citation sunfish out of Mechumps Creek. But, in order to preserve the integrity of large creeks and rivers downstream, we do care how well the ecosystem is functioning in Mechumps Creek. And, from a fish perspective, an indication of ecosystem function is how many different species are present (species richness) and how abundant each species is (species evenness). In short, we not only want to see many different species, we also want to see that individuals of each species are equally common throughout the stream as opposed to only one or two species dominating.
How do you increase both richness and evenness? By increasing habitat complexity and diversity- in this case reducing the number of deep pools and increasing the number of riffles and runs to provide habitat for many species that prefer many different types of habitat. This is one of the main goals of stream restoration that is best accomplished by reshaping the existing channel and reducing future streambank erosion (how this is accomplished is feat of skilled engineering, of which I won’t get into the details here).
So far, it seems past restoration efforts at Mechumps Creek have accomplished this goal. This year, while there were many species in the downstream, pre-restoration site (i.e., moderate richness), many of them were fairly rare (low evenness). Most of the fish we caught in the pre-restoration site this year were catfish, sunfish, and mudminnows, all species that we see most commonly in muddy backwaters with low oxygen(i.e,, the habitat that was most prevalent).
In the post-restoration site, we found many more species (higher richness) and improved evenness. There were fewer catfish and mudminnows, and far more darters, dace, and chubs, species that all prefer habitats with more moving water and less silt. So, we can tell from the difference between the fish communities that habitat restoration has long-term improvements to species richness and ecosystem function of Mechumps Creek. Hence the reason for moving on to phase two!
This year wasn’t just special because of the ability to do pre- and post-restoration comparisons. Because we’ve focused all of our attention on the post-restoration reach the last few years, I hadn’t visited the pre-restoration reach in about ten years, back when I was a college freshman hoping to pursue a career in surgery. So much has changed since then, but walking through the stream was like rewinding the clock. Trees we used for survey benchmarks still stood strong, sandbars we had group meetings on had only grown larger, and our little foot paths through the dense brush still seemed completely intact. I can remember many cold, rainy afternoons spent roaming around that stream with my comrades, Sonni and Arba, naïve to the future to come (nor knowing what I even wanted the future to hold), but having the time of my life trying to learn about stream ecology.
Now, here I am, ten years later. I’m turning the corner on my Ph.D., still naïve, but still having fun learning stream ecology. Surveying Mechumps Creek this year, I’m reminded of the leap of faith I took in deciding to pursue a career in Ecology. I won’t lie, I sometimes wonder what might have happened if I didn’t ____ (fill in the blank with any of about 100 serendipitous decisions that got me where I am today) and I had pursued medicine. But, I think back to the experiences I’ve had over the last ten years, the utterly ridiculous things I still find interesting about fish, and the curiosity I still have for research, and there’s no doubt I made the right call.
I’m excited for this next phase of restoration- the restoration project I pitched to Ashland Town Council ten years ago and worked on tirelessly my entire first year of college is finally being realized. But, it’s also bittersweet. The little ecosystem that taught me a love for field ecology was practically unchanged. But, in just a few months, it will all get ripped out with a few swings from the backhoe. It’s a little like renovating your childhood home. I now it needs restoration, but some good memories and a lifetime worth of professional gratitude are tied up in those ugly, eroding banks.
So, I bid farewell to pre-restoration Mechumps Creek. But, the story doesn’t stop here. I’ll go back next year to visit the new and improved stream, meet the new tenants, and start the next chapter of Mechumps Creek.
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