Science for Everyone

Digging Holes and Identifying Earthworms

Post by Ben Lemmond, Resident UVM Field Naturalist Masters Student

“Pieces, patterns, processes” is one of the fundamental mantras of the field naturalist program, some of the others being “don’t be a bird plow” and “use the layer cake approach.” About a week ago, one of my committee members by the name of Josef Gorres came to visit my project in situ here on Hurricane. Josef is a soil science professor and earthworm researcher at UVM, and, accordingly, we spent the weekend digging holes and identifying earthworms. Ever since his visit, I’ve had one such process on my mind: how have the soils formed here? And, perhaps more precisely, how has enough soil formed here to support a dense spruce-fir forest, after most of the trees were cleared around the turn of the 20th century?

Not being a soil scientist myself, I can’t give a totally satisfying answer to this question. But here are some of my observations so far.

First of all, I am surprised at how visible the disintegration of granite is. I always thought of granite as some sort of superlatively hard type of rock, but standing on some of the outcrops by the ocean on Hurricane, you can scuff a shoe on any of the rocks and feel the granite flake away; look around, and whole sections of the rock seem to be missing, sliced away in deep cuts by the waves or pulled out horizontally like pieces of some geologic game of Jenga. Standing on granite by the shore gives one the feeling of standing on a giant sugar cube, not on solid rock.

Secondly, the making of soil – that slowest-of-slow process, the inchworm on the ecologic freeway – seems to be happening very much in real time. On the south end of the island, near the old cutting shed, there are a number of rocks that were cut and left behind sometime very close to 1914. You can actually look from one rock to another and see the story of succession and soil development: crust lichens give way to foliose lichens, foliose lichens collect granite fragments and plant debris, eventually enough accumulates to host pincushion mosses, and then finally you start to see vascular plants, who demand the most of their host soils, springing up through it all. As an added bonus, you get a tiny little experiment in island biogeography happening on these rocks, as there is an apparent correlation between the size of the rock and the complexity of the life forms on it.

And, last of all, thanks to Josef, I’ve gotten a glimpse at what lies beneath. There are soils so acidic they expel the iron from the rock and ball it up into knotty concretions. There are weathered chunks of rock, rounded by water from a time when Hurricane Island stood below sea level. Near the cutting shed, there are flakes of granite chipped off by stone workers. Wherever Europeans settled, there are earthworms brought over in ballast soil or garden plants. I’ve got a few collections of soil that I’ll take to his lab now that I’m back in Burlington: I can’t wait to see what else I learn.

Subscribe in a reader