Column: Rewilding the yard — a story of succession

  • Micki Colbeck photograph

  • Micki Colbeck photograph

  • Micki Colbeck. Copyright (c) Valley News. May not be reprinted or used online without permission. Send requests to permission@vnews.com.

For the Valley News
Saturday, June 01, 2019

Our house sits on what we call our “half-acre-more-or-less.” It is bounded by the river, the pine snag that used to be, the rivulet and the road. Parcel descriptions like this are how un-surveyed plots of land in Vermont were often described in deeds. On our half-acre, which seems to be twice that, I only mow a few patches here and there. This lack of lawn care is partly due to us living on the vertical — the southwest slope of Grannyhand Hill — and partly due to my desire to provide habitat for animals other than those bipedal ones who drink coffee on the porch, gazing.

Succession is a term used to describe changes that occur naturally over time as one type of land cover becomes a different type. One of the most dramatic examples of succession is when a major disturbance scours the ground down to bare rock, and over time, this ground grows a forest. Only 13,000 years ago, mile-thick ice lay from Greenland down through Cape Cod. As the glaciers crept to the southeast, they scraped up the soil and surface rocks and deposited this mix where the ice ran out of land. A big chunk of debris became the well-loved terminal moraine we call Cape Cod. Eventually, the planet warmed and the ice retreated, leaving bare rock, glacial till and a variety of erratic boulders across a windy, treeless landscape.

Hearty crustose lichens can grow anywhere if the air is clean. Those intrepid bacteria-algae-fungi symbionts took hold on bare rock, loosening the structure just enough to allow mosses and eventually grasses to grow. The slightly taller plants trapped debris in their leaves, which decomposed and mixed with rock dust, making soil. Now, with enough nutrients, flowering herbs, shrubs and trees took root. Just a few thousand years ago, the rich forests of Grannyhand Hill that bloom with spring ephemerals and are home to turkey, grouse, deer and bear, were nothing but boulders, sand and gravel. The Ompompanoosuc River must have been a wild thing to see, with no vegetation to hold back the rain.

You can watch the process of succession happening as old New England sheep pastures and plowed fields, abandoned more than 100 years ago, succeeded, first to annuals like ragweed, then to perennials like goldenrod and clumped grasses, and eventually to shrubs and trees, often pines first, then hardwoods. Each step of old-field succession presented a greater diversity of food sources and habitats for animal species. Vertical complexity describes multiple layers of habitat — the canopy, the understory, the shrub layer, the groundcover. Simply put, as land cover becomes more vertically complex, there will be more food and shelter for a wider variety of organisms.

To look over our re-wilded hillside, one might think a negligent gardener lived here. Over the years it has gone from mowed lawn with various grazing animals to, once released, an explosion of pioneer species we think of as weeds, like ragweed and poison parsnip.

Pioneer species usually have long-lived seeds that can remain dormant in the soil, just waiting for a disturbance to set them free. They grow and reproduce quickly, and in the case of parsnip, will blister you badly. After a few years, perennial herbs like goldenrod and bunchgrasses took hold. Then came the shrubs and more herbs — red osier, juniper, cherry, apple, berries, evening primrose and, down by the river, great angelica. As the plants and animals died, their decomposing bodies enriched the soil.

Shrub cover also provided food and shelter for songbirds, who love complex habitat. Song sparrows, common yellow-throated warblers, chestnut-sided warblers, yellow warblers, American redstarts, red-eyed vireos, mourning doves, goldfinch, catbirds, robins, eastern phoebes, house wrens, and cedar waxwings all nest on our little half-acre-more-or-less. It is a wonder we get anything done in the summer with all this nest-building and feeding of young to keep an eye on.

I mow different patches every few years to keep things varied. For even more shelter, we maintain a major brush pile, which we call the Wildlife Housing Project, for local birds, mammals, reptiles, amphibians, and insects. We don’t seem to have a tick problem, which I attribute, without any scientific evidence, to all those birds insect-gleaning.

Allowing our little patch to rewild did have one serious downside: A young doe birthed her twins in the berries two years ago. This proved too much for our little dogs, who jumped the fence to do what dogs do, chase. The doe turned on them and gave chase instead. The bigger dog outran her, but little Luka couldn’t. They collided and the doe kicked her in the neck, rupturing a disc. Fortunately, Luka recovered after a very painful process.

That event caused me to reconsider how wild I wanted the patch to be. So now, I mow a little more, especially where the doe gave birth, but leave the rest to be. Half-acre-more-or-less is our own little biodiverse refuge, a microcosm for happiness.

Micki Colbeck, of Strafford, is an artist, a conservation biologist and a member of the Strafford Conservation Commission. Write to her at mjcolbeck@gmail.com.