The battle against invasive species is a new phase in
ecosystem conservation. The depth of our strategy and analysis is still
shallow. We have done a better job at raising the war cry than at planning the
campaigns.
“Obscene, in fetid
patches clustered,
Defiant stood the
garlic mustard …”
Thus began a poem by then North Branch poet laureate Jim
Cutler. In the early days, garlic mustard and wild parsnip seemed daunting. At
one point chest-high sweet clover filled all the major openings of Somme
Prairie Grove. Today it’s largely gone, as are the evil clover and parsnip.
Back in the daunting days, we wondered at times whether to
fight or give up on various species. Kentucky bluegrass was everywhere, but its
actual impact seemed modest. We ignored it. It’s fading out.
For a while we pulled wild carrot. But it wasn’t our top
priority, and we noticed that it went away on its own within a few years wherever
we didn’t have time for it, so we stopped wasting troops on carrot.
But what do we do when unfamiliar new “invasives” show up? Potential invaders present a different sort of challenge. When Japanese hedge parsley appeared, we worried. We studied in in the scientific literature without learning much. We looked nearby and found areas where it seemed to have taken over completely. We thought: perhaps the best solution is to eliminate it quick, while there are just a few plants. To ignore a new, possibly scary species – which may or may not turn out to be harmless – is a gamble.
We had made that gamble wrong – with white sweet clover. Just a few plants at first, we ignored them. Soon the dastardly stuff was waist-high over many acres. Grrrr.
Then sweet clover became a nightmare. We scythed, pulled, and taxed people’s backs. It challenged our energy and resolve at the hottest time of the year. I remember episodes of heat stroke and chiropractor bills. But we beat it, and it’s mostly gone.
But what do we do when unfamiliar new “invasives” show up? Potential invaders present a different sort of challenge. When Japanese hedge parsley appeared, we worried. We studied in in the scientific literature without learning much. We looked nearby and found areas where it seemed to have taken over completely. We thought: perhaps the best solution is to eliminate it quick, while there are just a few plants. To ignore a new, possibly scary species – which may or may not turn out to be harmless – is a gamble.
We had made that gamble wrong – with white sweet clover. Just a few plants at first, we ignored them. Soon the dastardly stuff was waist-high over many acres. Grrrr.
Then sweet clover became a nightmare. We scythed, pulled, and taxed people’s backs. It challenged our energy and resolve at the hottest time of the year. I remember episodes of heat stroke and chiropractor bills. But we beat it, and it’s mostly gone.
I now wonder if we perhaps made the wrong choice with Japanese thicket parsley (Torilis japonica). In that case, we made the opposite gamble. We tried to wipe it out. It even had its own poem:
“Torilis.
Horrilis.”
That’s the whole poem, a sub-haiku by North Branch steward Laurel Ross. We hated the nasty little parsley for many years. Worse than sweet clover, it hides in the shrubby edges where the mosquitoes are the thickest. Even worse, unlike sweet clover and garlic mustard, which we could just dump in out-of-the-way piles, this menace clings to animals, which then bring it everywhere. I stuffed it into bags, saved them in the garage,
and burned the evil mess in bonfires when summer weed-pulling season gave way to fall and winter brush-cutting.
This year I find it luxuriant in many places. Much thicker than ever. Next year I
anticipate it will be worse still. And yet I have some confidence it will fade away to very little over time. Yes, it will fester for a while where new brush has been cut and the
ecosystem is an open wound for a few years – while diversity builds from our
planted seeds.
But over the years, Torilis seems to have revealed itself as a Georgy-Porgy that only does its
mischief against weaklings. “When the big boys come out to play” – if it could
– it would run away. Instead it strangles, starves and dies against the better-adapted
competition.
I found the battle hard to give up. We had put so many years
of agony into combating it, just in case. We were successfully holding the worst populations
at bay. But we weren’t coming even close to wiping it out from the site. And it
was occupying our time.
A strategic retreat seemed best. We accepted defeat in a
battle – with some confidence that the larger war would go better if we
focused our forces more wisely.
Teasel, crown vetch, purple loosestrife, reed canary grass –
these are serious killers of rare ecosystems. We now battle the last of them at Somme with all our might – unencumbered by trivial visions of victory over
Torilis.
As with human medicine, the diagnoses and
prescriptions we use in restoration are partly art and judgment. Priorities and assessments change. We
learn, and many of our ecosystem patients get healthier, richer, and more
beautiful by the year.