Thursday, August 08, 2013

Accepting Defeat - as a strategy toward victory


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.

When we started, this was all buckthorn. We pulled the alien Japanese hedge parsley here – to make sure
that the native species could find spaces to thrive. Was that work necessary? Or were we wasting our time?
Some of us waged campaigns against thistle. But restored plant diversity defeated it too without our help. We now ignore it. Yes, I cringe when there’s a flair-up in a newly brush-cleared area. But I know it will be mostly gone in two years or four.  We devote our thistle time to more important things – like gathering seed.

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, 
Japanese parsley, the white stuff here, seemed ready to totally invade.

and burned the evil mess in bonfires when summer weed-pulling season gave way to fall and winter brush-cutting.

After two decades of annual mid-summer hard work, in 2012 we gave up on Torilis. Was that decision a wise strategic retreat? I shudder a bit as we face our eco-reality check over the next few years.

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.    

14 comments:

Anonymous said...

Stephen,

Thought-provoking prose as always. I think this issue brings up the need for inter-site, inter-county, inter-state networks of communication between stewards of the land. If everyone could similarly share their victories and defeats, it could encourage stewards to make the most of the little precious time they have out in the field. I have been to sites where Queen Anne's Lace is still fervently being pulled year to year. This huge time commitment, and disturbance of soil, could be avoided if stewards had a resource where decades of experience could be available easily.

Daniel

Anonymous said...

We first noticed Japanese hedge parsley on our land in southern Wisconsin in 2001. We decided not to control it due to all the other invasives we were dealing with. By the year 2006, it grew immensely in numbers and spread from the oak woodland/savanna areas into our prairies and sedge meadow. We got nervous and have been controlling it ever since 2006. Today, its numbers are low but it is widespread across our property. Surrounding lands are infested with it as well as all the other invasives. It is hard to say what the long term impacts will be with this species. Some say it does not limit diversity while other call it the “just hellish plant (JHP)” and worse than garlic mustard. I find it easier to control than garlic mustard and sweet clover for example.

This is a great blog site! I read through a few of the recent posts and they are really good – real issues that ecological restoration practitioners face every day. I like the emphasis on the uncertainty of our decisions and our limited knowledge. Thanks for taking the time to post.

David

Paul Showers said...


Could the degree of conservativeness use some additional numbers that connote degree of weediness in addition to what the present number suggests? I'd like to see coefficients for weediness. Eryngium is a nine on the conservative scale, yet it can get aggressive. Why is saw tooth sunflower rated so low, is it because it is very aggressive or because it can grow in a variety of habitats. Shooting star grows is a wide variety of habitats but it sure seems like a native deserving of a ten! It seems to me that many fives in Swink are conservative without being weedy. I understand that the coefficients of conservativeness are used to help managers establish priorities for restoration, but wouldn't a set of numbers for the ruderal be just as possibly more valuable? They could be negative numbers and thus give more credibility to the idea of negative numbers. Reed canary would probably be a negative 10 and carrot a negative one?

Anonymous said...

Stephen, Maybe my strategy toward invasive species is too simplified. I have always held the belief that it is best to clear areas of all invasive species simultaneously. I think much time is often wasted just walking around looking for the one invasive species being targeted. Frequently, other invasives are ignored in the pursuit of that one species. The result of targeting only a select invasive species is an opening of habitat to all the other invasive species that are getting ignored. I'm not saying this applies to your Torillis dilemma. I just wanted to share with you my most general strategy.

I also think the best defense is a good offense. Too many stewards focus strictly on controlling invasives without considering what will replace them. Seed sowing is the ecosystem building that must immediately follow a war on invasive species if lasting success is to be achieved.

Sincerely,

James

Stephen Packard said...

@Daniel. Interesting suggestion. I wonder what would be the best way to do it. The web-based forums I've seen sometimes seem helpful and other times seem like "pooling ignorance." One of our problems is that much of the innovation is on a small scale, and the prescriptions that work on a small scale may be different from what work on a large scale. But it's often the "large-scale folks" who have the resources to publish, etc. Even on the small scale, what works for professional contractors is likely different from what works for dedicated stewards (who are there year in and year out). I like the idea of developing something better sharing of results principally of, by, and for volunteers doing "hand-crafted" restoration. Anyone have ideas for that?

Stephen Packard said...

@David. Thanks for the good comments. I wonder if different kinds of soils could be at play here. We have zero Torilis (JHP) in our prairies and sedge meadows, except at edges near trees. And we seem to have zero in high quality areas anywhere. But your comments make me even more apprehensive as I watch it spread without control this year. Drama!

Stephen Packard said...

@Paul. I agree that it would be helpful to assess the degree of "invasiveness" or "malignancy" aside from the conservativeness ratings. Only a few plants would need to be rated.

Stephen Packard said...

@James. You make two points that are supported by my experience.
First, don't leave one bad invasive while combating others. On the other hand, do prioritize. If there's only so much time, get the worst ones first.
Second, yes, it's critically important to restore diversity as we control invasives. Bare soil is like an open wound. Soil covered with native species - but with little diversity and few conservatives - is only one step up from bare soil.

Anonymous said...

Response to Stephen.

Stephen,

We started with a severely degraded site and while some areas now are very nice, I don’t consider any of it high quality. Our soils have high sand content and Japanese hedge parsley (JHP) seems to love it. Our sedge meadow is Adrian muck but the hydrology was severely altered. We have since corrected this to the extent allowable and that has helped push out JHP. I find JHP in all of our prairies while dealing with sweet clover and it is concentrated along property boundary edges or game trails through the prairie. All of the neighboring lands are hostile (from an invasives standpoint) and well on the trajectory path towards novel ecosystems. I have no doubt that a diverse, stable and high-quality ecosystem can resist JHP. Unfortunately, the reality for us, and the other land practitioners we know, is that our lands are the highest quality around. As you know, it is the sad state of affairs we find ourselves in these days.

David

Anonymous said...

Hi Stephen, On the topic of "... what works for professional contractors is likely different from what works for dedicated stewards ... volunteers doing "hand-crafted" restoration." I went to DuPage County's Mallard Lake Forest Preserve a few weeks ago. There was a contractor there spraying weeds. I could not believe what they were doing. The contractor had a tank mounted on a gator and was spraying down everything from individual plants, to large patches of weeds, and even entire large trees with copious amounts of herbicide. Areas where so thoroughly covered is seemed like he was painting a house. An area that appeared to have been previously treated looked like a nuclear fallout zone where every tree, shrub, and plant was dead but still standing. The application of herbicide was so thick the air was saturated with the pervasive smell of almond extract. I fully know the problems caused by invasive species, but how much herbicide is really necessary to solve that problem? I have accidentally gotten herbicide on some of the plants I propagate and only a few drops are enough to kill them. There really needs to be guidelines made specifically for ecological restoration regarding herbicide usage. It is bad for the ecosystem and people’s perception of ecological restoration when someone is applying 1000 times the necessary dose to treat an invasive species infestation.
Sincerely,
James

Stephen Packard said...

Many of us have deep concerns about the competence of contractors. On some sites huge amounts of money are wasted, and more damage is done than good.

Perhaps sometimes the best strategy is to herbicide everything and start over. In these cases, the site does indeed look like a "nuclear fallout zone." Yet the results may be ultimately beneficial.

On the other hand, I've also seen examples where contractors herbicided old fields rich with pussytoes, gray goldenrod, heath aster, etc. and replaced that good start with a dismal near-monoculture of big bluestem and Indiangrass. In other words, we lose a community that would be easy to restore to high quality by inter-seeding. In its place we get a poor habitat that's likely to stay that way for a long time.

We need better ways to deal with these questions. We do not have a good system of standards.

Stephen Packard said...

@David: I agree with your concerns about "hostile surroundings." I work on sites with huge nearby populations of teasel and crown vetch. These will invade and hurt even high quality sites. Deer eat the seeds and carry them around. In the longer term, it seems crucial that we develop an ethic about what it means to be a good neighbor.

Marion said...

Stephen,
Checking in with you 2 years + after you stopped pulling Torillis japonica to ask "How's it going?"
As a site steward of a high quality woodland I have worried over this invasive, just as you once worried.
Comparing it to garlic mustard is apt for the speed of spread and the way it moves into a high quality woodland plant community. We know garlic mustard is allelopathic. Any work that you are aware of on Torillis in this regard?

thanks for any on-going insights you have gained by letting it go and watching competition play out

Marion

Stephen Packard said...

Marion,
Sorry to hear that Torillis is doing well in a high quality woodland.
My experience with the "do nothing alternative" at Somme has been encouraging. The plant seems to continue to spread initially through recently brush-cut areas, but it seems to decrease gradually down to nothing in the areas that are succeeding toward better quality as the conservatives in the initial seeding take over.
Is your woods an oak woods, and if so is it being burned?
I have the impression the unburned oak woods may have a lot of quality species but still be vulnerable to invasives.
With more time, I may learn more.
And sites may be different from each other in their responses to invasives, as you know.
Stephen