Showing posts with label invasive species. Show all posts
Showing posts with label invasive species. Show all posts

Tuesday, June 13, 2017

When Regulation Simplifies Our Lives

Many reflexively contend that regulation makes life harder, more complicated and constricting, and less convenient. And yet, here, in a packed room of people who wanted to learn more about invasive species, was ample evidence of how complicated an unregulated world becomes. Though many imported plant and animal species do not become invasive, the ones that do become a problem that each individual is then left to contend with. Uncontrolled transport of wood for packing crates coming from Asia, for instance, allowed the emerald ash borer to take hold in Michigan, and spread across the eastern U.S., causing millions of homeowners inconvenience and expense as the ash trees in our yards succumb. 

The same holds true for recycling. Because manufacturers can package their products in an endless variety of plastics, metals and papers, each one of us is then imposed upon to compare each piece of empty packaging to a long list of do's and don't's--a daunting project for even the passionate recycler. Packaging is geared towards maximizing purchase and convenience of consumption, leaving in its wake a hugely complex post-consumer dilemma that complicates our lives and fills our landfills and oceans with trash. Why not, instead, require all packaging be widely, easily, and demonstrably recycled, and expect manufacturers to use their ingenuity to figure out how to comply?

These are the sorts of quandaries that pack the community room at the library. If there were no food safety standards, we'd probably be cramming into the library to find out how to identify diseased beef at the unregulated supermarket, just as we'll each be seeking help to deal with the complicating, destabilizing consequences of climate change.

Regulations, if done well, can greatly simplify our lives. That truth needs to be repeated on a regular basis.

A previous post dealt with some aspects of invasive species in Princeton. 

Sunday, May 21, 2017

Invasive Plant Species in Princeton

This Monday, May 22 at 7pm, the Princeton Public Library will host a presentation on invasive species in Princeton by Mike van Clef, of the NJ Invasive Species Strike Team. There will also be representatives of FOPOS and DR Greenway participating. Princeton municipality hired Mike to develop a report on invasive species in Princeton preserves, and in 2016 he and two interns worked through the summer on invasive species control. Because of the massiveness of the problem, they focused on emerging species--those whose populations are still small enough that a summer's worth of control would make a difference. 

We may look back on 2016 as a pivotal year, when the town began investing in invasive species management, much as 2000 marked the beginning of professional deer management in town. 

Although it may sound self-congratulatory, another important date in Princeton's history of invasive species management would be 2006, when the Friends of Princeton Open Space hired me as their first Natural Resources Manager. 

When I arrived in town in 2003 on the coattails of my wife's appointment to the Princeton University faculty, a couple things quickly became obvious. First, Princeton had done wonderful work preserving land for open space. Second, the open space itself needed a lot of work. Though the trees in Princeton's woodlands were mostly native, the understory vegetation was often dominated by nonnative, invasive plants. Stiltgrass, honeysuckle and privet, to name but a few, had filled the void created long ago when the diverse native understory had been plowed under, back in Princeton's agricultural era. In the decades since, the native trees had rebounded, but the understory had either not come back, or succumbed to heavy browsing pressure from deer.

Because wildlife tend not to eat the leaves of nonnative plants, their proliferation in preserves renders the habitat largely inedible. Yes, birds can eat the berries of nonnative shrubs like honeysuckle, but if the insects and other wildlife aren't eating the leaves, then much less of the solar energy captured in the plants can move up the food chain. 

I proceeded to make the case that Princeton could expand its effective acreage of open space through management for native species. As most readers know, I've been leading workdays and nature walks ever since, for six years as an employee of FOPOS, and more recently as president of the Friends of Herrontown Woods (FOHW). Highly motivated volunteers like Tim Patrick-Miller and Andrew Thornton, and more recently Kurt and Sally Tazelaar at Herrontown Woods, have had a positive impact over time. Meanwhile, FOPOS has sustained its Natural Resources Manager position--having just hired the fourth to hold that position--and continues to do invasive species removal at Mountain Lakes Preserve. After so many years of nonprofit, largely volunteer efforts, to finally get municipal support through Mike's crew this past summer was a real boost that we hope will continue.  

It's important to note that Mike van Clef's study of invasive species in Princeton is limited to parks and preserves owned or managed by the town. There are large expanses of open space owned by the state (Princeton Battlefield and DR Canal) and by the Institute for Advanced Study (the 600 acre Institute Woods). Portions of the Battlefield and the DR Canal are being overrun by porcelainberry (in photo), which barely registers in Mike's survey, and mile-a-minute vine is beginning to show up there as well. I've been trying to help fill a void in management, co-leading workdays at the Battlefield and, in the proactive "early detection, rapid response" tradition, dealing with two small infestations of Mile-a-Minute in town before they become unmanageable. Another nonnative plant that's spreading rapidly, both in people's yards and in nature preserves, is lesser celandine (a.k.a. fig buttercup). It can only be controlled in the spring, long before summer interns begin work. Ideally, a town-wide coordination to manage invasive species would be developed.

The town's investment in invasive species control comes at a critical time. With the emerald ash borer (another highly invasive introduced species) poised to decimate Princeton's most numerous native tree, large gaps will be created in our forest canopy, allowing light to penetrate to the understory. Princeton's long investment in deer culling has allowed native shrubs like spicebush to make a comeback, but in many woodlands, the understory is dominated by nonnative shrubs and stiltgrass. Wildlife have evolved over millenia to eat native species. It's a question of whether edible natives will capture that extra sunlight in the understory, or the privet, winged euonymus, honeysuckle, barberry and Photinia. The foodchain depends on our intervention.

The primary argument for habitat management remains that, by improving the quality of habitat, Princeton effectively increases the functional acreage of open space. This is true not only for wildlife but also for people. Controlling invasive species also makes the human experience in preserves more rewarding. As we've cut down invasive shrubs at Herrontown Woods, we've not only made more sunlight, water and nutrients available for native species to prosper, but also have opened up pleasing vistas and made the woods more navigable. 

The problem of invasive plants may seem overwhelming, but we can take our inspiration from the deer, who transform landscapes through the cumulative impact of browsing here, there, and everywhere, one mouthful at a time. The pioneers, too, thought the continent too vast to ever tame. Though their goal wasn't exactly to increase native plant diversity, they showed how steady effort makes a difference over time. Ideally, professionals will complement existing volunteer efforts, and the locals who know the preserves best will help steer the professionals' interventions. 

At Monday's presentation, there will also be discussion of a list of invasive species that people are being discouraged from planting. It's a very long list, and I wish it could better reflect the broad spectrum of invasive behavior we see in the field. One reason the list is so long is that, though many of the species on the list may not be found spreading into Princeton's nature preserves, history shows that invasive behavior in nonnative species may not become manifest until many decades after they've been introduced. Chinese silver grass (Miscanthus sinensis) is a case in point. Though it has yet to spread to Princeton's Tusculum meadows, it is now posing a big problem for meadows at Duke Farms up in Hillsborough. The flyer for the library event includes a photo of butterfly bush, which I've never observed exhibiting invasive behavior. Monday's presentation may help put local observations in a broader context.

Update: Full house for the program! Good to see.

Friday, May 05, 2017

A Garlic Mustard Success Story from Michigan

Back in the 1980s, while I was accumulating credits for a masters degree in water quality at the University of Michigan, I did some academic moonlighting and took an "expository writing" course taught by Alyce Depree. She had us adopt pseudonyms (mine was Snupulus Lupulus), fed us a steady diet of George Orwell, and had us write and rewrite 2-page essays. It was a wonderful, validating experience.

Last summer, heading back to Michigan to play a jazz festival, I reconnected with her. Out of the blue, she told me the inspiring story of her long but successful battle with garlic mustard--an introduced species that has displaced trilliums and other native wildflowers in the woodlands where she lives in Holland, Michigan. She later wrote up an account of her experience.

I'm posting this when just a few blooms remain, but you should still be able to find it growing along the fringes of your yard, or in a woodland nearby. Perhaps you'll be moved to action, in your yard and beyond, as Alyce was many years ago, with heartening results.

Here's her account:

Hi, Steve...You've caused quite a chuckle here this few people for so long cared about what was occurring in their woods on the west side of the state that my cousin and I spent almost as much time encouraging ourselves not to give up as we did actually picking! The tables have turned (mixed metaphor), in the spring the local churches (of which there are many) organize their congregants and Sunday school kids to go over various ground areas and parks in the Holland area...that is making quite a difference.

In my cottage area along the lake, and my cousins', we noticed sixteen years ago that our lovely banks of trillium in the woods simply no longer appeared in springtime. What we had instead was this aggressive leafy plant with cute little white blooms that grew higher and higher during the spring until, by June or so, could be four feet tall and going to almost looked like phlox, except that the blooms were single, not developed into bunches or clumps. So we did some research, and discovered what it was called and how it was edible (yuck) and that our venerated forefathers had brought it with them from England, mostly, as it would give them something green...and last and last and last. Which it does. It's a two-cycle plant; first year establishes the root, second year establishes and spreads (by "popping" out) the seeds every time wind or an animal comes in contact to move the branches. Each mature second-stage plant can have hundreds to a thousand seeds. It is generally the first plant to begin showing after winter...spreading out quite quickly with many leaves that cut off the sunlight from surrounding and still dormant plants or seeds. Additionally, the root...which resembles a skinny parsnip...exudes a poisonous substance which makes the soil unfriendly to wildflower growth in general AND also strips the protective coating off tree soil diseases can then attack the trees.

 We found that, while people can be casual about wildflowers, they aren't casual about their trees; however, they are "terribly busy." Anyway, my cousin and I decided we'd rid ourselves and the immediate area of garlic-mustard. We figured we could do a five or six property area...talked and talked with the owners but didn't really convince them, so then took on the job ourselves. After experimenting with RoundUP and discovering not even that would kill the plants, and learning from internet that the state of Wisconsin had been trying to get rid of them with no luck, we began with local college kids, paid them $12 per hour, lunch, and snacks, and then joined them ourselves, pulling and digging (you have to get the root!) for about ten days. We filled hundreds of 30-gallon black plastic bags with the ill-smelling plants, let the contents rot for a month, and then gradually put them out for garbage pickup.

 We picked and pulled the five properties for the next ten or so years..."harvest" getting less and less (the seeds last 5 years in the ground) owner gets his own grandchildren to pick their woods now...we continue to work four properties and now only get about 15 bags, max. We figure we're down to just maintenance now plus some plants from seeds borne by the winds. The past three years we have not hired anyone to help...just do it ourselves and are glad for the exercise. The trillium is back and glorious. Also a wild yellow ground lily and jack-in-the-pulpits. Amazing how sixteen years flies by....and no chemicals, too.

(Thanks to Alyce for sharing this account!)

Photo below: Garlic mustard extending into the woodland below Quarry Park in Princeton.

Friday, March 03, 2017

Porcelainberry: the Vine that Ate Princeton

Here it's Friday of National Invasive Species Awareness Week, and nary a post about invasive species!

First, readers should be aware that there are contrarians out there, writing books, articles and opeds, trying to deny that invasive species are a big problem. It's fascinating to analyze their mental gymnastics and deceptions, which are similar to those used to deny the reality and danger of climate change. I've picked apart their faulty logic in posts that can be found at this link.

Now, on to our porcelainberry tour of Princeton. You won't find it in shady areas, where other invasives like stiltgrass, garlic mustard and winged euonymus thrive. Rather, porcelainberry threatens to smother all of those sunny openings and edges that shade-intolerant plants depend on for survival. Porcelainberry is related to our wild grape, but much more aggressive. Your first impression will be, "What lovely multicolored berries!"

Your second impression, as it climbs up the stems of your shrubs, like this elderberry, might be, "Oh, a little rambunctious, but those berries are so pretty!"

Your third impression, as it turns your yard or park into a monocultural topiary, will be more along the lines of, "OMG! HELP!" No, this is not kudzu growing along a freeway down south. This is porcelainberry winning a modern day Battle of Princeton, with stealth and persistence far beyond anything we distracted humans might muster.

This is what a nearby patch looks like in December, just down the road from the Princeton Battlefield, along Quaker Rd between Mercer and 206. Invasive vines and shrubs can seem less overwhelming in winter, which is actually a good time to remove them. In spring and summer, though, all that growth energy can be intimidating.

And this is what porcelainberry is doing to the sunnier portions of our lovely nature trail off the DR Canal Towpath near Harrison Street. The blackbirds may say hello to the berries, but it's bye bye to the diversity of native wildflowers underneath that foliar blanket.

Turns out porcelainberry's a soccer fan. Here it is in the cheap seats at Princeton University's Roberts Stadium, at one end of the field,

and at the other.

Here it is (light blue and pink berries) in that "second impression" stage, climbing over a honeysuckle shrub (red berries) at Quarry Park. Give it a few years and it may reach the "OMG" stage.

I haven't seen much of it in eastern Princeton yet, but we'd be smart to keep an eye out and remove it before the berries mature.

Otherwise, sunny edges everywhere will look like these hapless flowering dogwoods, planted at Princeton Battlefield in 1976 for the nation's bicentenial, and now struggling to survive beneath a spreading blanket of porcelainberry.

Note: You can help liberate the dogwoods from the porcelainberry and other vines on Saturday, April 1 at 1pm. I've been collaborating with the Princeton Battlefield Society on invasive species work for the past several years, and will be leading a group to preserve the dogwoods that line the field on the north side of Mercer Street.

Another group of volunteers will be continuing the multi-year effort to reduce the bamboo clones near the Clark House, which we're actually having considerable success without herbicide. 

For purposes of identification, here are a couple closeups of porcelainberry. The berries are distinctive, with different shades of blue, red and white.

The leaves are easily confused with wild grape. This photo shows how variable is the shape.

I hope everyone's having a happy National Invasive Species Awareness Week. We'll end with a short Q and A:
  • Are all nonnative plants invasive? No. Nonnative refers to origin. Invasive refers to behavior.
  • Why are invasive plants invasive? Oftentimes, it's because the native insects/deer, etc don't eat them, giving them a competitive advantage. To regain the balance we lost by introducing species that evolved elsewhere, people end up having to be the herbivores, wielding saws and loppers.
  • One nice thing about invasives? They get us out in the woods for workdays. 

Sunday, February 26, 2017

Winter Aconite and Fig Buttercup (lesser celandine)--Related Flowers, Contrasting Behaviors

Both of these non-native wildflowers are in the family Ranunculaceae. Both bloom early and have pretty yellow flowers. While one appears to be modest and highly local in its spread, the other spreads so quickly across yards and into neighbors' yards and floodplains as to pose a threat to gardens and natural areas alike.

Here's winter aconite (Eranthis hyemalis) opening up a week ago in my garden, a legacy from the previous owner. Its modest spread is easily contained. I've never seen it spreading into nature preserves. Note the leaf shape, which distinguishes it from the related wildflower below.

Update: For comparison, here is one of the first blooms of lesser celandine in 2021, on March 30. Note the shape of the leaves, which are "entire" rather than lobed. Just to confuse things, lesser celandine is also called fig buttercup, and its latin name Ranunculus ficaria has apparently changed to Ficaria verna

People think lesser celandine is pretty, transplant it to their gardens, then begin having regrets as it spreads uncontrollably to dominate their gardens and yards. If you are one of the distraught gardeners wishing you didn't have this flower, and not wanting to impose its spread on the rest of the neighborhood, late winter is the time to deal with it. 

Other posts on this subject can be found on this website by typing "celandine" into the search box. A post called "Will the real lesser celandine please stand up--a confusion of yellows" helps with identification.

Though I'm no fan of herbicide, that tends to be the only workable option in the majority of cases. I'm no expert on herbicides, but have been told that for lawns, a broadleaf herbicide like Weed Be Gone is effective. For flower beds, a 2% formulation of glyphosate (Roundup or equivalent) works well. Monsanto doesn't hold the patent any longer on glyphosate, so it's possible to buy if from other companies on the internet. I use a wetland-safe formulation, but for most yards, away from wetlands, some spot spraying with Roundup or equivalent should be okay. The plant itself is poisonous to wildlife. 

There have been other proposed means of killing the plant: 
If you blanket the whole infestation thoroughly with mulch, e.g. a layer of cardboard covered leaves or hay or woodchips, it might kill the lesser celandine if you mulch as soon as the plants leaf out in late winter. Chances are, you won't cover it soon enough, or you'll miss some spots, and the lesser celandine will benefit next year from the fertilizer in the mulch. 

This concoction has shown up on the internet: 1 gal white vinegar, 2 cups Epsom salts, 1/4 cup Dawn dishwashing detergent in a hand held 2 gal pump sprayer. Spray in bright sun on a windless day.
But I couldn't find evidence that it has been carefully tested, nor that it would kill the roots. If the roots survive, the plant will be back next year. The concoction contains an acid, and the salts are made of magnesium and sulphates. These may or may not be harmful to the soil if used to excess. 

Monday, January 16, 2017

Starlings, Passenger Pigeons, and the Uneaten Acorns

Acorns, anyone? It's called "flooding the zone"--a technical term commonly used by botanists who grew up playing sports. Some people see it as a mess, and curse the trees. An alternative target for cursing, just to put it out there, would be the tree-phobic landscape of concrete and lawn that we impose beneath the trees. A forest floor is far more accommodating of arboreal excess. There, a tree can let it all hang out, let it all fall down--seeds of all sorts, leaves, branches--and the forest floor will shrug, take it all in, and turn it into wildflowers.

In town, the blanketing of acorns turns into a blanketing of oak seedlings, few if any of which have any prospects of reaching maturity. The seedlings seem to be saying, "Move me to an opening along the street where I could shade some asphalt", but it doesn't look like people are listening.

For some people, a love of trees is layered with deep resentment of this fecundity. For me, looking for logic in nature's ways, the question is not "What to do with it all?", but "What's missing?" Past posts about osage orange and honey locust ask the same question, and suggest a missing herbivore that would have consumed the abundance in the past. Botanical abundance has lost a once complementary zoological abundance.

A partial answer came this past Nov. 10, when masses of starlings swept through, congregating in the pin oaks behind our house. A closer look revealed they were gobbling down acorns. Minutes later, they were gone, having left our pin oaks a little lighter.

The starling is not native, though, so doesn't speak to what would have consumed the oaks' abundance historically. And starlings appear too small to deal with the larger acorns of other species such as red oak. Still, it's behavior suggests that the spectacular fecundity of oaks might once have fed a complementary fecundity in the avian world--some highly mobile species, large enough to deal with a broader range of acorn size, that could make quick wing across eastern North America, swooping in to feast and move on.

Enter Ectopistes migratorius, a.k.a. the passenger pigeon, a bird of spectacular mobility and historical numbers. The photos are from a wonderful NJ State Museum exhibit two years ago.

A fine writeup on the Smithsonian website says "the mainstays of the passenger pigeon's diet were beechnuts, acorns, chestnuts, seeds, and berries found in the forests." They may also have swept in to feast on the seeds of our native bamboo, Arundinaria, which at one time covered large areas in the southeast and, like other bamboos, typically bloomed only once every several decades.

It can be tempting to say that the starling is providing a service by partially filling the void left by the extinction of the passenger pigeon. A few books have come out in recent years that claim invasive species like starlings aren't a big problem after all. The books in turn embolden news editors to publish articles and opeds with a similarly seductive revisionism, showing the same willingness to cherry pick evidence and rush to conclusions. I've written detailed critiques of various of these, including one recent article that mentioned starlings.

It would be interesting to explore to what extent the massive numbers of starlings have filled the niche left empty by the extinction of the passenger pigeon. Though feeding habits may overlap somewhat, one big difference is likely to be nesting behavior. Starlings compete with native birds for nesting sites, while the passenger pigeons appear to have built nests on branches, where they would not have displaced birds seeking tree cavities.