Combating an Aerial Assault: Phragmites Seed

A sea of Phragmites (about 20 acres worth) beneath an awe-inspiring blue October sky;
plants propagate quickly by rhizome (rooted expansion), but the broom-like seed heads also set new pioneers by wind

With raindrops steadily falling for the second day in a row, winds howling, temperatures nose-diving, and the possibility of snow showers in the extended forecast for the first time this season, I thought an image of last week's blue sky might be warranted. But for as beautiful as the top of the image above feels, the bottom is pretty ugly. This is an overview taken from the south side of one of our outlying parcels ("Parcel 2") facing northwest toward Sandusky Bay (which is just beyond the cottonwoods in the middle of the image).

Late last week, Phrag seed literally blanketed much of the
downwind vegetation; this dogwood is hardly recognizable
(click to enlarge)

The view encompasses about 20 acres (~20 football fields), but there isn't much visible other than the highly invasive thorn in the marsh community's proverbial side: Phragmites australis. I've spoken on this subject plenty already, but this plant truly is a menace. It can grow from nothing to 16' tall in a single season. It can produce an astounding 200 discrete stems in ONE SQUARE YARD! And as the image above demonstrates, it can make a monoculture out of a marsh in no time flat.

Dry conditions a year ago literally about sucked the life out of this stand. As of last fall, only a few smaller pockets of lush green sustained the dwindling Phrag, and it looked like more upland competition might actually win out. This is not something we are used to seeing. It looked like good fortune.

But note that I said the dry conditions about sucked the life out of the stand. This year's historically high water levels in the lake and bay meant an influx of new moisture, and the Phragmites got the upper hand . . . and then some.

This is our largest wetland area where we do NOT have the ability to manipulate water levels. If the water goes way down, a more upland mix may take root. If the water level goes up, a sea of Phragmites ensues.

Parking lot planter

This is a case not just for the ongoing funding of the aerial Phragmites spraying program (which we participated in back in 2015 but regionally lost funding for in 2017). It is also a case for the merits of marsh management within an earthen levy system (aka diked marshes). Water drives all life; and even an inch or two can make the difference between rich habitat and a virtual vegetative dessert in a wetland setting.

Seed dispersal like we are seeing at present at the marsh is disheartening on one hand, but the good news is we have learned how to minimize the negative impacts by keeping high water on adjacent habitats at this time of year and during the early couple months of next spring/summer. But make no mistake, as the photo-op from a recent visit to a Detroit Airport parking lot makes clear (see right), even the slightest opportunity can be made good by a strategically placed, opportunistic Phragmites seed. Like it or not (and I don't), it's one amazing plant.

[I have consciously decided not to include images taken off-site of the marsh, but this one was just too good -- or bad -- to pass up. Be sure to click to enlarge.]

The Fiercest Invader Yet

What may appear on first blush to be tranquil and serene now amounts to the single largest vegetative management challenge on Lake Erie coastal marshes (and beyond). It may present the biggest management challenge, period.

So, let's recap a bit. A bug can create problems (emerald ash borer) and a bug can solve problems (loosestrife beetles), but one common thread and nearly universal truth already developing is that invasive species tend to be a major problem with far-reaching negative consequences. Therefore, invasive species, particularly plant species, are central to both the marsh landscape and the management of the landscape. To continue the tale then, we move to the next chapter.

Just as researchers and managers on the ground were starting to make headway via the Galerucella beetle and purple loosestrife was starting to show a chink in the armor (late 1990s in the Western Basin), yet another aggressor, Phragmites australis, or "Phrag" as it is affectionately referred to by many, was on deck as the next big invader.

To understand why this invasive was poised to fill any void, the role of water levels should be briefly explained. One common refrain that I'll do my best not to repeat ad nauseum is that water levels -- and the timing and extent of water level fluctuations -- are the engine that drives most all other living things in the marsh. Even an inch or two more or less can mean all the difference as to what plants grow (or don't grow) . . . and the resulting plant diversity (or monoculture) has a profound domino effect on everything else that might visit or rely on the resulting vegetative community.

It is also important to understand that Lake Erie -- and all the Great Lakes, for that matter -- have historically undergone cyclical swings in basin-wide water levels, typically measured over decades. The southwestern Lake Erie region had undergone a significant spike aptly referred to as "high water years" in the early 1970s, but by 2000, Great Lakes water levels had returned to long-term averages. As water levels continued to drop, the table was set for "Common Reed" (P. australis) to become entirely too common.

While there is (or at least was) a native taxa, the Phrag that quickly began forming dense thickets of vegetation unsuitable for any other native fauna was another Eurasian import. The unusually broad growth tolerances in terms of water levels (moist soils to water depths of more than 3' -- unheard of by native species) along with the rapid expansion of above ground biomass (up to 20' horizontally per year) -- meant that Phrag could block light to other plants in an evolutionary instant and convert a broad range of wetland habitats into a Phragmites monoculture very quickly.

And convert it did. Consider further that Phrag can grow up to 20' tall (8-12' on average in Bay View) and so thick that a grown adult is hard-pressed to walk through it, and it becomes clear why Phrag quickly became a force to be reckoned with. At it's worst, Phragmites may have covered 25% of Standing Rush property. The only reason it didn't press further was (1) it was in a turf war with loosestrife early on, and (2) water levels could be intentionally kept high enough, long enough, that Phrag could only go so far.

This is a chapter with many subplots, so more on the oh-so COMMON reed will most certainly follow.