Foreign Invader Hydrilla Gets Its Green Card


The first reference I could find (via Nexis) in the Washington Post to hydrilla, an asian water plant that "invaded" the Potomac River in the early 1980s, is headlined "'Monster' Hydrilla Takes Hold on River; Aquatic Plant May Grow Out of Control." That article appeared in the April 29, 1984 edition. Five days later another short Post item read:

Hydrilla, called "the killer weed" by Mount Vernon District Supervisor Sandra Duckworth, is a rapidly reproducing, oxygen-eating plant that clogs waterways, interrupts the food chain and emits a foul odor when it decays in the fall. Since it was discovered on the Potomac's shores two years ago, hydrilla's growth has gone unchecked, and aquatic experts are forecasting a lifeless and foul-smelling river if the plant's progress is not soon checked.

The hydrilla story seemed to be following the well-worn script of ecological hysteria about introduced species. However, in this case, good sense fairly quickly prevailed over incipient alarmism. A year later Maryland's Department of Natural Resources supported a bill that would limit the cutting of hydrilla. Chesapeake Bay Foundation spokesperson Will C. Baker told the Post that hydrilla was beneficial, noting:

"Hydrilla does the same things" all aquatic grasses do, said Baker… "It buffers against erosion, screens sediments, reoxygenates and clarifies the water and serves as habitat for aquatic species and as food for waterfowl."

Twenty-two years later, a Science Notebook item in today's Post reports:

But a new study by the U.S. Geological Survey has found that hydrilla is not such a bad neighbor after all. The submerged plant, which can grow to the surface and form dense mats, did not impair the reemergence of native species at a time when officials were working to reduce nitrogen concentrations in the river from sewage-treatment facilities, the study found. Cutting nitrogen levels reduces algae blooms and allows more light to get to the bottom of the river, which in turn permits aquatic plants to grow.

Hydrologists Nancy B. Rybicki and Jurate M. Landwehr of the USGS examined data between 1985 and 2001 in aquatic plant beds in the Potomac.

"As hydrilla increased, the other plants increased," Rybicki said. "In a particular year, if the water quality was good and the plants increased, not only did one species increase, the others increased as well."

The hydrilla also has been a boon to waterfowl, which eat the plant's tubers, a kind of underground stem, in the winter, Rybicki said. The research appears in the May issue of the journal Limnology and Oceanography.

Of course not all introduced species are benign–West Nile Virus comes to mind–but the war on them is a bit hysterical. This point was well made by Alan Burdick in his 2005 Discover article "The Truth About Invasive Species: How to stop worrying and learn to love ecological intruders." I will immodestly note that this is exactly the point that I made five years earlier in my reason article "Bio-Invaders: Are we under attack by 'non-native' species? Should we care?"

Addendum: It is only fair to mention that folks in Florida have a different take on hydrilla.

NEXT: Climbing the Ladder...of Death

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  1. Bailey’s in the pocket of big kudzu!

  2. Yeah, kudzu. And those damn starlings and house sparrows.

  3. So, some invasives are a problem and some aren’t.

    And some that aren’t a problem in one location are a problem in another.

    And we don’t seem to be very good at pridicting what will happen in any environment.

    Still sounds like a pretty good case for caution.

  4. Speaking of Kudzu, did you know that if you take Kudzu extract and drink, you get drunk twice as quickly? It’s true, it’s true!

  5. ok, so I made up the “twice as quickly” part. But you get drunk more quickly, so take some kudzu next time you are going out to the bar and save some cash.

  6. So… because the CURRENT theory as reported in the Washington Post on hydrilla’s presence in the Potomac River is that it is benign, invasive species are therefore not something to be concerned about?
    This is the weakest argument I think I’ve EVER seen. It certainly doesn’t deserve an entire post like this.

  7. Well, since this is useless, let’s hijack the threat and drag it out for 50 or so posts…

    What about making a wacky comedy, staring the corpse of Jerry Falwell, in a Weekend at Bernie’s-style fun fest.

  8. Taktix.. I like your style

  9. Haven’t the Snakeheads eaten everything in the Potomac yet?

    Snakeheads. Snakeheads.
    Itty bitty snakeheads.
    Eat em up, yum.

  10. Look, if Hydrilla turns out to be a problem, we just get the hot midget chicks and have them summon Mothra. Geez, do I have to think of *everything*?

  11. How could a magazine called “Reason” take the side of the hydrilla deniers?

  12. *Hooks up IV line of Old Milwaukee to Stevo.

    4-6-4 is NOT a HAIKU.

    *summonses THUNDERCHICKEN to peck him on the taint.

    Awesome Taktix!!!!!

  13. I’m thinkin maybe a kudzu/wacky tabacky cross?

    purple haired sticky buds that grow 3 feet a day?

    if I could just make ethanol from the waste…

  14. Anything written in English is not a haiku, VM. Only the original Japanese is allowed.

    Since stupid HTML is unfriendly to the superior Japanese language, I am forced to type in cursed Romanji:

    Senbon-no kuki
    Kiri-o sasu

  15. And those dreaded zebra mussels and round gobies are now being credited with cleaning up and clearing up Lake Erie enough that it is now considered an exceptional body of water for fishing, especially smallmouth bass.

  16. oh yeah. um.

    Kyoto. Tokyo. hai.
    Seppuku. Nagasaki.
    Nippon Yamato

  17. Are Europeans an invasive species?

  18. You’re faking it, VM, I can tell. Your German est muy migliore.

    Say oki opai. It’s the most useful thing I learned in Japanese class, other than, perhaps, wakarimasen.

  19. d’oh.

    I would have gotten away with it, too. Had it not been for these kids. And their dog.

  20. Were those meddling kids, perchance?

  21. Nah – they were actually playing in their own yard, but they overheard me muttering to myself. The medication, you see. It’s the medication. I cannot tell if the inner monologue is an outie.

    My fault, really.

    Kinda like on the Howard-Dan Ryan/Red line El – in the tunnel you kinda space out and, next thing you know, you’ve started BATIN. Clark/Division… Chicago… BATIN… Grand (escorted off train)


  22. Rimfax,

    Yes the zebra mussel scare is instructive. I remember going out on Lake Erie as a kid and you couldn’t see one foot into the water. Today, in places you can see the bottom of the lake. Granted, apparently some of the beaches are constantly having to clean up washed-up mussel shells, but the way those little buggers cleaned that lake is amazing.

  23. VM,

    That’s okay. I was talking to my unborn daughter last night, trying to persuade her to be, well, um, born. My wife is no longer happy with the pregnancy process, you see. And she just can’t understand how she’s still carrying our child when she’s due this Friday. Of course, I’m speaking to a child who presumably has no ingl?s.

  24. Such is the mystery of childbirth!

  25. I missed your mention of the gobies. Now, the problem is that the gobies, which have arrived from Europe, are eating so many young zebra mussels that the population may decline that Lake Erie may once again become an algae-filled nightmare.

  26. Yeah, kudzu. And those damn starlings and house sparrows.

    But according to Alton Brown, Kudzu is good eats!

    We need to get Mitt Romney and his varmit gun going on the starlings and English sparrows.

  27. Oh, and anybody who’s happy about invasive species, I’ve got some fireants and wooly adelgids to sell them.

  28. Of course, I could speak to her in pure Indo European, reaching into her Aryan roots. Ve must Reichweite das Kind!!!

    Although my niece has the Hitler Youth look going, I think my German blood may fail when kombiniert with my wife’s rich, half-Columbian genes. We shall see.

    Oh, and all hail Alton Brown. My daughter will be spoon fed a regular diet of Good Eats and Mythbusters. Which I think may be the same show.

  29. Then there was the mythsmashers episode of Good Eats, just to throw your world into greater uncertainty and awesomeness.

  30. After I got West Nile Virus, I gained the ability to extract rents from Sally Struthers.

    Believe it, or not!

  31. lunchstealer,

    I sometimes wonder if Alton Brown and Adam Savage aren’t the same person.

  32. On Lake Guntersville, down here in Alabamee, the TVA freaked out when the hydrilla attacked. They sprayed. They cut. They drained it. To no avail. The lake is now full of it. That and milfoil. Turns out, this lake in now considered one of the best fisheries in the Southeast. They still cut boat lanes and do controlled spraying in rec. areas and for residents, but it’s no longer an issue and the fishing is awesome.

  33. Are the hydrilla illegal immigrants, or do they have green cards?

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