Connection between Lyme disease and invasive Japanese Barberry.

[Sarcasm the elf]

Hi All,

I recently came across this article about the connection between the invasive Japanese Barberry plant and the population of Lyme disease carrying ticks, and also found this video made by UCONN researchers on the same subject. I wanted to share them due to the significance this has to hiking both on the A.T. and on local trails in the northeast. I know that the local trails I hike in Connecticut that are covered with this plant are where I find the most deer ticks by far.

Originally from The Fairfield County Weekly.

Researchers from the Connecticut Agricultural Experiment Station returned from studying invasive woodland plant species one day to find themselves mysteriously crawling with ticks."I've been working in these forests for 30 years, and I'd never been covered with ticks like that before," recalls Jeffrey Ward, chief scientist with the station's forestry and horticulture division. It was a puzzle that triggered new research and a surprising link between an invasive plant, our rising deer population, and one possible explanation for why Lyme disease has become such a health threat.The woods through which Ward and his colleagues walked that day were filled with dense patches of Japanese barberry.Introduced into New England in 1875, once Japanese barberry spread, having no natural predators or pests in North America, this ornamental import went wild. It can now be found in patches hundreds of acres across in some Connecticut towns.Turns out that Japanese barberry is poisonous to deer. So deer browse on other woodland plants, which would otherwise compete with barberrry for space, sunlight and nutrients. Less competition gives this insidious invader more opportunity to spread, which it does with amazing speed in favorable locations."It spreads across the landscape like a fungus," Ward warns.Dense patches of Japanese barberry leaves are a perfect place for ticks to cling.In areas where there are lots of deer there are more ticks carrying Lyme disease.An experiment carried out by Ward and his colleague Scott Williams, an assistant scientist at the station, found that woodland areas uncontaminated with barberry had about 10 Lyme-disease-ticks per acre. In sections with dense Japanese barberry, the number of disease-carrying ticks was as high as 126 per acre. When they killed off all the alien barberry they could find in a specific portion of forest, the Lyme tick count rapidly dropped to about 41 per acre.And guess where you can find some of the biggest, densest concentrations of Japanese barberry in this state?That's right: Lyme, Connecticut, the place for which the disease is named. "In Lyme, there are huge patches," Ward says.It was in Lyme, in 1975, that doctors decided to classify the 50 cases of pediatric arthritis that had turned up as a new illness. (Later research traced indications of the disease as far back as 1883 or much earlier.)The trip into the woods that started this line of research occurred back in 2007, according to Ward. Scientists at the station and at the University of Connecticut have been studying the connection ever since.One confirmation of those studies is that, in states with high concentrations of Japanese barberry invasions, you also have high incidences of Lyme disease ticks.This stuff isn't easy to kill. Recommended treatments includes burning it out with controlled fires, using propane torches, brush saws, or (if it's taller than 3 feet high) mechanical "drum choppers," expensive machines that sort of resemble a combination snow blower and roto-tiller.Ward is still dazzled by the unanticipated connection between an alien plant and the spread of an insect-born disease.Ward says the apparent link between Lyme disease and this plant was one orf the most interesting findings they've [email protected]
Copyright, 2012, New Mass Media. All Rights Reserved.


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[coach lou]

Elf, very interesting. Here in Saybrook I haven't seen much, and our cats and I haven't gotten any ticks. But, our cat at work, in Branford, gets covered with them. Tommorrow, I will check the grounds at work for Barberry, and next weekend I will ride my bike over the bridge and go check Lyme out. I am very lucky, I am super sensitive to things crawling on me,so I have only had one bite me, ever, but she must have only been there for minutes 'cause she was not very deep. Good post!!!

[tiptoe]

Thanks for posting this, Sarcasm the Elf. I'm going to watch the other two videos as well. My back field has some barberry, but nothing like what the video shows. Nevertheless, the whole area is crawling with ticks, and I've had Lyme once and erlichiosis, another tick-borne disease, twice.

[Pedaling Fool]

I'm skeptical of the report, would have to see more data, which I couldn't find. This all was started by researchers from the Connecticut Agricultural department, and those guys are always complaining about invasive plant species, wouldn't be the first time I've seen them try and hype a situation.

I also watched their video on how to control barberry, typical methods nothing out of the ordinary. In other words not really a method for controlling if this plant is along the AT corridor (which I'm kind of curious how much it does cover). At least they didn't give the brain-dead advice of cleaning your shoes at trailheads, like that issue in Pa.

[Sarcasm the elf]

I'm skeptical of the report, would have to see more data, which I couldn't find. This all was started by researchers from the Connecticut Agricultural department, and those guys are always complaining about invasive plant species, wouldn't be the first time I've seen them try and hype a situation.

I agree that it seems premature to declare a causal relationship after such a limited study, but I do suspect that there is some merit to this theory. Having lived and hiked in Connecticut all my life I know that there is a definite correlation between the amount of the vegetation at ground level and the tick population. It would make sense that a plant that deer and mice come into contact with but don't eat, such as Japanese Barberry would make a handy place for ticks to congregate. I hope that other researchers pick this up so that there can be data from multiple sources.

[coach lou]

I did check the shop grounds today. No Barberry, but lots of the wild rose bush that covers Connecticut. very low and thick. 2 ticks on 'Mama' kitty today.
Side note for you hiking fisherman..... when that rose blooms, fish the Pale morning duns!

[Wise Old Owl]

Sarcasm T E thats what makes WB great.. always good to get a different perspective.

[Pedaling Fool]

I agree that it seems premature to declare a causal relationship after such a limited study, but I do suspect that there is some merit to this theory. Having lived and hiked in Connecticut all my life I know that there is a definite correlation between the amount of the vegetation at ground level and the tick population. It would make sense that a plant that deer and mice come into contact with but don't eat, such as Japanese Barberry would make a handy place for ticks to congregate. I hope that other researchers pick this up so that there can be data from multiple sources.

I agree with that, "that" being, more ticks will be found in an area with low foliage, because they want to sit on it as they wait for a ride.

And it makes one wonder how researchers look for/count ticks in a given area (I've seen how they swipe the foliage with large nets). The obvious place to look is on ground foliage, but if there's no foliage in that area, then I wonder if reasearchers even attempt to survey an area for ticks, because that would require looking on trees and in the leaf litter, seems like a very tough job, but that's what really makes me wonder about this finding -- well just one question, some other issues, but it's getting a little too long.

They say barberry out-competes native plants, which is entirely possible, but whatever would naturally be there would seemingly be just as good for a tick to sit on waiting for a ride.

Is there much barberry along the AT corridor in your area?

[Tinker]

I saw lots of Japanese Barberry in Pa. in spots between Port Clinton and Palmerton. I'm very familiar with the cultivated variety. As a former landscaper I was forever waiting for the ends of the barbs, which would break off under the skin, to fester enough to pop them out - very irritating. I saw acres of the stuff along the AT corridor in parts of New York and New Jersey, too.

[rocketsocks]

Some trail work that I did last fall after the halloween storm blowdowns was to remove as much of this plant as we could,but we had our hands full with blowdowns.This was for a local park I go to,"The Sourland Mountain Preserve"It's my "AT" when I need a fix.

[Pedaling Fool]

I saw lots of Japanese Barberry in Pa. in spots between Port Clinton and Palmerton. I'm very familiar with the cultivated variety. As a former landscaper I was forever waiting for the ends of the barbs, which would break off under the skin, to fester enough to pop them out - very irritating. I saw acres of the stuff along the AT corridor in parts of New York and New Jersey, too.

Thanks Tinker. I wish I was more into plants when I walked through there, would love to see how this plant is interacting in the environment. I've read about the infamous barbs of this plant since this post was started, which raises another question. Seems like a spiny plant infested with ticks is not a good strategy for the tick, at least for getting a ride on a human. I hate, and I know most people hate, walking through dense foliage, especially dense foliage packed with barbs. I also imagine the deer stay clear of there since they rather walk on the trail, especially since they don't eat this plant.

[tiptoe]

The ticks are rampant this year. I just went for a half-hour lunch-break walk, mostly along a road and cutting through two fields. I came back with two deer ticks crawling on me, and they were very active.

[quilteresq]

Grand fun - I too got my first tick on me yesterday - I finally stopped grabbing at every little itch sometime today. . . but now I have to go pick up 40 or so trees I ordered from the state nursery to plant, so I'll be doing that dance again.

[tiptoe]

quilteresq, these are far from my first ticks. I'm doing lots of pruning and gardening now, and tick inspection is a daily activity. In fact, I've found way more ticks on me than on my dog!

[WingedMonkey]

There is a good read in Scientific American on why Japanese Barberry is so attractive to ticks. It also explains how the fact that deer do dislike of it allows it to take over from native shrubs.

http://blogs.scientificamerican.com/...-lyme-disease/

[turtle fast]

So Japanese Barberry is a tick nightclub....Just wonder about the mice interaction with the Barberry as a lot is said about deer whom are not eating it but yet passing thru getting the buggers to get on them in that part of the cycle. So now the other part of the cycle is the mouse whom I think may be using the barberry for cover against predation thus having a higher number per acre which helps that part of the cycle. Interesting topic.

[WingedMonkey]

From the Scientific American:

The shrubs also provide nesting areas for white-footed mice and other rodents, which are primary sources for larval ticks’ first blood meal, and reservoirs for Borrelia burgdorferi.

[Pedaling Fool]

This is the reason they give:

“Japanese barberry has denser foliage than most native species. As a result, the plants retain higher humidity levels. Ticks need humidity and become desiccated when levels drop below 80 percent. Relative humidity under a barberry is about 100 percent at night. "The plant exists in an umbrella-like form, so the daytime humidity drop is much more subtle under the canopy of barberry than under other plants…"

I can see that – I didn’t know the shrub was that dense (they give a good image in the SA article). That’s what you call a microclimate and I had an outstanding example of one this year with my Cosmos plants, which once planted reseeds and spreads quickly, great flower plant for attracting pollinators. This past winter was mild, yet we still had a few cold-snaps, one of the last cold-snaps killed off all my Cosmos, but the small ones that were close to the ground and sheltered from above by the larger Cosmos survived – So I can see a little microclimate action if the foliage if it is that dense and ticks do need humid conditions.


My field of Cosmos shortly before being killed off.






So now the question is, how do they get out? Possibly by mice and birds, looks like deer can’t go through there (based on the photo) if they wanted to. I’m wondering, do the bears eat the berries or possibly other parts of the plant? I also wonder when it gets dry the tick must find a humid place, which would be the leaf litter, just curious if any researchers survey the mulch for ticks? I've seen how they do the surveys in the foliage with nets, but never seen anyone address tick populations in the mulch.

[Winds]

Great thread.

For my thru, I am contemplating using a flea comb for areas I can't see at all once a day as a preventative measure. Any opinions on this idea??

The 3rd in that series about lyme disease and the deer ticks is here:
http://www.youtube.com/watch?feature...&v=6TT7Q3VXfQQ

[turtle fast]

Ok, I can reasonably see that an increased vegetative density would help block evaporation and keep the area more moist, along with a higher mouse concentration and providing more surface area for ticks to climb up onto. The deer do not eat it so a loss of deer forage, but the deer are traveling through the area for ticks to attach more successfully due to increased tick numbers, so it could compensate for a slight decline in the deer population if the loss of forage was great. However, I do not believe that their is a decline in deer population, if anything probably an increase due to falling numbers of hunters due to various trends, increase in suburbinization which limits hunting, and the obvious lack of natural predators. I am all for pulling out the Barberry!! It does make sense, apart from the added benefit of removing an invasive species. From a public health standpoint, and forest ecological standpoint it seems like its a good experiment to try on a large scale somewhere to see the possibility of larger scale implementation. As well, maybe its time for more controlled burns to combat increased tick populations and invasive species.