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Re: Lyme - again
Board: State: Virginia
Reply to: #549778 by Otis' Friends
Sep 30, 2010 5:19pm
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Now, an invasive exotic understudy (which deer don't eat) does seem to increase lyme disease by providing better habitat to mice:

That study seems to indicate that the reason the invasive exotic plants had gotten a foothold was that there were too many deer and they had overbrowsed the native species.
Re: Lyme - again
Board: State: Virginia
Reply to: #549778 by Otis' Friends
Sep 30, 2010 5:48pm
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First study:

http://www.ncbi.nlm.nih.gov/pubmed/16669698
The authors state "This observation supports the assertion that, once deer abundance exceeds a low threshold value, further increases in deer density have little if any effect on nymphal densities." Exactly. In nature, effects are often not linear. There are "threshold effects", beyond which some phenomena kicks in. The Mumford study showed a dramatic effect at 10 deer per square mile, which is also the typical carrying capacity of the land (at populations greater than 10, the vegetation and other animals are negatively impacted). So the threshold would seem to be 10 or higher.

The authors of this study also state, "When deer are eliminated from some habitats by hunting or fencing, the abundance of ticks typically is strongly reduced." I cannot find anything in the study where they state what the deer population was in their study, which is very poor form. They should be reporting that information so it can be understood and duplicated. If the lowest density they studied was 25 deer per square mile, they cannot make any statement about deer population vs ticks at densities lower than that (and indeed have not).

The second study only went for three years, which is far too short, and they reduced the deer gradually each year. They noted increased questing ticks the second year. Yes, that happens predictably the second year because they can't find their host deer. The numbers of questing ticks don't begin to fall until the third year.

Certain invasive species like Barberry increase infected ticks. There is a strong correlation between these invasive species and deer populations. Deer eradicate the native plants, but cannot eat Barberry, so it spreads. I letterbox in regions with very high deer populations and others with moderate deer populations and there is a profound difference, which much more barberry in the overbrowsed areas (and pretty much nothing else growing).

So, are there any studies that show that if you reduce deer down to 10 per square mile (not 20 or 30), the Lyme Rate does NOT go down dramatically over the next several years?
Re: Lyme - again
Board: State: Virginia
Reply to: #549981 by Sheba
Oct 1, 2010 3:27am
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Which is why I cited it.
Re: Lyme - again
Board: State: Virginia
Reply to: #549647 by Zorket
Oct 1, 2010 8:38am
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Remember, ticks can be picked up off the trail and in the city. My daughter had Lyme Disease when she was 3 or 4. We lived in middle of Newport News and hadn't been on any trails or out to the country. The only way I can imagine her getting it is from drainage systems that run behind through the neighborhoods behind the houses. The first time we took her to the doctor, they diagnosed her with the flu...
Re: Lyme - again
Board: State: Virginia
Reply to: #549683 by 3crazyC's
Oct 1, 2010 5:06pm
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Thanks - he is already so much better. He's still sore, but running around - and I think he will be all better very soon, and back out on the trail! Funny little dog - he LOVES to hike - but HATES to take one little step off the trail when it's time to find the box!! If I leave him on the trail, he whines until I get back to him (he's always left with someone...). So, I suppose he will never be one to sniff out a good box. But I keep trying. LOL!!!
zorket
Re: Lyme - again
Board: State: Virginia
Reply to: #549647 by Zorket
Oct 13, 2010 3:34am
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Just wanted to report that little Dewey dog has bounced back in an amazing fashion. He has had his first trek out to Sky Meadows park (well near there) to pick some apples. He lamented the fact that he has no opposable thumbs, and therefore could do no apple picking.
zorket