Intro and question re magnesium chloride

[Whitman]

I'm new to the forum. Have been peripherally working with herps, mainly in Idaho, since 1971. Am a semi-retired predator biologist. Am currently doing "hobby" research (nobody's paying me ) on snake relative abundance and observed population trends in east-central Idaho. Relatively depauperate snake country, both in number of species and relative abundance. Main work is through road surveys with CPUE. Have been working the same transects from 2008 to the present. Mainly Crotalus viridis, Coluber constrictor mormon, Charina bottae, and Thamnophis elegans.

One of the observations I have that is glaringly noticeable, and am wondering if any others have seen this. Several governmental entities (BLM, USFS, County, etc.) have been spraying a magnesium chloride (MgCl2) slurry on gravel and dirt roads for dust abatement and to stabilize the surface. Before application, I see and catch moderate numbers of snakes along these routes. Following application, absolutely zero use of these roads as evidenced by complete lack of live snakes observed or of roadkills. I find nothing in the literature about serpents avoiding these chemicals. Anyone out there noticed the same thing, or know anything about it? If it is indeed a deterrent, very many ramifications.

[Richard F. Hoyer]

Whitman,
Interesting observation. As you likely have learned in your web searches, MgCl-2 has toxic properties. Have you identified the length of time it takes for the chemical to ‘dissipate’ or degrade to the point that it no longer act as a barrier to snakes which then began to cross those roads?

In my study of the Common Sharp-tailed Snake in Oregon, at one of my former study sites along a gravel road, the land owner (Christmas tree plantation) and county have used herbicides to suppress grass and weed growth along and beyond the shoulder of the road. When they have done this in the past, the Contia tenuis population has taken a severe nose dive. I do not know if that is due to direct mortality of the snakes and / or due to the loss of their prey base being poisoned and depleted.

With respect to E. Central Idaho, on my way to and from Utah to visit my kin, along I-84 near Sweetzer Pass I found shale outcrops on both sides of the freeway to contain a nice population of the Rubber Boa. The habitat is basically grassland, forbs, bitter brush, and sage brush with some cactus. I believe I may have encountered the Racer and T. elegans at that site but not certain.

Richard F. Hoyer (Corvallis, Oregon)

[Whitman]

Richard Hoyer -

First and foremost, thank you sir for your reply to my inquiry regarding MgCl2.

At this point, I've not designed a reasonable method of testing the effects of this application on the roads and the impacts it may have on herpetofauna. Started noticing the lack of serpents on the roads last year, and have payed close attention this summer along those routes where it is used, versus similar roads where it is not in use. The dissimilarities are striking. I will continue to look into it. Most of the applications on gravel or dirt roads have been in the late spring when dust starts to become an issue, and the single application seems to eliminate use throughout the summer. Thus, in my limited observations, it appears to be a severe problem for at least 4 months after application.

The majority of my current efforts with herps is being conducted in Lemhi County. I have been conducting wolf work for Idaho Fish and Game (as a contractor) in northern Idaho (Mostly Shoshone, Clearwater, and Idaho Counties), so have done limited herp work in those areas as well, mainly along the Coeur d'Alene, St. Joe, N. Fork Clearwater, Kelly Creek, and Lochsa Rivers, simply looking at distribution of northern tailed frogs, n. alligator lizards, western skinks, and Coeur d'Alene salamanders. Those herping efforts, however, have been a bit less formal than the work in the Lemhi River area.

As an aside, I've been reading and greatly enjoying your Charina work for many years. Thank you sir, for that work. I tip my hat to you...

If other forum members out there have any experience with magnesium chloride and it's effects on herpetofauna, I'd sure appreciate your observations.

Jack Whitman

[DRDAN]

I’ve never heard of magnesium chloride used for veg control, it’s typically used to de-ice roadways. The chlorine present in magnesium chloride may be the culprit as it can reach toxic levels easily if the MC is applied to frequently or over applied. Just my .02. I wonder if this is a response to the Monsanto lawsuits surrounding the use of Roundup??
Cheers

[Whitman]

DRDAN, et al. -

The MgCl2 is not being applied for veg control. It is used as a dust abatement agent and soil stabilizer rather than as an herbicide in summer, and used as a de-icer in winter. And no, I'm not pointing a finger at anyone or any entity at this point, just wondering why the apparent lack of herpetofauna where this chemical is being used, and if anyone else is seeing the same thing. I know nothing about the Monsanto/Roundup lawsuits. There is no hidden agenda in my original post.

Jack

[DRDAN]

Howdy Jacque
Nope just one of us and I must apologize for my veg reference (happened to be reading a tamarisk eradication plan) and while useful to that end, there are better ways and means.
There are many factors that dictate MgCl2’s efficacy for soil stabilization but chief among them is dryness so if you see them applying the material frequently it could be due to dryness combined with some of the other variables. Increase the materials use to stay on top of dust abatement and you increase chlorine residuals which are bad for everyone.
Of course all of this could just be climate change induced movement to better climes or the “road effect”.

It does seem like my encounters with larger native snake species, and some lizards, has dropped significantly during the past 30 or so years but then some of my hunting companions are pretty useless.



p.S. was curious why you thought there was more than one of me asking the question and also, I didn't think you had an agenda, when I mistook the reference for veg control it reminded me that there is quite a bit of litigation over Roundup...so no agenda on my end either.

Peace...

[Whitman]

DRDAN -

My 9 September reply to your post was addressed to you et al. (et al. = and others). Didn't want to exclude other herpers that may want to comment. Still looking for anyone who may have noticed the lack of herp use of dirt/gravel roads where MgCl2 is being applied. I'll keep looking into the quandary. Thanks for the comeback, DRDAN.

We've had recent rains on a road where MgCl2 was applied about 10 weeks ago. In those 10 weeks, no (zero) herps have been found. I drive the route daily. Before application, numerous T. elegans, C. viridis, and C. constrictor. For 10 weeks after application, no herps observed. Recent rains, and two evenings ago, two T. elegans and one DOR C. viridis. Not good science, but certainly suggests an avoidance.

Thanks in advance for any comments.

Jack

[jonathan]

Totally off topic Jack, but if you've been in Idaho since 1971, were you crossing paths with Lowell Diller or anyone else at the SRBPNCA in the 1970s?

[Whitman]

Jonathan -

Interesting that you would ask. I was going through old posts re: Idaho this morning and saw several of yours. Was going to contact you about your history in Idaho.

I worked several summers in the SRBPNA (1971 through 1976) on golden eagles, badgers, coyotes. Worked extensively with Lowell both in the Birds of Prey area and at Moscow, etc. Was very close friends with Lowell and Janice, as well as with Dick Wallace. Between 1980 and 2008, however, I was in Alaska. Now, of course, back in east-central Idaho (Lemhi County).

Thanks for making contact. Who are you?

Jack

[jonathan]

Ted Daehnke, Lowell's field assistant on the snakes for three years, is my dad. I think he would have started right near the back end of when you were there, either '75 or '76. Lauren Zabrowski, the intern park ranger at SRBPNCA for one of those summers, is my mom. They met in the preserve and got married and I was born in Moscow in 1980. They had to move for my dad's work (zookeeper) and never went back but my dad always told me stories about the field work and we stayed in touch with Lowell for quite some time. I got to meet him around 1990 when we passed over the California/Oregon border on vacation. Was sad to hear of his passing two years ago, it was amazing to see how many people I knew had crossed paths with him at some point over the years.

Did you know either of them at all?