Nay for the Mojave?

[monklet]

http://forecast.weather.gov/MapClick.ph ... it=0&lg=en

...just hope this is the first in a series through March!

[SurfinHerp]

Glad it's raining out there this week. Looks like it's mostly light showers though. I'm still optimistic that some heavier rains will hit at least a few times before April.

I was just checking the satellite imagery and it seems like the Colorado desert is getting some light to moderate rains right now. So hooray for the Colorado too!

[hellihooks]

And...this one (at least) ain't from Alaska... so is downright tolerable... jim

[monklet]

Uh oh, nothing on the horizon ...now it's looking like the typicial drought pattern. Aaarrggghhh

[SurfinHerp]

C'mon, show some patience Monklet. It wouldn't be a desert if it rained every week all winter. There's still plenty of time for 3 or 4 more good storms before the end of April.

[RobertH]

I thought I read that herps don't much respond to rain in the Mojave. So how much does it really matter?

Robert

[monklet]

Jeff, I have no patience.

I thought I read that herps don't much respond to rain in the Mojave. So how much does it really matter?

Well, quite frankly, I can't speak from experience because we've had only one half way decent winter since I've been herping the Mojave, and that was 2007-2008 and that was the only year I had a half decent night out in the east (west is very different). But, all the old timers keep hoping for rain so I figure they must know

Are you sure you aren't thinking of the summer monsoons not helping much? That is the common wisdom, that monsoons in the eastern Mojave don't seem to bring out more animals. The theory is that summer precipitation is very unreliable in the Mojave, and becoming ever more so, relative to the Sonoran, so the Mojave animals write it out of their schedule.

I want 4-5 storms that dump 4-6 inches in the Mojave from late February through late March ...now
is that asking to much?

Btw, all thoughts, corrections welcome.

[hellihooks]

OK, OK...FINE. I can take a hint. I'll go out and check on conditions...
Other than lots of rain producing lots of veg, which produces a bumper crop of rodents, which means lots of snake food (general habitat health)... the main thing the rain determines is the rosy flipping season, as in down the hill. Ground moisture levels are more important than warmth... Other than rosys... flipping's not that great a 'method' in the desert. jim

[monklet]

My understanding/assumption whatever is that drought years place moisture stress on all snake as well as inhibiting food production and so they are more reserved in there activities and stay deep to conserve body water.

I wonder if there really is any science behind that of if it is just a "just so" story?

[RobertH]

Yeah, now that you say that, I think you're right. What I read was probably only or mostly about summer monsoons having little or no effect on herp activity in the Mojave (not sure West and/or East).

Still, I really wonder what difference, if any, there is in surface activity in the Mojave (and any other desert with extremely low average annual rainfall). Even in an average year, rain fall is just a few inches in winter/spring. If it's a an inch or two less, does this really change conditions so much that there is a perceptible difference in activity throughout the season (roughly March-July)? And, conversely,it the Mojave gets a few extra inches, does this really make any appreciable difference? It seems that whatever rain falls, will not have a lasting effect on soil humidity or food availability as the season goes on. Kangaroo rats, for example, do not drink water at all, but get all of their moisture needs filled by their diet.

But, hey, I am just sort of thinking out loud here. Obviously, rain probably isn't a bad thing even in the Mojave, and I do hope that we will have a wetter and better season than last year.

Robert

[monklet]

Sure wish some others would chime in here. May have to open a new thread with a more relevant title or just change the title of this one and bump

I'd like to hear some PhD's with knowledge offer a contribution ...like Hamilton, Hansen or Sweet who all know the west very well I'm sure. They may know of studies etc.

[Brian Hubbs]

Those of us who understand the effects of rain on the Mohave will not be explaining anything here...for obvious reasons aligned with keeping too much info off a public forum...thank you for understanding...have a nice day...

[monklet]

Hmmm, so, you're suggesting that knowledgable individuals are all aligned toward withholding interesting and helpful information regarding climate and weather, and how those are related to herp activity in the Mojave? ...on a field herping forum?

WTF?

[hellihooks]

Hmmm, so, you're suggesting that knowledgable individuals are all aligned toward withholding interesting and helpful information regarding climate and weather, and how those are related to herp activity in the Mojave? ...on a field herping forum?

WTF?

He hasn't finished his book on the subject... why give away knowledge, when you can sell it... jim

[monklet]

Yeah, but he wasn't among those I specifically listed as hoping for information from. He may be their spokesman though, don't know about that.

[RobertH]

Brian, I have to say too that it's ridiculous to suggest that a discussion of how weather may affect herp activity in as large an area as the Mojave Desert and over the course of an entire is off-limits.

If your database records are any indication, you are also far from being an expert on the Mojave.

Robert

[Robert Hansen]

As most here know, the Mojave (at least the California portion) is a winter rainfall desert. Winter precip levels affect primary production--the germination of annual plants. In turn, this affects insects, rodents, birds, lizards, and things that feed on them. Data for snake populations are largely non-existent, but I'd guess that most of the lizard and rodent-eating species don't experience major annual fluctuations in numbers, although females might skip breeding in years when their fat reserves are low, as in drought years. Lizards like Uta and Aspidoscelis, however, do respond more directly to low winter rainfall levels, and can experience population crashes (see Pianka's work based on studies near California City). Multi-year droughts presumably are more consequential, and I'd imagine you'd see some reduction in snake numbers, too, though there should be a lag relative to lizard numbers.

But the comments in the posts above might have been related to "activity" in the sense of an immediate response to winter/spring rains, as in, "What can we expect come May and June?" Just guessing here, but it seems reasonable that in years with substantially lower rainfall, there will be fewer arthropods, lizards, rodents, etc. Hard to confirm cause and effect, but my experience in drought years is that snake activity is depressed (fewer animals moving during prime time) and the season is abbreviated. Snakes are relatively long-lived species (at least compared to most lizards and rodents) and do a good job of conserving energy. Thus, it's energetically beneficial to lay low if prey items are scarce.

BH

[hellihooks]

For me... I notice the effects of wet vs drought years, not so much that year, as in following years, in the number of yearlings and sub-adults. For example... a really wet year will produce a bumper crop of yearlings the following year, while a dry year will produce low numbers the next year.
Our society has trained folks to expect immediate gratification... Nature does not necessarily operate on those timescales. Rather than try to assess productivity year to year, it's (IMO) better to look to 'trends'... several wet years in a row will bump up numbers for the next several years.
Also... when food and water are easily had... snakes don't need to move as much. A hungry/thirsty snake will be out looking for food/water. jim

[monklet]

Thanks much Robert. Just the kind of informed response I was hoping for. No where do you suggest that moisture conservation by snakes during droughy years/cycles is a factor in their activity. Can I assume that you don't give much weight to that supposition?

edit: Jim, your post hit before while I was writing. Good points I would think.

Thanks,
Brad

[Robert Hansen]

Thanks much Robert. Just the kind of informed response I was hoping for. No where do you suggest that moisture conservation by snakes during droughy years/cycles is a factor in their activity. Can I assume that you don't give much weight to that supposition?

edit: Jim, your post hit before while I was writing. Good points I would think.

Thanks,
Brad

Brad: Yes to water conservation, although it's hard to tease out the "moisture" part from the overall "energy conservation" scheme. Water loss is a bigger deal for smaller species and juveiles of larger species (surface area / volume relationship at work here). Some species are more susceptible to water loss than others; I'll use a lizard example here: Coleonyx variegatus vs. C. switaki (the latter, of course, is more prone to water loss and tends to be surface activite during periods of relatively high humidity).

Cheers,

BH

[monklet]

Roger, thanks again Robert

To me all of the Coleonyx seem like they'd be especially vulnerable to transdermal water loss, but that is just my impression based on their soft, almost translucent looking, skin. Always hard for me to imagine such seemingly delicate looking creatures surviving in such harsh environs. ...but apparently my impression ain't worth much in this case

[Robert Hansen]

Roger, thanks again Robert

To me all of the Coleonyx seem like they'd be especially vulnerable to transdermal water loss, but that is just my impression based on their soft, almost translucent looking, skin. Always hard for me to imagine such seemingly delicate looking creatures surviving in such harsh environs. ...but apparently my impression ain't worth much in this case

There is a great paper by the late Ben Dial and Lee Grismer that nicely details the physiological differences between the "big" geckos (switaki and reticulatus) vs. the small northern species (brevis and variegatus). The latter two are physiologically better equipped to survive in a very xeric environment, whereas the two biggies have comparatively "leaky" skin that restricts when they can be active and where they can live.

Dial, B. E., and L. L. Grismer. 1992. A Phylogenetic Analysis of Physiological-Ecological Character Evolution in the Lizard Genus Coleonyx and its Implications for Historical Biogeographic Reconstruction. Systematic Biology 41(2):178-195.

[klawnskale]

Do I detect some prejudicial bias in terms of interest in specific families of herpetofauna? Not one mention is made here regarding the affect on Testudines inhabiting the Mojave Desert with regards to activity/rainfall. Let us not forget the Desert Tortoise is a Mojave Desert herp. I digress; there are many citations out there indicating that Desert Tortoise surface activity can be profoundly affected by the incidence of rainfall. They will awake in the middle of the winter to come out of their burrows to drink. In fact there is documentation of this during different seasons. When I was doing Mohave Ground Squirrel survey work in late February early March, it was not unusual to find a Desert Tort here and there present on the surface after a rainfall. There are reports of some surface activity during summer monsoon as well.
I do not know if this is unique to Desert Torts only, but it would be interesting to see if this is true with snakes and lizards as well. Also, none of you mentioned anything regarding Mojave resident anurans.
What about Red Spotted Toads, Baja Chorus Frogs and Spadefoot Toads?

[monklet]

Do I detect some prejudicial bias in terms of interest in specific families of herpetofauna?

Perhaps, but I'm interested in diverse herpetofauna families, Colubridae, Crotalidae, Boidae, Hydrophiidae, Renadae, for instance

Love Torts too ... thanks for bringing them into the mix. Thanks for the info, good stuff.

[monklet]

A Phylogenetic Analysis of Physiological-Ecological Character Evolution in the Lizard Genus Coleonyx and its Implications for Historical Biogeographic Reconstruction

http://sysbio.oxfordjournals.org/conten ... 8.abstract

Wow, that's a dense little paragraph

Thx Robert ...not quite sure I have full comprehension though but I get the general idea.

[hellihooks]

In case anyone's interested, conditions are pretty good in the hi-d right now... but still too early for any significant herp activity... we dry out quick up here, so we will need more rain, for 'good conditions' to persist into the herping season... Don't waste your time/ gas coming up now... jim

[monklet]

Thanks for the update Jim. I would think that until freezing overnights are pretty much over that would be the case.

Another piss-ant storm moving in ...just like almost all of them in recent years. Haven't seen a gully washer since I started herping as an adult in '07

btw, another thing that pisses me off ...the normal pattern is that a front move through, dropping some rain, then the post-frontal wash of high winds and dry air substantially negate the goodness.

[hellihooks]

Where were you 2 years ago?


but yeah...'hot air' does have a way of messing up good things that happen (backhanded social commentary... ) jim
BTW... that stretch of the Mojave is Bone Dry, right now...

[monklet]

Oh yeah, do remember that. Was early season though right? Early season doesn't count.