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 Post subject: USGS Desert Tortoise Project: Part 3
PostPosted: April 28th, 2011, 5:27 pm 
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Joined: June 7th, 2010, 6:27 pm
Posts: 195
Sorry if you don’t like flowers, cause they outnumber the herps in this post! I’ve decided to start including range maps for all herp species I post, courtesy of NatureServe Explorer. Keep in mind, though, that these distributions do not differentiate subspecies’ ranges, and only species’ U.S. ranges are shown. As always, corrections/additions are encouraged.




Goldfields (Lasthenia californica)

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Someone’s secret desert gardening project?

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Lupine (Lupinus sp.)

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My first Mojave Green Rattlesnake (Crotalus scutulatus scutulatus). I spotted this one stretched out on the side of the road as we were driving by. These are the most commonly encountered snakes out here, and we have to drive carefully as they (and other animals) like to hang out on the dirt roads.

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Range of C. scutulatus:

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Sunset in the desert

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Yellow/Desert Evening Primrose (Oenothera primiveris)

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A tortoise with a really funky shell. Congenital scute anomalies are fairly common in desert tortoises, but incidence may vary significantly by locality. Factors influencing the development of scute anomalies may be environmental (temperature, moisture levels, oxygen content, presence of chemical pollutants/radiation at the nest site), genetic, or both (see Grover and DeFalco 1995 for summary).

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Coyote skull (Canis latrans) on dry lake bed. Coyotes are one of the few species capable of preying on adult tortoises. Although coyotes prefer to eat mammals (rodents and lagomorphs), it is thought that they become less selective if such prey is not abundant (i.e. during drought years), and consequently tortoises may experience heavier predation during these times.

Coyotes are “subsidized predators,” meaning they flourish in urbanized areas where human resources allow them to reach exceptionally high densities. So, it is not surprising that recent studies have shown a positive relationship between coyote predation on tortoises relative to human population. For more on this, see Esque et al. 2010.

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Mojave Sun Cup, aka Field Primrose (Camissonia campestris)

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2nd rattler encounter - C. scutulatus is a dangerous animal. First off, while I hesitate to use the word “aggressive” (“tending toward unprovoked offenses”), there is no question that Mojave Greens are very easily agitated relative to other venomous snakes. Secondly, the species produces some of the most toxic venom of any snake in North America, which is unusual in that it functions as both a neurotoxin (attacks the nervous system, causing paralysis which can lead to cardiovascular/respiratory failure) and hemotoxin (attacks the circulatory system, causing necrosis).

So we watch where we step. (Though from my experience they seem to sense our presence well before we do theirs, and they do a great job at making themselves known. I think it would be difficult to surprise one).

They feed on small mammals (especially kangaroo rats), lizards, snakes, and birds.


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A beautiful canyon, one of the many randomly generated sites for a tortoise-searching transect (this photo does not come close to capturing how colorful the rocks were). It’s always fun going on these searching missions, because often times we’re sent to (virtually) uncharted areas, and you never know what you’re gonna get.

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Down inside the canyon

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Golden Evening Primrose (Camissonia brevipes)

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Fremont’s Pincushion, aka Desert Pincushion (Chaenactis fremontii)

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Chia (Salvia columbariae). Used by Native Americans for food and medicine (for more info go here).

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Bladderpod (Isomeris arborea)

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Mojave Aster (Xylorhiza tortifolia)

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Desert Five-Spot (Eremalche rotundifolia)

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Thistle Sage (Salvia carduacea)

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Spiny Hopsage (Grayia spinosa)

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Brown-Eyed Primrose (Camissonia claviformis)

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Yellow Pepper-Grass (Lepidium flavum)

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Small Desert Star (Monoptilon bellidiforme)

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Male tortoise (right, with radio) courting unmarked female. We’ve found quite a few new tortoises this way.

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Inspecting the camera

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Purple Mat (Nama demissum)

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Cool seed-sphere

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A young (but equally pugnacious) Mojave Green. Females give birth to 2-17 live young July-September. Adults may reach lengths of 24-51 in (61-129 cm).

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Coachwhip, aka “Red Racer” (Masticophis flagellum piceus). These snakes are fast, and for that reason these are the best photos I could manage (and I was only able to get these because it was early and this one had not yet completely warmed up).

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Coachwhips are long and slender (36-102 in; 91-260 cm), and possess scalation resembling a braided whip, for which they were named. Of all snakes populating the Mojave, coachwhips are among the most heat-tolerant, and are more likely to remain active at times when other species are seeking shelter in the shade. Their diet includes small mammals, birds/eggs, lizards, snakes, frogs, young turtles/eggs, insects, and carrion. If threatened they usually attempt to escape to a rodent burrow or hide in the branches of a bush (as this one did). However, they can be aggressive if cornered.

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Range of M. flagellum:

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Mojave Shovel-Nosed Snake (Chionactis occipitalis occipitalis). This was an exciting find for me. Shovel–nosed snakes are small (10-17 in; 25-43 cm), and nocturnal. They generally remain burrowed underground during the day, so I was surprised to find this one out and about in broad daylight. In contrast with other burrowing snakes that “tunnel” through loose substrate, C. occipitalis is instead adapted to “wriggling,” and is aided by smooth scales, a shovel-shaped snout with an inset lower jaw, nasal valves, and a concave abdomen (see photos). They eat insects/larvae, spiders, scoripions, and centipedes.

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Range of C. occipitalis:

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Desert Larkspur (Delphenium parishii)

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Cool rocky slopes

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Desert Globemallow, aka Apricot Mallow (Sphaeralcea ambigua)

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Someone’s been leaving half-eaten animals around. I think the first one is a kangaroo rat (Dipodomys sp.).

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Great Basin Gopher Snake (Pituophis catenifer deserticola)

P. catenifer is a wide-ranging species (see map below), capable of surviving in a variety of habitats. While their appearance (which may vary significantly by locale) bears only a superficial resemblance to a rattlesnakes’, when threatened they often adopt a rattlesnake-like attitude by standing their ground, flattening their head, hissing, and vibrating their tails (see photos).

While this impression serves an adaptive purpose in fending off potential predators that may fall for the trick, today it probably also results in many gopher snakes being killed by ignorant rattler-fearing humans (not to mention their intimidating behavior won’t help scare away cars). Gopher snakes are in fact non-venomous, and subdue their prey (rodents, rabbits, moles, birds/eggs, lizards, insects) by constriction.

Gopher snakes are active mostly during the day, except in extreme heat. This one was in the middle of the road, and was kindly moved out of the way by some conscientious commuters.

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Range of P. catenifer:

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Great Basin Whiptail (Aspidoscelis tigris tigris)

Whiptails are one of the most abundant lizards here in the Mojave, but they are very quick, and I usually just catch a glimpse of them running from one creosote bush to another. They eat insects, spiders, scorpions, and other lizards.

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Range of A. tigris:

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Juvenile Desert Iguana (Dipsosaurus dorsalis)

Desert Iguanas are one of the larger lizards we have out here, though this one was just a baby. They are mostly herbivorous, and will climb the branches of creosote bushes and other plants to get at leaves, buds, and flowers, though they will also eat insects and carrion. They are very heat-tolerant, and more likely to be active on days too hot for other lizards. Desert Iguanas breed in April-July, and females lay a clutch of 3-8 eggs June-August.

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Range of D. dorsalis:

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ATV-ing is a popular activity out here, and I was told this trail is one of the most favored spots to do it – I could see why.

Thanks for looking,

-Zach








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Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7


Last edited by Zach Cava on December 17th, 2012, 7:17 pm, edited 7 times in total.

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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 28th, 2011, 5:37 pm 
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Joined: June 13th, 2010, 12:51 pm
Posts: 193
Location: Sugar Land Tx
That gopher is outstanding!! Very nice post. Gotta love some of the desert flowers. I take pics of them too.

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Chris


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 28th, 2011, 7:54 pm 
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Joined: June 7th, 2010, 10:22 am
Posts: 431
Location: Athens, OH
Nice post. No problem with the flower shots.


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 28th, 2011, 8:21 pm 
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Joined: June 7th, 2010, 8:47 am
Posts: 76
Location: West Central Florida
That Gopher Snake is beautiful! It's neat to see so much color and 'life' growing in the deserts... from someone who's never been out west it's not the first thing I think of when I think of "dry, sand, rocks, mountains" lol.

Very cool and enjoyed the explanations accompanying your photos.

Thanks for sharing,

Mike


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 28th, 2011, 8:27 pm 
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Joined: June 7th, 2010, 7:05 am
Posts: 1028
Location: Albuquerque
love that faded pattern on the gopher!

Josh


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 29th, 2011, 4:29 am 

Joined: June 20th, 2010, 7:37 am
Posts: 47
-Thank you much! I didn't know how beautiful it could be, that gopher snake is the bomb! The front of my sulcatas look just like the torti in the pics!


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 29th, 2011, 3:28 pm 
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Joined: June 7th, 2010, 6:09 pm
Posts: 952
I have really grown to hate invasive Arabian Grass (Shismus) It is so bad for species that love loose, duney sand like horned lizards, fringe toeds and zebra tailed lizards. Damn stuff is everywhere! The red grass in some of your shots is Bromus rubens, (Red Brome) which thank goodness for the small things, is native.


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 30th, 2011, 4:37 am 
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Joined: June 7th, 2010, 10:42 am
Posts: 188
According to the Calflora website Red Brome is also a nonnative.
http://www.calflora.org/cgi-bin/species ... ecnum=1209


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 30th, 2011, 7:15 am 

Joined: June 7th, 2010, 4:48 pm
Posts: 147
klawnskale wrote:
The red grass in some of your shots is Bromus rubens, (Red Brome) which thank goodness for the small things, is native.


Yikes! Where were you told this? Red brome is a non-native invasive that has been pegged as one of the main plants that has drastically changed natural fire regimes in our deserts, which is also one of the many, many causes of desert tortoise declines.


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 30th, 2011, 10:37 am 
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Joined: April 18th, 2011, 9:05 am
Posts: 6
Location: Phoenix, AZ
I usually just browse the forums but had to post...beautiful pics!! That sonoran gopher is outstanding, certainly looks to be a hypomelansetic color mutation/variant. I'm a Pituophis fan so had to comment. I've been on a few of the desert tortoise surveys with AZ G&F, lots of fun. Looks like you had a very productive outing!!

Greg


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: April 30th, 2011, 10:53 am 
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Joined: June 7th, 2010, 6:09 pm
Posts: 952
Yikes! Where were you told this? Red brome is a non-native invasive that has been pegged as one of the main plants that has drastically changed natural fire regimes in our deserts, which is also one of the many, many causes of desert tortoise declines.[/quote]
Sorry my bad. That's what happens when I'm expected to learn about plant species in the Mojave Desert in 2 weeks what some biologists have taken decades to learn. Too much info to process and remember at all once.


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: May 2nd, 2011, 10:50 pm 
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Joined: June 7th, 2010, 10:41 am
Posts: 3863
Location: "Buy My Books"-land
Nice post Zack. You must be getting addicted to CA...


Last edited by Brian Hubbs on May 3rd, 2011, 9:33 am, edited 1 time in total.

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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: May 2nd, 2011, 11:13 pm 
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Joined: June 10th, 2010, 7:37 pm
Posts: 1338
Location: San Francisco, CA
That is one GORGEOUS pit!


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 Post subject: Re: USGS Desert Tortoise Project: Part 3
PostPosted: May 3rd, 2011, 5:14 am 
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Joined: June 7th, 2010, 6:11 am
Posts: 5229
Location: Los Angeles County
That Gophersnake is Beautiful..

Fundad :shock: :thumb:


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