Monday, December 14, 2015

The Sonoran Desert Toad

"Bart: 'Dad, are you licking toads?'  Homer: I'm not NOT licking toads." - The Simpsons

The Sonoran Desert Toad, Bufo alvarius, note enlarged paratoid glands

The Sonoran Desert Toad is a large amphibian native to the lower Colorado River area of Arizona's Sonoran Desert. It is large, green, and can be quite aggressive if provoked. It has a special surprise for predators that try to make a meal of a what would at first glance be a feast for many a desert animal. 

Look but don't touch, and definitely don't lick this toad. 

The Sonoran Desert Toad has been made famous because of its potent toxins. Dog owners report seizures, high fevers, and rapid heart beat in their dogs following unfortunate encounters with this toad.

In fact the poison is so toxic that the Sonoran Desert Toad is responsible for more canine deaths per year than Rattlesnakes. Remember to keep an eye on your dog during summer monsoons so that you can avoid any unpleasant experiences with this amphibian. 

Because of its potent toxins the Sonoran Desert Toad has made its way into pop culture. Any references to "licking toads" are often referencing this species, which produces copious amounts of the potent neurotoxin in its enlarged paratoid glands (the fat pockets behind the ear in the first picture). So yes, this desert amphibian has even been referenced on an episode of The Simpsons, though the writers did not identify the Sonoran Desert Toad specifically as the one Homer "did not not lick". 

Some anthropologists have suggested that ancient peoples of mesoamerica used a toad as a ritualistic hallucinogen, citing mythological representations of toads. If the peoples of mesoamerica did use toads in ritualistic ways, it was likely this one due to the potent, hallucinogenic nature of its toxin. In the past some suggested that the Cane Toad, found further South, could have been used in this way, but its toxin is more a pure poison than a hallucinogen. 

 Many media outlets have reported that people have resorted to extracting this toad's toxin and smoking or ingesting it to gain a desired hallucinogenic experience. Given the high toxicity of this toxin and the contracting range of the species this action can be both illegal and stupid. 

Interestingly, the toad's toxin is not a banned substance but drug enforcement officials have prosecuted drug offenders by inciting bans on the exportation of this toad(in States where the toad is not native). The Sonoran Desert Toad is protected across some portion of its range, so officials have used the legal protection of this toad to prosecute drug offenders who would use the toxin for a cheap high.

References and Further Reading:

Musgrave, M. E., and Doris M. Cochran. "Bufo alvarius, a poisonous toad."Copeia 173 (1929): 96-99.

Hanson, Joe A., and James L. Vial. "Defensive behavior and effects of toxins in Bufo alvarius." Herpetologica (1956): 141-149.

Weil, Andrew T., and Wade Davis. "Bufo alvarius: a potent hallucinogen of animal origin." Journal of ethnopharmacology 41.1 (1994): 1-8.

Wednesday, December 2, 2015

Endangered Habitats: Joshua Tree National Park

"But those trees! Those Trees!... All my life I've been searching for trees such as these!" -Dr. Seuss, The Lorax

Lost Palms Oasis in Joshua Tree National Park

Today I'm launching a new and regular feature of this blog. A focus on habitats and special areas in desert systems which are threatened. Without complete and intact habitats we would not know much that we currently do about how the world functions. I've focused much on adaptations which desert animals possess and some ecological interactions in desert systems; but from time to time it is important to remember that without relatively undisturbed, intact habitat for these organisms we would lose so much of what we value in these unique systems.

Importantly, when it comes to conservation of intact ecosystems we must often fight many unique battles to preserve these special places. The stakes are especially high in these battles as margin for error is minimal. It is not easy to restore and ecosystem and it is impossible to undo extinction. Too many times in conservation do we forget that sometimes losing even a single battle amounts to losing the war. In this sense, conservation can be likened to evolution where the stakes are equally high for individual organisms.

I'll start this habitat spotlight with the place where I first experienced a true desert wilderness. Joshua Tree National Park in California's Mojave Desert.

Joshua Tree supports a diverse group of desert organisms, being the meeting point and melting pot for two vastly different systems, the Sonoran Desert (Colorado subsection) and the Mojave Desert. The boundary of the two is readily apparent. In the higher sections of the park in the Mojave Desert, the namesake plant dominates. In lower sections Creosote dominates the landscape.

Fan palm oases dot the park and provide unique habitats to creatures which otherwise would not be able to live in the harsh landscapes. Water bubbles to the surface and provides critical habitat to Red Spotted Toads and California Treefrogs as well as native California Fan Palm Trees.

Even a place that is formally protected such as Joshua Tree is still faced with a plethora of threats externally and internally.
The Joshua Tree, Yucca brevifolia

First and foremost is the threat of climate change which has the potential to drastically reduce the range of Joshua Trees. In fact warmer temperatures have the potential to push Joshua Trees to extinction within Joshua Tree National Park.

Ironically the people who love Joshua Tree National Park so much also have the potential to alter the systems here. The park is a geologic wonderland and is popular with rock climbers who visit from all over the world to climb here. Surveys of popular climbing routes show that ecological communities of plants and birds in and around popular climbing areas are altered compared to similar communities which are not heavily frequented. Loving a natural area to death is a very real threat, especially in fragile desert parks where footprints can mark the landscape for years.

What can be done to address these threats? Acting on climate change will be important if we hope to protect the biological feature the park was originally intended for. All of the formal protection in the world will not save a plant from a system that will no longer support it biologically. Making sure that certain critical ecological areas are subject to limited use by climbers and hikers could also be important for the future of this park which is only a two hour drive from almost 20 million people.

References and further reading:

Cole, Kenneth L., et al. "Past and ongoing shifts in Joshua tree distribution support future modeled range contraction." Ecological Applications 21.1 (2011): 137-149.

Camp, Richard J., and Richard L. Knight. "Rock climbing and cliff bird communities at Joshua Tree National Park, California." Wildlife Society Bulletin(1998): 892-898.

Camp, Richard J., and Richard L. Knight. "Effects of rock climbing on cliff plant communities at Joshua Tree National Park, California." Conservation Biology12.6 (1998): 1302-1306.