Sonoran Desert BioArt

Last year I told you about our course in BioArt. Students work in teams to conduct research in the Sonoran Desert, and they communicate that research through a creative work of art. In the Spring semester of 2021, we had another great group of students work on projects in this course, creating wonderful works of Sonoran Desert art!

Anastasia and Rachael studied the role of desert vertebrates in the spread of cholla, a common cactus species in the Sonoran Desert. Cholla spreads to new habitats by dropping segments of the plant (called "tubercles") that can take root in the soil where they land. These tubercles are covered in hooked spines that work like velcro: they catch on the fur of coyotes, rabbits, and other mammals to be carried around and dropped somewhere new, away from the parent plant. So these animals are important to help spread this cactus, but humans are changing the abundance of these animals! How will urbanization impact the spread of this desert plant species? Anastasia and Rachael used camera traps and other survey techniques to learn which animals were associated with cholla plants. They learned that coyotes, deer, rabbits, and packrats were active in the area around chollas in the Sonoran Desert. Learn more about it in their research poster.

To demonstrate the action of a tubercle being removed from the cactus and spread to new habitats, Anastasia and Rachael created a soundscape video and an interactive cactus model. You can play the video to hear the sound of a tubercle being ripped from the cactus as it would be by a passing desert mammal. Tubercles stick to mammalian pelts because of tiny barbs on the cactus arms, ripping the tubercle off the main body like Velcro is ripped apart. This is the reasoning behind creating the interactive cactus model – arms are attached to the cactus body via Velcro, so viewers can experience the sensation of ripping a cactus arm off the main body. 

Joe and Mikayla explored whether the number of arms on saguaro cacti are related to water availability. Scientists don't actually know what signals saguaros to grow their iconic arms. We know it doesn't happen until they are older, and some saguaros don't grow arms at all! One hypothesis is that the arms are for extra water storage, in which case the number of arms would relate to water availability. Mikayla and Joe measured soil moisture along gradients from sources of water, and counted the number of arms on the saguaros at those locations. They did not find a relationship between soil water (or distance from the source of water) on the number of arms on the saguaros growing there. So... the reason for saguaros to grow arms remains a mystery! Learn more about it in their research poster.

To communicate their research, they created a glass tile mosaic that highlights the impact water availability has on Saguaro cactus branching. The recycled glasses contain blue marbles, representing the availability of water to each mosaic Saguaro it sits below. Both glasses contain the same amount of marbles, due to the research determining no significant difference between the water available to a Saguaro and its number of branches. This beautiful mosaic also sheds light on the complexity of Saguaro growth and the need for more research in this area. 

Jared and Irvin designed a rain garden that can maximize plant productivity with efficient water use in the Sonoran Desert. Rain gardens are a common form of "urban agriculture" that rely on rainwater to survive, but is that actually feasible in a desert city that doesn't receive a lot of rain? They used an infrared gas analyzer to measure the water use efficiency of native desert plants, and used their results to select the best plants to include in their design for a Sonoran Desert rain garden. Learn more about it in their research poster.

Irvin and Jared then designed the landscape for the garden using these efficient native plants, focusing on those that have tangible benefits to the community (like being a source of food or fiber for people). Of course one semester is not enough time to actually construct an entire garden, but in their blueprint, they designed it to contain artistic elements that would make it beautiful for visitors. The garden consists of three terraces: the ground level, level two at 2’ down, and level three at 3’ down. The blueprint features natural colors from the biotic elements with highlights of the pink milkweed flower and purple fruit from prickly pear. The abiotic elements are made to match the Sonoran Desert aesthetic.