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FINAL REPORTS OF OUR 2022 GRANTEES
A key issue in the Sonoran Desert is potential deterioration of the ecosystem due to pollinator insufficiency. To that end, it is important to understand the health of pollinators of Sonoran Desert plants, like the digger bees which specialize on pollination of the yellow palo verde (Parkinsonia microphylla), an iconic and important Sonoran Desert tree.
Meredith Johnson is particularly interested in the thermal physiology of native bees in the Sonoran Desert, specifically, the digger bees in the Centris genus. In summer 2022, Johnson used sophisticated micro-instrumentation to study the heat balance of Sonoran Desert Centris pallida males and females during flight at a mating aggregation. How bees manage their body heat is critically important to understand, as many desert pollinators, including C. pallida, may be living at or near their thermal limits. Johnson found that rather than physiologically regulating their body temperature, males use heat gain from the sun to warm up and convection to cool down. Large males in another closely related Sonoran Desert bee species, C. caesalpiniae, use a different strategy—when it is hot, they maintain a stable thorax temperature by “dumping” heat to the abdomen. If climate change short-circuits these adaptive mechanisms and these bees can’t survive, the structure of the Sonoran Desert ecosystem could drastically change.
Johnson, in collaboration with Dr. Meghan Barrett, also analyzed body size changes in C. pallida over the last 48 years and found that the mean body size of C. pallida males has declined tremendously. The proportion of larger males in the population near the Salt River has declined more than 8%. More than 80% of flowering plants depend on insect pollinators, and pollinator body size plays a significant role in pollination efficiency. With fewer and smaller pollinators, seed production by plants is seriously compromised. Fewer and weaker plants are propagated each generation, resulting in an overall decrease in plant biodiversity.
The digging of C. pallida may play an important role in soil nutrient cycling, which improves plant health. Female nest volumes are roughly 63 cm3 in volume. In 2020, Johnson calculated that the number of nests over a 3,525 m2 large aggregation site was approximately 592,200. Multiplied by the volume of a nest, this is about 37 cubic meters of soil moved by bees!
Brittany Burgard studies the effects of wildfire on Sonoran Desert vegetation. The Sonoran Desert is not considered historically fire-adapted, but the combination of drought and increased fuels from the spread of non-native plants has made fire increasingly common. A new fire regime fueled by climate change could result in key native plant species having to adapt to a habitat different from the one in which they evolved.
Brittany chose the 2021 Telegraph Wildfire to assess the effect of wildfire on Sonoran Desert plants. This fire burned 180,757 acres south and east of Superior, Arizona, and around 29,500 of those acres occurred in the Arizona Upland Subdivision of the Sonoran Desert. Brittany is collecting and identifying annual plants for deposit as voucher specimens in the herbariums at Arizona State University and the Boyce Thompson Arboretum, and she is constructing a comprehensive inventory of plants found inside and outside of the burn perimeter from these specimens.
Brittany’s preliminary results, based on 125 specimens, indicate that the species composition of annual plants does not appear markedly different between burned and unburned desert. More importantly, her data show a decline in the health and number of dominant, slower growing, long-lived species such as desert trees (palo verdes) and cacti (saguaros) within the burn area. Without conservation efforts to suppress wildfire and conserve iconic desert plants, the character of the Sonoran Desert is likely to change markedly over time.
Cassidy Kyler’s project involved improving the habitat in a burrowing owl re-location project on the Arizona State University Polytechnic campus. Recent studies have shown that burrowing owls can thrive in urban environments and co-exist with humans if provided with adequate habitat conditions. In May 2021, four adult burrowing owls were re-located into six artificial burrows where they produced several successful clutches.
Cassidy cleared the immediate area surrounding the owl burrows of noxious invasive weeds (prickly Russian thistle; stinknet) to make room for native desert plantings and make the demonstration site more presentable. She planted a variety of native Sonoran Desert species on site and distributed seeds of a large number of native plants. Seeds were dispersed in seed balls, using a mix of five parts potting mix to one part powdered clay. Seed balls are designed to reduce the chance of seed loss until germinating rains break apart the soil.
Unfortunately, the owls disappeared from the site in fall of 2022; the exact timing and reasons for their loss are unknown. Nevertheless, the habitat improvements provided by Cassidy’s work remain a valuable resource for other native Sonoran Desert wildlife species like cottontail rabbits, round-tailed ground squirrels, and desert lizards, snakes, and invertebrates. Cassidy’s project also precipitated the removal of noxious and fast-spreading weeds and provided an aesthetically pleasing site for visitors to the ASU Polytechnic campus. Arizonans are increasingly concerned about water conservation, and this site is a great example of how to create a less thirsty environment that showcases native desert species.
2022 STUDENT GRANT AWARD WINNERS
Meredith Johnson is a Ph.D. student in Arizona State University's School of Life Sciences. Meredith is studying the thermal biology of a native Sonoran Desert bee species that is the primary pollinator of three species of palo verde trees, crucial plant species in upland Sonoran Desert habitats. Her work will help us to understand the impact of climate change on the health of this important Sonoran Desert pollinator.
Brittany Burgard is a Master's degree student in Arizona State University's School of Life Sciences. Brittany is studying the effects of wildfire on plant communities in the Sonoran Desert. As native Sonoran Desert plants are not adapted to wildfire, Brittany will document the changes in these plant communities after wildfires, comparing the distribution of plants in burned and unburned areas.
Honorable Mention. Cassidy Kyler is a senior at Arizona State University majoring in Sustainability. Concerned with the decline of burrowing owl populations in Arizona, Cassidy's project involves creating a safe habitat for burrowing owls on the ASU Polytechnic campus. The project will contribute to the conservation education of the public, as visitors will be welcome to observe the owls on a public walking trail.
STUDENT GRANT PROGRAM
FRIENDS OF THE SONORAN DESERT (FSD) is pleased to invite applications for our student grant program. Grants will be awarded to students for proposals that will increase our understanding of the Sonoran Desert ecosystem and facilitate our mission to protect and conserve the Sonoran Desert throughout its range.
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Qualified applicants include advanced undergraduate students and graduate students currently enrolled in a university. In 2022, two awards will be made of $500 each.
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Criteria used to evaluate applications:
1. Overall quality of the proposed project
2. Match of the proposal with FSD ongoing programs
The proposed project can be part of a larger student-driven project (honors thesis; MS thesis; etc.).
Applicants should make clear how FSD funds will advance the completion of their project.
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Applications must include:
1. Title of project
2. 500 word summary of proposed project
3. Project budget and brief justification
4. Two letters of reference sent to the email address below. One letter must be from the student's academic supervisor.
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Grant Program Timeline:
Call for proposals: 2 February 2022
Deadline for proposal submission: 15 March 2022
Award notification: 31 March 2022
Short update of findings due: 15 September 2022
Final report due: 1 December 2022
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Short Update and Final Reports
Grant recipients will submit a short update on their findings, a final project report, and 3 high-quality images
(JPEGs) with permission for FSD to use these photos to promote their work: one image will be of the student
investigator, preferably in the field (required); and two from the following list, as applicable: the species being
studied; the​ habitat in which the study was conducted; workshop; product produced; etc.
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EMAIL APPLICATION TO: info@friendsofthesonorandesert.org
Student Grant Application
PAGE 1 (of 2)
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Applicant Name:
Affiliation (university/department):
Grade Level:
Contact Information – e-mail address and phone number:
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Reference 1: Supervisor's name:
Affiliation (university/department):
Contact Information – e-mail address and phone number:
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Reference 2: Name:
Affiliation (university/department):
Contact Information – e-mail address and phone number:
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Project Title:
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Budget plus justification of expenses (use remainder of Page 1):
Budget guidelines: no salaries allowed. Allowed expenses include $15/day per diem;
$0.25/mile mileage allowance; supplies and minor equipment.
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PAGE 2 (of 2)
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Project Description:
500 words maximum/no longer than 1 page
Single spaced; include up to 3 relevant citation references.
Address overarching issue, how you will address the issue, and relevance of the issue to the
goals of FSD.
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FINAL REPORTS OF OUR 2021 GRANTEES
Iris Garthwaite studies how environmental factors can limit the fitness and distribution of plants. Her study species is the Fremont cottonwood (Populus fremontii), an important but threatened tree native to southwestern riparian ecosystems. Recent studies show that climate change is likely to differentially impact genetically distinct populations of Fremont’s cottonwood.
Iris utilizes common garden experiments in which genetically distinct strains of a species are grown under identical environmental conditions. This protocol allows investigators to disentangle the effects of genetic and environmental variation on the growth pattern across the range of a species. Because plants must have water to survive, Iris focuses on the veins in leaves which are the transporters of water and nutrients. The architecture of leaf veins determines the ability of plants to transfer water, which in turn affects overall plant fitness.
Iris found that leaf-vein architecture varied significantly across a gradient of climates from which her common gardens were established – ranging from sites with mean annual temperatures of 10.7 – 22.8 degrees C. Furthermore, the magnitude of leaf-trait adaptability differed among populations of Fremont’s cottonwood.
The results of this study suggest that, to conserve this threatened riparian tree species, managers engaged in ecological restoration could improve conservation project outcomes by choosing cuttings of Fremont’s cottonwood that are most resilient in response to climate change.
Sofia Salazar studies the species richness of oribatid mites, small organisms related to spiders, scorpions, and ticks, which are the most abundant and diverse group of small animals inhabiting soils. Oribatids play a key role in global biogeochemical cycles, biological regulation, and soil aeration.
Sophia collects soil oribatids in the Madrean Sky Islands of southern Arizona. While soil communities are recognized as a critical component of the biosphere, the below-ground biodiversity in this region, particularly the diversity of oribatids, is poorly known. To date, Sofia has collected 366 soil samples from two mountain ranges (Santa Rita and Dragoon) from which she has identified 8,557 adult oribatid mites belonging to 116 morphospecies (a morphospecies is defined by its most easily observable physical characters). Sofia has classified these morphospecies into 40 families and 25 superfamilies,17 of which are new records for Arizona. Sofia extracts DNA from each morphospecies, and these data are then uploaded as “barcodes” into an international database that will facilitate species identification and comparison of her data with other species.
Sofia is also examining the dispersal advantages of asexual and sexual oribatid species, determining the genetic structure of oribatid populations, and analyzing the relationship between species diversity and environmental and altitudinal variables. As many species of oribatids are used as indicators of overall soil biodiversity and health, becoming familiar with these organisms will help us more effectively conserve the fragile soils of the Sonoran Desert and its sky islands.
2021 STUDENT GRANT AWARD WINNERS
Sofia Salazar is a Ph.D. student in Arizona State University's School of Life Sciences. She was awarded a $500 student grant for her project to identify and describe the oribatid mites that inhabit the Madrean Sky Islands in southern Arizona. Sofia's project will help us to understand the vast underground biodiversity in Arizona's southern mountains, and will inform our advocacy for protecting soil habitats in the Sonoran Desert.
Iris Garthwaite is a Master's student in the Northern Arizona University's School of Earth and Sustainability. She was awarded a $500 student grant for her project that will use innovative methods to assess the adaptability of the Fremont cottonwood tree, an important and widespread species in riparian areas in the Sonoran Desert, to the impacts of climate change.
FINAL REPORTS OF OUR 2020 GRANTEES
Miguel Grageda studies endangered Sonoran pronghorn in the Pinacate Biosphere Reserve in Sonora, Mexico, to see how nearby human development (roads, other barriers, and livestock grazing) might affect their population.
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Miguel's 81 camera traps cover 200,000 acres, a significant portion of the pronghorn habitat within the Reserve. He recorded an increase in camera-trap records (each time an individual or a group of individuals was obtained at a specific time and location) from 123 in 2019 to 137 in 2020. The sex ratio was approximately two males for every female.
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One of Miguel's most exciting findings for 2020 was a group of fawns born during the first week of March, demonstrating recruitment of pronghorn into this area. These animals were also recorded in September and October, thus they survived the harsh summer in the region. Overall, six independent records of fawns were recorded in 2019, and 11 in 2020.
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While pronghorn were distributed throughout the Reserve, 37% of records (51/137) were made at four camera-trap locations along Highway 2, in proximity to the international border. The majority of these records (92%) were made at a distance of either 750 m or 1500 m from the highway, rather than close to this disturbance.​ These records were made in February, May, and November 2020, suggesting that pronghorn were present in the area for most of the year.
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​Miguel plans to collect data throughout 2021 in order to compare his findings over a three-year time span.
Julie Rakes studies biocrusts, the topsoil microbial communities found atop desert soils. It is important to understand what affects the health of biocrusts as they provide nutrients to soils in nutrient-poor regions such as the Sonoran Desert.
Recent field surveys of biocrusts have revealed the presence of virulent predatory bacteria (the “plaques” seen in Julie's photo), which infect healthy biocrusts. Julie's research involves analyzing the effects of rainfall and temperature on the health of biocrusts in desert soils.
Julie's data show that increased rainfall facilitates the rate of infection by predatory bacteria, killing up to 28% of the biocrusts that they inhabit. Intense sunlight has the opposite effect, killing about half of the infectious bacteria on the soil surface.
By learning more about what factors influence the health of biocrusts, we will be able to develop better management plans to protect them.
2020 STUDENT GRANT AWARD WINNERS
Julie Bethany Rakes is a Ph.D. student in ASU's School of Life Sciences. She was awarded a $500 grant to help her complete her studies on a predatory bacterium found in the the soil crusts of the Sonoran Desert. Julie's work will increase our understanding of how desert microbes impact topsoil communities in arid, desert environments.
Miguel Angel Grageda Garcia is a Ph.D. student in the University of Arizona's School of Natural Resources. He was awarded a $500 grant to continue his camera trap studies on the endangered Sonoran pronghorn in the El Pinacate Biosphere Reserve in Sonora, Mexico. Miguel is examining how obstacles like roads and physical barriers affect the movements and range of Sonoran pronghorn, as well as their ability to compete with livestock for food and space.