Current Research

The Sweeney Granite Mountains Desert Research Center supports research in a wide array of disciplines through providing researcher lodging, laboratory space and equipment, logistical support, and protected areas on which to implement research projects. All proposed projects are reviewed by the resident Director to minimize impacts on resources and ensure that project implementation will not affect existing research projects. We currently have over 160 research projects affiliated with the GMDRC, below are some examples.

Meagan Mnich is a Ph.D. candidate working under Dr. Benjamin Houlton in the Department of Land, Air, and Water Resources at UC Davis.  They are interested in isotopic constraints on ecosystem-scale nitrogen balances in the desert. This work is part of a larger project funded by a NSF-CAREERS grant awarded to Dr. Houlton in 2012 titled, “Large-scale nitrogen cycles and underrepresented groups: A plan for advancement”.  Dr. Houlton and his students, including Meagan, use a range of natural isotopic techniques, models, and experimental approaches to advance our understanding of ecosystem responses to global environmental change.  In particular, the research at the Center will focus on nitrogen cycling within desert ecosystems by comparing isotopic measures of soil, plants, and rainfall deposition on a local and regional scale.  Data collected at the Center will be used to build better models for predicting global nutrient cycling.

Timothy Higham, Ph.D., Assistant Professor at UC Riverside, and his students are broadly interested in how animals move in their natural environment in relation to ecological pressures. More specifically, the focus of their research at the Center is part of an ongoing project examining muscle dynamics and biomechanics of locomotion and predator-prey interactions of desert-dwelling lizards in California.  Dr. Higham is expanding his research interests to include several lizard species from the Mojave Desert, including Uma scoparia, Uta stansburiana, Callisaurus draconoides, Coleonyx variegatus, Aspidoscelis tigris, Phrynosoma platyrhinos, Crotaphytus bicinctores (shown in photo), and Sceloporus magister.  By studying the relationship of ecology to biomechanics he hopes to gain a better understanding of how habitat structure acts as an underlying selective pressure on these animals, which will then allow him to predict impacts of future or current habitat modifications.

Jacob Landis, Ph.D. candidate under Dr. Pamela Soltis at the University of Florida, is studying the morphological and molecular evolution of flower color in Polemoniaceae.  Specifically he is interested in species of Leptosiphon and Linanthus, as these two genera contain multiple examples of polymorphic flower color.  He visited the Center in April of 2013 as he was traveling throughout the Southwest in hopes of collecting material for his phylogenetic analyses.  We assisted his efforts by providing him with locality information, as well as collections of species encountered prior to his visit.  This type of assistance from Center staff is of great value to researchers like Jacob, who may have limited opportunities to be in the field (i.e. at the right place, at the right time).  This is especially true in the case of desert annuals, a challenging group to study because they are both temporally and geographically ephemeral.

Alex Filazolla, Ph. D. candidate at York University, is working under Dr. Christopher Lortie to study direct and indirect effects of nurse plants on seedbanks and annual plant communities.  Alex, along with two undergraduate students (Amanda Liczner and Ally Ruttan), came to the Center this spring to establish study plots that will allow them to test for biotic and abiotic effects of shrubs on germination and pollination rates for neighboring annual plants. They are employing an interesting method of monitoring pollinator visitation, in which small video cameras are placed in and around each study plot to capture pollinator visitation rates. Apparently the cameras pick up amazing detail. Germination studies will be used to test for the effect of microhabitat (open canopy vs. shrub canopy) and seed density. The first round of germination trials is currently underway in growth chambers back in Toronto.

Dr. James E. Russell, Associate Professor of Biology at Georgia Gwinnett College (GGC), spent 3 weeks at the Center in the spring of 2013 collecting data and specimens for a long-term project that he started as a graduate student more than a decade ago.  As a graduate student Dr. Russell studied the ecological and evolutionary consequences of infection by the bacterial symbiont Wolbachia in parasitoid wasps of the genus Trichogramma.  In his current position at GGC he is leading several Student-Faculty Research Collaborations, which are required courses for undergraduates in the science disciplines, all of which revolve around the ecology of parasitoid wasps.  In June of 2013, Dr. Russell and his team of students, collected thousands of butterfly eggs in order to begin several studies addressing population structure, sex ratio selection, and Wolbachia infection rates among natural populations of Apodemia mormo, a butterfly that is host to several Trichogramma species. The data collected this year will be used to compare rates of parasitism and offspring sex-ratios in the Wolbachia-Trichogramma parasitoid system to data collected 15 years ago, but more importantly it will be used to launch additional Student-Faculty Research Collaborations.  (A short story about this research was posted on the GGC website, to read that article visit their website at:

John Regus, Ph.D. candidate in the Evolution, Ecology, & Organismal Biology program at UC Riverside, is interested in the evolution of interspecific symbiotic interactions.  For his doctoral work he is studying a legume-rhizobia symbiosis using several annual species of the Acmispon (Lotus) genus.  He is testing how variation in exogenous nitrogen can alter the cost and benefits of symbiosis for the host and symbiont, and more specifically, he is interested in how the host legume controls the spread of ineffective rhizobia.  His research will shed light on how external sources of nitrogen, such as fertilizer and atmospheric deposition of NOx, will impact agronomic and natural systems.

Jeffrey Jenkins is a doctoral student in the Environmental Studies Department at UC Santa Cruz.  His dissertation research focuses on environmental policy of rare earth element (REE) extraction and life cycle analysis of minerals used for renewable energy applications and high-tech devices.  He is exploring the relationship between government, private industry, and civil society in the development of policies for environmental impacts, mining and processing techniques, and sustainability of consumer demand.  There are four REE mines scheduled to re-open in the U.S. by 2015, one of which is located near the GMDRC at Mountain Pass.

Dylan Rood is a geomorphologist specializing in the use of cosmogenic nuclides and accelerator mass spectrometry to study the evolution of Earth surface processes, tectonic geomorphology, and paleoclimatology.  He is a Research Fellow at the Scottish Universities Environmental Research Centre, as well as an Assistant Researcher at UC Santa Barbara’s Earth Research Institute.  His research in the Mojave Desert focuses on the timing, formation rate, and geomorphic development of precariously balanced rocks (PBR’s).  The study site he is using at the Granite Mountains represents a region of low seismicity, which he then compares to another location with high seismicity near the San Andreas Fault.  He will be using his data and analyses to directly test seismicity models, ground motion prediction equations, and hazard estimates associated with the 2008 USGS National Seismic Hazard Maps (NSHM) and Cybershake.

Terry Griswold is a research entomologist who runs the USDA-ARS Bee Biology & Systematics Lab, as well as being adjunct faculty for Utah State University.  His research interests include systematics, biogeography, and biodiversity of native bees.  Through his many years of research in the region he has made several discoveries of new species to science, as well as documented range extensions for a number of bee species.  In addition, his studies have focused on floral preferences and spatial patterns in bee communities.

Shannon Still, postdoctoral Research Associate at the Chicago Botanic Garden, is working on species distribution modeling of rare plants in the western US.  His research examines the impact of global climate change on the species distribution of rare plants in the Great Basin. With this work they are examining the current distributions of rare plants, then making projections as to how these distributions will change between now and the year 2080.

Dr. Don Miller, Assistant Professor, studies Entomology in the Biological Sciences Department at Chico State University.  His research involves galling aphids (Tamalia spp.) that act as inquilines by invading and co-occupying galls.  He is interested in determining whether the origin of inquilinism in Tamalia was associated with a host-plant shift, and whether this reflects the phylogeographic history of the host-plant (Arctostaphylos spp.) clade.  By applying both field- and molecular methods, he and his students hope to elucidate any phylogenetic evidence for host-race formation in gall-inducers and inquilines. Evaluating whether the apparently greater rate of host-race formation in inquilines is upheld across large geographic areas and over a wide range of host plants.

Janet Harvey, graduate student at California Institute of Technology in the Division of Geological and Planetary Sciences, is conducting her research on the south Bristol Mountains fault.  This range lies just south and west of the Granite Mountains.  The fault was last active in the Quaternary and played a role in accommodating plate boundary slip between the Pacific and North American plates.  She is interested in mapping the range to better elucidate the total accumulated slip and assess potential seismic risk this fault might pose.  Her field efforts are focused on detailed mapping of the fault zone and reconstruction of dismembered early to middle Miocene sedimentary and volcanic rock sequences.

Dr. Ellen Simms, Professor in the Department of Integrative Biology at UC Berkeley, visited the GMDRC in 2011 to collect specimens for her research on phylogenetic patterns of rhizobium specificity in California Acmispon (Fabaceae).  She and her students are interested in the evolution of mutualistic traits in legumes and nitrogen-fixing bacteria, as well as population genetic structure of N-fixing Bradyrhizobium in a wild legume community.

Dr. Darren Sandquist, Associate Professor of Botany in the Department of Biological Sciences at CSU Fullerton, studies physiological ecology of plants in the context of how plants respond to environmental variability. He and his colleagues from USGS, David Bedford and David Miller, are collaborating on a project at the base of the Providence Mountains where they are measuring the physiological responses of two common Mojave desert shrubs, Larrea tridentata and Ambrosia dumosa, to simulated summer wash flow. In order to achieve this a complex network of irrigation lines was used to control the amount of water reaching each shrub, then a suite of physiological measurements, such as xylem potential and stomatal conductance, were recorded.  This research will help predict how plants utilize water during intense rain events, as well as provide insight for responses to altered precipitation patterns.

Last updated: June 2014