When I first started my PhD program in ecology at Northern Arizona University, I was a bit fearful of aridland ecosystems. I am originally from Southern Louisiana and grew up near enough to the Gulf Coast that water as a limiting resource was completely outside of my experience. Having now completed two years of my program, I find that I am captivated by the stories these harshest of landscapes have to share with us. The lessons learned here have the potential to be regionally, and even globally, important as researchers predict further drought and water stress to many parts of the planet.
As part of my research program, I have embarked on a project in Navajo County, Arizona, studying the role of plant-soil interactions in facilitating the success of invasive plant species. Water use among the native plant community requires a tenuous balance that has evolved over millions of years, withstanding severe drought and other ecologically disruptive forces. Non-native, invasive plants do not exhibit the efficient water use strategies employed by native species, and these introduced species can jeopardize long-term water usage in an already water-starved region.
The invasive plant that I am studying, camelthorn, is able to root deeply and tap into groundwater resources. This species is able to tolerate the stressful conditions associated with disturbed riparian ecosystems and is often found growing in association with saltcedar. Saltcedar, another non-native invasive, is well known across the southwest as a riparian invader. This species makes conditions inhospitable for most native plants species by drawing down water tables and depositing salt on soil surfaces. Both of these plants further stress water budgets in these already water-limited environments. The management and removal of these non-native species is currently a priority in restoration of southwestern riparian areas.
These plants are a detrimental addition to not only native ecosystems but also to the culturally rich agricultural lands of the Hopi Nation. Hopi are one of the longest running, continually practicing cultures in North America, with tribal members retaining their language and ancestral ways to the present day. The Hopi were historically an agricultural people; they remain very tied to the land and possess a unique understanding of plant cultivation in aridland ecosystems. For over 3000 years, the Hopi have grown genotypes of corn, beans, and squash that are uniquely adapted to the region. These genotypes now act as important reservoirs of genetic information and have the potential to inform more sustainable growth and production of food across the arid southwest. Hopi are stewards of these arid, agricultural lands and may have some very important things to share about land management, especially as water becomes even more limiting across aridland ecosystems.
On Hopi tribal land along the Little Colorado River Basin, river restoration will be required to restore natural hydrologic function (water cycling), culturally important plant species, and sustainable land management practices. Complete removal and eradication of these invasive species may be infeasible. We may need to come up with some alternative strategies for keeping these species in check. Camelthorn, for example, is documented to have medicinal value in its native habitat (the Middle East). As a way to encourage both riparian restoration and alternative management strategies, I am pondering ways to bring the knowledge of this medicinal plant to the Hopi tribe.
After years of research on land adjacent to the Hopi reservation, I now have a strong connection with these people, with this land, and with these species. Tribal members are supportive of my research program – discussing it with them has garnered both positive feedback and interest. I hope to connect the knowledge gained in my research project to these people. Connecting my research to the native tribe and to local restoration efforts is a major goal of my dissertation. This unique approach will allow me to merge the social, scientific, and cultural aspects of land management. With this broader context to my work on plant-soil interactions, I hope my scientific contributions will also benefit the people whose land gave me this insight.