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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #352227
Title: Fungal facilitation in rangelands: do arbuscular mycorrhizal fungi mediate resilience and resistance in sagebrush steppe

Author
item HOVLAND, MATTHEW - Oregon State University
item MATA-GONZÁLEZ, RICARDO - Oregon State University
item Schreiner, Roger - Paul
item RODHOUSE, THOMAS - National Park Service

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/8/2019
Publication Date: 7/1/2019
Citation: Hovland, M., Mata-González, R., Schreiner, R.P., Rodhouse, T.J. 2019. Fungal facilitation in rangelands: do arbuscular mycorrhizal fungi mediate resilience and resistance in sagebrush steppe. Rangeland Ecology and Management. 72(4):678-691. https://doi.org/10.1016/j.rama.2019.02.004.
DOI: https://doi.org/10.1016/j.rama.2019.02.004

Interpretive Summary: A review of published research regarding the role that arbuscular mycorrhizal fungi play in stabilizing native plant communities of the sagebrush steppe was conducted to develop a framework for land managers and scientists to use to better understand and better manage mycorrhizal fungi to preserve these ecosystems. Fungal colonization within the roots of a native perennial bunchgrass and an invading annual grass along an invasion gradient was also determined. Our summary of prior research indicates that arbuscular mycorrhizal fungi likely play a key role in maintaining native sagebrush steppe plant communities through a variety of mechanisms, but the need to manage mycorrhizal fungi and the protocols to do this in order to increase the invasion resistance of sagebrush steppe systems cannot be predicted based on our present state of knowledge. The key factors that need to be determined to understand if mycorrhizal fungi will increase invasion resistance at a given site include knowledge of the mycorrhizal host status of the native and invading plants, the functional guild of the native and invading plants, and how mycorrhizal fungi alter competition between native and invading plant species under the prevailing local conditions. Furthering our understanding of how mycorrhizal fungi influence resistance of native plant communities to exotic plant invasion may provide a critical component to preserve these arid sagebrush steppe ecosystems.

Technical Abstract: Arbuscular mycorrhizal fungi (AMF) may exert profound influences on ecosystem resilience and invasion resistance in rangelands. Maintenance of plant community structure through ecological feedback mechanisms such as facilitation of nutrient cycling and uptake by host plants, physical and chemical contributions to soil structural stability, and mediation of plant competition suggest AMF may act as keystone facilitators in stressful arid environments. Plant-AMF interactions could affect succession by increasing native plant community resilience to drought, grazing, and fire, resistance to exotic plant invasion, and by reinforcing positive feedback loops in invaded sites. Here, we review scientific literature relevant to AMF in sagebrush (Artemisia spp.) steppe rangelands, with specific focus on impacts of land management, disturbance, and invasion on AMF communities. We present a case study that reveals differences in mycorrhizal colonization between the native perennial bunchgrass Pseudoroegneria spicata (Pursh.) Á. Löve (bluebunch wheatgrass) and the exotic invasive annual grass Taeniatherum caput-medusae (L.) Nevski (medusahead) along an invasion gradient in eastern Oregon, USA. Our review found compelling evidence that AMF mediated resilience to disturbance and resistance to plant invasion will vary with plant and fungi community composition including individual plant mycorrhizal host status, physiological adaptations to disturbances of both plants and fungi, and functional guild of both established and invading plant species. We conclude by outlining a framework to advance knowledge of AMF in rangeland invasion ecology. We emphasize the importance of field studies focusing on AMF mediated competition between native and exotic plants, the levels of AMF dependency of natives on specific AMF communities, and the soil conditioning effects of exotic plants. It is likely that current emphases on soil abiotic attributes and plant community characteristics will be insufficient to effectively address lack of resiliency and invasion resistance in rangeland ecosystems.