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University of Nevada, Las Vegas (2019)

Assessing Minimal-Input Restoration Strategies for Desert Soil and Vegetation Restoration

Rader, Audrey Jean

Titre : Assessing Minimal-Input Restoration Strategies for Desert Soil and Vegetation Restoration

Auteur : Rader, Audrey Jean

Université de soutenance : University of Nevada, Las Vegas

Grade : Master of Science-Biological Sciences 2019

Résumé partiel
The Mojave and Sonoran Deserts have been negatively impacted by anthropogenic disturbances. Considering that these ecosystems may recover on millennial timescales, research has shown that restoration techniques can be fairly successful in initiating long-term recovery processes in these sensitive environments. However, uncertainty remains as to which techniques are effective in different circumstances, such as in different climates or across different soil properties, and which techniques may best avoid unintended consequences, such as facilitating non-native plants. To reduce fugitive dust as a human health hazard, increase soil stability, and enhance wildlife habitat, further work is necessary to develop restoration techniques for disturbed desert landscapes. The aims of this thesis were to examine the impacts of severe disturbances on soils of the Mojave and Sonoran Deserts and to investigate the efficacy of target restoration techniques within these ecoregions. Studies were conducted in the field, laboratory, and greenhouse to determine how anthropogenic disturbances impact soil characteristics and test the effectiveness of the three implemented restoration techniques. The target restoration techniques chosen for this study span varying levels of effort and financial cost to better understand how effective minimal-input restoration strategies are in contrast to costlier, more intensive strategies. The minimal-input techniques examined here included vertical mulch (placing dead branches upright in the soil to simulate the appearance of dead shrubs), soil surface manipulations (such as surface de-compaction and contouring the soil to create water catchments), outplanting, and seeding with litter. My research analyzes the effectiveness of vertical mulch treatments, surface de-compaction, and seeding with litter in the Dead Mountains Wilderness Area located 18 km northwest of Needles, CA in the Mojave Desert. I analyzed the influence of vertical mulch, water catchments, and outplanting in four distinct study sites south of Joshua Tree National Park along the Devers Palo II Transmission Corridor from Indio, CA to Blythe, CA. I conducted laboratory analyses of soil conditions at each of the sites. Before establishing restoration treatments in both regions, soil conditions were characterized by a lack of natural recovery of native perennial vegetation, and lower vegetation cover in disturbed sites in comparison to undisturbed sites.

Mots clés  : Mojave Desert ; Restoration ecology ; Revegetation ; Soil surface manipulation ; Sonoran Desert ; Vertical mulch


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Page publiée le 19 décembre 2019