Effects of Rate of Drying, Life History Phase, and Ecotype on the Ability of the Moss Bryum Argenteum to Survive Desiccation Events and the Influence on Conservation and Selection of Material for Restoration

Desiccation stress is frequently experienced by the moss Bryum argenteum and can influence survival, propagation and niche selection. We attempted to disentangle the interacting factors of life history phase (five categories) and rate of desiccation (time allotted for induction of desiccation tolerance) for 13 ecotypes of B. argenteum. Using chlorophyll fluorescence as a stress index, we determined how these parameters influenced desiccation tolerance. Rate of drying and life phase significantly affected desiccation tolerance. The reaction norms of desiccation tolerance displayed by the 13 ecotypes showed a substantial degree of variation in phenotypic plasticity. We observed differences in survival and fluorescence between rapid and slow drying events in juveniles. These same drying applications did not produce as large of a response for adult shoots (which consistently displayed high values). Some juvenile and protonemal ecotypes, such as those from the southwest United States, possessed higher innate tolerance to rapid drying, and greater resilience compared to ecotypes sourced from mesic localities in the United States. These results show a complex nuanced response to desiccation with ecotypes displaying a range of responses to desiccation reflecting both inherently different capacities for tolerating desiccation as well as variation in capacity for phenotypic plasticity. Our results suggest that we should expect few short-term effects of climate change due to high desiccation tolerance of adult shoots, but significant adverse long-term effects on colony establishment due to low tolerance of protonema and juvenile shoots. Further, we would recommend that future studies using mosses for habitat restoration of aridlands consider the desiccation tolerance capacity of individual ecotypes used for cultivation and later re-introduction. Understanding how mosses respond to desiccation is essential to interpret ecological roles, habitat preferences, selective pressures, and responses to climate change, and to estimate the potential effects of climate changes on bryophyte species and populations

Restoration of Biological Soil Crust on Disturbed Gypsiferous Soils in Lake Mead National Recreation Area, Eastern Mojave Desert

Biological soil crusts (BSCs) are sensitive to anthropogenic disturbances. Natural recovery takes many years. Active restoration decreases recovery time. Native BSC inocula, which included lichens and mosses, salvaged from gypsiferous soil habitats in Lake Mead National Recreation Area (LMNRA) in the eastern Mojave Desert were stored dry for two years and applied to disturbed soil after a road reconstruction in LMNRA and also used in laboratory experiments to test inoculation technique effectiveness. After 18 months, field results revealed positive relationships between inoculation and the presence of macroscopic BSC cover, cyanobacteria abundance, soil stability, and ammonium concentrations. Chlorophyll fluorescence monitoring of the dominant lichen Collema revealed specimens from field sites had equivalent or higher values than undisturbed specimens indicating photosynthetic recovery after salvage, storage, and field application. Laboratory slurry treatments showed significant evidence of cyanobacteria growth after eight months. The results from this thesis research have direct implications for ecosystem management

Rapidly Restoring Biological Soil Crusts and Ecosystem Functions in a Severely Disturbed Desert Ecosystem

Restoring biological soil crusts (biocrusts) in degraded drylands can contribute to recovery of ecosystem functions that have global implications, including erosion resistance and nutrient cycling. To examine techniques for restoring biocrusts, we conducted a replicated, factorial experiment on recently abandoned road surfaces by applying biocrust inoculation (salvaged and stored dry for two years), salvaged topsoil, an abiotic soil amendment (wood shavings), and planting of a dominant perennial shrub (Ambrosia dumosa). Eighteen months after treatments, we measured biocrust abundance and species composition, soil chlorophyll a content and fertility, and soil resistance to erosion. Biocrust addition significantly accelerated biocrust recovery on disturbed soils, including increasing lichen and moss cover and cyanobacteria colonization. Compared to undisturbed controls, inoculated plots had similar lichen and moss composition, recovered 43% of total cyanobacteria density, had similar soil chlorophyll content, and exhibited recovery of soil fertility and soil stability. Inoculation was the only treatment that generated lichen and moss cover. Topsoil application resulted in partial recovery of the cyanobacteria community and soil properties. Compared to untreated disturbed plots, topsoil application without inoculum increased cyanobacteria density by 186% and moderately improved soil chlorophyll and ammonium content and soil stability. Topsoil application produced 22% and 51% of the cyanobacteria density g−1 soil compared to undisturbed and inoculated plots, respectively. Plots not treated with either topsoil or inoculum had significantly lower cyanobacteria density, soil chlorophyll and ammonium concentrations, and significantly higher soil nitrate concentration. Wood shavings and Ambrosia had no influence on biocrust lichen and moss species recovery but did affect cyanobacteria composition and soil fertility. Inoculation of severely disturbed soil with native biocrusts rapidly restored biocrust communities and soil stability such that restored areas were similar to undisturbed desert within three years. Using salvaged biocrust as inoculum can be an effective tool in ecological restoration because of its efficacy and simple implementation. Although salvaging biocrust material can be technically difficult and potentially costly, utilizing opportunities to salvage material in planned future disturbance can provide additional land management tools

Improving Germination Rates for Select Native Perennial Seeds of The Sonoran Desert

Anthropogenic influences, such as the removal of vegetation for road and alternative energy construction, have degraded deserts of the southwestern United States (Abella, 2010). Sensitive and endangered wildlife, such as the desert tortoise, are dependent on desert vegetation for their diet and habitat in the Mojave and Sonoran Deserts (Nussear et al., 2009). Disturbed desert lands contribute to increasing dust storms, which pose as a human health hazard (Pointing and Belnap, 2014). Revegetation by outplanting nursery-grown plants has been more reliable than seeding for establishing native desert perennials, suggesting a need for further research if seeding is to be successful (Abella et al., 2012). To minimize time and expenses for restoration projects, it is important to develop seed treatment techniques that raise germination rates

Mojave Applied Ecology Notes Winter 2009

Chronology of forest structure and use in the Spring Mountains, Soil-Tech’s restoration work balancing construction with nature, species performance and treatment effectiveness for revegetation projects, and strategic research areas for Mojave conservation and managemen

Mojave Applied Ecology Notes Summer 2009

BLM and wildfire protection in the Mojave, studies of the sticky ringstem flowering phenology in Lake Mead NRA, restoration work within gypsum soils, post-fire response synthesis for Mojave and Sonoran desert

Mojave Applied Ecology Notes Spring 2010

Seed removal rates of Sahara mustard by rodents and ants, Mojave Desert Network exotic invasive inventory, gypsum roadside disturbance restoration update, new paper out on post-fire plant establishment, UNLV establishes school of environmental and public affair