Physical Sciences and Mathematics Commons^™

Disturbance, Vegetation Co-Occurrence, And Human Intervention As Drivers Of Plant Species Distributions In The Sagebrush Steppe, Fiona Claire Schaus Noonan

Boise State University Theses and Dissertations

Changes in fire regimes, invasive species dynamics, human land use, and drought conditions have shifted important plant species in the Northern Great Basin (NGB)—including big sagebrush (Artemisia tridentata ssp.), conifers (e.g., Juniperus spp.) and invasive annual grasses (e.g., Bromus tectorum). Characterizing how these overlapping disturbances influence species distributions is critical for land management decision-making. Previous research has explored the individual effects of drought, wildfire, restoration, and invasive species on sagebrush steppe communities, but the specific effects of these disturbances in context with one another remain poorly understood at a landscape scale. To address this …

Fire Effects On Soil Properties: Amending Post-Fire Soils With Native Microbial Communities And Biochar To Improve Sagebrush Performance, Sabrina Marie Schuler

Boise State University Theses and Dissertations

Within the sagebrush steppe, fire has been shown to affect biogeochemical properties and the microbial community composition in soils. However, there is uncertainty about the magnitude and direction of these effects, since they vary by sites that differ in abiotic and biotic conditions. Moreover, differences in post-fire management strategies are likely to mediate the effect of fire on soil properties, thus further compounding this uncertainty. Any changes in soil biogeochemical properties following fire can prevent successful restoration of Artemisia tridentata sp. wyomingensis (sagebrush), leading to variable outcomes of restoration success in the sagebrush steppe. Previous research has shown that addition …

Assessment Of Unmanned Aerial Systems (Uas) Surveys In Dryland Ecosystems: Estimates Of Fractional Photosynthetic Cover And Plant Functional Types, Anna V. Roser

Boise State University Theses and Dissertations

Drylands cover 41% of the global land surface and provide ecosystem services to 38% of the world’s population. Dryland ecosystems have already been degraded or threatened by the increased rates of wildfire and invasive annual grasses, as well as changes in precipitation patterns. We cannot protect, mitigate, or restore drylands without comprehensive vegetation surveys. To understand ecosystem processes, we need to know the composition of vegetation at the patch and plant scales. Field observations are limited in coverage, and are expensive and time intensive. Data from Unmanned Aircraft Systems (UAS) will fill the niche between field data and medium scale …

Deriving Landscape-Scale Vegetation Cover And Aboveground Biomass In A Semi-Arid Ecosystem Using Imaging Spectroscopy, Andrew Poley

Boise State University Theses and Dissertations

Environmental disturbances in semi-arid ecosystems have highlighted the need to monitor current and future vegetation conditions across the landscape. Imaging spectroscopy provide the necessary information to derive vegetation characteristics at high-spatial resolutions across large geographic areas. The work of this thesis is divided into two sections focused on using imaging spectroscopy to estimate and classify vegetation cover, and approximate aboveground biomass in a semi-arid ecosystem.

The first half of this thesis assesses the ability of imaging spectroscopy to derive vegetation classes and their respective cover across large environmental gradients and ecotones often associated with semi-arid ecosystems. Optimal endmember selection and …

The Carbon Budget Impact Of Sagebrush Degradation, Andrew Connor Austreng

Boise State University Theses and Dissertations

More than 20,000 km2 of sagebrush (Artemesia spp.) ecosystems within the Great Basin have been replaced, often following wildfire, by the nonnative winter annual cheatgrass (Bromus tectorum). At a field site in the central Snake River Plain of southern Idaho, the impact of this invasion on the soil carbon (C) reservoir has been evaluated and the potential soil C benefits of bunchgrass (Agropyron cristatum) seeding was assessed. Using a large soil C dataset (n = 850), differences in total organic carbon and root biomass were quantified in immediately-adjacent sagebrush, cheatgrass, and bunchgrass communities. Statistical …