Earth Sciences Commons^™

Patch-Differentiation Of Vegetation And Nutrient Cycling In An Extensive Pasture System, Bettina Tonn, Anika Wirsig, Manfred Kayser, Nicole Wrage-Mönnig, Johannes Isselstein

IGC Proceedings (1977-2023)

In extensive grazing systems, ‘patch-grazing’ may lead to the development of a mosaic structure consisting of short, frequently defoliated, and tall, infrequently defoliated patches. If spatial patterns of sward structure are stable over time, this may result in a long-term differentiation of botanical composition and matter fluxes between patch types within a pasture. Patch dynamics, botanical composition and topsoil nutrient concentrations of different patch types were investigated in a long-term grazing experiment in the Solling hills, Germany, where differentiated grazing intensities have been applied for 10 years. Continuously stocked beef cattle grazed to target sward heights of 6 or12 cm …

Evaluating The Benefits Of Restricted Grazing To Protect Wet Pasture Soils In Two Dairy Regions Of New Zealand, Pierre C. Beukes, Alvaro J. Romera, David A. Clark, Dawn E. Dalley, Mike J. Hedley, David J. Horne, Ross M. Monaghan, Seth Laurenson

IGC Proceedings (1977-2023)

Many dairy farms in the Manawatu and Southland regions of New Zealand have poorly drained soils that are prone to treading damage, an undesirable outcome on grazed pastures during the wetter months of the year. Removing cows to a stand-off pad during wet conditions can reduce damage, but incurs costs. The objective of this study was to evaluate the impact of different levels of restricted grazing (from 0 to 10 hours grazing time/day for lactating cows) on pasture yield, damage and wastage, feed and stand-off expenses, and farm operating profit. A simulated farm from each region was used in a …

Hydrogeology Of The Gillingarra Palaeochannel, Russell Speed, Adele Killen

Resource management technical reports

Previous groundwater investigations had identified the presence of palaeochannel sediments under the Capitela Valley in the Perth Basin, about 25 kilometres south-west of Moora. The sediments of this Capitela Palaeochannel were thought to form a discrete aquifer of good quality groundwater suitable for agriculture.

To improve our understanding of the Capitela Palaeochannel, its distribution, water quality and potential as a groundwater resource, we undertook an airborne electromagnetic (AEM) geophysical survey of the area in December 2012. This led to the discovery of a palaeochannel located in the Darling Range between Gillingarra and New Norcia, and we named this the Gillingarra …

Geological Origins Of The Ridley Creek Valley Landscape And Its Influence On Human Land Use, Walt Cressler

University Libraries Faculty Publications

Ridley Creek is a 24-mile long tributary of the Delaware River located in southeastern Pennsylvania. Its geological history has determined the topography of its watershed. The rolling Piedmont hills along most of its length, and the flat Coastal Plain at its confluence with the river have profoundly influenced the history of human land use within this landscape.

Orogenic Link ∼41°N–46°N: Collisional Mountain Building And Basin Closure In The Cordillera Of Western North America, Keith D. Gray, V. Isakson, D. Schwartz, Jeffrey D. Vervoort

Geosciences Faculty Publications and Presentations

Polyphase structural mapping and mineral age dating across the Salmon River suture zone in west-central Idaho (Riggins region; ∼45°30′N, ∼117°W–116°W) support a late Mesozoic history of penetrative deformation, dynamothermal metamorphism, and intermittent magmatism in response to right-oblique oceanic-continental plate convergence (Farallon–North America). High-strain linear-planar tectonite fabrics are recorded along an unbroken ∼48 km west-to-east transect extending from the Snake River (Wallowa intra-oceanic arc terrane; eastern Blue Mountains Province) over the northern Seven Devils Mountains into the lower Salmon River Canyon (ancestral North America; western Laurentia). Given the temporally overlapping nature (ca. 145–90 Ma) of east-west contraction in the Sevier fold-and-thrust …

Co-Eruptive Tremor From Bogoslof Volcano: Seismic Wavefield Composition At Regional Distances, Matthew M. Haney, David Fee, Kathleen F. Mckee, John J. Lyons, Robin S. Matoza, Aaron G. Wech, Gabrielle Tepp, Cheryl Searcy, T. Dylan Mikesell

Geosciences Faculty Publications and Presentations

We analyze seismic tremor recorded during eruptive activity over the course of the 2016–2017 eruption of Bogoslof volcano, Alaska. Only regional recordings of the tremor wavefield exist for Bogoslof, making it a challenge to place the recordings in context with other eruptions that are normally captured by local seismic data. We apply a technique of time-frequency polarization analysis to three-component seismic data to reveal the wavefield composition of Bogoslof eruption tremor.We find that at regional distances, the tremor is dominated by P-waves in the band from 1.5 to 10 Hz. Using this information, along with an enriched Bogoslof earthquake catalog, …

Future Evolution Of Greenland's Marine-Terminating Outlet Glaciers, G. A. Catania, L. A. Stearns, T. A. Moon, E. M. Enderlin, R. H. Jackson

Geosciences Faculty Publications and Presentations

Mass loss from the Greenland ice sheet (GrIS) has increased over the last two decades in response to changes in global climate, motivating the scientific community to question how the GrIS will contribute to sea-level rise on timescales that are relevant to coastal communities. Observations also indicate that the impact of a melting GrIS extends beyond sea-level rise, including changes to ocean properties and circulation, nutrient and sediment cycling, and ecosystem function. Unfortunately, despite the rapid growth of interest in GrIS mass loss and its impacts, we still lack the ability to confidently predict the rate of future mass loss …

High-Velocity Surface Layer Effects On Rayleigh Waves: Recommendations For Improved Shear-Wave Velocity Modeling, Gabriel Gribler, Lee M. Liberty, T. Dylan Mikesell

Geosciences Faculty Publications and Presentations

Soil stiffness estimates are critical to geologic hazard and risk assessment in urban centers. Multichannel analysis of surface-wave (MASW) data collection along city streets is now a standard, cost-effective, and noninvasive soil stiffness approximation tool. With this approach, shear-wave velocities (V_S) are derived from Rayleigh-wave signals. Although the current MASW practice is to neglect the effect of a high-velocity road layer on soil V_S estimates, our models show measurable impacts on Rayleigh-wave amplitudes and phase velocities when seismic data are acquired on a road surface. Here, we compare synthetic models with field MASW and downhole V …

Quantifying Rates Of “Rifting While Drifting” In The Southern Gulf Of California: The Role Of The Southern Baja California Microplate And Its Eastern Boundary Zone, Paul J. Umhoefer, C. Plattner, Rocco Malservisi

School of Geosciences Faculty and Staff Publications

The southern Baja California (Mexico) microplate has been rapidly moving away from the North America plate since ca. 12 Ma. This relative motion toward the northwest developed an oblique-divergent plate boundary that formed the Gulf of California. The rift-drift hypothesis postulates that when a continent ruptures and seafloor spreading commences, rifting on the plate margins ceases, and the margins start to drift, subside, and accumulate postrift sediments, eventually becoming a passive margin. In contrast to this hypothesis, the southern part of the Baja California microplate (BCM), and in particular its actively deforming eastern boundary zone, has continued significant rifting for …

Geochronology Of The Middle Eocene Purple Bench Locality (Devil’S Graveyard Formation), Trans-Pecos Texas, Usa, Amy L. Atwater, Kelly D. Thomson, E. Christopher Kirk, Meaghan Emery-Wetherell, Logan Wetherell, Daniel F. Stockli

All Faculty Scholarship for the College of the Sciences

Purple Bench is a middle Eocene fossil locality in the Devil’s Graveyard Formation of the Trans-Pecos region of West Texas. In addition to yielding a range of taxa characteristic of the Uintan North American Land Mammal Age, the Purple Bench locality is noteworthy in documenting a number of endemic species that are known only from the site. Despite the Uintan character of the mammalian fauna, the absolute age of Purple Bench is a matter of debate. This uncertainty stems from the wide interval of time encompassed by current radiometric dates bracketing the Purple Bench locality and from conflicting magnetostratigraphic correlations …

Mantle Structure And Flow Beneath An Early-Stage Continental Rift: Constraints From P Wave Anisotropic Tomography, Youqiang Yu, Stephen S. Gao, Dapeng Zhao, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

To explore 3-D seismic velocity and radial anisotropy structures of the upper mantle and mantle transition zone beneath the Malawi and Luangwa rift zones of the East African Rift System, we conduct the first study of P wave anisotropic tomography using data recorded at 75 seismic stations including 34 stations that we installed along two profiles as part of the Seismic Arrays for African Rift Initiation experiment. Both rift zones are revealed to have normal or slightly low velocity anomalies in the lithosphere and upper asthenosphere. The surrounding cratonic lithosphere is characterized by high-velocity anomalies with amplitudes ranging from +1.0% …

Organic Sulfur: A Spatially Variable And Understudied Component Of Marine Organic Matter, Krista Longnecker, Lisa Oswald, Melissa C. Kido Soule, Gregory A. Cutter, Elizabeth B. Kujawinski

OES Faculty Publications

Sulfur (S) is a major heteroatom in organic matter. This project evaluated spatial variability in the concentration and molecular-level composition of organic sulfur along gradients of depth and latitude. We measured the concentration of total organic sulfur (TOS) directly from whole seawater. Our data reveal high variability in organic sulfur, relative to established variability in total organic carbon or nitrogen. The deep ocean contained significant amounts of organic sulfur, and the concentration of TOS in North Atlantic Deep Water (NADW) decreased with increasing age while total organic carbon remained stable. Analysis of dissolved organic matter extracts by ultrahigh resolution mass …

Provenance Of Tin In The Late Bronze Age Balkans: Preparation Of Cassiterite For Sn Isotope Analysis And The Probabilistic And Spatial Analysis Of Sn Isotopes, Andrea H. Mason

Dissertations, Theses, and Capstone Projects

The sources of tin for the European Bronze Age (2200-1050 B.C.E.) have remained undetermined. Isotopic analysis has shown promise as a means of providing “fingerprints” of bronze artifacts that can be matched to their parental ore sources. This project has accomplished the following: (1) further tested and defined a method for the preparation of cassiterite for isotopic analysis, and (2), determined the provenance of tin used for metallurgy in the central Balkans during the later Bronze Age based on Sn isotopic compositions of bronze artifacts and local tin ores.

Two distinct methods have been applied in recent isotopic studies of …

Mapping The Base Of The High Plains Aquifer Using Borehole Geophysical Logs And Airborne Electromagnetic Surveys In Western Nebraska, Steven S. Sibray, Douglas R. Hallum, Joseph Reedy, Jason Yuill, Thadeus Kuntz

Conservation and Survey Division: Faculty and Staff Publications

The project scanned and reviewed data from 15,421 oil and gas well geophysical logs in 13 counties to delineate the base of aquifer and thickness of the High Plains Aquifer (HPA). The data and interpretations from this study can be used in a regional groundwater modeling effort that includes the Western Water Use Management Modeling (WWUMM) and the and the Cooperative Hydrology Study (COHYST) model. The area studied is in the Upper Platte River Basin. The Nebraska Department of Natural Resources (NeDNR) has designated most of the area as either overappropriated or fully appropriated, where groundwater is managed jointly

by …

Rock Mass Slope Stability Analysis Based On Terrestrial Lidar Survey On Selected Limestone Hills In Kinta Valley, Perak, Mohd Hellmy Muhammad Afiq Ariff

Student Works (2020-2029)

The use modern mapping technology is necessary in assessing slopes and cliffs, especially in tropical countries as it is mostly inaccessible and covered with thick vegetation which restricts the conventional data collection only at the base of the cliff. Overhanging and sub-vertical characteristics of limestone hills in Kinta Valley together with highly fractured and day-lighting joints increase the possibility of rock slope failure. The main objective of this research is to assess the stability and rock mass properties of the limestone hills in Kinta Valley based on the output provided by terrestrial LiDAR and scanline survey. Terrestrial laser scanning (TLS) …

Urban Heat In Tropical Kuala Lumpur: Microclimate, Outdoor Thermal Comfort And Mitigation By Land-Cover Modification, Chng Saun Fong

Student Works (2020-2029)

Urban heat island (UHI) is an urban warming phenomenon characterized by steep urban-rural temperature difference. Rapid land-use change in the urbanization process has introduced urban morphologies with impermeable surfaces and materials which causes higher heat retention in city centres. The emergence of urban hotspots is a growing concern due to the impact on the urban microclimate and human population. The comprehension of the multi-dimensional impact of UHI has become imperative to ensure good urban liveability especially in tropical cities where it is hot and humid annually. Hence, this study aims to explore the complex nexus of urban heat in terms …

Reshuffling The Columbia River Basalt Chronology — Picture Gorge Basalt, The Earliest- And Longest-Erupting Formation, Emily B. Cahoon, Martin J. Streck, Anthony A.P. Koppers, Daniel P. Miggins

Geology Faculty Publications and Presentations

The Columbia River Basalt Group (CRBG) is the world’s youngest continental flood basalt province, presumably sourced from the deep-seated plume that currently resides underneath Yellowstone National Park in the northwestern United States. The earliest-erupted basalts from this province aid in understanding and modeling plume impingement and the subsequent evolution of basaltic volcanism. We explore the Picture Gorge Basalt (PGB) formation of the CRBG, and discuss the location and geochemical significance in a temporal context of early CRBG magmatism. We report new ARGUS-VI multicollector 40Ar/39Ar incremental heating ages from known PGB localities and additional outcrops that we can geochemically classify as …

Effects Of Stocking Rate On The Variability Of Ecosystem Productivity In Desert Steppe, Zhongwu Wang, Shuying Jiao, Guodong Han, Mengli Zhao, Jing Wang, Walter D. Willms

IGC Proceedings (1977-2023)

Management practices can increase biodiversity and generate corresponding compensatory effects on biomass production, which may reduce inter-annual variability of productivity in some grassland ecosystems. However, it remains unclear how stocking rate influences variability of ecosystem productivity. Four stocking rates were compared in a completely randomized block experiment in the desert steppe of Inner Mongolia, China: non-grazed control (0 sheep/ha/mo), lightly grazed (LG, 0.15 sheep/ha/mo), moderately grazed (MG, 0.30 sheep/ha/mo) and heavily grazed (HG, 0.45 sheep/ha/mo). Aboveground net primary productivity (ANPP) was measured every August for eight consecutive years (2004-2011). ANPP decreased significantly (P < 0.05) with increasing stocking rate. Coefficients of variation for community (CV_comm) in LG and MG …

Sustainable Grazing Management For Temporal And Spatial Variability In North Australian Rangelands–A Synthesis Of The Latest Evidence And Recommendations, Peter O’Reagain, Joe C. Scanlan, Leigh Hunt, Robyn A. Cowley, Dionne Walsh

IGC Proceedings (1977-2023)

Rainfall variability is a major challenge to sustainable grazing management in northern Australia, with management often complicated further by large, spatially heterogeneous paddocks. This paper presents the latest grazing research and associated bio-economic modeling from northern Australia and assesses the extent to which current recommendations to manage for these issues are supported. Overall, stocking at around the safe long term carrying capacity will maintain land condition and maximize long term profitability. However, stocking rates should be varied in a risk-averse manner as pasture availability varies between years. Periodic wet season spelling is also essential to maintain pasture condition and allow …

Management Effects On The Vegetation Of Rangeland In The Middle Of Southern Slope Of Tianshan Mountains, Linqiao Xi, Shuqi Wu, Hui Liu, Dong Wang, Chunhui Ma

IGC Proceedings (1977-2023)

Rangeland degradation is a widespread problem and its restoration remains a major challenge. In recent years, many scientists have discussed the primary causes of over-grazing and approaches to restoration of China’s grasslands (e.g. Harris 2010; Wang and Han 2005; Lu et al. 2005). The major evidence of grassland degradation is lower plant productivity, reduced biodiversity and increase in poisonous weeds (Zhao et al. 2010), increased frequency of rodent and grasshopper infestations, and large scale dust storms (Lu et al. 2005). Restoration of these impacted ecosystems is an important and challenging task, especially in Xinjiang Province, China, …

Resource Variations Across The Landscape Mediate The Impact Of Grazing On Vegetation In Mongolian Rangeland Under High Climatic Variability, Kaoru Kakinuma, Tomoo Okayasu, Takehiro Sasaki, Undarmaa Jamsran, Toshiya Okuro, Kazuhiko Takeuchi

IGC Proceedings (1977-2023)

Assessment of grazing-induced degradation of arid and semi-arid rangelands with stochastic rainfall regimes is challenging. For the last two decades, rangeland ecologists have been discussing the relative importance of biotic and abiotic factors in controlling vegetation dynamics. According to the non-equilibrium concept, which emerged as a new paradigm to describe ecosystems in highly variable and poorly predictable environments, vegetation dynamics are driven primarily by abiotic factors such as rainfall, rather than by internal biotic regulation (e.g. grazing impact). Although a number of studies have emphasized the non-equilibrium nature of most rangelands, they have produced inconsistent results and there …

Spatial Variability And Seasonal Change Of Radioactive Caesium Concentration In Grassland Vegetation, Mikinori Tsuiki, Saaya Eguchi, Yusuke Nagata, Takeki Maeda

IGC Proceedings (1977-2023)

The damage from the Fukushima Daiichi Nuclear Power Plant caused by the Great East Japan Earthquake and tsunami on March 11, 2011 resulted in serious radioactive pollution over Eastern Japan. The distribution of radioactive fallout was largely determined by wind and rainfall patterns in March 2011. Distribution patterns were not necessarily in accordance with the distance from the nuclear power plant. In Iwate Prefecture (160 to 340 km north of the nuclear power plant), the amount of fallout of radioactive material in the southern region was greater than in the northern, but the distribution pattern was complex (Fig. 1, Tsuiki …

Graphical Analysis Of Spatio-Temporal Patterns In Forage Quality, A. Bracher, M. Böhlen, F. Cafagna, A. Taliun

IGC Proceedings (1977-2023)

Due to the highly structured topography in Switzerland, crop growth conditions vary within short distances. Differences in altitude are one of the major causes for climatic variation resulting in significant spatio-temporal effects on forage quality in terms of nutrient content and feeding value, particularly in grassland dominated regions. It is one of the goals of the Swiss feed database to support queries that visualize and quantify the temporal and spatial influence on feed quality.

Spatio-Temporal Dynamics Of Global Potential Vegetation Distributions Simulated By Cscs Approach, Qisheng Feng, Tiangang Liang, Jiexie Hong, Xiaodong Huang, Jizhou Ren

IGC Proceedings (1977-2023)

The study of Potential Natural Vegetation (PNV) has been proposed as a way to examine the impact of changes in climate on the distribution of vegetation. This study analyzes the influence of climate change in the potential vegetation distribution at global scale, using the Comprehensive Sequential Classification System (CSCS) approach to explore the changes of area, shift distance and direction for each broad vegetation category.

Uncertainties Associated With The Use Of Erosional Cave Scallop Lengths To Calculate Stream Discharges, Gregory S. Springer, Andrew Hall

International Journal of Speleology

Scallops are extremely valuable indicators of past water flows in caves because they often record events that cannot be safely witnessed nor measured. Qualitatively, the inverse relationship between their lengths and formative water velocities is useful for determining how flow changes along a cave passage, but they are most valuable because they can be used to directly estimate actual water velocities and discharges. We explore the effects of sample size, measurement choices, and other methods commonly applied to the use of cave scallops in estimating cave stream velocities and discharges. We measured 100 scallops on a cave wall and find …

Monitoring Snow-Caused Disasters Using Remote Sensing And Gis Technologies In Pastoral Areas, Tiangang Liang, Wei Wang, Qisheng Feng, Xiaodong Huang

IGC Proceedings (1977-2023)

To date, the emphasis in snow-caused disasters that occur in pastoral areas in China has been in monitoring the change in the distribution of snow and in assessing livestock loss in post-disaster. The lack of an operational model and information system for real-time warning of snow dis-asters has made it difficult to make risk assessments and provide early snow disaster warnings (Liu et al. 2008). The aim of this study is to establish an indicator system for the early warning of snow-caused livestock disasters based on data collected from 2001 to 2010 on the Tibetan Plateau, China.

Structure And Formation Of Cattle Tracks In Sloping Pasture, Yoshiharu Hosokawa

IGC Proceedings (1977-2023)

Cattle tracks are usually formed as lines of narrow de-pressed bare paths after cattle repeatedly move across sloping pasture. In steep pasture, we can often see cattle create parallel lines through their grazing behaviour. Factors that may influence the formation of cattle tracks include hoof pressure, pasture slope/angle, grazing infra-structure such as fences and water troughs, and type of vegetation. However, if these tracks connect up the pasture may be degraded to such an extent that bare areas emerge leading to soil erosion. Therefore, it is important to under-stand the characteristics of the structure and formation of cattle tracks, to …

Grazing Alters Ecosystem Functioning And C:N:P Stoichiometry Of Grasslands Along A Regional Precipitation, Yongfei Bai, Jianguo Wu, Chris M. Clark, Qingmin Pan, Lixia Zhang, Shiping Chen, Qibing Wang, Xingguo Han

IGC Proceedings (1977-2023)

Grasslands have experienced dramatic shifts in structure and functioning driven primarily by human disturbances and global climate change. The long-term grazing has resulted in widespread declines in biodiversity and ecosystem functioning and services. This is triggered by the direct and indirect effects of grazing and often mediated by the complex interactions between vegetation and environmental. Thus, it is critical to obtain a better understanding of how grazing, abiotic factors and biotic–abiotic interactions influence key properties of ecosystem functioning and sustainability and thereby provide guideline for improving grassland management practices in the Eurasian steppe. While abundant evidence demonstrates that heavy grazing …

The Impact Of Different Herdsmen’S Size On Grassland Ecosystem Of Eastern Transect In Tibetan Plateau: A Case Study From Maqu, Huilan Wei, Xin Zong, Da Guo, Longfei Yan, Yang Liu

IGC Proceedings (1977-2023)

In order to address grassland degradation, an individual contracting system, or namely, single-household rangeland management, based on Garrett Hardin theory of “tragedy of the commons”, had been conducted in Maqu since 1980s. Despite the support of local government, such a well-intentioned system saw little fruits on managing degradation, encountering extensive frustration due to its poor practical outcomes. Meanwhile, joint-household rangeland management, as an inheritance of locality-based management, has been vigorously pursued and has played an important role on Maqu’s grassland management system. In order to better illustrate the impact of size on managing the grassland ecosystem, an experiment was set …

Introducing The Gis-Based Ecological Carrying Capacity Model Of Nutrition Resources, Gholamreza Badjian

IGC Proceedings (1977-2023)

The GIS-based Ecological Carrying Capacity Model of Nutrition Resources (ECCNR-GIS) software is a new approach based on rangeland assessment and the estimated energy content of forage. This software is derived from Badjian (2005) following studies on the ecological capacity model of livestock feed resources in Bakkan plain area, Southern Iran. ECCNR-GIS software is designed to calculate the regional ecological carrying capacity based on available forage resources and considers the energy metabolism (ME) requirements in relation to livestock management to estimate the animal needs. ECCNR-GIS software is written in Visual Basic, as a set of mathematical equations that represent a system …