Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 5 of 5

Full-Text Articles in Physical Sciences and Mathematics

Seasonality Of Nitrogen Balances In A Mediterranean Climate Watershed, Oregon, Us, Jiajia Lin, Jana E. Compton, Scott G. Leibowitz, George Mueller-Warrant, William Matthews, Stephen H. Schoenholtz, Daniel M. Evans, Rob A. Coulombe Dec 2018

Seasonality Of Nitrogen Balances In A Mediterranean Climate Watershed, Oregon, Us, Jiajia Lin, Jana E. Compton, Scott G. Leibowitz, George Mueller-Warrant, William Matthews, Stephen H. Schoenholtz, Daniel M. Evans, Rob A. Coulombe

United States Environmental Protection Agency: Staff Publications

We constructed a seasonal nitrogen (N) budget for the year 2008 in the Calapooia River Watershed (CRW), an agriculturally dominated tributary of the Willamette River (Oregon, U.S.) under Mediterranean climate. Synthetic fertilizer application to agricultural land (dominated by grass seed crops) was the source of 90% of total N input to the CRW. Over 70% of the stream N export occurred during the wet winter, the primary time of fertilization and precipitation, and the lowest export occurred in the dry summer. Averaging across all 58 tributary subwatersheds, 19% of annual N inputs were exported by streams, and 41% by crop …


An Investigation Of Habitat Suitability Factors And Their Interactions For Predicting Gopher Tortoise Habitat, Abigail V. Lavallin Oct 2018

An Investigation Of Habitat Suitability Factors And Their Interactions For Predicting Gopher Tortoise Habitat, Abigail V. Lavallin

USF Tampa Graduate Theses and Dissertations

This thesis evaluates the interaction between four habitat factors vital to the gopher tortoise in Florida. Federally and state listed as threatened throughout its entire range, the gopher tortoise is vital to protect, not only for itself individually but its burrows provide an essential habitat to over 300 species making it a key stone species within its environment. Historic habitat modeling methods are reviewed for the gopher tortoise to highlight the gap on this topic. This research expanded on the methods utilized by Baskaran et al. (2006) evaluating the soil, landcover, percentage of canopy cover and the depth to water …


Land-Use/Land-Cover Changes And Their Influence On The Ecosystem In Chengdu City, China During The Period Of 1992–2018, Xiaojuan Lin, Min Xu, Chunxiang Cao, Ramesh P. Singh, Wei Chen, Hongrun Ju Oct 2018

Land-Use/Land-Cover Changes And Their Influence On The Ecosystem In Chengdu City, China During The Period Of 1992–2018, Xiaojuan Lin, Min Xu, Chunxiang Cao, Ramesh P. Singh, Wei Chen, Hongrun Ju

Mathematics, Physics, and Computer Science Faculty Articles and Research

Due to urban expansion, economic development, and rapid population growth, land use/land cover (LULC) is changing in major cities around the globe. Quantitative analysis of LULC change is important for studying the corresponding impact on the ecosystem service value (ESV) that helps in decision-making and ecosystem conservation. Based on LULC data retrieved from remote-sensing interpretation, we computed the changes of ESV associated with the LULC dynamics using the benefits transfer method and geographic information system (GIS) technologies during the period of 1992–2018 following self-modified coefficients which were corrected by net primary productivity (NPP). This improved approach aimed to establish a …


A Land Use Regression Model For Explaining Spatial Variation In Air Pollution Levels Using A Wind Sector Based Approach, Owen Naughton, Aoife Donnelly, Paul Nolan, Francesco Pilla, Bruce Misstear, Brian Broderick Jan 2018

A Land Use Regression Model For Explaining Spatial Variation In Air Pollution Levels Using A Wind Sector Based Approach, Owen Naughton, Aoife Donnelly, Paul Nolan, Francesco Pilla, Bruce Misstear, Brian Broderick

Articles

Estimating pollutant concentrations at a local and regional scale is essential for good ambient air quality information in environmental and health policy decision making. Here we present a land use regression (LUR) modelling methodology that exploits the high temporal resolution of fixed-site monitoring (FSM) to produce viable air quality maps. The methodology partitions concentration time series from a national FSM network into wind-dependent sectors or “wedges”. A LUR model is derived using predictor variables calculated within the directional wind sectors, and compared against the long-term average concentrations within each sector. This study demonstrates the value of incorporating the relative position …


Assessing Spatio-Temporal Patterns Of Forest Decline Across A Diverse Landscape In The Klamath Mountains Using A 28-Year Landsat Time-Series Analysis, Drew S. Bost Jan 2018

Assessing Spatio-Temporal Patterns Of Forest Decline Across A Diverse Landscape In The Klamath Mountains Using A 28-Year Landsat Time-Series Analysis, Drew S. Bost

Cal Poly Humboldt theses and projects

Rates of tree mortality in California and the Pacific Northwest have greatly increased in recent years, driven largely by pest and pathogen outbreaks as well as the effects of hotter, warmer droughts. While there have been a multitude of regional-scale assessments of mortality and forest decline, landscape-level studies are necessary to better identify forests that are most vulnerable to decline and to anticipate future changes. This need is particularly notable in the remote and little-studied mountains of northwest California, which are renowned for their diverse, heterogeneous vegetation types. A recent observation of elevated levels of Shasta red fir (Abies …