Digital Commons Network^™

Can Community Structure Track Sea-Level Rise? Stress And Competitive Controls In Tidal Wetlands, Lisa M. Schile, John Callaway, K M. Suding, N M. Kelly

Environmental Science

Climate change impacts, such as accelerated sea-level rise, will affect stress gradients, yet impacts on competition/stress tolerance trade-offs and shifts in distributions are unclear. Ecosystems with strong stress gradients, such as estuaries, allow for space-for-time substitutions of stress factors and can give insight into future climate-related shifts in both resource and nonresource stresses. We tested the stress gradient hypothesis and examined the effect of increased inundation stress and biotic interactions on growth and survival of two congeneric wetland sedges, Schoenoplectus acutus and Schoenoplectus americanus. We simulated sea-level rise across existing marsh elevations and those not currently found to reflect …

Smoothing-Based Compressed State Kalman Filter For Joint State-Parameter Estimation: Applications In Reservoir Characterization And Co2 Storage Monitoring, Y. J. Li, Amalia Kokkinaki, E F. Darve, P K. Kitanidis

Environmental Science

The operation of most engineered hydrogeological systems relies on simulating physical processes using numerical models with uncertain parameters and initial conditions. Predictions by such uncertain models can be greatly improved by Kalman-filter techniques that sequentially assimilate monitoring data. Each assimilation constitutes a nonlinear optimization, which is solved by linearizing an objective function about the model prediction and applying a linear correction to this prediction. However, if model parameters and initial conditions are uncertain, the optimization problem becomes strongly nonlinear and a linear correction may yield unphysical results. In this paper, we investigate the utility of one-step ahead smoothing, a variant …

A Self-Calibrating Runoff And Streamflow Remote Sensing Model For Ungauged Basins Using Open-Access Earth Observation Data, A Poortinga, W Bastiaanssen, G Simons, David Saah, G Senay, M Fenn, B Bean, J Kadyszewski

Environmental Science

Due to increasing pressures on water resources, there is a need to monitor regional water resource availability in a spatially and temporally explicit manner. However, for many parts of the world, there is insufficient data to quantify stream flow or ground water infiltration rates. We present the results of a pixel-based water balance formulation to partition rainfall into evapotranspiration, surface water runoff and potential ground water infiltration. The method leverages remote sensing derived estimates of precipitation, evapotranspiration, soil moisture, Leaf Area Index, and a single F coefficient to distinguish between runoff and storage changes. The study produced significant correlations between …

A Global Meta-Analysis Of Forest Bioenergy Greenhouse Gas Emission Accounting Studies, T Buchholz, M D. Hurteau, J Gunn, David Saah

Environmental Science

The potential greenhouse gas benefits of displacing fossil energy with biofuels are driving policy development in the absence of complete information. The potential carbon neutrality of forest biomass is a source of considerable scientific debate because of the complexity of dynamic forest ecosystems, varied feedstock types, and multiple energy production pathways. The lack of scientific consensus leaves decision makers struggling with contradicting technical advice. Analyzing previously published studies, our goal was to identify and prioritize those attributes of bioenergy greenhouse gas (GHG) emissions analysis that are most influential on length of carbon payback period. We investigated outcomes of 59 previously …

Contributions Of Organic And Inorganic Matter To Sediment Volume And Accretion In Tidal Wetlands At Steady State, J T. Morris, D C. Barber, John Callaway, R Chambers, S C. Hagen, C S. Hopkinson, B J. Johnson, P Megonigal, S C. Neubauer, T Troxler, C Wigand

Environmental Science

A mixing model derived from first principles describes the bulk density (BD) of intertidal wetland sediments as a function of loss on ignition (LOI). The model assumes that the bulk volume of sediment equates to the sum of self-packing volumes of organic and mineral components or BD = 1/[LOI/k₁ + (1-LOI)/k₂], where k₁ and k₂ are the self-packing densities of the pure organic and inorganic components, respectively. The model explained 78% of the variability in total BD when fitted to 5075 measurements drawn from 33 wetlands distributed around the conterminous United States. The …

Estimating China’S Urban Energy Demand And Co2 Emissions: A Bottom-Up Modeling Perspective, N Khanna, D Fridley, L Price, N Zhou, Stephanie Ohshita

Environmental Science

China is experiencing unprecedented urbanization with the urban share of population expected to grow to nearly 80% by 2050. Chinese urban residents consume nearly 1.6 times as much commercial energy as rural residents, and account for an even larger share of energy and carbon dioxide (CO2) emissions embodied in urban infrastructure and goods. As a result, cities can play an increasingly important role in helping China meet its future energy and CO2 intensity reduction targets. While some individual cities have conducted energy and greenhouse gas emission inventories, China lacks estimates of aggregate urban energy consumption and CO2 emissions that take …

Best Cities: Software User Guide, Stephanie Ohshita, C Fino-Chen, L Hong, N Khanna

Environmental Science

The Benchmarking and Energy-Saving Tool for Low Carbon Cities (BEST Cities) is a dynamic decision-making tool, designed to assist local policy makers and urban planners in prioritizing strategies for energy and carbon saving at the city level in China.

China’s 12^th Five-Year Plan (2011-2015) targets a reduction in carbon intensity of the economy (CO₂ emissions per unit of GDP) by 17%. In the "Low Carbon Development 2014-2015 energy saving action plan," the State Council calls for interim targets of more than 4% in 2014 and more than 3.5% in 2015. The …

Low-Carbon City Policy Databook: 72 Policy Recommendations For Chinese Cities From The Benchmarking And Energy Savings Tool For Low Carbon Cities, L Price, N Zhou, D Fridley, Stephanie Ohshita, N Khanna, Hongyou Lu, L Hong, G He, J Romankiewicz, M Hu

Environmental Science

This report is designed to help city authorities evaluate and prioritize more than 70 different policy strategies that can reduce their city’s energy use and carbon-based greenhouse gas emissions of carbon dioxide (CO2) and methane (CH4). Local government officials, researchers, and planners can utilize the report to identify policies most relevant to local circumstances and to develop a low carbon city action plan that can be implemented in phases, over a multi-year timeframe.

The policies cover nine city sectors: industry, public and commercial buildings, residential buildings, transportation, power and heat, street lighting, water & wastewater, solid waste, and urban green …

The Role Of Chinese Cities In Greenhouse Gas Emission Reduction, Stephanie Ohshita, L Price, N Zhou, N Khanna, D Fridley, X Liu, China Energy Group, Lawrence Berkeley National Laboratory

Environmental Science

Currently, 3.9 billion people live in cities, representing 54% of the world’s population.1 Cities, as hubs of fossil fuel-based economic activity, emit over 70% of global energy-related greenhouse gas (GHG) emissions. The world’s 50 largest cities are collectively the third largest emitter of energy-related GHGs, after China and the U.S.2 In many North American cities, transportation accounts for the largest share of emissions, while industry and buildings are major sources in many Asian cities. The rate of urbanization is accelerating in the world's most populous countries, with associated rapid and high-volume production of energy- and carbon-intensive building materials to construct …

The Compressed State Kalman Filter For Nonlinear State Estimation: Application To Large-Scale Reservoir Monitoring, J Y. Li, Amalia Kokkinaki, H Ghorbanidehno, E F. Darve, P K. Kitanidis

Environmental Science

Reservoir monitoring aims to provide snapshots of reservoir conditions and their uncertainties to assist operation management and risk analysis. These snapshots may contain millions of state variables, e.g., pressures and saturations, which can be estimated by assimilating data in real time using the Kalman filter (KF). However, the KF has a computational cost that scales quadratically with the number of unknowns, m, due to the cost of computing and storing the covariance and Jacobian matrices, along with their products. The compressed state Kalman filter (CSKF) adapts the KF for solving large-scale monitoring problems. The CSKF uses N preselected orthogonal …

Low Carbon Development For Cities: Methods And Measures, Stephanie Ohshita, N Zhou, L Price, D Fridley, N Khanna, L X. Hong, H Y. Lu, C Fino-Chen, G He

Environmental Science

Cities consume more than 60% of global energy and that share is expected to rise with the rapid rate of urbanization now underway (van der Hoeven, 2012). Cities' energy consumption, along with the reshaping and resurfacing of land and the food and other resources they demand, lead to a similarly large share of global greenhouse gas (GHG) emissions, carbon-based and otherwise. With cities playing a crucial role in sustainable energy and climate systems, this chapter examines emerging efforts by cities around the world to shift to a development pattern with less energy and less carbon.

Modeling Tidal Marsh Distribution With Sea-Level Rise: Evaluating The Role Of Vegetation, Sediment, And Upland Habitat In Marsh Resiliency, Lisa M. Schile, John Callaway, J T. Morris, Diana Stralberg, V Thomas Parker, Maggi Kelly

Environmental Science

Tidal marshes maintain elevation relative to sea level through accumulation of mineral and organic matter, yet this dynamic accumulation feedback mechanism has not been modeled widely in the context of accelerated sea-level rise. Uncertainties exist about tidal marsh resiliency to accelerated sea-level rise, reduced sediment supply, reduced plant productivity under increased inundation, and limited upland habitat for marsh migration. We examined marsh resiliency under these uncertainties using the Marsh Equilibrium Model, a mechanistic, elevation-based soil cohort model, using a rich data set of plant productivity and physical properties from sites across the estuarine salinity gradient. Four tidal marshes were chosen …

Using Field Data To Assess Model Predictions Of Surface And Ground Fuel Consumption By Wildfire In Coniferous Forests Of California, J M. Lydersen, B M. Collins, C M. Ewell, A L. Reiner, J A. Fites, C B. Dow, P Gonzalez, David Saah, J J. Battles

Environmental Science

Inventories of greenhouse gas (GHG) emissions from wildfire provide essential information to the state of California, USA, and other governments that have enacted emission reductions. Wildfires can release a substantial amount of GHGs and other compounds to the atmosphere, so recent increases in fire activity may be increasing GHG emissions. Quantifying wildfire emissions however can be difficult due to inherent variability in fuel loads and consumption and a lack of field data of fuel consumption by wildfire. We compare a unique set of fuel data collected immediately before and after six wildfires in coniferous forests of California to fuel consumption …

Comparison Of Upscaled Models For Multistage Mass Discharge From Dnapl Source Zones, Amalia Kokkinaki, C J. Werth, B E. Sleep

Environmental Science

Analytical upscaled models that can describe the depletion of dense nonaqueous phase liquids (DNAPLs) and the associated mass discharge are a practical alternative to computationally demanding and data-intensive multiphase numerical simulators. A major shortcoming of most existing upscaled models is that they cannot reproduce the nonmonotonic, multistage effluent concentrations often observed in experiments and numerical simulations. Upscaled models that can produce multistage concentrations either require calibration, which increases the cost of applying them in the field, or use dual-domain conceptual models that may not apply for spatially complex source zones. In this study, a new upscaled model is presented that …

Energy-Efficiency And Greenhouse Gas Mitigation Policy Options: Assisting Chinese Cities In Prioritizing And Choosing Strategies, L Price, N Zhou, D Fridley, H Lu, L Hong, C Fino-Chen, J Ke, Stephanie Ohshita, Hu Min, Yong Zhou

Environmental Science

Myriad energy-efficiency and greenhouse gas mitigation policy options are available for urban communities to reduce energy use and emissions from buildings, transportation systems, industries, utilities, public lighting, water and wastewater, and solid waste disposal. This paper describes a methodology to assist urban community planners and policymakers in China to prioritize and choose strategies to implement for their particular situation. The methodology was developed for use in a dynamic decision-making tool, the Benchmarking and Energy-Saving Tool for Low Carbon Cities (BEST-Cities), which was specifically designed for urban communities in China but which could be used internationally. The methodology builds on concepts …

Lack Of Quantitative Training Among Early-Career Ecologists: A Survey Of The Problem And Potential Solutions, F. Barraquand, T. G. Ezard, P. Søgaard Jørgensen, Naupaka B. Zimmerman, S. Chamberlain, R. Salguero-Gómez, T. J. Curran, T. Poisot

Biology Faculty Publications

Proficiency in mathematics and statistics is essential to modern ecological science, yet few studies have assessed the level of quantitative training received by ecologists. To do so, we conducted an online survey. The 937 respondents were mostly early-career scientists who studied biology as undergraduates. We found a clear self-perceived lack of quantitative training: 75% were not satisfied with their understanding of mathematical models; 75% felt that the level of mathematics was “too low” in their ecology classes; 90% wanted more mathematics classes for ecologists; and 95% more statistics classes. Respondents thought that 30% of classes in ecology-related degrees should be …

Coupled Simulation Of Dnapl Infiltration And Dissolution In Three-Dimensional Heterogeneous Domains: Process Model Validation, Amalia Kokkinaki, D M. O'Carroll, C J. Werth, B E. Sleep

Environmental Science

A three-dimensional multiphase numerical model was used to simulate the infiltration and dissolution of a dense nonaqueous phase liquid (DNAPL) release in two experimental flow cells containing different heterogeneous and well-characterized permeability fields. DNAPL infiltration was modeled using Brooks-Corey-Burdine hysteretic constitutive relationships. DNAPL dissolution was simulated using a rate-limited mass transfer expression with a velocity-dependent mass transfer coefficient and a thermodynamically based calculation of DNAPL-water interfacial area. The model did not require calibration of any parameters. The model predictions were compared to experimental measurements of high-resolution DNAPL saturations and effluent concentrations. The predicted concentrations were in close agreement with measurements …

Development Of An End-Use Sector-Based Low-Carbon Indicator System For Cities In China, L Price, N Zhou, D Fridley, H Lu, N Zheng, C Fino-Chen, Stephanie Ohshita

Environmental Science

In 2009, China committed to reducing its carbon dioxide intensity (CO2/unit of gross domestic product, GDP) by 40 to 45 percent by 2020 from a 2005 baseline. In March 2011, China’s 12th Five-Year Plan established a carbon intensity reduction goal of 17% between 2011 and 2015. China’s National Development and Reform Commission (NDRC) then announced the selection of five provinces and eight cities to pilot low carbon development work. Macro-level indicators of low carbon development, such as energy use or CO2 emissions per unit of GDP or per capita may be too aggregated to be meaningful measurements of whether a …

Strategies For Local Low-Carbon Development, N Zhou, L Price, D Fridley, Stephanie Ohshita, N Khanna, Min Hu, Xiulian Hu

Environmental Science

Cities around the world are implementing policies and programs with the goal to reduce greenhouse gas emissions, as well as save energy, reduce costs, and protect the local, regional, and global environment. In China, low-carbon development is a key element of the 12th Five Year Plan. Pilot low-carbon development zones have been initiated in five provinces and eight cities and many other locations around China also want to pursue a low-carbon development pathway.

This booklet provides information for government officials, policy makers, program designers and implementers, provincial and city planners, and others who want an overview of the key options …

Evaluating Tidal Marsh Sustainability In The Face Of Sea-Level Rise: A Hybrid Modeling Approach Applied To San Francisco Bay, Diana Stralberg, Matthew Brennan, John Callaway, Julian K. Wood, Lisa M. Schile, Dennis Jongsomjit, Maggi Kelly, V Thomas Parker, Stephen Crooks

Environmental Science

Background: Tidal marshes will be threatened by increasing rates of sea-level rise (SLR) over the next century. Managers seek guidance on whether existing and restored marshes will be resilient under a range of potential future conditions, and on prioritizing marsh restoration and conservation activities.

Methodology: Building upon established models, we developed a hybrid approach that involves a mechanistic treatment of marsh accretion dynamics and incorporates spatial variation at a scale relevant for conservation and restoration decisionmaking. We applied this model to San Francisco Bay, using best-available elevation data and estimates of sediment supply and organic matter accumulation developed for 15 …

Diversity-Function Relationships Changed In A Long-Term Restoration Experiment, James M. Doherty, John Callaway, Joy B. Zedler

Environmental Science

The central tenet of biodiversity-ecosystem function (BEF) theory, that species richness increases function, could motivate restoration practitioners to incorporate a greater number of species into their projects. But it is not yet clear how well BEF theory predicts outcomes of restoration, because it has been developed through tests involving short-run and tightly controlled (e.g., weeded) experiments. Thus, we resampled our 1997 BEF experiment in a restored salt marsh to test for long-term effects of species richness (plantings with 1, 3, and 6 species per 2 x 2 m plot), with multiple ecosystem functions as response variables. Over 11 years, 1- …

Climate Change And San Francisco Bay-Delta Tidal Wetlands, V Thomas Parker, John Callaway, Lisa M. Schile, Michael C. Vasey, Ellen R. Herbert

Environmental Science

Climate change will affect tidal wetlands with higher rates of sea-level rise and higher concentrations of salt in brackish and freshwater tidal systems, in addition to causing increases in atmospheric CO2 concentration, warmer temperatures, and shifts in precipitation. In the San Francisco Bay–Delta, the areas most likely to be affected—brackish and freshwater tidal wetlands—are also the sites with the majority of endemic plant species and the greater biodiversity and productivity. Effects on the San Francisco Bay– Delta estuary are complex and difficult to predict, but a few things are clear. Biodiversity of the tidal wetland system in the San Francisco …

Target Allocation Methodology For China's Provinces: Energy Intensity In The 12th Five-Year Plan, Stephanie Ohshita, L Price

Environmental Science

Experience with China’s 20% energy intensity improvement target during the 11th Five-Year Plan (FYP) (2006-2010) has shown the challenges of rapidly setting targets and implementing measures to meet them. For the 12th FYP (2011 – 2015), there is an urgent need for a more scientific methodology to allocate targets among the provinces and to track physical and economic indicators of energy and carbon saving progress.

This report provides a sectoral methodology for allocating a national energy intensity target – expressed as percent change in energy per unit gross domestic product (GDP) - among China’s provinces in the 12th FYP. Drawing …

Wildfire Promotes Dominance Of Invasive Giant Reed (Arundo Donax) In Riparian Ecosystems, Gretchen Coffman, R F. Ambrose, P W. Rundel

Environmental Science

Widespread invasion of riparian ecosystems by the large bamboo-like grass Arundo donax L. has altered community structure and ecological function of streams in California. This study evaluated the influence of wildfire on A. donax invasion by investigating its relative rate of reestablishment versus native riparian species after wildfire burned 300 ha of riparian woodlands along the Santa Clara River in southern California in October 2003. Post-fire A. donax growth rates and productivity were compared to those of native woody riparian species in plots established before and after the fire. Arundo donax resprouted within days after the fire and exhibited higher …

Role Of Phytoplankton In Mercury Cycling In The San Francisco Bay Estuary, Allison C. Luengen, A. Russell Flegal

Environmental Science

To study the role of phytoplankton in mercury cycling, we measured methylmercury (MeHg) and total mercury (Hg_T) in surface waters during the spring 2003 phytoplankton bloom in San Francisco Bay. Conditions that described the peak of the bloom, the amount of sorbent, and decay of the bloom were summarized by principal component analysis (PCA). Multivariate analyses conducted with the PCA factors demonstrated that the bloom accounted for a significant (p = 0.03) decrease in dissolved (-1 and was unaffected when chlorophyll a concentrations nearly tripled, indicating that bloom dilution could occur as a result of a limited …

Plant Assemblage Composition Explains And Predicts How Biodiversity Affects Salt Marsh Functioning, Gary Sullivan, John Callaway, Joy B. Zedler

Environmental Science

Knowing that diverse plantings enhanced biomass and nitrogen (N) accumulation in a restored California salt marsh, we asked if the “biodiversity effect” was due to species selection or complementarity. In a two-year greenhouse experiment, we found positive biodiversity effects on total, root, and shoot biomass, total and root N crop, and on biomass and N allocation; negative effects on root and shoot N concentration; and no effect on shoot N crop. Overyielding among trios and sextets was supported by significant deviations in observed yield from that expected relative to solo yields (D_T). However, both trios and sextets …

Contrasting Biogeochemistry Of Six Trace Metals During The Rise And Decay Of A Spring Phytoplankton Bloom In San Francisco Bay, Allison C. Luengen, Peter T. Raimondi, A. Russell Flegal

Environmental Science

The spring 2003 phytoplankton bloom in South San Francisco Bay (South Bay) affected the cycling of Mn, Co, Zn, Ni, and Pb, but not Cu. We followed this diatom bloom for 2 months, capturing a peak in chlorophyll a (Chl a) of >150 µg L^-1 and then an increase in dissolved organic carbon of >400 µmol L^-1 as phytoplankton decomposed. To determine how the stages of the bloom affected metal concentrations, we used principal component analysis to reduce our 15 water chemistry variables into a bloom factor, a sorbent factor, and a decay factor. Increasing values of the …

Investigating The Spring Bloom In San Francisco Bay: Links Between Water Chemistry, Metal Cycling, Mercury Speciation, And Phytoplankton Community Composition, Allison C. Luengen

Environmental Science

Investigating the spring bloom in San Francisco Bay: Links between water chemistry, metal cycling, mercury speciation, and phytoplankton community composition This dissertation addresses the relationship between two problems facing estuaries nationwide: nutrient enrichment and metal contamination. The focus is on the southern reach of San Francisco Bay, where high nutrient concentrations can control the magnitude of the predictably occurring spring phytoplankton bloom. The bloom in this study, in spring 2003, was one of the largest blooms on record, exceeding 150 μg L ^-1 of chlorophyll α. As the bloom grew, diatoms (e.g. Thalassiosira punctigera ) depleted dissolved nutrients from the …

Fire Behavior Modeling To Assess Net Benefits Of Forest Treatments On Fire Hazard Mitigation And Bioenergy Production In Northeastern California, David J. Ganz, David Saah, Klaus Barber, Mark Nechodom

Environmental Science

The fire behavior modeling described here, conducted as part of the Biomass to Energy (B2E) life cycle assessment, is funded by the California Energy Commission to evaluate the potential net benefits associated with treating and utilizing forest biomass. The B2E project facilitates economic, environmental, energy, and effectiveness assessments of the potential public benefits associated with: (1) various options for treatment, disposition, and utilization of forest biomass and (2) energy production from biomass produced by forest remediation activities. The study models forest conditions, fire behavior and fuel changes over a 40-year period, under three fuel treatment scenarios: no treatment; harvest and …

Factors Controlling Structural And Floristic Variation Of Riparian Zones In A Mountainous Landscape Of The Western United States, A G. Merrill, Tracy Benning, J A. Fites

Environmental Science

We examined landscape patterns in the physical conditions and vegetative composition of montane riparian zones to identify their most important sources of variation. Information on plant species cover and on physical characteristics that occur at coarse, medium, and fine scales was collected for 144 riparian plots located throughout the Lake Tahoe Basin, which straddles the California-Nevada border in the western United States. Constrained and unconstrained ordination analyses were used to identify the most important correlates of physical form and plant species composition. Through multivariate analysis of environmental variables (principal components analysis), vegetation data (detrended correspondence analysis), and the combined relationship …