Henriette Jager

Oak Ridge National Laboratory | ORNL · Environmental Sciences Division

What is the best way to arrange dams within river basins to benefit society? Recent interest in this question has grown in response to the worldwide trend toward developing hydropower as a source of renewable energy in Asia and South America, and the movement toward removing unnecessary dams in the US. Environmental and energy sustainability are im...

We predicted the consequences of climate change for sympatric populations of brown trout Salmo trutta and rainbow trout Oncorhynchus mykiss in an upstream and a downstream reach of a Sierra Nevada stream with the help of an individual-based trout population model. The model evaluated the ecological effects of two anticipated responses to climate ch...

Reducing uncertainty in predictions of regional-scale models depends on meaningful contrasts with field measurements. This paper introduces a two-stage process that works from the premise that an appropriate goal for regional models is to produce reasonable behavior over dominant environmental gradients. We demonstrate two techniques for contrastin...

Damming of large rivers in the U.S. Pacific Northwest and Canada has divided the historical population of white sturgeon Acipenser transmontanus into more than 36 fragmented populations, few of which are thriving. We now face the challenge of managing these populations to avoid extirpation. Two goals of this study were to identify extinction thresh...

Greenhouse gas (GHG) emissions from reservoirs have most often been evaluated on a global extent through areal scaling or linear-regression models. These models typically rely on a limited number of characteristics such as age, size, and average temperature to estimate per reservoir or areal flux. Such approaches may not be sufficient for describin...

Hydropower generation may play an increasingly important role in the power grid under increasing contribution of variable renewable sources such as wind and solar. An improved understanding of the changes to hydropower dispatch under future higher VRE grid conditions reveals research gap that should be informed power grid planning and reservoir wat...

In the transition to low-carbon electricity, well-quantified estimates of carbon dynamics are needed to ensure that emissions reduction targets are achieved. We review the state of the science on carbon accounting for hydropower reservoirs and identify limitations and future solutions. Nearly all research on reservoir greenhouse-gas (GHG) emissions...

To avoid negative consequences to freshwater biota from climate change, society must complete the transition from fossil to renewable electricity sources. In this study, we describe temporal patterns in hydropower generation that are expected to change with increased wind and solar penetration. We used power cost modeling using PLEXOS to characteri...

Bioenergy aims to reduce greenhouse gas (GHG) emissions and contribute to meeting global climate change mitigation targets. Nevertheless, several sustainability concerns are associated with bioenergy, especially related to the impacts of using land for dedicated energy crop production. Cultivating energy crops can result in synergies or trade-offs...

Although many agree that a transition to renewable energy sources is needed to avoid the climate consequences of continued reliance on fossil sources, price is a barrier. For renewable energy sources, including bioenergy, penetrating energy markets depends on lowering prices to compete with the price of fossil sources, but the tools used in decisio...

Without a shift to renewable energy sources, climate change will have adverse effects on many terrestrial and aquatic species. On the other hand, replacing fossil fuels with renewable energy will have different effects on wildlife, some negative. To protect biota, while navigating the complexities surrounding the transition to renewable energy, wil...

The US has large potential to grow perennial energy crops, but because these crops are rarely grown in current agricultural landscapes, it is unclear how biodiversity may be affected. Over time, as agriculture has increased, many grassland species have declined. In addition, not all agricultural land is profitable for growing annual crops. Unprofit...

Wildfires in many western North American forests are becoming more frequent, larger, and severe, with changed seasonal patterns. In response, coniferous forest ecosystems will transition toward dominance by fire-adapted hardwoods, shrubs, meadows, and grasslands, which may benefit some faunal communities, but not others. We describe factors that li...

Addressing climate mitigation while meeting global electrification goals will require major transitions from fossil-fuel dependence to large-scale renewable energy deployment. However, renewables require significant land assets per unit energy and could come at high cost to ecosystems, creating potential conflicts between global climate mitigation...

Assessing the sustainability of natural resource management choices for agricultural and forest lands requires quantification of potential changes to a set of environmental and socioeconomic indicators selected to characterize reference scenarios relative to projected future scenarios. Correctly framing the questions with local stakeholders is a cr...

Potential economic and environmental benefits of increasing nitrogen-use efficiency (NUE) are widely recognized but scarcely quantified. This study quantifies the effects of increased NUE on 1) the national agricultural economy using a simulation model of US agriculture and 2) regional water quality effects using a biogeochemical model for the Arka...

The commercialization of biofuels produced from microalgae is in its infancy; therefore, many resource-management practices and production processes are still flexible. The purpose of this paper is to guide development of supply chains toward more environmentally sustainable practices. We review current and projected technologies and practices for...

Poor water quality is one of the greatest threats to fish population recovery, fisheries, and aquaculture. There are examples of game fish species and species of conservation concern threatened by poor water quality conditions across North America (Warren and Burr 1994; Couillard et al. 2008). In the Missouri River–Fort Peck Reservoir, low dissolve...

New domestic, renewable energy resources must be considered to increase energy security in the U.S. Ethanol production through second-generation (cellulosic) feedstocks will help the U.S. meet the legislative Renewable Fuel Standard, which mandates 36 billion gallons of renewable fuels by 2022. However, conversion of cropland to meet the cellulosic...

Practicing agriculture decreases downstream water quality when compared to non-agricultural lands. Agricultural watersheds that also grow perennial biofuel feedstocks can be designed to improve water quality compared to agricultural watersheds without perennials. The question then becomes which conservation practices should be employed and where in...

Assessing and managing risks of anthropogenic activities to ecological systems is necessary to ensure sustained delivery of ecosystem services for future generations. Ecological models provide a means of quantitatively linking measured risk assessment endpoints with protection goals, by integrating potential chemical effects with species life histo...

Sustainable production of algae will depend on understanding trade-offs at the energy-water nexus. Algal biofuels promise to improve the environmental sustainability profile of renewable energy along most dimensions. In this assessment of potential US freshwater production, we assumed sustainable production along the carbon dimension by simulating...

Minimum nitrogen requirement Mean annual temperature Mean annual precipitation Pairwise meta-analyses Regression-based models A B S T R A C T Perennial grasses are touted as sustainable feedstocks for energy production. Such benefits, however, may be offset if excessive nitrogen (N) fertilization leads to economic and environmental issues. Furtherm...

Movement within stream corridors is a basic life history requirement of many aquatic organisms. Barrier removal in streams has become a common practice in the United States aimed to restore organism dispersal and meet conservation objectives; however, there are social and economic costs to the removal of barriers. Accordingly, tools to prioritize b...

Replacing fossil with biomass-based sources of energy may help to reduce climate threats to biodiversity. However, some geographic areas with high potential value for producing biomass are also biodiversity hot spots. Guidance is needed to manage landscapes to successfully co-produce biomass for energy and habitat for wildlife. The land-sharing ver...

Advanced biomass feedstocks tend to provide more non-fuel ecosystem goods and services (ES) than 1st-generation alternatives. We explore the idea that payment for non-fuel ES could facilitate market penetration of advanced biofuels by closing the profitability gap. As a specific example, we discuss the Mississippi-Atchafalaya River Basin (MARB), wh...

Coastal hypoxia is increasing worldwide in response to human‐caused changes in global climate and biogeochemical cycles. In this paper, we view anthropogenic trends in coastal hypoxia through the lens of disturbance ecology and complexity theory. Complexity theory provides a framework for describing how estuaries and other coastal aquatic ecosystem...

We demonstrate how mechanistic modeling can be used to predict whether and how biological responses to chemicals at (sub)organismal levels in model species (i.e., what we typically measure) translate into impacts on ecosystem service delivery (i.e., what we care about). We consider a hypothetical case study of two species of trout, brown trout (Sal...

Reducing dependence on fossil‐based energy has raised interest in biofuels as a potential energy source, but concerns have been raised about potential implications for water quality. These effects may vary regionally depending on the biomass feedstocks and changes in land management. Here, we focused on the Tennessee River Basin (TRB), USA. Accordi...

In this review article, we trace the history of events leading to the development of individual-based models (IBMs) to represent aquatic organisms in rivers and streams. As a metaphor, we present this history as a series of confluences between individual scientists (tributaries) sharing ideas. We describe contributions of these models to science an...

Detecting and avoiding environmental thresholds that lead to catastrophic change in ecological communities is an important goal, and one that is especially challenging to address over broad geographic extents. Here, we conducted a regional-scale climate vulnerability assessment (RCVA) to quantify the risk of violating thermal and minimum-flow thres...

Time series analysis is an essential method for decomposing the influences of density and exogenous factors such as weather and climate on population regulation. However, there has been little work focused on understanding how well commonly collected data can reconstruct the effects of environmental factors on population dynamics. We show that anal...

Protection of ecosystem services is increasingly emphasized as a risk-assessment goal, but there are wide gaps between current ecological risk-assessment endpoints and potential effects on services provided by ecosystems. The authors present a framework that links common ecotoxicological endpoints to chemical impacts on populations and communities...

The global recognition of the importance of natural flow regimes to sustain the ecological integrity of river systems has led to increased societal pressure on the hydropower industry to change plant operations to improve downstream aquatic ecosystems. However, a complete reinstatement of natural flow regimes is often unrealistic when balancing wat...

142 Fisheries | Vol. 41 • No. 3 • March 2016 The majority of large North American rivers are fragmented by dams that interrupt migrations of wide-ranging fishes like sturgeons. Reconnecting habitat is viewed as an important means of protecting sturgeon species in U.S. rivers because these species have lost between 5% and 60% of their historica...

Model-data comparisons are always challenging, especially when working at a large spatial scale and evaluating multiple response variables. We implemented the Soil and Water Assessment Tool (SWAT) to simulate water quantity and quality for the Tennessee River Basin. We developed three innovations to overcome hurdles associated with limited data for...

Standardization and sensitivity analysis of a Global Carbon model described by Peng et al. (1983).

The Basin Scale Opportunity Assessment (BSOA) initiative, led by the Department of Energy’s (DOE) Water Power Program, was designed to establish an integrative approach to assess the potential for combined increases in hydropower energy and improvements in the environment at a basin scale. Methods were developed to isolate mutual benefits to hydrop...

This study reports hydrologic modeling that will ultimately allow us to evaluate how growing cellulosic bioenergy feedstocks in the Tennessee River Basin (TRB) will influence water quantity and quality. We are interested both in local effects on streams and smaller rivers, as well as downstream effects, as this basin drains to the Mississippi River...

In order to mitigate the environmental effects of hydropower development and operation, the Federal Energy Regulatory Commission requires environmental compliance by private owners of hydropower facilities. The environmental issues considered are usually within the vicinity of hydropower facilities because many, if not all, are a direct result of d...

What is the best way to arrange dams within river basins to benefit society? Hydropower development has never been planned with the goal of providing society with a portfolio of ecosystem services into the future. We synthesized a review of river basin design around four spatial decisions, Is it better to build fewer mainstem dams or more tributary...

Excess nutrients from agriculture in the Mississippi River drainage, USA have degraded water quality in freshwaters and contributed to anoxic conditions in downstream estuaries. Consequently, water quality is a significant concern associated with conversion of lands to bioenergy production. This study focused on the Arkansas-White-Red river basin (...

Long-term fish assemblage monitoring requires investigators account for within-year variation in species' detection. An occupancy modelling framework is presented that accounts for variation in species presence and estimates the effort required to minimise within-year variation. Species detections from snorkelling surveys and an electrofishing surv...

quality and quantity. The magnitude and direction of change will likely depend on how current and future land cover and management practices compare. Focusing on the Arkansas-White-Red river basin (AWR), we describe our method for projecting future shifts in water quantity and quality in rivers based on economic projections for future changes in la...

This presentation will highlight traps that this modeler has fallen into and strategies for avoiding them. First, avoid spending more effort on well-known processes that we know how to model (e.g., flow-physical habitat) at the expense of complex, poorly understood processes (e.g., ecological) with larger effects. This adds an undeserved veneer of...

Weighing contrasting evidence is an integral element of science (Osborne 2010). The dominant forum for doing this and for scientific exchange in general is the peer-review and publication process. It tends to be slow because of the time required to conduct critical reviews. Rapid exchange and discourse, in the form of a live debate, can also move s...

Southern populations of the federally endangered Shortnose Sturgeon Acipenser brevirostrum are considered to be at greater risk of extirpation than northern populations. Our study focused on the Ogeechee River, Georgia, a small, undeveloped, coastal river that supports a population with fewer than 300 Shortnose Sturgeon. We designed a population vi...

. Plots describing observed versus predicted values (left column) and residuals (right column) for each analyte modeled, including a, b total suspended sediment (TSS); c, d total organic carbon (TOC); e, f dissolved organic carbon (DOC); g, h total nitrogen (TN); and i, j organic nitrogen

The Natural Flow (NF) paradigm asserts that a natural flow regime is best for aquatic communities because populations evolved to deal with historical conditions. By emphasizing the importance of flow variability, the NF paradigm shifted the emphasis from moderate, stable flow regimes and within-channel habitat-flow relationships typically explored...

Fall Chinook salmon Oncorhynchus tshawytscha typically migrate to the ocean as subyearlings (age 0), but a strategy whereby juveniles overwinter in freshwater and migrate to the ocean as yearlings (age 1) has emerged over the past few decades in Idaho's Snake River population. The recent appearance of the yearling strategy has conservation implicat...

Indicators are needed to assess environmental sustainability of bioenergy systems. Effective indicators will help in the quantification of benefits and costs of bioenergy options and resource uses. We identify 19 measurable indicators for soil quality, water quality and quantity, greenhouse gases, biodiversity, air quality, and productivity, buildi...

The patterns of biodiversity in freshwater systems are shaped by biogeography, environmental gradients, and human-induced factors. In this study, we developed empirical models to explain fish species richness in subbasins of the Arkansas White Red River basin as a function of discharge, elevation, climate, land cover, water quality, dams, and longi...

Military landscapes represent a mixture of undisturbed natural ecosystems, developed areas, and lands that support different types and intensities of military training. Research to understand water-quality influences of military landscapes usually involves intensive sampling in a few watersheds. In this study, we developed a survey design of access...

The effects of changes in the annual temperature cycle on energy acquisition and the allocation of that energy to respiration, growth, and reproduction of female rainbow trout (Oncorhynchus mykiss) are evaluated using a new type of simulation model. We tested the effects of warmer (+2 and +4 degrees C) and cooler (-2 degrees C) water temperature cy...

Switchgrass (Panicum virgatum L.) is a perennial grass native to the United States that has been studied as a sustainable source of biomass fuel. Although many field-scale studies have examined the potential of this grass as a bioenergy crop, these studies have not been integrated. In this study, we present an empirical model for switchgrass yield...

A decision framework for setting management goals for species at risk is presented. Species at risk are those whose potential future rarity is of concern. Listing these species as threatened or endangered could potentially result in significant restrictions to activities in resource management areas in order to maintain those species. The decision...

With the increasing appreciation of global warming impacts on ecological systems, in addition to the myriad of land management effects on water quality, the number of literature citations dealing with the effects of water temperature on freshwater fish has escalated in the past decade. Given the many biological scales at which water temperature eff...

The white sturgeon (Acipenser transmontanus) shows great individual variation in the age at maturation. This study examines the consequences of model assumptions about individual variation in the age at maturation on predicted population viability. I considered: (1) the effects of variation in age at maturation alone; (2) the effects of heritabilit...

We consider a distinction for fishes, often made for birds and reptiles, between capital-breeding and income-breeding species. Species that follow a capital-breeding strategy tend to evolve longer intervals between reproductive events and tend to have characteristics that we associate with higher extinction risk. To examine whether these ideas are...

Hydroelectric power provides a cheap source of electricity with few carbon emissions. Yet, reservoirs are not operated sustainably, which we define as meeting societal needs for water and power while protecting long-term health of the river ecosystem. Reservoirs that generate hydropower are typically operated with the goal of maximizing energy reve...

We consider a distinction for fishes, often made for birds and reptiles, between capital-breeding and income-breeding species. Species that follow a capital-breeding strategy tend to evolve longer intervals between reproductive events and tend to have characteristics that we associate with higher extinction risk. To examine whether these ideas are...

Regulated rivers in the United States are required to support human water uses while preserving aquatic ecosystems. However, the effectiveness of hydropower license requirements nationwide has not been demonstrated. One requirement that has become more common is "run-of-river" (ROR) operation, which restores a natural flow regime. It is widely beli...