Walter K Dodds

Walter K Dodds
Kansas State University | KSU · Department of Biology

PhD

About

324
Publications
75,739
Reads
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20,902
Citations
Introduction
Walter K Dodds currently works at the Division of Biology, Kansas State University. My overarching goal is to provide a general and predictive understanding of aquatic ecology, and to promote the application of basic ecological science to water quality and conservation. A central focus of my research has been on river and stream ecosystems and how human influences affect water quality and biological integrity. Nutrient dynamics, especially nitrogen, and eutrophication are major highlights of my program, as are scaling and metabolism in flowing waters. I have also emphasized valuation of aquatic ecosystem services.
Additional affiliations
August 1990 - present
Kansas State University
Position
  • University Distinguished Professor

Publications

Publications (324)
Article
Full-text available
Previous studies have evaluated how changes in atmospheric nitrogen (N) inputs and cli- mate affect stream N concentrations and fluxes, but none have synthesized data from sites around the globe. We identified variables controlling stream inorganic N concentrations and fluxes, and how they have changed, by synthesizing 20 time series ranging from 5...
Article
Full-text available
Knowing where and when rivers flow is paramount to managing freshwater ecosystems. Yet stream gauging stations are dis- tributed sparsely across rivers globally and may not capture the diversity of fluvial network properties and anthropogenic influences. Here we evaluate the placement bias of a global stream gauge dataset on its representation of s...
Article
Intermittent streams are characterized by significant periods of low to no flow, yet are also frequently subjected to flashy, high floods. Floods alter ecosystem function and result in variable successional patterns across the stream network. Yet, the timing of restored function after floods in intermittent stream networks is relatively unexplored....
Article
Full-text available
Woody encroachment has impacted grassland ecohydrology worldwide, prompting management strategies aimed at woody vegetation removal to prevent or mitigate loss of water yield. We measured stream discharge following sustained cutting of riparian trees (2010–2020) in a native tallgrass prairie (northeastern Kansas, USA). Discharge has declined at thi...
Technical Report
We identified variables controlling stream nitrogen concentrations and fluxes, and how they have changed over time, by synthesizing 20 time series ranging from 5 to 51 years of data collected from forest and grassland dominated watersheds across Europe, North America, and East Asia and across four climate types (tropical, temperate, Mediterranean,...
Article
Full-text available
Water quality monitoring networks (WQMNs) are essential to provide good data for management decisions. Nevertheless, some WQMNs may not appropriately reflect the conditions of the water bodies and their temporal/spatial dimensions, more particularly in developing countries. Also, some WQMNs may use more resources to attain management goals than nec...
Article
Rivers and streams provide many ecosystem services, including provision of food, water purification, and nutrient abatement. Ecosystem functioning, the set of processes that regulate the fluxes of energy and matter, is the backbone of ecosystem services. A myriad of human impacts affects the functioning of running waters. To reduce these impacts, s...
Article
Full-text available
Riparian zones, the interfaces between land and stream, perform vital ecosystem functions including transformation and retention of nutrients and sediment moving across the landscape. Although many studies assess transport through and transformation of materials in riparian zones, less is known about the direct influence of precipitation falling on...
Chapter
We cover basic concepts and advances in stream ecology related to the River Continuum Concept (RCC). The RCC describes how position in the watershed influences rivers and streams. These influences include materials washing in from the watershed above and those properties dictated by terrestrial habitats that border the rivers or streams in the vici...
Article
Full-text available
Dissolved organic carbon (DOC) and nitrogen (DON) are important energy and nutrient sources for aquatic ecosystems. In many northern temperate freshwater systems DOC has increased in the past 50 years. Less is known about how changes in DOC may vary across latitudes, and whether changes in DON track those of DOC. Here we present long‐term DOC and D...
Article
Full-text available
Trophic state indexes (TSI) guide management strategies regarding eutrophication control worldwide. Such indexes usually consider chlorophyll-a (Chl-a), total phosphorus (TP), and Secchi disk depth (SDD) as independent variables for estimating aquatic productivity and the degree of impairment. TSIs for each of these components are frequently averag...
Data
A global compilation of stream chemistry data was synthesized to evaluate spatial and temporal trends in solutes with a particular focus on dissolved organic matter and nitrogen (inorganic and organic forms). Data span a global array of streams and rivers ranging from the tropics to the arctic. Data include concentrations of dissolved organic nitro...
Article
Full-text available
A comprehensive cross‐biome assessment of major nitrogen (N) species that includes dissolved organic N (DON) is central to understanding interactions between inorganic nutrients and organic matter in running waters. Here, we synthesize stream water N chemistry across biomes and find that the composition of the dissolved N pool shifts from highly he...
Article
Full-text available
Non-perennial streams are widespread, critical to ecosystems and society, and the subject of ongoing policy debate. Prior large-scale research on stream intermittency has been based on long-term averages, generally using annually aggregated data to characterize a highly variable process. As a result, it is not well understood if, how, or why the hy...
Article
River metabolism modeled from diurnal dissolved oxygen (DO) has become a widely used metric of ecosystem function, yet many papers provide insufficient methodological detail for replication. Only 79% of 43 sampled papers published from 2015 to 2019 mention calibration, 44% describe sensor placement, and 34% did not describe estimation approaches su...
Chapter
Riparian ecosystems occupy land-water interfaces along upland-to-lowland and coastal gradients of river networks. Global changes in riparian vegetation alter the types and processing of organic matter at these interfaces and throughout river networks. Dominant pathways of structural changes in riparian vegetation are associated with (i) temperature...
Article
The global environment annually receives thousands of tons of engineered nanomaterials (ENMs, particles less than 100 nm diameter). These particles have high active surface area, unique chemical properties, and can enter cells. Humanity uses many ENMs for their biological reactivity (e.g. microbicides), but their environmental effects are complex....
Article
Full-text available
Understanding the complex and unpredictable ways ecosystems are changing and predicting the state of ecosystems and the services they will provide in the future requires coordinated, long-term research. This paper is a product of a U.S. National Science Foundation funded Long Term Ecological Research (LTER) network synthesis effort that addressed a...
Article
Full-text available
We analyze here the nature of research in freshwater macrosystem biology (especially lotic studies) from both conceptual and current research perspectives. The boundaries of permanent and transitional lotic macrosystems from the smallest to largest spatial extents are described. We contrast ecosystem vs. macrosystem research and macroecology vs. ma...
Article
Full-text available
Macrosystems are integrated human–natural systems, in recognition of the fact that virtually every natural system on Earth influences and is influenced by human activities, even over long distances. It is therefore crucial to incorporate inherent properties of broad-scale systems, such as human–nature connectivity and feedbacks at multi-scales, int...
Article
Full-text available
In an era of unprecedented human impacts on the planet, macrosystems biology (MSB) was developed to understand ecological patterns and processes within and across spatial and temporal scales. We used machine-learning and qualitative literature review approaches to evaluate the thematic composition of MSB from articles published since the 2010 creat...
Article
Full-text available
Macrosystems biology research has expanded and evolved over the past decade as the scientific community grapples with ecological issues at regional to continental scales relevant to human interactions within the biosphere. Macrosystems biology builds on established fields of study like population and community ecology, biogeography, and global biog...
Article
Full-text available
Over half of global rivers and streams lack perennial flow, and understanding the distribution and drivers of their flow regimes is critical for understanding their hydrologic, biogeochemical, and ecological functions. We analyzed nonperennial flow regimes using 540 U.S. Geological Survey watersheds across the contiguous United States from 1979 to...
Article
Anthropogenic increases in nitrogen (N) and phosphorus (P) concentrations can strongly influence the structure and function of ecosystems. Even though lotic ecosystems receive cumulative inputs of nutrients applied to and deposited on land, no comprehensive assessment has quantified nutrient‐enrichment effects within streams and rivers. We conducte...
Article
Secondary production estimates are an important element of ecosystem ecology because they facilitate quantification of the roles of consumers in material and energy cycling. We estimated production and resource consumption of stream macroinvertebrates, along with stream metabolism and organic matter storage in 3 relatively undisturbed Savanna headw...
Article
Full-text available
Conceptual models underpin river ecosystem research. However, current models focus on continuously flowing rivers and few explicitly address characteristics such as flow cessation and drying. The applicability of existing conceptual models to nonperennial rivers that cease to flow (intermittent rivers and ephemeral streams, IRES) has not been evalu...
Article
Full-text available
Rivers that cease to flow are globally prevalent. Although many epithets have been used for these rivers, a consensus on terminology has not yet been reached. Doing so would facilitate a marked increase in interdisciplinary interest as well as critical need for clear regulations. Here we reviewed literature from Web of Science database searches of...
Article
Full-text available
Cattle degrade streams by increasing sediment, nutrient, and fecal bacteria levels. Riparian fencing is one best management practice that may protect water quality within many grazed lands. Here we surveyed the literature and summarized the responses of sediment, nutrient, and fecal indicator bacteria levels to riparian exclosure fencing in cattle-...
Article
Plant, soil, and aquatic microbiomes interact, but scientists often study them independently. Integrating knowledge across these traditionally separate subdisciplines will generate better understanding of microbial ecological properties. Interactions among plant, soil, and aquatic microbiomes, as well as anthropogenic factors, influence important e...
Article
Streamflow observations can be used to understand, predict, and contextualize hydrologic, ecological, and biogeochemical processes and conditions in streams. Stream gages are point measurements along rivers where streamflow is measured, and are often used to infer upstream watershed‐scale processes. When stream gages read zero, this may indicate th...
Article
Patch‐burn grazing (PBG) can promote terrestrial heterogeneity and biodiversity, but can temporarily increase stream nutrients, ecosystem metabolism, and alter macroinvertebrate assemblages. The impacts of grazing on stream channel morphology and post‐PBG recovery patterns are unclear. We assessed the influence of grazing in PBG managed grassland s...
Article
Biogeochemical rates within streams vary with ecosystem properties including the distribution of fishes. While many studies investigate the singular effect of fishes on ecosystem components, there is a limited understanding of how fish presence interacts with other ecosystem properties to affect ecosystem structure and function. Here, we used path...
Article
Nonperennial rivers are a major—and growing—part of the global river network. New research and science-based policies are needed to ensure the sustainability of these long-overlooked waterways.
Article
Full-text available
The reaeration coefficient (Ka20) is one of the main indicators of dissolved O2 movement to and from aquatic systems via the atmosphere. Direct gas tracer measurements, physical models, and models of O2 dynamics have been used for Ka20 estimation, especially in temperate aquatic ecosystems, with fewer examples in their tropical counterparts. Here w...
Article
Full-text available
Quantifying ecosystem respiration remains challenging in aquatic ecosystems. Most investigators assume that nighttime and daytime respiration are equal. Recent studies suggest measuring dissolved oxygen isotopes during periods with and without photosynthesis can account for variations in daytime and nighttime respiration. These models are extremely...
Article
Agricultural activities can affect the delivery of nutrients to streams, riparian canopy cover, and the capacity of aquatic systems to process nutrients and sediments. There are few measures of nutrient uptake and metabolism from tropical or sub-tropical streams in general, and even fewer from tropical regions of South America. We examined ammonium...
Chapter
International cooperation will be required to solve global problems. International agreements, agencies, and organizations are discussed. The idea of a global society is explored.
Chapter
Here I estimate the economic costs to solve each of the problems based on the steps necessary to solve them. This includes costs to protect the environment, eradicate diseases, protect against asteroids, protect against interruptions of food supply, stop naturally and bioterrorist-caused pandemics, and disarm nuclear weapons.
Chapter
Here I provide other viewpoints on the worst problems. This includes informal surveys from several classes of students as well as discussions with an array of individuals. It also provides results of some large-scale surveys done by several different global initiatives.
Chapter
The beginning of this chapter provides a view on how many people lack adequate nutrition globally. It considers the causes of hunger and the possibilities for feeding a growing human population as standards of living increase worldwide, requiring even more food production. The science behind increasing crop production is explained, the possibility...
Chapter
This chapter is centered on both the potential for environmental harm that will negatively influence humans and the harm to the rest of the species on the planet. It provides data on the global economic benefits of maintaining the environment (ecosystem services). Then the discussion turns to the greenhouse effect, ozone depletion, limitations on q...
Chapter
Here I provide my view on how global problems might be solved. This chapter suggests that there needs to be a new model of operation for global society and economics. The dangers and potential usefulness of thresholds and social media in the process of solving problems are guessed at. Consilience, enlightenment, and hope will be necessary to solve...
Chapter
A general equation is introduced to allow comparison of environmental problems. The equation takes into account current and future potential for human deaths as well as current and future suffering. It deliberates over the unknowns in predicting the number of deaths and amount of suffering for major causes and how to compare death to suffering for...
Chapter
This chapter delineates how I will define global problems including the general moral assumptions that will guide the approach taken in future chapters. It starts discussing the major causes of death currently and lists potential future catastrophes. It considers major global causes of suffering and how we can estimate risk of human death and suffe...
Chapter
The chapter reviews diseases of humanity, both chronic disease and emergent diseases, that may harp much of humanity over short periods of time. It explains why the chances for pandemics are increasing and how they are inevitable. The threats of biological warfare and bioterrorism are covered, and the ways that we can stop pandemics are brought to...
Chapter
Here we consider the possibility of global catastrophe from forces that are mostly out of human control. These causes include the Earth being struck by a large asteroid, explosion of a super volcano, and gamma ray bursts from the universe. Some potential technological threats are considered such as physics experiments gone wrong and global takeover...
Chapter
Here I cover advances in social science that can be used to predict average human behavior. It considers costs and benefits to cooperation. There is also discussion of why some people are unwilling to accept scientific facts, even though it might ultimately not be in their best interests to do so. Finally, these aspects are considered with respect...
Chapter
The basic science behind nuclear weapons and the global environmental effects of full-scale and more limited nuclear war are considered first in this chapter. These effects include nuclear winter, ozone depletion, electromagnetic pulses, and radiation poisoning. The possibility of nuclear terrorism and the potential for harm are discussed as well.
Article
Agricultural, urban and industrial activities have dramatically increased aquatic nitrogen and phosphorus pollution (eutrophication), threatening water quality and biotic integrity from headwater streams to coastal areas world‐wide. Eutrophication creates multiple problems, including hypoxic “dead zones” that reduce fish and shellfish production; h...
Article
Evolutionary history and adaptation to climate shape plant traits. Some include leaf traits that influence litter quality. Thus, evolutionary history should affect litter decomposition, a crucial ecosystem process. In addition, litter decomposition is directly influenced by climate. We consequently expect plant phylogeny, adaptation and climate to...
Article
Full-text available
Understanding global ecological patterns and processes, from biogeochemical to biogeographical, requires broad‐scale macrosystems context for comparing and contrasting ecosystems. Climate gradients (precipitation and temperature) and other continental‐scale patterns shape freshwater environments due to their influences on terrestrial environments a...
Article
Full-text available
The dissolved oxygen diel cycle is an inherent feature of stream ecosystems, and the amplitude in this diel fluctuation is thought to strongly influence the composition of stream communities. For instance, extremely low dissolved oxygen saturation (DDO) values have well-documented effects on stream macroinvertebrates. Less is known, however, about...
Article
Full-text available
Riparian zones are key interfaces between stream and terrestrial ecosystems. Yet, we know of no whole-watershed experiments that cut only woody vegetation in the riparian zone in an otherwise intact watershed to isolate the role of riparian zones on stream ecology. We removed all of the woody riparian vegetation (from 10- and 30-m-wide buffers in h...
Book
This book addresses the worst problems currently facing humanity and those that may pose future threats. The problems are explained and approached through a scientific lens, and categorized based on data involving global mortality, vulnerability, and threat level. The book presents indices of problem severity to compare relative intensity of curren...
Article
Mounting evidence suggests ecosystem changes that alter subsurface water fluxes and carbon dioxide concentrations in carbonate terrains may drive measurable changes in chemical weathering rates, stream water chemistry, and flow path evolution on human timescales. We test this idea by exploring if the encroachment of woody vegetation into grasslands...
Article
Stream restoration efforts have aimed at increasing hydraulic residence time (HRT) and transient storage (TS) to enhance nutrient uptake, but there have been few controlled studies quantifying HRT and TS influences on nutrient uptake dynamics. We assessed the effects of HRT and TS on ammonium (NH4⁺) and phosphate (PO43‐) uptake through controlled e...
Article
Studies of the environmental factors that lead to cyanotoxic blooms in tropical/subtropical reservoirs are limited. While technological advances for water treatment and remediation techniques can mitigate the effects of cyanobacterial blooms, the identification of initial drivers and tipping points for minimizing cyanotoxin concentrations could be...