Margaret Palmer

Margaret Palmer
University of Maryland, College Park | UMD, UMCP, University of Maryland College Park

PhD

About

231
Publications
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Publications

Publications (231)
Article
Wetlands store significant soil organic carbon (SOC) globally due to anoxic conditions that suppress SOC loss. However, stored SOC may become vulnerable to decomposition where climate and land use change alter wetland hydrology. Seasonally saturated wetlands experience fluctuating hydrologic conditions that could promote physicochemical mechanisms...
Chapter
Aim: To describe current ecological understanding of how best to restore river ecosystems toward self-sustainability and how ecological science is applied in practice. Main Concepts Covered: Process-based restoration, process based vs. state-based approach to restoration, restoring for river self-sustainability, restoration as part of watershed man...
Article
Full-text available
Conservation and provision of ecosystem services (ES) have been adopted as high‐level policy in many countries, yet there has been surprisingly little application of these broad policies in the field; for example, ES are rarely considered in permit issuance or other discrete agency actions. This large implementation gap arises in part because the s...
Article
Full-text available
Methane emissions from small freshwater ecosystems represent one of the largest components of uncertainty in the global methane budget. While these systems are known to produce large amounts of methane relative to their size, quantifying the timing, magnitude, and spatial extent of their emissions remains challenging. We begin to address this chall...
Preprint
Full-text available
Wetlands store significant soil organic carbon (SOC) globally, yet this SOC is sensitive to climate and land use change. Seasonally saturated wetlands experience fluctuating hydrologic conditions that may promote the physicochemical mechanisms known to control SOC stabilization in upland soils; these wetlands are therefore likely to be important fo...
Preprint
Full-text available
Wetlands store significant soil organic carbon (SOC) globally due to anoxic conditions that suppress SOC loss, yet this SOC is sensitive to climate and land use change. Seasonally saturated wetlands experience fluctuating hydrologic conditions that may also promote mechanisms known to control SOC stabilization in upland soils; these wetlands are th...
Article
The forthcoming UN Decade of Ecosystem Restoration brings the challenge of massively increasing restoration efforts to halt and reverse environmental degradation. This challenge must move beyond a focus on the size and number of projects to a focus on how those projects are designed and implemented. Approaches based on restoring the fundamental eco...
Article
Full-text available
Seasonally saturated wetlands are hydrologically dynamic ecosystems that provide various ecosystem services; however, their variable hydrologic conditions may promote greenhouse gas emissions. The extent to which wetlands produce and emit greenhouse gases is intimately tied to the underlying microbial community. We established a linear transect spa...
Article
Gully development following agricultural land use change is well documented in many tropical developing countries. However, the impact of specific agricultural intensification practices on gully formation, such as the construction of unpaved roads and contour terracing, remains poorly understood. We studied gully formation in catchments with sugarc...
Article
Full-text available
At the present rate of loss (since 1990), half of the remaining wetlands worldwide will be developed within ~140 years, underscoring the importance of improving the creation and restoration of wetlands. Organic amendments are sometimes used during wetland creation. To evaluate the effectiveness of adding organic amendments we used a combined numeri...
Article
Geographically isolated wetlands (GIWs) provide a portfolio of ecosystem services in low-gradient, Coastal Plain landscapes. Understanding how GIWs influence downstream waters is becoming increasingly important for conservation and management of these unique and important wetland ecosystems. Climatic conditions are known to be key drivers of water...
Article
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River ecosystems are highly biodiverse, influence global biogeochemical cycles, and provide valued services. However, humans are increasingly degrading fluvial ecosystems by altering their streamflows. Effective river restoration requires advancing our mechanistic understanding of how flow regimes affect biota and ecosystem processes. Here, we revi...
Article
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The Trump administration has proposed replacing the Clean Water Rule, a 2015 regulation that defined the statutory term “waters of the United States” to clarify the geographic jurisdiction of the Clean Water Act. Since its promulgation, the Clean Water Rule has been subjected to numerous judicial challenges. We submitted an amici curiae brief to th...
Article
The economic development-environmental protection dichotomy is an out-dated construct. A 21st century approach to the world's water problems is progressively being developed by researchers and practitioners, who are combining traditional and ecosystem-based engineering systems to yield cost-effective solutions. Given the continuing and widespread l...
Data
Data S1. Supporting Information Table T1. Water year 2015 temporary stream baseflow discharge measurements. ‐‐‐ = site not visited, * = non‐continuous surface flow present,! = continuous surface flow present, but no measurement taken Figure F1. Correlation matrix of landscape predictor metrics, where circle colour and size represent the strength...
Article
Full-text available
Geographically isolated wetlands, those entirely surrounded by uplands, provide numerous landscape-scale ecological functions, many of which are dependent on the degree to which they are hydrologically connected to nearby waters. There is a growing need for field-validated, landscape-scale approaches for classifying wetlands based on their expected...
Article
Full-text available
There is a growing movement in government, environmental non-governmental organizations and the private sector to include ecosystem services in decision making. Adding ecosystem services into assessments implies measuring how much a change in ecological conditions affects people, social benefit, or value to society. Despite consensus around the gen...
Article
Full-text available
Dissolved organic matter (DOM) is integral to fluvial biogeochemical functions and wetlands are broadly recognized as substantial sources of aromatic DOM to fluvial networks. Yet, how land use change alters biogeochemical connectivity of upland wetlands to streams remains unclear. We studied depressional geographically isolated wetlands (GIWs) on t...
Article
Full-text available
Background Enhancing water provision services is a common target in forest restoration projects worldwide due to growing concerns over freshwater scarcity. However, whether or not forest cover expansion or restoration can improve water provision services is still unclear and highly disputed. Purpose The goal of this review is to provide a balanced...
Data
PRISMA checklist. Checklist of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). (DOC)
Data
Database for meta-analises. Summary of data extracted from a sub-set of publications for the meta-analyses. The paper ID column corresponds to the same column in S1 Table. (PDF)
Data
Selected papers. Complete list of publications selected in the systematic review and summary of the relevant information used in analyses. Publications with more than one study case had the information entered separately for each one. (PDF)
Article
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Urbanization strongly influences headwater stream chemistry and hydrology, but little is known about how these conditions impact bacterial community composition. We predicted that urbanization would impact bacterial community composition, but that stream water column bacterial communities would be most strongly linked to urbanization at a watershed...
Article
Urbanization threatens headwater stream ecosystems globally. Watershed restoration practices, such as infiltration-based stormwater management, are implemented to mitigate the detrimental effects of urbanization on aquatic ecosystems. However, their effectiveness for restoring hydrologic processes and watershed storage remains poorly understood. Ou...
Book
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This second edition provides the latest emerging theories and ideas in the science of restoration ecology. Fully one-third longer than the first edition and comprehensive in scope, it has been dramatically updated to reflect new research. Included are new sections devoted to concepts critical to all restoration projects as well as restoration of sp...
Article
Full-text available
This paper describes the programs and processes of a new center designed to enhance interdisciplinary team effectiveness and the building of new communities of social and natural scientists undertaking socio-environmental synthesis research. The theory and organizational structure of the center is motivated by research on interdisciplinary team sci...
Article
The call for integrated social–environmental science, complete with outreach to applications and solutions, is escalating worldwide. Drawing on several decades of experience, researchers engaged in such science, completed an assessment of the design and management attributes and impact pathways that lead to successful projects and programs and to u...
Chapter
Understanding the fundamentals of water flux and storage is essential to restoration ecology. Watersheds capture, store, and release water, and the flow of water links ecosystems, transports organisms and material, influences temperature regimes, and drives many biogeochemical processes. Losses and gains of water in one part of a watershed—whether...
Chapter
Since the last edition of Foundations was written a decade ago, two factors have intersected resulting in transformative impacts on ecological science. First, the growth in the availability of data that is captivating scientists from all fields is also being felt by ecologists. The volume and types of ecological data being shared among researchers...
Conference Paper
Full-text available
We tested the hypotheses that increased hydrological connectivity is associated with gully formation due to sugarcane agriculture, and, that this in turn, compromises the effectiveness of stream riparian buffers at protecting streams. Based largely on results from temperate regions, national-level programs to restore riparian buffers have been prom...
Article
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Abstract We reply to a comment on our recent structured expert judgment analysis of stormwater nitrogen retention in suburban watersheds. Low relief, permeable soils, a dynamic stream channel, and subsurface flows characterize many lowland Coastal Plain watersheds. These features result in unique catchment hydrology, limit the precision of streamfl...
Article
Full-text available
Ecological restoration as grounded in modern science is based on a systems perspective - it seeks to recover ecological systems characteristic of past or least-disturbed contemporary landscapes. This requires recovery of organisms along with the ecosystem features and dynamic processes that support them. Since self-sustainability is the goal, it al...
Article
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Managing freshwater resources sustainably under future climatic and hydrological uncertainty poses novel challenges. Rehabilitation of ageing infrastructure and construction of new dams are widely viewed as solutions to diminish climate risk, but attaining the broad goal of freshwater sustainability will require expansion of the prevailing water re...
Article
Full-text available
Reliance on “hard,” human-engineered structures—“gray” infrastructure—has been the conventional way to manage water needs for economic development. But building dams, piping water, and constructing protective barriers is capital intensive and may address only a few water problems ( 1 ). Gray infrastructure often damages or eliminates biophysical pr...
Article
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Building engineered structures, such as dams and dikes, has been the conven- tional approach to water management. Some suggest that such “gray” infrastruc- ture make way for “green” ecosystem-based approaches. In this second of three debates, Science invited arguments for how these approaches can address the challenge of building the water security...
Article
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Excess nitrogen (N) is a primary driver of freshwater and coastal eutrophication globally, and urban stormwater is a rapidly growing source of N pollution. Stormwater best management practices (BMPs) are used widely to remove excess N from runoff in urban and suburban areas, and are expected to perform under a wide variety of environmental conditio...
Article
Studies documenting the capacity of restored streams to reduce pollutant loads indicate that they are relatively ineffective when principal watershed stressors remain intact. Novel restorations are being designed to increase the hydraulic connectivity between stream channels and floodplains to enhance pollutant removal, and their popularity has inc...
Conference Paper
Full-text available
Degradation of streams draining intensive agriculture in the humid tropics may be driven by gully formation from the combination of heavy seasonal rainfall associated with agricultural practices. However, the formation of gullies in association with intensive agriculture is rarely assessed. I investigated the impacts of intensive agriculture on gul...
Article
Full-text available
Microbial communities are responsible for the bulk of biogeochemical processing in temporary headwater streams, yet there is still relatively little known about how community structure and function respond to periodic drying and re-wetting. Moreover, the ability to sample temporary habitats can be a logistical challenge due to the capability to mea...
Chapter
4.1 INTRODUCTION Covering less than 1% of the Earth’s surface, freshwater - streams, rivers, ponds, wetlands, and lakes - supports as much as 10% of all animal species, including one-third of all vertebrates (Strayer & Dudgeon 2010; Figure 4.1). While being among the most biologically diverse, freshwater ecosystems are also among the most imperiled...
Article
Full-text available
Ecological restoration has grown rapidly and now encompasses not only classic ecological theory but also utilitarian concerns, such as preparedness for climate change and provisioning of ecosystem services. Three dominant perspectives compete to influence the science and practice of river restoration. A strong focus on channel morphology has led to...
Article
Full-text available
An age-old conflict around a seemingly simple question has resurfaced: why do we conserve nature? Contention around this issue has come and gone many times, but in the past several years we believe that it has reappeared as an increasingly acrimonious debate between, in essence, those who argue that nature should be protected for its own sake (intr...
Article
Full-text available
Although recent U.S. Supreme Court rulings indicate surface hydrologic connectivity (SHC) between geographically isolated wetlands and nearby streams may be used, in part, to determine wetland jurisdictional status, and ecologic implications are considerable regardless of policies, wetland–stream SHC has rarely been quantified. Furthermore, the imp...
Article
A comprehensive synthesis of data from empirically based published studies and a widely used stormwater best management practice (BMP) database were used to assess the variability in nitrogen (N) removal performance of urban stormwater ponds, wetlands, and swales and to identify factors that may explain this variability. While the data suggest that...
Article
Compensatory mitigation is commonly used to replace aquatic natural resources being lost or degraded but little is known about the success of stream mitigation. This article presents a synthesis of information about 434 stream mitigation projects from 117 permits for surface mining in Appalachia. Data from annual monitoring reports indicate that th...
Article
Full-text available
Landscape urbanization broadly alters watersheds and stream ecosystems, yet the impact of non-point source urban inputs on the quantity, quality, and ultimate fate of dissolved organic matter (DOM) is poorly understood. We assessed DOM quality and microbial bioavailability in eight first-order Coastal Plain headwater streams along a gradient of urb...
Article
The article by Simonit and Perrings (1) describes development of a spatially explicit model of ecosystem service flows associated with reforestation of the Panama Canal watershed. Critical to their study are estimates of water flows, particularly during dry seasons.
Article
Full-text available
An Open Community Engagement Process (OCEP) applies open source mechanics and software engineering to water science research. To operationalize OCEP, the authors conceptualize a Water Science Software Institute whose mission is to support and accelerate water science by transforming both the software and research cultures of the water science commu...
Article
Full-text available
Ecosystem restoration was originally founded upon recovering ecosystems using wildlands as a reference state. More recently there has been interest in shifting to the restoration of ecosystem services – the benefits that natural systems can provide to humans. This shift is resulting in new restoration goals as well as new methodological approaches....
Article
Full-text available
A proposed ruling by the U.S. Environmental Protection Agency (EPA), aimed at clarifying which bodies of water that flow intermittently are protected under law (1), has provoked conflict between developers and environmental advocates. Some argue that temporary streams and rivers, defined as waterways that cease to flow at some points in space and t...
Article
Full-text available
Riverine macrosystems are described here as watershed-scale networks of connected and interacting riverine and upland habitat patches. Such systems are driven by variable responses of nutrients and organisms to a suite of global and regional factors (eg climate, human social systems) interacting with finer-scale variations in geology, topography, a...
Chapter
Although inland waters make up only about 1% of the earth’s surface, these fresh waters contain about 10% of all animal species, the majority of which are invertebrates. Inhabiting ground, surface, and running waters, diverse assemblages of freshwater invertebrates play key roles in ecological processes that ensure that our water is clean and that...
Article
Stream restoration is often employed in efforts to stabilize eroding channel banks. Banks are stabilized through a designed channel approach, which involves grading and armoring of stream banks using heavy machinery, or alternatively through planting of seedlings and saplings to establish forested riparian buffers. We hypothesized that designed cha...
Article
Human water security is often achieved with little consideration of environmental consequences and, even when these are acknowledged, the trade-offs between human and environmental water needs are increasing in frequency and amplitude on the increase. The environmental flows concept has continued to evolve in response to these challenges. However,...
Conference Paper
We have conceptualized a public/private Water Science Software Institute (WSSI) whose mission is “to enable and accelerate transformative water science by concurrently transforming both the software culture and the research culture of the water science community”. To achieve our goals, we have applied an Open Community Engagement Process (OCEP), ba...
Article
Which indicators of ecosystem structure and function must be measured to assess ecosystem health?