About
172
Publications
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Introduction
Specialist in wetland plant ecology, particularly global change effects (sea-level rise, elevated CO2, climate change, hurricanes), and science communication.
Website and Blogs:
https://www.usgs.gov/staff-profiles/karen-mckee
http://thescientistvideographer.com/wordpress
Writing Tips:
https://www.youtube.com/channel/UCNDEeAVnl0p1Wj5ngF8JlMA
Twitter: @scivideographer
Additional affiliations
November 2009 - March 2010
Landcare Research, Hamilton, New Zealand
Position
- Visiting Scientist
October 1998 - July 2012
September 1994 - December 1994
Education
August 1989 - May 1993
August 1973 - May 1977
August 1968 - May 1972
Publications
Publications (172)
To avoid submergence during sea-level rise, coastal wetlands build soil surfaces vertically through accumulation of inorganic sediment and organic matter. At climatic boundaries where mangroves are expanding and replacing salt marsh, wetland capacity to respond to sea-level rise may change. To compare how well mangroves and salt marshes accommodate...
Hurricanes periodically deliver sediment to coastal wetlands, such as those in the Mississippi River Delta Complex (MRDC), slowing elevation loss and improving resilience to sea-level rise. However, the amount of hurricane sediment deposited and retained in a wetland may vary depending on the dominant vegetation. In the subtropical climate of the M...
This review evaluates the importance of plants and associated biological processes in determining the vulnerability of coastal wetlands to sea-level rise. Coastal wetlands occur across a broad sedimentary continuum from minerogenic to biogenic, providing an opportunity to examine the relative importance of biological processes in wetland resilience...
Coastal wetlands adapt to rising seas via feedbacks that build soil elevation, which lead to wetland stability. However, accelerated rates of sea-level rise can exceed soil elevation gain, leading to wetland instability and loss. Thus, there is a pressing need to better understand regional and landscape variability in rates of wetland soil elevatio...
Climate change is altering species’ range limits and transforming ecosystems. For example, warming temperatures are leading to the range expansion of tropical, cold-sensitive species at the expense of their cold-tolerant counterparts. In some temperate and subtropical coastal wetlands, warming winters are enabling mangrove forest encroachment into...
Coastal wetlands are dynamic ecosystems that exist along a landscape continuum that can range from freshwater forested wetlands to tidal marsh to mudflat communities. Climate-driven stressors, such as sea-level rise, can cause shifts among these communities, resulting in changes to ecological functions and services. While a growing body of research...
Global climate change is leading to large-scale shifts in species' range limits. For example, rising winter temperatures are shifting the abundance and distributions of tropical, cold sensitive plant species towards higher latitudes. Coastal wetlands provide a prime example of such shifts, with tropical mangrove forests expanding into temperate sal...
The greatest climate-based threat to coastlines worldwide is sea-level rise. We tested the hypothesis that tropical coasts fringed by mangroves and receiving high inputs of terrigenous sediment are less vulnerable to sea-level rise than biogenic systems dependent upon peat formation for vertical land development. An analysis of published data spann...
Positioned in the intertidal zone, mangrove forests are a key model ecosystem with which to observe and test biogeomorphological concepts. Understanding how mangroves interact with their intertidal environment, particularly tidal inundation, is important if we are to assess their vulnerability or resilience to accelerated sea-level rise. While vari...
This chapter is included in a book of essays written by leading wetland scientists and that provide different perspectives about a career in wetland science. In this chapter, McKee described her early wetland experiences and some of the factors that influenced her career choices.
Coastal wetland responses to sea-level rise are greatly influenced by biogeomorphic processes that affect wetland surface elevation. Small changes in elevation relative to sea level can lead to comparatively large changes in ecosystem structure, function, and stability. The surface elevation table-marker horizon (SET-MH) approach is being used glob...
Mangroves occur on upper intertidal shorelines in the tropics and subtropics. Complex hydrodynamic and salinity conditions influence mangrove distributions, primarily related to elevation and hydroperiod; this review considers how these adjust through time. Accumulation rates of allochthonous and autochthonous sediment, both inorganic and organic,...
Organic matter accumulation, the net effect of plant production and decomposition, contributes to vertical soil accretion in coastal wetlands, thereby playing a key role in whether they keep pace with sea-level rise. Any factor that affects decomposition may affect wetland accretion, including atmospheric CO2 concentrations. Higher CO2 can influenc...
Our study investigated the carbon:nitrogen:phosphorus (C:N:P) stoichiometry of mangrove island of the Mesoamerican Barrier Reef (Twin Cays, Belize). The C:N:P of abiotic and biotic components of this oligotrophic ecosystem was measured and served to build networks of nutrient flows for three distinct mangrove forest zones (tall seaward fringing for...
Thumbnail and link to a visual abstract summarizing an article in press. Download the page and click on the hyperlink to access the interactive file.
The 2011 Mississippi River flood in the Lower Mississippi River Basin was one of the largest flood events in recorded history, producing the largest or next to largest peak streamflow for the period of record at a number of streamgages on the lower Mississippi River. Ecosystem effects include changes to wetlands, nutrient transport, and land accret...
Mangroves are expanding into warm temperate-zone salt marsh communities in several locations globally. Although scientists have discovered that expansion might have modest effects on ecosystem functioning, water use characteristics have not been assessed relative to this transition. We measured early growing season sapflow (Js) and leaf transpirati...
Aim
To reassess the capacity of mangroves for ecosystem services in the light of recent data.
Location
Global mangrove ecosystems.
Methods
We review four long‐standing roles of mangroves: (1) carbon dynamics – export or sink; (2) nursery role; (3) shoreline protection; (4) land‐building capacity. The origins of pertinent hypotheses, current under...
Abstract: The composition and diversity of indigenous wetland vegetation is known to be strongly influenced by nutrient availability. To test the nutrient status (nitrogen or phosphorus limitation) of wetlands in the Waikato and their response to nutrient addition, we undertook a fertilisation experiment across a gradient from an early successional...
The Scientist Videographer is a detailed how-to for scientists, science educators, and students who wish to make their own videos. Using a new authoring platform to combine text, video, and other interactive content, the author has created an electronic guidebook to science videography. This ebook shows how to plan, shoot, edit, and publish a profe...
Mangroves are among the most well described and widely studied wetland communities in the world. The greatest threats to mangrove persistence are deforestation and other anthropogenic disturbances that can compromise habitat stability and resilience to sea-level rise. To persist, mangrove ecosystems must adjust to rising sea level by building verti...
This video describes causes of wetland loss in the Mississippi River Delta. Rapid land subsidence due to sediment compaction and dewatering increases the rate of submergence in this deltaic system. The construction of levees along the lower Mississippi River also has reduced delivery of sediments to coastal wetlands, which have been deteriorating a...
Management and restoration of the Mississippi River deltaic plain (southern United States) and associated wetlands require a quantitative understanding of sediment delivery during large flood events, past and present. Here, we investigate the sedimentary fingerprint of the 2011 Mississippi River flood across the Louisiana coast (Atchafalaya Delta,...
Wetlands in the Mississippi River deltaic plain are deteriorating in part because levees and control structures starve them of sediment. In spring 2011 a record-breaking flood brought discharge on the lower Mississippi River to dangerous levels, forcing managers to divert up to 3,500m3s-1 of water to the Atchafalaya River Basin. Here we use field-c...
Background/Question/Methods
Climate change associated increases in atmospheric CO2 are driving changes in marine storm patterns and raising sea-levels. Low-lying coastal wetlands are becoming increasingly threatened by encroaching seas, and thus, must gain elevation at a rate comparable to sea-level rise (SLR) or risk being converted to open-wate...
Coastal salt marsh and mangrove ecosystems are particularly vulnerable to changes in atmospheric CO2 concentrations and associated climate and climate-induced changes. We provide a review of the literature detailing theoretical predictions and observed responses of coastal wetlands to a range of climate change stressors, including CO2, temperature,...
Higher atmospheric concentrations of CO2 can offset the negative effects of flooding or salinity on plant species, but previous studies have focused on mature, rather than regenerating vegetation. This study examined how interacting environments of CO2, water regime, and salinity affect seed germination and seedling biomass of floating freshwater m...
The 2011 Mississippi River flood was arguably the largest in history.
Although the massive inundation resulting from the flood was devastating
for residents on the Delta, sediment carried to sea by the swollen river
had the potential to combat wetland loss in some areas. There is
currently much debate regarding how, and to what degree, sediment fro...
The marshes of coastal Louisiana are disappearing at a rapid rate due to
both natural and anthropogenic processes. Maintenance of soil elevations
relative to water levels is key to marsh sustainability, but leveeing of
the Mississippi River prevents overbank flooding and direct delivery of
sediment to counterbalance rapid rates of subsidence in the...
Premise of the study:
Climate warming is predicted to have far-reaching effects on the distribution of species, but those effects may depend on the flexibility of regenerating species in responding to climate gradients. We conducted a study to determine whether the variation in the response of seed banks to temperature varied across the latitudina...
Habitat stability of coastal ecosystems, such as marshes and mangroves, depends on maintenance of soil elevations relative to sea level. Many such systems are characterized by limited mineral sedimentation and/or rapid subsidence and are consequently dependent upon accumulation of organic matter to maintain elevations. However, little field informa...
Wetlands are recognized as potentially important carbon sinks, but few studies have focused on tropical and sub-tropical systems that accumulate organic carbon. Soil organic carbon (SOC) density was analyzed in multiple mangrove forests, representing 30 geographic locations and six forest types (total of 230 study plots overall). SOC density varied...
Background/Question/Methods The persistence of coastal wetlands depends on the maintenance of soil elevations relative to sea-level. Physical processes of erosion, sedimentation, and subsidence influence the capacity of coastal wetlands to adjust to rising seas. However, it is also important to consider biological responses, such as plant productio...
Cattail (Typha domingensis) has been spreading in phosphorus (P) enriched areas of the oligotrophic Florida Everglades at the expense of sawgrass (Cladium mariscus spp. jamaicense). Abundant evidence in the literature explains how the opportunistic features of Typha might lead to a complete dominance in P-enriched areas. Less clear is how Typha can...
Mangroves are an ecological assemblage of trees and shrubs adapted to grow in intertidal environments along tropical coasts. Despite repeated demonstration of their economic and societal value, more than 50% of the world's mangroves have been destroyed, 35% in the past two decades to aquaculture and coastal development, altered hydrology, sea-level...
Summary • Sea-level rise, one indirect consequence of increasing atmospheric CO2, poses a major challenge to long-term stability of coastal wetlands. An important question is whether direct effects of elevated CO2 on the capacity of marsh plants to accrete organic material and to maintain surface elevations outweigh indirect negative effects of str...
A Comment by Rey et al. (2009; Mar Ecol Prog Ser 389:295-300) documents disagreements with Middleton et al. (2008; Mar Ecol Prog Ser 371:117-129), which explored the characteristics of mangrove swamps managed for mosquito control in the Indian River Lagoon, Florida, USA. Rey et al. (2009) provide no data or evidence that invalidate the conclusions...
In the Florida Everglades, the expansion of cattail (Typha domingensis) into areas once dominated by sawgrass (Cladium jamaicense) has been attributed to altered hydrology and phosphorus (P) enrichment. The objective of this study was to quantify the interactive effects of P availability and soil redox potential (Eh) on the growth and nutrient resp...
Tidal wetlands experiencing increased rates of sea-level rise (SLR) must increase rates of soil elevation gain to avoid permanent conversion to open water. The maximal rate of SLR that these ecosystems can tolerate depends partly on mineral sediment deposition, but the accumulation of organic matter is equally important for many wetlands. Plant pro...
Although hurricanes can damage or destroy coastal wetlands, they may play a beneficial role in reinvigorating marshes by delivering
sediments that raise soil elevations and stimulate organic matter production. Hurricane Katrina altered elevation dynamics
of two subsiding brackish marshes in the Mississippi River deltaic plain by adding 3 to 8 cm of...
Manipulations of the vegetation and hydrology of wetlands for mosquito control are common worldwide, but these modifications may affect vital ecosystem processes. To control mosquitoes in mangrove swamps in eastern Florida, managers have used rotational impoundment management
(RIM) as an alternative to the worldwide practice of mosquito ditching. L...
The Mesoamerican Barrier Reef System (MBRS) is the longest unbroken reef in the Western Hemisphere and contains hundreds of mangrove-dominated islands. These islands provide critical habitat supporting marine biodiversity and create a self-sustaining system that counterbalances sea-level rise. Undisturbed mangrove islands build vertically through a...
Sound Waves C o a s t a l S c i e n c e a n d R e s e a r c h N e w s f r o m A c r o s s t h e U S G S Research Global Warming View of a brackish marsh in the Mississippi River Delta, with a simplifi ed diagram showing how biological processes infl uence marsh elevation relative to sea level. Plant production contributes organic matter, causing up...
Manipulations of the vegetation and hydrology of wetlands for mosquito control are common worldwide, but these modifications may affect vital ecosystem processes. To control mosqui- toes in mangrove swamps in eastern Florida, managers have used rotational impoundment manage- ment (RIM) as an alternative to the worldwide practice of mosquito ditchin...
Mangroves have a global distribution within coastal tropical and subtropical climates, and have even expanded to some temperate locales. Where they do occur, mangroves provide a plethora of goods and services, ranging from coastal protection from storms and erosion to direct income for human societies. The mangrove literature has become rather volu...
Our understanding of how elevated CO2 and interactions with other factors will affect coastal plant communities is limited. Such information is particularly needed for transitional communities where major vegetation types converge. Tropical mangroves (Avicennia germinans) intergrade with temperate salt marshes (Spartina alterniflora) in the norther...
Seasonal variability in biogeochemical signatures was used to elucidate the dominant pathways of soil microbial metabolism
and elemental cycling in an oligotrophic mangrove system. Three interior dwarf mangrove habitats (Twin Cays, Belize) where
surface soils were overlain by microbial mats were sampled during wet and dry periods of the year. Porew...
Plant communities along tropical coastlines are often affected by natural and human disturbances, but little is known about factors influencing recovery. We focused on mangrove forests, which are among the most threatened ecosystems globally, to examine how facilitation by herbaceous vegetation might improve forest restoration after disturbance. We...
Aim: The long-term stability of coastal ecosystems such as mangroves and salt marshes depends upon the maintenance of soil elevations within the intertidal habitat as sea level changes. We examined the rates and processes of peat formation by man-groves of the Caribbean Region to better understand biological controls on habitat stability.
Location...
Nutrient over-enrichment is a major threat to marine environments, but system-specific attributes of coastal ecosystems may
result in differences in their sensitivity and susceptibility to eutrophication. We used fertilization experiments in nitrogen
(N)- and phosphorus (P)-limited mangrove forests to test the hypothesis that alleviating different...
Seasonal changes in adenylate levels and adenylate energy charge (AEC) of four perennial marsh plant species growing in their natural environment were monitored. Leaf tissue was collected bimonthly from Spartina patens (Aiton) Muhl., S. cynosuroides (L.) Roth., S. alterniflora Loisel. and Distichlis spicata (L.) Greene using a method designed for f...
Mangrove forest structure and sediment characteristics were examined in the extensive mangroves of Bocas del Toro, Republic of Panama. Forest structure was characterized to determine if spatial vegetation patterns were repeated over the Bocas del Toro landscape. Using a series of permanent plots and transects we found that the forests of Bocas del...
The ability of baldcypress (Taxodium distichum)swamps to maintain themselves near the northern limit of their range depends on their levels of production, which is not only are response to climate but also to local environmental factors(e.g., impoundment). We asked if primary production was reduced under impounded conditions and if species response...
Aim Predictions of vegetation change with global warming require models that accurately reflect physiological processes underlying growth limitations and species distributions. However, information about environmental controls on physiology and consequent effects on species boundaries and ecosystem functions such as production is limited, especiall...
Dwarf stands of the mangrove Rhizophora mangle L. are extensive in the Caribbean. We fertilized dwarf trees in Almirante Bay, Bocas del Toro Province, north‐eastern Panamá with nitrogen (N) and phosphorus (P) to determine (1) if growth limitations are due to nutrient deficiency; and (2) what morphological and/or physiological factors underlie nutri...
Aims Extensive dieback of salt marsh dominated by the perennial grass Spartina alterniflora occurred throughout the Mississippi River deltaic plain during 2000. More than 100,000 ha were affected, with 43,000 ha severely damaged. The aim of this work was to determine if sudden dieback could have been caused by a coincident drought and to assess the...
Summary • We measured sediment elevation and accretion dynamics in mangrove forests on the islands of Guanaja and Roatan, Honduras, impacted by Hurricane Mitch in 1998 to determine if collapse of underlying peat was occurring as a result of mass tree mortality. Little is known about the balance between production and decomposition of soil organic m...
Expansion of Typha domingensis into areas previously dominated by Cladium jamaicense in the Florida Everglades has been linked to anthropogenic phosphorus (P) enrichment and increased hydroperiod. The principal stress factor for plants in flooded soils is biochemical reduction, the intensity of which is measured as redox potential (Eh). The objecti...
The objectives of this study were to determine effects of nutrient enrichment on plant growth, nutrient dynamics, and photosynthesis in a disturbed mangrove forest in an abandoned mosquito impoundment in Florida. Impounding altered the hydrology and soil chemistry of the site. In 1997, we established a factorial experiment along a tree-height gradi...
Mangrove forests are characterized by distinctive tree-height gradients that reflect complex spatial, within-stand differences in environmental factors, including nutrient dynamics, salinity, and tidal inundation, across narrow gradients. To determine patterns of nutrient limitation and the effects of nutrient availability on plant growth and withi...
Activity of root phosphatase was examined in Cladium jamaicense (sawgrass) and Typha domingensis (cattail) grown under controlled conditions in Everglades peat with different inorganic P availabilities and flooding regimes.
Cladium root phosphatase activity was significantly greater than for Typha when both were subjected to relatively low inorgani...
Activity of root phosphatase was examined in Cladium jamaicense (sawgrass) and Typha domingensis (cattail) grown under controlled conditions in Everglades peat with different inorganic P availabilities and flooding regimes. Cladium root phosphatase activity was significantly greater than for Typha when both were subjected to relatively low inorgani...
Questions
Questions (4)
A relatively new trend is the publication of a video (or visual) abstract alongside a written article. In a video abstract, authors can describe their work in a way that is not possible to do in print—such as showing their experimental methods or explaining their motivations for the study. Some journals are now providing a service to help authors create a video or a narrated slide show of their work. A few organizations have been holding contests for the best video abstracts (here’s an example: http://ocean180.org/video-abstract-entries/video-10.html). Video abstracts can raise online visibility, leading more people to the technical article as well as inform a broader audience about their research topic. Here is a blog post I wrote on the topic with more info: http://goo.gl/aENYMa
Have you or colleagues ever made a video abstract—or considered it? If you've done a video abstract, what was your experience like? Do you think the benefits are worth the effort involved in making a video abstract? Do video abstracts help or hurt scholarly communication? Do you think that video abstracts are a passing fad or will become standard practice in the future?
Some studies suggest that a surprisingly high percentage of work in the biological sciences is not reproducible (see Nature article series at http://www.nature.com/nature/focus/reproducibility/ for more background).
Here are some explanations for failure to replicate the findings of a published study:
1. Inaccurate or incomplete methods reported in original study
2. Inappropriate statistics (see this essay: http://goo.gl/OLqCyU for background)
3. Inability to precisely reproduce experimental conditions due to natural variation or logistical reasons (e.g., for a field experiment)
One suggested solution, which addresses the first reason, is to use video to show precisely how an experiment or procedure was carried out (see this essay: http://goo.gl/Z5BFCw).
What do you think? What are your observations with respect to reproducibility in your specific field and to what do you attribute it?
Most of us are taught to follow a formulaic approach when describing our research, which can fail to generate excitement, interest, or curiosity in the reader or listener. Some advocate using storytelling techniques; see these articles for more information: http://goo.gl/QnAXDe
Is this a good idea or not? What about for communicating scientific findings to a non-technical audience?
