Rebecca J Howard , Ph.D.
Rebecca Howard is a Scientist Emeritus at the USGS Wetland and Aquatic Research Center.
Rebecca Howard directed a research program on wetland plant community dynamics, including the effects of stressors and disturbances on plant community structure and function. She also conducted research on seed bank ecology, wetland restoration ecology, and plant response to factors associated with climate change.
Her research program centered on plant community dynamics in coastal wetlands of the northern Gulf of Mexico and inland wetlands of the southeastern U.S. The major goals of Howard's research were to: (1) determine how wetland plants respond to physicochemical stressors and disturbance, (2) develop an understanding of how biotic and abiotic factors affect plant community structure and composition, and (3) determine the mechanisms responsible for spatial and temporal variation in plant communities. Specific studies have included determining the effects of increased flooding and salinity on the growth of common perennial marsh macrophytes in field and greenhouse experiments, detailing vegetation succession patterns and seed bank characteristics on exposed soils of a large freshwater reservoir, describing soil and plant community response to disturbance associated with oil and gas exploration, and identifying intraspecific variation in stress tolerance of wetland plant species with the goal of identifying plants for use in restoration projects.
Professional Experience
Research Ecologist, USGS National Wetlands Research Center / Wetland and Aquatic Research Center (1995 – 2020)
Ecologist, USFWS National Wetlands Research Center (1984 – 1995)
Wildife Biologist, USFWS National Coastal Ecosystems Team (1982 - 1984)
Education and Certifications
Ph.D., Oceanography and Coastal Sciences, Louisiana State University
M.S., Wildlife Biology (Minor: Botany) University of Massachusetts, Amherst
B.S., Wildlife Biology (Minor: Botany),&nbs
Science and Products
Response of Schoenoplectus acutus and Schoenoplectus californicus at different life-history stages to hydrologic regime
Plant-plant interactions in a subtropical mangrove-to-marsh transition zone: effects of environmental drivers
Effects of disturbance associated with seismic exploration for oil and gas reserves in coastal marshes
Phragmites australis expansion in a restored brackish marsh: documentation at different time scales
Effects of a drawdown on plant communities in a freshwater impoundment at Lacassine National Wildlife Refuge, Louisiana
On the relative roles of hydrology, salinity, temperature, and root productivity in controlling soil respiration from coastal swamps (freshwater)
Vegetation of Lacassine National Wildlife Refuge, Louisiana-Recent plant communities with comparison to a three-decade-old survey
Intraspecific variation in growth of marsh macrophytes in response to salinity and soil type: Implications for wetland restoration
Is there evidence of adaptation to tidal flooding in saplings of baldcypress subjected to different salinity regimes?
Plant community establishment following drawdown of a reservoir in southern Arkansas, USA
Rapid growth of a Eurasian haplotype of Phragmites australis in a restored brackish marsh in Louisiana, USA
Vegetation Response to the 1995 Drawdown of the Navigation Pool at Felsenthal National Wildlife Refuge, Crossett, Arkansas
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Filter Total Items: 37
Response of Schoenoplectus acutus and Schoenoplectus californicus at different life-history stages to hydrologic regime
For wetland restoration success to be maximized, restoration managers need better information regarding how the frequency, depth, and duration of flooding affect soil chemistry and the survival, growth, and morphology of targeted plant species. In a greenhouse study we investigated the impact of four different flooding durations (0 %, 40 %, 60 %, and 100 %) on soil physicochemistry and the responsAuthorsTaylor M Sloey, Rebecca J. Howard, Mark W. HesterPlant-plant interactions in a subtropical mangrove-to-marsh transition zone: effects of environmental drivers
Questions Does the presence of herbaceous vegetation affect the establishment success of mangrove tree species in the transition zone between subtropical coastal mangrove forests and marshes? How do plant–plant interactions in this transition zone respond to variation in two primary coastal environmental drivers? Location Subtropical coastal region of the southern United States. MethodsAuthorsRebecca J. Howard, Ken W. Krauss, Nicole Cormier, Richard H. Day, Janelda M. Biagas, Larry K. AllainEffects of disturbance associated with seismic exploration for oil and gas reserves in coastal marshes
Anthropogenic disturbances in wetland ecosystems can alter the composition and structure of plant assemblages and affect system functions. Extensive oil and gas extraction has occurred in wetland habitats along the northern Gulf of Mexico coast since the early 1900s. Activities involved with three-dimensional (3D) seismic exploration for these resources cause various disturbances to vegetation andAuthorsRebecca J. Howard, Christopher J. Wells, Thomas C. Michot, Darren J. JohnsonPhragmites australis expansion in a restored brackish marsh: documentation at different time scales
Invasive plants in restored habitats can alter the system such that restoration goals are not met. Non-native lineages of Phragmites australis (hereafter Phragmites) are invasive in North American wetlands, and their presence can be problematic because of decreased species diversity and altered physicochemical processes. Phragmites is a challenging species for restoration because both native and nAuthorsRebecca J. Howard, Theodore D. TurluckEffects of a drawdown on plant communities in a freshwater impoundment at Lacassine National Wildlife Refuge, Louisiana
Disturbance is an important natural process in the creation and maintenance of wetlands. Water depth manipulation and prescribed fire are two types of disturbance commonly used by humans to influence vegetation succession and composition in wetlands with the intention of improving wildlife habitat value. A 6,475-hectare (ha) impoundment was constructed in 1943 on Lacassine National Wildlife RefugeAuthorsRebecca J. Howard, Larry AllainOn the relative roles of hydrology, salinity, temperature, and root productivity in controlling soil respiration from coastal swamps (freshwater)
Background and aims Soil CO2 emissions can dominate gaseous carbon losses from forested wetlands (swamps), especially those positioned in coastal environments. Understanding the varied roles of hydroperiod, salinity, temperature, and root productivity on soil respiration is important in discerning how carbon balances may shift as freshwater swamps retreat inland with sea-level rise and salinity inAuthorsKen W. Krauss, Julie L. Whitbeck, Rebecca J. HowardVegetation of Lacassine National Wildlife Refuge, Louisiana-Recent plant communities with comparison to a three-decade-old survey
Shifts in plant community composition and structure can affect the quality of habitat for wildlife species. Lacassine National Wildlife Refuge in southwestern Louisiana was established in 1937 with a primary goal of providing habitat for wintering waterfowl species. A large freshwater impoundment constructed on the refuge to improve waterfowl habitat value was completed in 1943. About 10 years aftAuthorsRebecca J. Howard, Thomas C. Michot, Larry AllainIntraspecific variation in growth of marsh macrophytes in response to salinity and soil type: Implications for wetland restoration
Genetic diversity within plant populations can influence plant community structure along environmental gradients. In wetland habitats, salinity and soil type are factors that can vary along gradients and therefore affect plant growth. To test for intraspecific growth variation in response to these factors, a greenhouse study was conducted using common plants that occur in northern Gulf of Mexico bAuthorsR.J. HowardIs there evidence of adaptation to tidal flooding in saplings of baldcypress subjected to different salinity regimes?
Plant populations may adapt to environmental conditions over time by developing genetically based morphological or physiological characteristics. For tidal freshwater forested wetlands, we hypothesized that the conditions under which trees developed led to ecotypic difference in response of progeny to hydroperiod. Specifically, we looked for evidence of ecotypic adaptation for tidal flooding at diAuthorsK. W. Krauss, T.W. Doyle, R.J. HowardPlant community establishment following drawdown of a reservoir in southern Arkansas, USA
Wetland area, function and wildlife habitat value are extensively altered by the construction of freshwater reservoirs. We studied the effects of a temporary drawdown on shoreline vegetation communities of Felsenthal Navigation Pool (“the pool”), an impoundment at Felsenthal National Wildlife Refuge in southern Arkansas that is managed as a greentree reservoir. The pool was permanently flooded froAuthorsRebecca J. Howard, Christopher J. WellsRapid growth of a Eurasian haplotype of Phragmites australis in a restored brackish marsh in Louisiana, USA
While numerous studies have documented patterns of invasion by non-indigenous plant species, few have considered the invasive properties of non-native genotypes of native species. Characteristics associated with specific genotypes, such as tolerance to disturbance, may mistakenly be applied to an entire species in the absence of genetic information, which consequently may affect management decisioAuthorsRebecca J. Howard, Steven E. Travis, Benjamin A. SikesVegetation Response to the 1995 Drawdown of the Navigation Pool at Felsenthal National Wildlife Refuge, Crossett, Arkansas
Felsenthal Navigation Pool (?the pool?) at Felsenthal National Wildlife Refuge near Crossett, Ark., was continuously flooded to a baseline elevation of 19.8 m (65.0 ft) mean sea level (m.s.l.) from late fall 1985, when the final in a series of locks and dams was constructed, until the summer of 1995. Water level within the pool was reduced by 0.3 m (1.0 ft) beginning July 5, 1995, exposing about 1AuthorsRebecca J. Howard, Christopher J. Wells