J. Patrick Megonigal

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For decades, ecosystem scientists have used global warming potentials (GWPs) to compare the radiative forcing of various greenhouse gases to determine if ecosystems have a net warming or cooling effect on climate. On a conceptual basis, the continued use of GWPs by the ecological community may be untenable because the use of GWPs requires the implicit(More)
Coastal populations and wetlands have been intertwined for centuries, whereby humans both influence and depend on the extensive ecosystem services that wetlands provide. Although coastal wetlands have long been considered vulnerable to sea-level rise, recent work has identified fascinating feedbacks between plant growth and geomorphology that allow wetlands(More)
Terrestrial ecosystems gain carbon through photosynthesis and lose it mostly in the form of carbon dioxide (CO(2)). The extent to which the biosphere can act as a buffer against rising atmospheric CO(2) concentration in global climate change projections remains uncertain at the present stage. Biogeochemical theory predicts that soil nitrogen (N) scarcity(More)
Global change is predicted to promote plant invasions world-wide, reducing biodiversity and ecosystem function. Phenotypic plasticity may influence the ability of introduced plant species to invade and dominate extant communities. However, interpreting differences in plasticity can be confounded by phylogenetic differences in morphology and physiology. Here(More)
Rising atmospheric carbon dioxide (CO₂) could alter the carbon (C) and nitrogen (N) content of ecosystems, yet the magnitude of these effects are not well known. We examined C and N budgets of a subtropical woodland after 11 yr of exposure to elevated CO₂. We used open-top chambers to manipulate CO₂ during regrowth after fire, and measured C, N and tracer(More)
North American wetlands have been invaded by an introduced lineage of the common reed, Phragmites australis. Native lineages occur in North America, but many populations have been extirpated by the introduced conspecific lineage. Little is known about how subtle changes in plant lineage may affect methane (CH4) emissions. Native and introduced Phragmites(More)
Elevated atmospheric CO(2) generally increases plant productivity and subsequently increases the availability of cellulose in soil to microbial decomposers. As key cellulose degraders, soil fungi are likely to be one of the most impacted and responsive microbial groups to elevated atmospheric CO(2). To investigate the impacts of ecosystem type and elevated(More)
Abiotic global change factors, such as rising atmospheric CO2, and biotic factors, such as exotic plant invasion, interact to alter the function of terrestrial ecosystems. An invasive lineage of the common reed, Phragmites australis, was introduced to North America over a century ago, but the belowground mechanisms underlying Phragmites invasion and(More)
Invasive plants can influence ecosystem processes such as greenhouse gas (GHG) emissions from wetland systems directly through plant-mediated transfer of GHGs to the atmosphere or through indirect modification of the environment. However, patterns of plant invasion often co-vary with other environmental gradients, so attributing ecosystem effects to(More)
The effects of elevated CO2 on ecosystem element stocks are equivocal, in part because cumulative effects of CO2 on element pools are difficult to detect. We conducted a complete above and belowground inventory of non-nitrogen macro- and micronutrient stocks in a subtropical woodland exposed to twice-ambient CO2 concentrations for 11 years. We analyzed a(More)