Isla Heather Myers-Smith

Learn More
With a warmer climate, the wetlands of Interior Alaska may experience more frequent or extensive stand-replacing fires and permafrost degradation. This, in turn may change the primary factors controlling carbon emissions. I measured carbon exchange along a moisture transect from the center of a Sphagnum-dominated bog into a burned forest (2001 Survey Line(More)
A central current debate in community ecology concerns the relative importance of deterministic versus stochastic processes underlying community structure. However, the concept of stochasticity presents several profound philosophical, theoretical and empirical challenges, which we address here. The philosophical argument that nothing in nature is truly(More)
Inference about future climate change impacts typically relies on one of three approaches: manipulative experiments, historical comparisons (broadly defined to include monitoring the response to ambient climate fluctuations using repeat sampling of plots, dendroecology, and paleoecology techniques), and space-for-time substitutions derived from sampling(More)
We investigated long-term and seasonal patterns of N imports and exports, as well as patterns following climate perturbations, across biomes using data from 15 watersheds from nine Long-Term Ecological Research (LTER) sites in North America. Mean dissolved inorganic nitrogen (DIN) import–export budgets (N import via precipitation–N export via stream flow)(More)
Wetlands are the largest natural source of atmospheric methane. Here, we assess controls on methane flux using a database of approximately 19 000 instantaneous measurements from 71 wetland sites located across subtropical, temperate, and northern high latitude regions. Our analyses confirm general controls on wetland methane emissions from soil temperature,(More)
[1] We measured CO 2 and CH 4 exchange from the center of a Sphagnum-dominated permafrost collapse, through an aquatic moat, and into a recently burned black spruce forest on the Tanana River floodplain in interior Alaska. In the anomalously dry growing season of 2004, both the collapse and the surrounding burned area were net sinks for CO 2 , with a mean(More)
To determine the influence of fire and thermokarst in a boreal landscape, we investigated peat cores within and adjacent to a permafrost collapse feature on the Tanana River Floodplain of Interior Alaska. Radioisotope dating, di-atom assemblages, plant macrofossils, charcoal fragments, and carbon and nitrogen content of the peat profile indicate ∼600 years(More)
Shrubs are the largest plant life form in tundra ecosystems; therefore, any changes in the abundance of shrubs will feedback to influence biodiversity, ecosystem function, and climate. The snow-shrub hypothesis asserts that shrub canopies trap snow and insulate soils in winter, increasing the rates of nutrient cycling to create a positive feedback to shrub(More)
To determine the influence of fire and thermokarst in a boreal landscape, we investigated ∼600 years of vegetation succession from peat cores within and adjacent to a permafrost collapse feature on the Tanana River Floodplain of Interior Alaska. Ra-dioisotope dating, diatom assemblages, plant macrofossils, charcoal fragments, and 5 carbon and nitrogen(More)
Oil development in the Arctic has wide-reaching effects on ecosystem health, including both direct habitat destruction and indirect cumulative impacts on the adjacent landscape (Walker & Walker, 1991; NRC, 2003). Vehicle transport is one of the most widespread forms of arctic disturbance (Forbes, Ebersole & Strandberg, 2001). The direct ecological impacts(More)