High-severity wildfires create heterogeneous patterns of vegetation across burned landscapes. While these spatial patterns are well-documented, less is known about the short- and long-term effects of large-scale high-severity wildfires on insect community assemblages and dynamics. Ants are bottom-up indicators of ecosystem health and function that are sensitive to disturbance and fill a variety of roles in their ecosystems, including altering soil chemistry, dispersing seeds, and serving as a key food resource for many species, including the federally endangered Jemez Mountain salamander (Plethodon neomexicanus). We examined the post-fire effects of the 2011 Las Conchas Wildfire on ant communities in the Valles Caldera National Preserve (Sandoval County, New Mexico, USA). We collected ants via pitfall traps in replicated burned and unburned sites across three habitats: ponderosa pine forests, mixed-conifer forests, and montane grassland. We analyzed trends in species richness, abundance, recruitment, loss, turnover, and composition over five sequential years of post-fire succession (2011-2015). Ant foraging assemblage was influenced by burn presence, season of sampling, and macrohabitat. We also found strong seasonal trends and decreases over time since fire in ant species richness and ant abundance. However, habitat and seasonal effects may be a stronger predictor of ant species richness than the presence of fire or post-fire successional patterns.

Smoldering combustion during wildfires contributes significantly to emissions of pollutants, can burn for days or months, may damage roots and soil, and can transition to flaming combustion. Mitigating these hazards requires an understanding of how physical parameters control smoldering combustion, such as the chemical composition of the fuel. The main organic constituents of biomass are cellulose, hemicellulose, and lignin. Understanding how these constituents influence smoldering is an important step in further developing physics -based models and developing understanding that applies across multiple fuel sources. Previous experimental studies have investigated how varying the amount of cellulose and hemicellulose in fuel influences smoldering behavior, but have not considered the impacts of varying the lignin content. The objective of this study was to identify the influence of lignin on smoldering behavior. This objective was achieved by experimentally and numerically studying the smoldering behavior of various concentrations of lignin in mixtures of cellulose and hemicellulose. These were tested at densities of 200 and 300 kg/m 3 . An infrared camera and thermocouples were used to determine the propagation of the smoldering front in the horizontal and vertical directions, respectively. A one-dimensional reactive porous media model with global chemistry was used to simulate downward smoldering propagation. The horizontal and downward smoldering propagation velocities decrease when more lignin is present due to the slower pyrolysis rates and higher activation energy of lignin. Additionally, results from simulations match this trend for downward propagation. At higher lignin contents, the effect of the mass percentage of cellulose and hemicellulose on downward and horizontal smoldering decreases, indicating that lignin content has the largest impact on smoldering velocities of the three constituents. Increasing the density decreases both the horizontal and vertical propagation velocities due to lower oxygen diffusion and the additional mass being consumed.

This paper provides an overview and summary of the current state of knowledge regarding critical atmospheric processes that affect the distribution and concentrations of greenhouse gases and aerosols emitted from wildland fires or produced through subsequent chemical reactions in the atmosphere. These critical atmospheric processes include the dynamics of plume rise, chemical reactions involving smoke plume constituents, the long-range transport of smoke plumes, and the potential transport of gases and aerosols from wildland fires into the stratosphere. In the area of plume-rise dynamics, synthesis information is provided on (I) the relevance of plume height for assessing impacts of gases and aerosol from wildland fires on the climate system, (2) recent scientific advances in understanding the role of multiple updraft cores in plume behavior, and (3) some of the current modeling tools and remote sensing monitoring techniques available for predicting and measuring smoke plume heights. In the area of atmospheric chemistry associated with wildland fire emissions, synthesis information is provided on what is currently known about the atmospheric fate of wildland fire smoke-plume constituents and the relationship of their atmospheric chemistry to radiative forcing. Synthesis information related to long-range atmospheric transport of wildland fire emissions is presented and summarizes many of the recent published observational and modeling studies that provide clear evidence of intercontinental, continental, and regional transport of North American fire emissions, including black carbon, to locations far-removed from the fire-event locations. Recent studies are also highlighted that examined the significance of troposphere-stratosphere exchange processes, which can result in the transport of greenhouse gases and aerosols from North American wildland fires into the stratosphere where they can remain for very long periods of time and alter the radiative balance and typical chemical reactions that occur there. Finally, specific research gaps and needs related to plume dynamics, atmospheric transport and deposition processes, and the atmospheric chemistry of wildland fire emissions are identified and discussed. Published by Elsevier B.V.