Wind erosion and associated dust emissions play a fundamental role in many ecological processes and provide important biogeochemical connectivity at scales ranging from individual plants up to the entire globe. Yet, most ecological studies do not explicitly consider dust‐driven processes, perhaps because most relevant research on aeolian (wind‐driven) processes has been presented in a geosciences rather than an ecological context. To bridge this disciplinary gap, we provide a general overview of the ecological importance of dust, examine complex interactions between wind erosion and ecosystem dynamics from the scale of plants and surrounding space to regional and global scales, and highlight specific examples of how disturbance affects these interactions and their consequences. It is likely that changes in climate and intensification of land use will lead to increased dust production from many drylands. To address these issues, environmental scientists, land managers, and policy makers need to consider wind erosion and dust emissions more explicitly in resource management decisions.

[1] Aeolian processes affect the biosphere in a wide variety of contexts, including landform evolution, biogeochemical cycles, regional climate, human health, and desertification. Collectively, research on aeolian processes and the biosphere is developing rapidly in many diverse and specialized areas, but integration of these recent advances is needed to better address management issues and to set future research priorities. Here we review recent literature on aeolian processes and their interactions with the biosphere, focusing on (1) geography of dust emissions, (2) impacts, interactions, and feedbacks, (3) drivers of dust emissions, and (4) methodological approaches. Geographically, dust emissions are highly spatially variable but also provide connectivity at global scales between sources and effects, with "hot spots" being of particular concern. Recent research reveals that aeolian processes have impacts, interactions, and feedbacks at a variety of scales, including large-scale dust transport and global biogeochemical cycles, climate mediated interactions between atmospheric dust and ecosystems, impacts on human health, impacts on agriculture, and interactions between aeolian processes and dryland vegetation. Aeolian dust emissions are driven largely by, in addition to climate, a combination of soil properties, soil moisture, vegetation and roughness, biological and physical crusts, and disturbances. Aeolian research methods span laboratory and field techniques, modeling, and remote sensing. Together these integrated perspectives on aeolian processes and the biosphere provide insights into management options and aid in identifying research priorities, both of which are increasingly important given that global climate models predict an increase in aridity in many dryland systems of the world.

Soil erosion is an important process in dryland ecosystems, yet measurements and comparisons of wind and water erosion within and among such ecosystems are lacking. Here we compare wind erosion and transport field measurements with water erosion and transport from rainfall-simulation for three different semi-arid ecosystems: a shrubland near Carlsbad, New Mexico; a grassland near Denver, Colorado; and a forest near Los Alamos, New Mexico. In addition to comparing erosion loss from an area, we propose a framework for comparing horizontal mass transport of wind-and water-driven materials as a metric for local soil redistribution. Median erosion rates from wind for vertical mass flux measurements (g m −2 d −1 ) were 1·5 × 10 −2 for the shrubland, 8·3 × 10 −3 for the grassland, and 9·1 × 10 −3 for the forest. Wind-driven transport from horizontal mass flux measurements was greatest in the shrubland (15·0 g m) followed by the grassland (1·5 g m −2 d −1 ) and the forest sites (0·17 g m −2 d −1 ). Annual projections accounting for longer-term site meteorology suggest that wind erosion exceeds water erosion at the shrubland by c. 33 times and by c. five times at the forest, but not the grassland site, where the high clay content of the soils contributed to greater amounts of water erosion: water erosion exceeded wind erosion by about three times. Horizontal transport by wind was greater than that by water for all three systems, overwhelmingly so in the shrubland (factor of c. 2200). Our results, which include some of the only wind erosion measurements to date for semi-arid grasslands and forests, provide a basis for hypothesizing trends in wind and water erosion among ecosystems, highlight the importance of wind erosion and transport in semi-arid ecosystems, and have implications for land surface geomorphology, contaminant transport, and ecosystem biogeochemistry.

Redistribution of soil, nutrients, and contaminants is often driven by wind erosion in semiarid shrublands. Wind erosion depends on wind velocity (particularly during episodic, high-velocity winds) and on vegetation, which is generally sparse and spatially heterogeneous in semiarid ecosystems. Further, the vegetation cover can be rapidly and greatly altered due to disturbances, particularly fire. Few studies, however, have evaluated key temporal and spatial components of wind erosion with respect to (i) erosion rates on the scale of weeks as a function of episodic high-velocity winds, (ii) rates at unburned and burned sites, and (iii) within-site spatial heterogeneity in erosion. Measuring wind erosion in unburned and recently burned Chihuahuan desert shrubland, we found (i) weekly wind erosion was related more to daily peak wind velocities than to daily average velocities as consistent with our findings of a threshold wind velocity at approximately 7 m s(-1); (ii) greater erodibility in burned vs. unburned shrubland as indicated by erosion thresholds, aerodynamic roughness, and nearground soil movement; and (iii) burned shrubland lost soil from intercanopy and especially canopy patches in contrast to unburned shrubland, where soil accumulated in canopy patches. Our results are among the first to quantify post-fire wind erosion and highlight the importance of accounting for finer temporal and spatial variation in shrubland wind erosion. This finer-scale variation relates to semiarid land degradation, and is particularly relevant for predictions of contaminant resuspension and redistribution, both of which historically ignore finer-scale temporal and spatial variation in wind erosion.

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[1] Desertification impacts a large proportion of drylands and can be driven by a variety of climate and land use factors. Most conceptual models of desertification include the underlying assumption that when herbaceous cover is reduced, increased erosion from bare patches is redistributed to shrub canopy patches, resulting in self-reinforcing "islands of fertility." Notably, however, this underlying assumption has not been explicitly tested with direct field measurements. Here we provide direct measurements of horizontal sediment flux moving into and out of bare-, herbaceous-, and shrub-dominated patch types in a semiarid ecosystem for both simulated and natural dust events, as well as in response to simulated disturbance. Horizontal sediment flux out of the bare patches was $20% greater than the herbaceous patches and $50% greater than sediment flux out of the shrub-dominated patches. Differences among vegetation patch types indicate that shrub patches capture more sediment than herbaceous patches and, importantly, that bare patches serve as amplified sediment sources following disturbance. Our results provide explicit support for the pervasive but untested desertification redistribution assumption, highlighting that loss of grass cover is a compounding problem that not only increases dust emissions but also precludes capture, and may have global relevance for coupled human-environmental systems at risk due to current or potential desertification.

Assessments of contaminant-related human and ecological risk require estimation of transport rates, but few data exist on wind-driven transport rates in nonagricultural systems, particularly in response to ecosystem disturbances such as forest wildfire and also relative to water-driven transport. The Cerro Grande wildfire in May of 2000 burned across ponderosa pine (Pinus ponderosa Douglas ex P.&C. Lawson var. scopulorum Englem.) forest within Los Alamos National Laboratory in northern New Mexico, where contaminant transport and associated post-fire inhalation risks are of concern. In response, the objectives of this study were to measure and compare wind-driven horizontal and vertical dust fluxes, metrics of transport related to wind erosion, for 3 yr for sites differentially affected by the Cerro Grande wildfire: unburned, moderately burned (fire mostly confined to ground vegetation), and severely burned (crown fire). Wind-driven dust flux was significantly greater in both types of burned areas relative to unburned areas, by more than one order of magnitude initially and by two to three times 1 yr after the fire. Unexpectedly, the elevated dust fluxes did not decrease during the second and third years in burned areas, apparently because ongoing drought delayed post-fire recovery. Our estimates enable assessment of amplification in contaminantrelated risks following a major type of disturbance-wildfire, which is expected to increase in intensity and frequency due to climate change. More generally, our results highlight the importance of considering wind-as well as water-driven transport and erosion, particularly following disturbance, for ecosystem biogeochemistry in general and human and ecological risk assessment in particular. P ROCESSES driving erosion and transport of soil and associated nutrients and contaminants are of central concern for a diverse set of issues related to ecosystem management and risk assessment. Soil loss and redistribution through erosion can result in significant shortand long-term effects on human and ecosystem health