Implications of disturbance and drought on aeolian processes in the southwestern US

Background/Question/Methods

During past millennia, dust has been an important source of fertility for soils in dryland regions, adding plant-essential nutrients and water-holding capacity to infertile and coarse-textured soils. The enhanced fertility, in turn, has helped shape plant distribution patterns, including patterns of weed invasion.
Results/Conclusions

In recent years, the input of far-traveled dust into dryland regions has remained fairly constant and low. However, disruption of physical and biological soil crusts by off-road vehicles and livestock has accelerated dust production. Dust production has also increased in ecosystems dominated by invasive annual grasses in dry years when the plants do not germinate or following wet years when accumulated fuels carry fire. The interaction of drought, invasive-dominated ecosystems, and surface disturbance can create a large increase in dust production Increased dust production can have many negative impacts on humans and ecosystems. Increased particulates in the air threaten human health both through disease (e.g., Valley Fever, asthma) and highway accidents. National economies have been shut down for days, as in China, Japan, and Iceland. Where dust losses are greater than the inputs, the source areas lose soil carbon, nitrogen, phosphorus, and other nutrients. Many of these aerosols are transferred to high elevation regions, where deposition of dust fertilizes lakes, likely impacting ecosystem function. Deposition of dust on mountain snowpack darkens the surface, increasing snowmelt by 30 days or more. As temperatures, pumping of shallow aquifers, human activities, and invasion of exotic annual plants increase in dryland regions, dust production can be expected to increase as well, and we will discuss possible future scenarios.