The association of land cover with aeolian sediment production at Jornada Basin, New Mexico, USA.
We investigated amounts and particle size distributions (PSDs) of aeolian sediments collected at ﬁve heights in ﬁve ecosystem types at the Jornada Basin, Chihuahuan Desert, New Mexico, USA. Particle size distributions, mass ﬂuxes, and percent of dust-sized (650 lm) mass ﬂux were determined for all heights and all ecosystem types. Differences between sites were determined using ANOVA followed by Tukey– Kramer post hoc tests to ﬁnd groupings. For creosote shrublands, grasslands, and two tarbush-dominated alluvial ﬂats, samples collected at 5, 10, and 20 cm had >80% sand-sized (>50 lm) particles, while one playa and tarbush site yielded 45% dust-sized particles at 5 and 10 cm. The transition from saltation to suspension was 20 cm for most sites. Two mesquite dune sites and an anthropogenically devegetated site, all with high overall mass ﬂuxes, shifted to suspension at 50 cm. Highest dust ﬂuxes occurred at the devegetated site, followed by the playa, a mesquite site with unvegetated ‘‘streets,’’ and tarbush sites. These ﬁeld observations are consistent with laboratory-based dust emission experiments and remote sensing studies in the Chihuahuan Desert. Playas and tarbush sites are major dust producers due to high proportions of ﬁnes, whereas the mesquite site produces much dust because of greater overall mass ﬂux. Mesquite dunes covering most of the basin likely produce the most dust overall, though playas and tar- bush-dominated alluvial ﬂats (which cover about 8%) can emit large amounts of dust. Continuing shrub- land encroachment will likely increase dust emissions from the Jornada Basin, as well as in other arid regions.