When one invasive species promotes the establishment of other invasive species it's called an invasional meltdown. Forest Service scientists observed that soils underlying the invasive plant, Chinese privet, had much higher numbers of non-native invasive earthworms than soils where the plant was not yet established. The scientists conducted an experiment to see what would happen if the Chinese privet was removed, using two different techniques: simply cutting the privet with power saws, or grinding the privet into mulch and leaving the mulch on the soil surface. Five years after the removal of the plant, they found lower numbers of the most abundant non-native earthworm species. Perhaps more importantly, removal of privet appeared to promote the recovery of one North American native earthworm species. When Chinese privet was removed, the level of acidity in soils increased nearly to levels of soils where privet had not yet invaded (soils in the floodplains of southeastern rivers are naturally highly acidic), and the scientists think that these changes in acidity are large enough to be a disadvantage to the invasive species and favorable for the native species. They conclude that the removal of one invasive species can result in the control of another, and thus short-circuits the invasional meltdown that the expansion of Chinese privet causes.