Effects of Population Density on Revegetation of Artemisia sphaerocephala and Soil Traits in a Desert Ecosystem

Soil desertification is a serious problem in arid northwestern China that threatens ecological sustainability. Artemisia sphaerocephala, a dominant shrub species, play an important role in the conservation of water and the restoration of soil in the desert ecosystem. However, the poor establishment of A. sphaerocephala often limits plant revegetation, and the optimal population density for sustainable growth is largely unknown. Here, we determined key soil properties and plant growth characteristics associated with different population densities of A. sphaerocephala (including from 1.1, 2.1, 3.1, 3.9 to 5.3 plants per m(2)) in the resource-limited Alashan desert of northwestern China. The results showed that plant population density was the primary factor determining the revegetation of A. sphaerocephala, followed by soil water availability. Soil N, P and K content, and soil fractal dimensions also contributed to the vegetation and productivity. Soil nutrients were mostly accumulated in the topsoil layers, coincidental with the root distribution pattern in which 57% to 82% of total roots were distributed in the top 20 cm soil layer. The concentrations of soil nutrients in higher population densities (3.9 to 5.3 plants per m(2)) were greater than those in lower population densities (1.1 to 2.1 plants per m(2)), suggesting that A. sphaerocephala may have the ability to promote nutrient cycling in the desert ecosystem. We conclude that the optimal population density for the best growth of revegetated A. sphaerocephala was 3 plants per m(2).

Automated summary

This study investigated the population density of Artemisia sphaerocephala and its effects on soil properties and plant growth characteristics in the Alashan desert of northwestern China. The results showed that population density was the primary factor determining vegetation growth, with soil water availability, nutrients, and fractal dimensions also playing a role. The optimal population density for A. sphaerocephala was found to be 3 plants per m(2).