Variation in soil chemical properties in relation to vegetation characteristics in a serpentine area of Hokkaido, Japan

Abstract

Serpentine soils typically have chemical characteristics that can create adverse conditions for plant growth (e.g., low plant nutrients, low Ca/Mg ratio, and high heavy metal concentrations). Many studies have reported the unique characteristics of soils and plant communities (including endemic plants) in serpentine areas, especially on outcrop landscapes. However, little is known about variation in soil conditions within the geographical range of serpentine areas, such as from outcrops to adjacent grasslands and forests. The objective of this study was to assess the variation in soil chemistry among vegetation types in a serpentine soil area. We measured the chemical properties of soils for four vegetation types: outcrop, grassland, forest-edge, and mid-forest, in a serpentine area of Hokkaido, Japan. The results showed wide variation in the chemical properties of soil among vegetation types. In particular, outcrop and grassland sites showed extremely low Ca/Mg ratios and had higher Ni concentrations than those for the two forest sites. In addition, these differences in soil chemistry were strongly related to soil carbon content. These results suggest that forest litter alters the soil chemistry in serpentine areas, via soil development associated with organic matter accumulation, to conditions that are more conducive to a broader range of plants.