Spatial Linkages Between Plant Diversity And Soil Properties In Meadow Steppe, Northern China

Linkages between plant diversity and soil properties are related to ecological processes of feedback between aboveground and belowground subsystems. Such interactions may have an important participation as underlying mechanisms associated with species diversity and species coexistence and revealed in terms of spatial structure. A rapidly inclusion of spatial structure in ecological thinking has been seen as a very important issue and an increasing number of studies have focused on the effects of grazing on spatial heterogeneity of plants and soils. However, there is a lack of information concerning interactions between soil resources and plant diversity in a spatial context. We investigated the magnitude and correlation of spatial heterogeneity between plant diversity and soil properties, providing insights about underlying ecological processes and their spatial structure.Measurements of plant diversity, nitrogen, carbon, pH and electrical conductivity (EC) were followed by comparisons of their spatial structure in twelve 50 x 50m plots of a natural meadow steppe area. Each plot was randomly surveyed using 30 lm x lm sampling units. Heterogeneous and homogeneous plots were defined according to the degree of dissimilarity of plant diversity in each sampling point. We found higher percentage of nitrogen and higher values of EC in homogenous plots and heterogeneous plots, respectively. Closer positive spatial correspondence was found when plant diversity was compared with carbon and nitrogen spatial distribution among heterogeneous plots. Among homogeneous plots, pH and carbon values had higher negative correspondence. Negative spatial correlation was found when diversity index of plants was compared to spatial autocorrelation index of EC, carbon and nitrogen in each plot.Results from spatial heterogeneity plots suggested a differentiate use of soil nitrogen in space and also a distinct microenvironment around plant roots, particularly in relation to EC. The identity of each point in space, which may be described in terms of plant composition, exerted influence on soil properties even when the overall spatial structure was similar. We may suggest a possible greater use of nitrogen by means of niche specialization processes. Adaptations of plant species in meadow steppe for soil nutrient access, coexistence and diversity might reflect underlying ecological processes in space which ultimately leads to survival by means of generation and maintenance of spatial heterogeneity.