Small‐scale heterogeneity in the soil environment influences the distribution of lawn grass and weeds
2010
Tanaka, Satoru | MIURA, REIICHI | TOMINAGA, TOHRU
The association of the micro‐scale distribution of six plant species in a lawn, including the lawn grass, Zoysia japonica, with the soil's environmental factors was studied in an urban park in Kyoto, Japan. The cover of each plant species was scored in July and August. The relative elevation, depth of waterlogging after a shower, soil water content, and soil hardness were measured in 144 quadrats in a 12 m × 12 m plot. The subsurface soil was sampled at every fourth quadrat and was analyzed for the percentage of fine earth and the levels of total carbon, total nitrogen, and available phosphate. Three correlation criteria, namely the Pearson's, Mantel, and partial Mantel correlations, showed considerable disagreement in indicating whether or not there was a significant correlation between each plant species and environmental variable. Although the reason for the disagreement was not always clear, some unimodal or inverted unimodal responses of a plant species against an environmental factor, which was not detectable by the Pearson's correlation coefficient, were indicated to be significant by the Mantel or partial Mantel tests. There were four plant-environment pairs that had a significant correlation in all three criteria: Juncus tenuis in August had a positive correlation with the soil water content in July and August and a negative correlation with soil hardness and Z. japonica showed a negative correlation with the water content in August. The results suggest that the small patches of lawn with poor drainage are the sites of invasion by J. tenuis.
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