The relations between variation in edaphic factors and microdistribution of winter annuals

The variations in edaphic factors associated with the small scale pattern of distribution of some winter annuals in the coastal dunes near Oostvoorne have been studied. Analysis of the soil samples showed a wide variation in edaphic factors which may occur over short distances and which indicated an evident relationship between edaphic factors and the micropatterns within pioneer vegetation of dry, sandy soils. Also the microdistribution of winter annuals appeared to be related to these small scale variations in the edaphic factors. The most important factors appeared to be the nutrient status, the lime content and the shading of the soils. However, other factors, still unknown, must play an important role in controlling the microdistribution of the annuals considered.