Effect of conspecific adult plants on the spatial patterns of the soil seed bank of Calligonum rubicundum

Deterministic functions that aim at quantifying and modelling the spatial effects of shrubs on the soil seed bank of a Calligonum rubicundum stand are described. The procedure utilises data on the spatial location of 99 individual C. rubicundum plants and the number of seeds of this species in the soil at 169 grid-nodes. We developed a regression equation that quantified the effects of shrub size, shrub height and prevailing wind direction on seed dispersal. The deterministic models revealed a good fit between the measured and simulated data using parameters estimated from the data set of soil seed bank values. The results presented in this paper provide a way to examine, quantify and model the spatial effects of shrubs on soil seed banks at the stand level. The method presented here can be applied to examine and estimate the influence of dominant plants on other biotic or abiotic properties of an ecosystem.