Potential climatic control of seedbank density

The relationship between Calluna vulgaris seedbank density and climate was investigated using regression analysis and two related techniques (factor-c eiling analysis). The seedbank data originated from published and unpublish ed studies. Low seedbank densities were associated with sites in the relati vely dry, sunny and warm south and east of Great Britain. However, as the c limatic variables used in the study were highly intercorrelated, it was not possible to determine which climatic variable had the greatest influence o n seedbank density. A hypothesis is described suggesting that the limits of seedbank density can be described for single environmental factors. The op eration of other environmental and management factors may reduce the seedba nk density to less than this maximum. This is illustrated for a range of cl imatic variables using factor-ceiling analysis. The processes following see d deposition and the longevity of seeds in the soil are highlighted as poss ible factors controlled by climate which determine seedbank density.