RESOURCE-ALLOCATION PATTERNS AS A FUNCTION OF CLONAL MORPHOLOGY - A GENERAL-MODEL APPLIED TO A FORAGING CLONAL PLANT

(1) A general model is presented that relates resource investment in clonal plants, in terms of allocation to spacers (rhizomes, stolons), to clonal morphology in terms of spacer length and branching intensity (i.e. the number of spacers produced per ramet). Based on the branching pattern and biomass accumulation of spacers and ramets (i.e. roots and shoots) of a hypothetical clonal plant, equations were derived that relate spacer mass S to ramet mass R. For sufficiently large R, this allocation function was linear. (2) The morphological parameters of the model were modified as a function of patch quality (resource availability). In accordance with characteristic responses of foraging clonal plants, spacer length was decreased and branching intensity increased with increasing patch quality. The model was used to predict the consequences of this behaviour for resource allocation to spacers. (3) Simulations show that resource allocation to spacers (in terms of slope alpha of the allocation function) will be low both at extremely low and at extremely high levels of patch quality, but higher at intermediate qualities. This bell-shaped pattern appeared to be a direct result of the opposite responses of branching intensity and spacer length to patch quality. (4) These results suggest that foraging behaviour in clonal plants produces much more complicated patterns of resource investment than foraging in animals. The significance of the allocation model in a foraging theory of clonal plants is discussed.