Fungi have higher C : N ratios than
bacteria (Fig. 1; Sterner & Elser, 2002). Consequently,
stoichiometric imbalances between senescent leaf litter
(high C : N and C : P ratios) and the nutritional
requirements for fungal growth are lower than those
for bacteria. In contrast, bacteria in general are the most
nutrient-rich of all organisms, perhaps because of their
high specific growth rates and consequent high RNA
content. It seems possible that the high C : N and C : P
ratios of freshly fallen leaf litter is a constraint to
bacterial colonisation; a constraint that may eventually
be relaxed by nutrient immobilisation and selective
assimilation and respiratory losses of carbon by fungi