SAPROTROPHIC CORD-FORMING FUNGI - WARFARE STRATEGIES AND OTHER ECOLOGICAL ASPECTS

A number of saprotrophic fungi, particularly wood-decaying basidiomycetes, form mycelial cords, which are aggregations of predominantly parallel, longitudinally aligned hyphae. These linear organs often form extensive, long-lived systems which connect between discrete nutrient resources on the floor of temperate and tropical forests, and can form nets in tropical canopies. They are a very successful group of decomposers which exhibit many strategies analogous to those adopted in warfare, including: securing territory by aggressive/combative action; economic and efficient discovery of potential resources; establishing lines of communication; economic and efficient deployment of resources; and adoption of different strategies according to the home economic situation. Thus, nutrients are sequestered by foraging mycelial fronts and translocated to different parts of the mycelial system. On encountering new resources mycelial biomass and nutrients may be reallocated depending on a number of factors including: the relative size of inoculum base and new resources, state of decay of resources, whether the new resource is already colonized, the relative positioning of one new resource compared with another, and the fungal species involved. Cord-forming saprotrophic fungi probably play a major role in ecosystems, since they are major wood decomposers and can translocate large quantities of essential nutrients over several metres. They may, however, immobilize nutrients for considerable periods, perhaps months or longer, but by so doing may act as a buffer against nutrient loss from the system. The ease with which they can be inoculated into the forest floor could possibly be used as a management tool by virtue of their antagonism to tree root pathogens and their abilities as agents of nutrient cycling and translocation.