How would the Garden Route National Park (GRNP) indigenous forest function without fungi?
Many people think of fungi as small organisms that kill trees and grasses, rot bread and toenails or maybe just as weird things that grow on lawns and taste good on pizza. Although most of these statements may be acceptable, it should be noted that fungi also play a major role in the functioning of forest ecosystems.
Currently, a research project conducted by Michel Tchotet (PhD student at the Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria) with the assistance of SANParks Scientific Services aims to determine the diversity of macro-fungi in compartments of the GRNP forests where timber has recently been harvested.
Wood-rot fungi are essential components for the equilibrium of terrestrial forest ecosystems. While some are pathogenic (capable of causing disease) to living trees, the large majority are secondary invaders that feed on dead or dying plant material.
Pathogenic wood-rotting fungi can attack and kill a wide range of forest trees including small and mature ones, resulting in a drastic shift in the structure and composition of forests. These fungi infect trees through wounds and/or broken branches or via root systems. Spores that settle on these openings are produced on specialized structures known as fruiting bodies and are either transported by air currents or by some wood-boring insects. Spores germinate into mycelium, which colonizes the tree and eventually may result in the formation of new fruiting bodies. By the time a fruiting body is visible, the host tree is in an advanced state of decay and is a potential hazard.
Leftovers of trees weakened or killed by primary wood-rot fungi are easily colonized by the secondary invaders, which digest their main cell wall components and carbohydrates and convert them into nutrients, which are redistributed in the soil. Forest trees softened and decayed by these fungi are also used as habitat by many animals, cavity nesting birds and other fungi. Ultimately, although being able to parasitize and kill living trees, wood-rot fungi also contribute efficiently to the maintenance of forest health.
Written by Diba Rikhotso (SANParks biotechnician) for the SANParks Times: www.sanparkstimes.co.za)