Chapter 13 : Fungal Ecology: Principles and Mechanisms of Colonization and Competition by Saprotrophic Fungi

How R-C-S characteristics relate to r-K strategies.

Foraging strategies of cord-forming basidiomycetes growing out of precolonized beech wood blocks across compacted soil. (A) Hypholoma fasciculare, a short-range forager, produces highly dense hyphae and mycelia. (B) Phanerochaete velutina is a longer-range forager with a more open cord system. (C) Resinicium bicolor has an even more open system than P. velutina, with thicker cords.

Sectioned beech trunk showing decay columns running longitudinally through the wood. Arrows indicate dark zone lines (pseudosclerotial plates) surrounding different decay columns.

Fungal community development pathways in woody resources. Newly available wood (top) becomes progressively colonized, initially through primary resource capture in an open community stage where there is still unoccupied territory, until all territory becomes occupied, resulting in a closed community where further colonization occurs as secondary resource capture. As the community moves from open to closed, combat becomes the driving force for change. Finally, communities in well-decayed wood are characterized by substrate modification and invasion by soil invertebrates. The ecological characteristics of the dominant organisms are indicated in boxes: R, ruderal; C, combative; S, stress-tolerant. Driving forces are indicated in italic, and direction of community change is indicated by arrows. The community may be driven toward the left by stress aggravation or to the right by stress alleviation, although destructive disturbance will drive the community toward species with R-selected characteristics. (Adapted from references 5 and 58 .)

Interspecific interactions of fungi growing in natural and artificial media. (A) Cross section of a decaying beech branch with dark zone lines (pseudosclerotial plates) surrounding competing mycelia. (B, C) Growth of Trametes versicolor when exposed to the diffusible organic compounds (DOCs) from uncolonized malt broth (control) (B) or DOCs from Fomes fomentarius (C). (D, E) Phallus impudicus cord systems growing across compacted soil when exposed to volatile organic compounds (VOCs) from uncolonized soil (control) (D) or VOCs from Hypholoma fasciculare growing across soil (E). (F) Interaction between H. fasciculare and Resinicium bicolor cord systems across compacted soil. (G) Accumulation of reactive oxygen species (ROS) at the interaction zone between Bjerkandera adusta (left) and T. versicolor (left) on 2% malt agar (MA). ROS are stained purple using nitro blue tetrazolium (methods in reference 92 ). (H) Three-way interaction between mycelia of H. fasciculare (left), P. velutina (center), and Stereum hirsutum (right) growing on 2% malt agar (MA). H. fasciculare cords are beginning to encroach over the P. velutina mycelium, while H. fasciculare itself is overgrown by P. velutina cords. A thick barrage separates the mycelia of S. hirsutum and P. velutina, with a distinct orange/yellow band of pigment deposited in the agar at the regions of contact between the two mycelia.