Hutchinson, G. E. Homage to Santa Rosalia, or: Why are there so many kinds of animals? Am. Nat. 93, 145 (1959). Billick, I. & Case, T. J. Higher order interactions in ecological communities: what are they and how can they be detected? Ecology 75, 1529–1543 (1994). Baldrian, P. et al. Production of extracellular enzymes and degradation of biopolymers by saprotrophic microfungi from the upper layers of forest soil . Plant Soil 338, 111–125 (2010). Evans, J. A., Eyre, C. A., Rogers, H. J., Boddy, L. & Müller, C. T.