Arbuscular endomycorrhizas are dominant in the organic soil of a neotropical montane cloud forest

Abstract

The ecology and forest management of tropical montane cloud forests of the Neotropics have attracted little scientific attention so far, and understanding of the ecosystem is still fragmentary (Churchill et al. 1995). The montane forests of southern Ecuador are an outstanding biodiversity hotspot for vascular plants (Barthlott et al. 1996), including a multitude of tree species (Madsen & Øllgard 1994). However, identification of species, studies of phenology, productivity, seed production and growth of seedlings have only just begun (Homeier & Breckle 2002). None of the trees has been investigated with respect to their mycorrhizal status, although it is well established that mycorrhizal symbioses are not only important for survival of trees in nutrient-poor habitats (Read 1991) and play a key role for nutrient cycling and nutrient retention in the humus layers (Medina & Cuevas 1993, Rilling et al. 2001), but also have an important impact on the composition of plant communities (Allen et al. 1995, Kottke 2002, van der Heijden et al. 1998).