Arbuscular mycorrhiza of endangered plant species: Potential impacts on restoration strategies

Abstract

A site-specific flora and fauna characterize natural habitats. However, the plant diversity in ecosystems rapidly decreases more than often due to anthropogenic activities. The destruction of habitats leads to a decrease in ecosystem diversity, plant diversity and, in worst cases, to the extinction of plant species (Tilman et al. 1994). About 3% of the described plant species of the world are considered to be threatened, although according to some estimation this value may reach a maximum of 70%. In any case, over the years the number of plant species belonging to different categories of threat (critical, endangered, and vulnerable) is rising continually (IUCN 2006). In nature symbiotic associations between plant roots and mycorrhizal fungi appear to be the norm (Smith and Read 2008). Numerous experiments have shown the positive influence of arbuscular mycorrhizal fungi (AMF) on plant fitness by enhancing the uptake of essential nutrients, the resistance against root pathogens, and the tolerance of environmental stress like drought and heavy metals. The stability and diversity of plant communities have been shown to be influenced by the microbial community in soil including mycorrhizal fungi, and vice versa plant communities affect arbuscular mycorrhizal fungi. These interactions underline the importance of a functioning soil micro-flora including mycorrhizal fungi for a well functioning ecosystem and therefore indicate the potential significance of fungal symbionts of plants for restoration practices (Haselwandter 1997), especially as there seems to be a defined relationship between single types of AMF and their plant hosts (van der Heijden 1998a).