|Biodiversity at risk: soil microflora|
Chanway, CP. (1993). Biodiversity at risk: soil microflora, in: Fenger, M.A. et al. (Ed.) Our living legacy: Proceedings of a Symposium on Biological Diversity. pp. 229-238
In: Fenger, M.A. et al. (Ed.) (1993). Our living legacy: Proceedings of a Symposium on Biological Diversity. The Royal British Columbia Museum: Victoria. ISBN 0-7718-9355-8. XIII, 392 pp., more
The soil micro flora comprises thousands of fungal and bacterial species that are integral components of all terrestrial ecosystems. Many of these are soil dwelling saprophytic fungi that reach population sizes of up to one million spores and hyphal fragments per gram of soil. Soil bacteria live in close association with saprophytic fungi, often performing tasks that are similar or complementary to those performed by fungi. Up to 80% of bacterial species in natural communities have not been described. A single gram of soil may contain billions of bacterial cells. Together, bacteria and fungi in the top 20 cm of fertile soil may reach five tonnes per hectare. It is no wonder that these organisms exert a major influence on the soil, mainly by facilitating decomposition of organic matter and by influencing soil structure. Mutualistic soil fungi and bacteria are a particularly important part of the soil micro flora. Their importance to ecosystem functioning is underscored by the fact that most plant species, including all conifers growing in the wild, are mycorrhizal. Nitrogen-fixing species provide a critical link in the successional processes that are characteristic of our forests. In addition, several species of mutualistic bacteria may proliferate around, on, or more rarely, in root or mycorrhizal tissue without forming any special root structure. These can fix nitrogen, stimulate tree growth or suppress pathogen populations through their activity. Certain plant species appear to be able to form stable associations above ground due to their common ability to associate with similar plant-beneficial micro-organisms below ground. Therefore, the role of below-ground diversity in the microbial community may be central to establishing and maintaining healthy and resilient forests. At present, we know little about the ecology of soil micro-organisms and critical gaps exist in our knowledge. Examples of plantation failure caused by the apparent loss of important soil micr0-0rganisms after harvesting demonstrate the danger of our ignorance.