Fungi and cryptogams get little attention

Much publicity is given towards tigers, otters, eagles and other animals at risk of extinction; unfortunately, fungi and other cryptogams tend to get little attention. For the past 20 or 30 years the number of, diversity and range of fungi have decreased greatly. What impact will this have on ecosystems? And what is causing these losses?

With maybe upto 40% of fungi species in Europe at risk of extinction, over 130 genera are listed in various European Red Lists, plans need to be put into place to prevent further declines. Loss of many of these genera could have permanent negative effects on many types of ecosystems. Fungi plays major roles in the environment which would be difficult to replicate:

Ecologically, fungi are major decomposers of organic material and play an important role in the cycling of nutrients. Mycorhizal fungi act as a widespread network in woods, reabsorbing and delivering water, metal ions and inorganic acids. They have also been shown to transport leaf-produced soluble carbohydrates between different tree individuals. Fungi are useful bioindicators; allowing us to be made aware of the impacts of air pollution on forests at an early stage. Grassland fungi diversity also helps us to find out approximate ages and health of undisturbed grasslands. The fruiting bodies of fungi are an essential source of food for many insects and mammals.

· Economically, fungi are important in agriculture. Ectomycorrhizal fungi (fungi found around the root zone of plants) are essential in commercial forestry and afforestation programmes. Fungi are also used to help combat pests and plant diseases such as root rot control by Phlebiopsis gigantea. Introduced shrubs can sometimes be best controlled by fungi (e.g. Chondrostereum purpureum and Prunus serotina).

· Recreationally, people enjoy picking and eating mushrooms and also fungi are important in offering diversity within a habitat, which can please many people.

 

When the drop in fungi was first noticed it was thought that the picking of fungi was causing much of the loss. Many people called for the picking of mushrooms to be banned or at least severely restricted, but many studies has shown that picking of mushrooms have limited impact on long term survival of species. Eef Arnolds in 1988 published results of a 7 year project where he removed all fruiting bodies at fortnightly intervals from permanent plots during the fruiting seasons. After 7 years, he found no impact of the picking on numbers of fungi fruitbodies. A larger study by Elisabeth Jansen on the reduction in chanterelle numbers in the Netherlands found that numbers of fungi began to drop at the end of the fifties and accelerated during the sixties. The drop in numbers occurred whether the land was accessible to the public or not. This indicated that picking had little to do with the general widespread reduction in chanterelles.

So what is causing these losses? The Jansen study also discovered that soil and vegetation cover at the sites also changed. It appeared that the habitats were becoming more acid. Lichens (indicating oligotrophic soils) were also disappearing and Vaccinium myrtillus and Deschampia flexuosa cover increased (both indicators of acid soils). Organic matter also increased from around 10% to 23% content. The main reasons for these changes were put at being natural succession and also atmospheric pollution causing increased soil acidity and eutrophication.

Studies on the reduction in fungi have shown some worrying trends. The species least effected by these changes are the wood decaying fungi. And in some instances these numbers are increasing. The types of fungi most affected by these changes are the mycorrhiza-forming fungi, those with most ecological and economic impacts. In Saarland, almost 55% of these root symbiotic species are endangered (compared with 20% wood decomposing). Other threats are placing fungi at risk. Habitat destruction has as much effect on fungi as any other species. Those habitats most at risk are wetlands and oligotrophic (poor in nutrients) forest, grasslands, heaths and dunes. Modern forestry and parkland management also plays its role. No longer are old trees left to die naturally and left in place when they fall. Most commercial trees are cut down early in life. In parks when trees become old they are removed for aesthetic or safety reason, fungi rarely get a look in. There's little room for unfertilised permanent meadows in modern agriculture.

Another possible cause for loss of fungi is the 'Global Warming'. Studies have shown that fruiting bodies are greatly reduced when autumns are dry and warm. During the long warm autumns of 1959 and 1961 in Germany, fruiting bodies of Boletales were reduced by over 90%. Examining the pattern of decrease of chanterelles and other species in the Netherlands, we see that the decline first happened in the south of the country and then the decline spread northwards. This pattern is what may be expected of a consequence of increased warming.

A plan to protect the diversity of fungi will need to be wide-ranging. Setting up of reserves and management of established nature reserves is an obvious step, however this type of action will not prevent the major cause of loss. Air pollution, particularly the nitrogen emissions, will not evade nature reserves and this threat can only be dealt with at source. Large-scale commercial mushroom picking in natural areas need to be controlled, however there is no reason why mushroom picking should be banned altogether. In fact mushroom pickers are very positive about ensuring the conservation of species and are important as pressure groups in some regions to ensure action.

It is regretful that the study of fungi has received so little attention and as such many species may be gone before their role in the ecosystem can be fully understood. While it is easy to store spores to ensure the survival of fungal species, it is preferable to have these species in nature rather than in laboratories.