Biodiversity of fungi: How to conserve these myriad eukaryotic life forms for posterity?

Debananda S Ningthoujam *

Prelude

What are the life forms most intimately associated with the hoary past of human civilization, organisms which are the agents for bread- and wine-making etc? They are also the life forms from which we get drugs and several other products for human welfare. Though they look like plants and are immobile like them, biochemically they seem closer to animals.

Unlike plants, they cannot photosynthesize. So they have to live either as saprophytes or as parasites. Though some of them can be pathogenic, most are beneficial for humans, animals and plants.

Who are they? We are talking about fungi, eukaryotic organisms which can be unicellular or multicellular. The total number of fungal species is estimated to be around 1.5 million, whereas the number so far described is just about 1, 00,000 only.

What are fungi?

Fungi are a large group of eukaryotic organisms that includes unicellular yeasts, multicellular molds and mildews and the more familiar mushrooms, toadstools and puffballs. They make a kingdom separate from plants, animals, protists and bacteria.

Fungal habitats

Fungi thrive in just about any habitat, from seas to freshwater, air, soils, plants, animals, human skin and even on CD-ROMs. The major habitats of fungi are:

• Soil
• Live and dead plants
• Burnt and disturbed grounds
• Decaying leaves
• Meadows
• Dung
• Homes
• Air
• Animal and human bodies

Fungal nutrition

Unlike green plants, fungi cannot manufacture their own food by photosynthesis. So they need to absorb their nutrients from the surroundings. Many are saprophytes, which mean they get their food from decaying organic matter. Other fungi thrive as human or animal parasites or as endophytes inside plants.

Threats to fungal diversity

Most of the major threats to plant diversity also apply to the biodiversity of fungi. The major threats are:

• Habitat loss
• Habitat degradation
• Introduced alien species(IAS)
• Pollution
• Disease
• Climate change
• Forest fires
• Logging
• Tourism
• Others

Logging and deforestation are the greatest causes of erosion of plant diversity including that of fungal diversity and the culprits are none other than we human beings. Climate change is an added threat in recent times. Natural disasters and natural forest wild-fires worsen the fast decline in plant (including fungal) diversity.

Why conserve fungi?

Why should we bother to save fungi? Can't we keep them in the botanical gardens or other artificial habitats? There are several reasons for conserving fern biodiversity. Arguments for saving fern diversity are many. There are several economic values for fungi. Some of them are:

• Medicinal: many fungi produce drugs and other compounds used for human and veterinary medicine. For example, the antibiotic penicillin is obtained from Penicillium chrysogenum, immunosuppressive agent, cyclosporine from Tolypocladium nivenum, antifungal e'g griseofulvin from Penicillium fulvum, antihypertensive lovastatin from M. ruber and A terreus etc, anticancer drug taxol from Taxomyces spp and eastern herbal medicines from Cordyceps sinensis etc
• Recycling: many fungi recycle plant debris and other organic matter
• Mycorrizha: Many fungi form beneficial associations with plant roots known as mycorrizhae
• Biocontrol: Fungi such as Trichoderma spp. are excellent biocontrol agents against plant pets and fungal pathogens
• Food: Mushrooms and many other edible fungi are nutritious food sources for humans
• Food production: Many fungi are involved in food and beverage production
• Industrial enzymes: Many fungi are good sources of industrial enzymes such as proteases, amylases, pectinases etc.

In addition, fungi are models for basic research on eukaryotic systems and also for study of mechanisms for human, animal and plant pathogenesis.

How to conserve fungal diversity?

Some of the short-term and long-term programs for fern biodiversity conservation may include:

• ex-situ conservation
• in-situ conservation
• sustainable consumption
• Taking pro-active steps to control climate change

Ex-situ conservation of fungi means conserving fungi away from the natural settings, for example, in botanical gardens, home gardens, germplasm banks etc.
In-situ conservation refers to saving fungal species in their natural locations. This means creation of wildlife parks, reserved forests, biosphere reserves, eco-parks etc.
Cultural symbols such as sacred groves may yet be another way of in-situ conservation of fungal biodiversity.

Coda

A rough estimate in 2010 by IUCN is that 100% of lichens and mushroom species that were evaluated are threatened with extinction. Many fungal species may yet remain to be discovered. But the tragedy is that many may go extinct before they are found out.

The health of plants including ferns and fungi is intimately linked with human well-being. If fungi are taken away from the Earth's ecosystems, it would jeopardize the long-term survival of animals, plants and even humans on our planet. We need to protect these ancient life forms. Long live the benevolent fungi!

---

* Debananda S Ningthoujam wrote the article for Huieyen Lanpao (English Edition)
The author teaches biochemistry in Manipur University and researches on biodiversity and biotechnology areas esp. microbial biodiversity and biotechnology. He also writes popular science articles on scientific biography and science, environment & biodiversity issues.
This article was webcasted on September 21 2010.

---