SUBJECT: RE: Biodiversity conservation and knowledge synthesis
AUTHOR: Alan Feest
DATE: 2nd April 2003

KEYWORDS: Biodiversity assessment, taxonomic groups, macrofungi, biodiversity quality.

SUMMARY: The need for a unified approach to the estimation of biodiversity is discussed in response to the issues raised by Jari Niemela.

A very good way to stop a discussion about biodiversity is to ask each person how they would define biodiversity. The conversation then continues on this latter track for some time without reaching a consensus!

Jari Niemela gives some indication of this complexity by inferring that biodiversity has structural, compositional and functional aspects i.e. it is more than a list of species. In my own research I have taken this approach and now describe the biodiversity of a taxonomic group in the following way:
- The number of species in a unit area (Species Richness)
- The evenness or dominance of the species present (Shannon-Wiener, Simpson and Berger-Parker Indices)
- The density of individuals present (number per square metre)
- The relative rarity of the species present (a calculated Species Value Index)
- The biomass of the taxonomic group present (calculated from standard reference to the size of a typical individual)

Not all of these indices can be calculated for all taxonomic groups thus biomass is not calculated when working on Bryophytes but can be for Arachnids and macrofungi. By measuring these different biodiversity qualities, an overall biodiversity quality picture is derived for a particular taxonomic group and thus by adding together the various taxonomic groups, a more complete picture for site comparison is derived. This approach is necessary for several reasons not least the need to present decision makers with concise standardised information that can form the background for objective decisions.

To be more practical, the following is an actual case:
In surveying two adjacent woodlands for macrofungi we found that the modern (30 years old) coniferous forestry was far superior in all of the above indices than the ancient oak woodland (there are reasons but these need not be discussed here). This has meant that the management plan to remove the coniferous woodland and replant with oaks had to be revisited as this would remove the best macrofungal biodiversity of the site. A compromise was instigated that included leaving substantial quantities of harvested coniferous woodland on site to rot to be followed by a management plan designed to rectify the macrofungal poverty of the oak woodland.

In response to Tor-Bjorn Larsson I would therefore say that only by measuring the biodiversity qualities of as many taxonomic groups as we can will we approach a knowledge of the biodiversity quality of a site and compare it with others. This will allow us to make decisions and plans that conserve as much of the totality of biodiversity as possible.

What is now needed is the input to allow this sort of data to be collected across Europe (in the first palce) so that an idea of the real biodiversity hotspots can be identified before it is too late.

A contribution by:

Alan Feest
Bristol University
Faculty of Engineering