Survey and Interpretation of (Particularly Invertebrate) Species Lists

By David M. Green

It's widely stated in conservation circles that interpretation of survey lists, particularly of invertebrates, is beyond the abilities normally available, unless you have about 20 years of practice and a specialist library. This belief cause people to think progress is beyond their own ability and apply the same opinion elsewhere possibly impeding progress further. But now the circumstances are obviously easier there is literature and a database so a that list can usually be interpreted for conservation even by non-specialists, as explained:

  1. There are texts widely available that enable many species to be looked up for their conservation significance and with supporting information such as the JNCC UK Nature Conservation series of reviews that for example review the RDB and scarce categories of many invertebrates, e.g. Coleoptera (beetles), Diptera (true flies) and Hemiptera (bugs).
  2. The database Recorder (JNCC) enables you to find out some basic known biology and habitat of many species, and the updated national conservation categories of RDB1, 2, 3, notable (scarce), nationally local, and regionally local. Recorder presently available is more value as a source of information than perhaps for recording species but a new version is to be available in 2000. By interrogating Recorder it is easy to indicate the conservation (national and regional) significance of a list of species in terms of category. The presence of such species indicates the significance of a site. There are also habitat indicators in Recorder associated with some species. Saproxylic (dead wood) weightings are under development, published, enable you to sum the number for each species, and then divide by the number of species contributing, to gain an overall indicator of site saproxylic importance.
  3. There are texts widely available providing plenty of help on the site management of sites of conservation habitats. Such texts for invertebrate conservation can be used without surveying the invertebrates.

If no conservation species occur in the lists available for a site, you have to ask for what reason. Have the groups that could be special been searched for, or suitable traps been used, properly at the site? If the habitat appears commonplace then conservation species would not be normally expected. If for example the habitat were ancient woodland or unimproved limestone grassland you would reasonably expect some significant conservation species to be living there. But until a place is properly surveyed the whole facts are not known, and invertebrate survey takes a long time. Some species may require particular habitats for idiosyncratic reason. Rare species may not show themselves readily, they might occur at low densities in low numbers in limited places, variable over the years, only visible for limited periods, possibly only revealed by trapping (rarely a threat to species). Rare species especially RDB1 and RDB2, should be known, least they die out unnoticed, and to provide national indication of the national category that might need revision. Possibly a period of adverse weather might finally, in combination with less than ideal habitat, or uncomprehending habitat change, cause termination of a species colony, even a colony that has survived for decades on a site despite other adversity and changes. Climate change, that appears accepted now, might for a species or group cause increased criticality of conditions, even if the species has managed to survive during periods of habitat damage over previous years. Many groups have limited dispersal. Colonies might be isolated by the deterioration of the wider countryside.

If the site has conservation-rated species, or species that are at least localised, then the special habitat is indicated. Specialists, including those who run recording schemes, might provide the latest information on a species. There are many practical texts available that provide information for site management of habitats and invertebrate groups. The significance of a site and the site management required might be deduced from general principles, as a result of viewing the vegetation, to the extent that the invertebrate survey indicates little in the way of site management recommendation. Rare and endangered species have to be revealed so habitat can be considered specifically, at least when knowledge becomes sufficient eventually, and to note the significance of the site. Records make the categories nationally and regionally accurate, provide better information on habitat, and information on those species that are presently unknown in distribution, whether nationally and locally. There is more to the survey of invertebrates than functional site management and determination of site importance. National advance and local advance to be made on conservation of species by local survey, and in taxonomy as species remain unknown to science.

If a species is unknown to the area, there is no appreciation of existence: it will not be drawn to attention of the appreciation of the human population. So there need to be links between survey and interpretation to the human population. A well-designed RDB would be one link especially if the species groups were illustrated. Survey should not be a remote technical event. Survey enables biodiversity to be revealed to the human population for wider appreciation.

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