DIN EN ISO 23611-4:2011-09

This part of ISO 23611 specifies a method for sampling and handling free-living nematodes from terrestrial field soils as a prerequisite for using them as bio-indicators (for example, to assess the quality of a soil as a habitat for organisms). This part of ISO 23611 applies to all terrestrial biotopes in which nematodes occur. The sampling design of field studies in general is specified in ISO 10381-1. This part of ISO 23611 is not applicable to aquatic nematodes because these nematodes do not pass through the filter. Methods for some other soil organism groups such as earthworms, enchytraeids or collembolans are covered in other parts of ISO 23611. This standard has been drawn up since there is a growing need for the standardization of terrestrial zoological field methods. Such methods, mainly covering the sampling, extraction and handling of soil invertebrates, are necessary for the following purposes: - biological classification of soils including soil quality assessment; - terrestrial bio-indication and long-term monitoring; - evaluation of the effects of chemicals on soil animals (ISO 11268-3). Data for these purposes are gained by standardized methods since they can form the basis for far-reaching decisions (for example, whether a given site should be remediated or not). In fact, the lack of such standardized methods is one of the most important reasons why bio-classification and bio-assessment in terrestrial (that is, soil) habitats has so far been relatively rarely used in comparison to aquatic sites. Nematodes are an important and major part of the soil fauna. Some authors estimate that this group is probably the most dominant one of the multicellular organisms (Metazoa) on earth. Nematodes occur from the Antarctic to the tropics and from deep sea sediments to mountain regions. They are active in every place with sufficient water and organic material. The species diversity and functional variety are impressive. Nematodes are commonly known as parasites of animals and plants, but the major part of the nematode fauna participates in decomposition processes by feeding on bacteria and fungi. Nematodes occur in high numbers [(5 000 to 100 000)/kg fresh soil] and with a high (20 to 100) species diversity in almost every soil sample. Moreover, there is a broad ecological spectrum of feeding types and food web relations among the nematodes such as bacterivores, fungivores, herbivores, predators and omnivores. These factors make the group highly suitable as indicators for ecological soil quality, but standardization of methods is urgently needed for comparison and combination of results. The text of ISO 23611-4:2007 has been prepared by Technical Committee ISO/TC 190 "Soil quality" of the International Organization for Standardization (ISO) and been adopted as EN ISO 23611-4:2011 by Technical Committee CEN/TC 345 "Characterization of soils", the secretariat of which is held by NEN. The text of ISO 23611-4:2007 has been approved by CEN as EN ISO 23611-4:2011 without any modifications. The committee responsible for this standard is NA 119-01-02-04 UA "Biologische Verfahren" ("Biological Methods") at DIN.