The need for a guidance document on the development and selection of keys for use in freshwater biological monitoring A

1. The need for a guidance document on the development and selection of keys for use in freshwater biological monitoringA Dutch Perspective M. Swarte, A. Veen & F. Kouwets, RIZA 15/11/2005

2. Hydrobiological analyses in the Netherlands • Regional waters • 26 Local water administrations (1955: 2480,organized in STOWA: Foundation for applied water research) • 18 laboratories • Main rivers, channels and lakes • RIZA (RIKZ coastal waters) • 1 laboratory • Drinking water • 3 laboratories • Consultancies • 6 laboratories • (Organized) amateurs • ? (main, desm, amph...)

3. The Dutch laboratory technicians • technical college • no specific training for identification • specific on-the-job training • poorly educated in taxonomy • natural born splitters (Dutch youth organisation for nature observation) • laboratory management often in hands of a chemist

4. Practice of identification in the Netherlands • Species level by tradition • Many identification keys • macro-invertebrates (without Hydracarina) • English 21 • German 17 • French 3 • Dutch 27 • Romanian 1 • only for Hydracarina (water mites) : 30 articles and books!

5. (Semi)-aquatic taxa in the Netherlands marine and freshwater • total number of taxa in databases 35000 (circa) • total number reported 12371 • Diatoms 1721 • Fish 24 • Phytoplankton 1974 • Macro-invertebrates 6610 • Macrophytes 1393 • Zooplankton 536 project on standardization of taxon names for the use in databases www.ecosys.nl (in Dutch)

6. Different specialists • Skillful in identification • close to the work area • regional taxonomic keys • Skillful in systematics and taxonomic codes • “endangered species” • academic world • flora / faunal handbooks

7. Preconditions of identification works • Introduction • definition/description of region • definition/description of taxonomic group • glossary with figures • Key • lay-out • (un)ambiguous characteristics • Taxonomic justification and traceability

8. Introduction-1 • Definition of geographic region (map) • Chironomidae larvae of the Lowlands of Northwestern Europe • Oligochaeta of North-West Europe • Chironomidae exuviae of the West Paleartic Region

9. Introduction-2 • Definition of taxonomic group • “The Dutch Trichoptera larvae” • 2 Drusus species described: D. trifidus and D. annulatus • D. annulatus similar to D. biguttatus (“not far from the Dutch border but not (yet) found in the Netherlands”) • “Freshwater Bivalves of Britain and Ireland” • Two confusing species of Corbicula - C. fluminea described - C fluminalis not described, spreading over Europe

10. Introduction-3 • Glossary • Characteristics • Topographic description and Illustration of eachcharacteristic

11. Key-1 • Lay-out • clear guidance through the key (page nr. internal references) • structured description of the species identification specific, matrix description comprehensive • dichotomous key: • keep it simple, only decision points • correction after wrong choice • images from species of the region • unicellular algae: microscopic images (not only EM) preferably in combination with drawings • biometrics including distribution and n

12. Key-2Eggers, Th.O. & A. Martens (2004). Ergänzungen und Korrekturen zum "Bestimmungsschlüssel der Süßwasser-Amphipoda (Crustacea) Deutschlands". Lauterbornia 50: 1-13. ISSN 0935-333-X. • Lay-out “keep it simple” • Uropod III of male with densily, curled setae (Fig 51), female at least distal with densely setae.1st and 2ndurosome segment lateral with 2-3 groups of spines (2-3 spines each).Uropod III and urosome (excl. telson) in the ratio of about 1.1:1.0. Adults >12mm Echinogammarus trichiatus p.49 • Uropod III with scattered setae (Fig 52). 1st and 2nd urosome segment lateral with 1-2 solitary spines, accompanied with 1 setae. Uropod III and urosome (excl. telson) in the ratio of about 1.5:1.0. Bodysize up to 12 mmEchinogammarus ischnus p.39

13. Key-3Wallace, I.D., B. Wallace & G.N. Philipson (2003). Keys to the case-bearing caddis larvae of Britain and Ireland. Scientific Publications of the Freshwater Biological Association 61: 1-259. • (un)ambiguous characteristics • Fool proof 27(25) Found from August to May - Ceraclea albimacula (Rambur) Instar II Rivers, large streams and canals. Widespread. Overwinters at instar II (but not necessarily in sponges) - Found from July to September -Ceraclea anulicornis (Stephens) Instar II Rivers, also occasionally on lake-shores; associated with large stones. Widespread and common in Britain, rarer in Ireland. Overwinters at instar V.

14. Key-4 • (un)ambiguous characteristics • relative measures (“relatively long”, “not so long”) • use of: • generally, usually • overlapping measures as diagnostic characteristic

15. Taxonomic justification and traceability • species concept (monothetic,...) • classification system • higher taxon levels • synonyms (not only ‘most common’) • Linnean code (generic name, epith, author, year of publication) • original reference in reference list • diacritics • Kroyer • Kröyer • Krøyer • Kroeyer

16. Electronic media: digital keys • ‘Not’ in use: • European Limnofauna • Chironomidae larvae of the Lowlands of Northwestern Europe • Chironomidae exuviae of the West Paleartic Region • Oligochaeta of North-West Europe • What’s wrong? • Digital key should not be a translation of a paper key • technicians prefer books • no PC near the microscope • Matrix table (probability result) • no guidance, interactive with feedback expert judgement • no overview good multi windows functionality

17. Summarizing: • most keys lack a systematic approach • ask end-users of keys to judge the correctness(unknown test-species and reference collection) • digital keys need intelligent design first • CEN-guidance necessary for both authors, publishers and sponsors • title: General requirements for the usefulness of taxonomic keys