1 / 26

Species indicator values as an important tool in applied plant ecol ogy

Species indicator values as an important tool in applied plant ecol ogy Session: Databases and information systems 46th IAVS Symposium 8-14 June 2003 Naples (Napoli), Italy Martin Diekmann. Vegetation Ecology and Nature Conservation Biology, IFOE. Contents.

purity
Download Presentation

Species indicator values as an important tool in applied plant ecol ogy

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Species indicator values as an important tool in applied plant ecology Session: Databases and information systems 46th IAVS Symposium 8-14 June 2003 Naples (Napoli), Italy Martin Diekmann Vegetation Ecology and Nature Conservation Biology, IFOE

  2. Contents • Biological indication: Introduction • Species responses and indicator values • Applications of indicator values • Indicator values and measurements • Calibration of indicator values • Conclusions 46th IAVS Symposium 8-14 June 2003, Naples

  3. Biological indication – making use of the specific reactions of organisms to their environment Examples Indicator values for climatic and soil variables (Ellenberg et al. 1992) Indicators of habitat continuity (e.g. ancient forests) (Wulf 1997) Indicators of management (e.g. mowing sensitivity) (Briemle & Ellenberg 1994) Grime’s classification of species into habitat and strategy types (Grime et al. 1988) 46th IAVS Symposium 8-14 June 2003, Naples

  4. Ellenberg values Example: Reaction – soil or water pH (R) 1 Indicator of extreme acidity (Andromeda polifolia) 2 Between 1 and 33 Acidity indicator (Pteridium aquilinum) 4 Between 3 and 55 Indicator of moderately acid soils (Milium effusum) 6 Between 5 and 77 Indicator of weakly acid to weakly basic conditions (Hepatica nobilis) 8 Between 7 and 99 Indicator of calcareous or other high-pH soils (Primula farinosa) 46th IAVS Symposium 8-14 June 2003, Naples

  5. Species responses and indicator values Criticism: Species have no distinct ecological optima. Species response, e.g. biomass production Gauss curve Ecological gradient (e.g. pH) 46th IAVS Symposium 8-14 June 2003, Naples

  6. A Gaussian response is preferable, but it is sufficient that the • response is unimodal or linearly increasing/decreasing (skewed). • Most species response curves look that way, if • The environmental variable in question is important. • The total variation is large enough. • The distribution of measured values along a gradient is more or less • regular. 46th IAVS Symposium 8-14 June 2003, Naples

  7. Anemone nemorosa Anemone ranunculoides Melica nutans Actaea spicata Response curves of forest vascular plants in Sweden (Diekmann, unpubl.) 46th IAVS Symposium 8-14 June 2003, Naples

  8. Applications of indicator values Weighted site averages Site score = (x1y1 + x2y2 + ... + xnyn) / (x1 + x2 + ... + xn) x1, x2, ..., xn frequencies of species 1 to n; y1, y2, ..., yn indicator values of species 1 to n. 46th IAVS Symposium 8-14 June 2003, Naples

  9. Weighted site averages serve to: • Obtain information about the environment of relevés, habitat patches, • grid squares, etc., and to make environmental comparisons between sites. • Interpret ordination diagrams, by correlating the axis scores of sites with • the corresponding values of measurements. 46th IAVS Symposium 8-14 June 2003, Naples

  10. ... calculate the size of the species pool of communities. (Ewald, in press) 46th IAVS Symposium 8-14 June 2003, Naples

  11. ... predict the occurrence of species. (Dupré & Diekmann 1998) [based on logistic regression] 46th IAVS Symposium 8-14 June 2003, Naples

  12. examine changes in environmental conditions and reconstruct historical • site conditions on the basis of former species assemblages. (Diekmann et al. 1999) 46th IAVS Symposium 8-14 June 2003, Naples

  13. Weighted averages may be unreliable, if • The plots studied are spatially highly heterogeneous. • The environmental gradient is too short. • The habitat is strongly affected by management • (e.g. heavy grazing). • There is a sudden environmental shift. • The vegetation mainly responds to extremes and not to mean values. 46th IAVS Symposium 8-14 June 2003, Naples

  14. Indicator spectra (Diekmann 2003) 46th IAVS Symposium 8-14 June 2003, Naples

  15. (Diekmann 2003) 46th IAVS Symposium 8-14 June 2003, Naples

  16. Indicator values and measurements Criticism: Indicator values are not systematically derived from measurements, but mainly inferred from field experience. They may prevent us from conducting measurements! • If weighted averages and measurements are • - highly correlated, • We conclude that the indicator values for the variable in question work well. • - weakly correlated, there are two possible conclusions: • The indicator values for that variable are unreliable. • 2) We have measured the wrong variable! 46th IAVS Symposium 8-14 June 2003, Naples

  17. Parameter Correlation Soil reaction pH (H2O), pH (KCl) + (Persson 1980, Degorski 1982, or pH (CaCl2) Lawesson & Mark 2000, Wamelink et al. 2002) + (Rodenkirchen 1982) + (Ellenberg 1992, Herzberger & Karrer 1992, Seidling & Rohner 1993, Diekmann 1995, Hill & Carey 1997, Ertsen et al. 1998, Schaffers & Sýkora 2000, Diekmann, unpubl.) Base saturation ++ (Degorski 1982, Seidling & Rohner 1993, Schaffers & Sýkora 2000) Al/Ca ratio ++ (Seidling & Rohner 1993) Ca2+ saturation ++ (Schaffers & Sýkora 2000) Ca2+ amount ++ (Degorski 1982, Schaffers & Sýkora 2000) Total calcium ++ (Schaffers & Sýkora 2000) 46th IAVS Symposium 8-14 June 2003, Naples

  18. Correlation measured values – weighted site scores Swedish forests (Diekmann 2003) 46th IAVS Symposium 8-14 June 2003, Naples

  19. Parameter Correlation Nitrogen N PARAMETERS Total N + (Vevle & Aase 1980, Schaffers & Sýkora 2000) - (Hill & Carey 1997, Ertsen et al. 1998) Total C/Organic matter - (Hill & Carey 1997) + (Diekmann, unpubl.) C/N ratio + (Ellenberg 1992, Schaffers & Sýkora 2000) - (Diekmann, unpubl.) Mineral N (NO3- + NH4+) + (Schaffers & Sýkora 2000) - (Lawesson, unpubl.) Mineral NO3- + (Schaffers & Sýkora 2000) % NO3- + (Schaffers & Sýkora 2000) Total mineralisation + (Rodenkirchen 1982, Ellenberg 1992) -     (Schaffers & Sýkora 2000, Ammonification rate + (Diekmann, unpubl.) Nitrification rate + (Diekmann, unpubl.) Nitrification ratio ++ (Diekmann, unpubl.) 46th IAVS Symposium 8-14 June 2003, Naples

  20. Correlation measured values – weighted site scores Swedish forests (Diekmann 2003) 46th IAVS Symposium 8-14 June 2003, Naples

  21. Parameter Correlation Nitrogen OTHER NUTRIENTS Total P + (Hill & Carey 1997, Ertsen et al. 1998) Available PO43- + (Ertsen et al. 1998, Schaffers & Sýkora 2000) - (Lawesson, unpubl.) Total K + (Ertsen et al. 1998) Available K+ + (Hill & Carey 1997, Schaffers & Sýkora 2000) - (Lawesson, unpubl.) Exchangeable Mg - (Lawesson, unpubl.) VEGETATION-DERIVED PARAMETERS Biomass/”standing crop” + (Boller-Elmer 1977, Briemle 1986) ++ (Melman et al. 1988, Hill & Carey 1997, Ertsen et al. 1998, Schaffers & Sýkora 2000) N accumulation of plants ++ (Ertsen et al. 1998, Schaffers & Sýkora 2000) Foliar N concentration ++ (Thompson et al. 1993) Tissue N concentration + (Schaffers & Sýkora 2000) 46th IAVS Symposium 8-14 June 2003, Naples

  22. Calibration of indicator values 46th IAVS Symposium 8-14 June 2003, Naples

  23. Criticism: Species may shift in their responses, especially across geographical gradients. Three calibration approaches: 1) Observation of single species. 2) Indirect calibration on the basis of large phytosociological data sets. 3) Measurements of environmental parameters. 46th IAVS Symposium 8-14 June 2003, Naples

  24. (Hill et al. 2000) 46th IAVS Symposium 8-14 June 2003, Naples

  25. (Diekmann 2003; data from Hill et al. 1999 and Schaffers & Sýkora 2000) 46th IAVS Symposium 8-14 June 2003, Naples

  26. Conclusions • Indicator values are subjective, but if they coincide with the ecological • optima of species, they are very useful for many applications. • Indicator values need to be verified by measurements and calibrated. • Whenever possible, the use of indicator values should be accompanied • by measurements. 46th IAVS Symposium 8-14 June 2003, Naples

More Related