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'''Indicator value''' is a term that has been used in [[ecology]] for two different indices. The older usage of the term refers to [[Heinz Ellenberg|Ellenberg]]'s indicator values, which are based on a simple ordinal classification of plants according to the position of their realized [[ecological niche]] along an [[environmental gradient]].<ref name=Ellenberg1974>Ellenberg H. Zeigerwerte der Gefässpflanzen Mitteleuropas / H. Ellenberg // Scripta geobotanica. Göttingen, 1974. – Vol. 9. – 197 p.</ref> More recently, the term has also been used to refer to Dufrêne & Legendre's indicator value, which is a quantitative index that measures the statistical alliance of a species to any one of the classes in a classification of sites.<ref name=Dufrene1997>Dufrene, M., and P. Legendre. 1997. Species assemblages and indicator species: The need for a flexible asymmetrical approach. Ecological Monographs 67:345-366.</ref>
 
==Ellenberg's Indicator Value==
 
Ellenberg's indicator values<ref name="Ellenberg1974"/> were the first model of bioindication proposed and applied to the flora of Germany, and they have a long tradition in interpretation and understanding of plant communities and their evolution. The latest edition of Ellenberg's indicator values applies a 9 point scale for each of six gradients: soil acidity, soil productivity or fertility, soil humidity, soil salinity, climatic continentality and light availability.<ref>Ellenberg H., Weber H.E., Dull R., Wirth V., Werner W., Paulisen D. Zeigerwerte von Pflanzen in Mitteleuropa [Indicator values of plants in Central Europe] / H. Ellenberg, H.E. Weber, R. Dull, V. Wirth, W. Werner, D. Paulisen // Scripta Geobotanics. – V. 18. – Verlag Erich Goltze KG, Göttingen, 1991. – 248 s.</ref> Indicator values also exist in Landolt's Flora of Switzerland<ref>Landolt E. Okologische Zeigerwerts zur Schweizer Flora / E. Landolt // Veroff. Geobot. Inst. ETH. Zurich. – 1977. – H. 64. – S. 1-208.</ref> and some other floras. A substantial advance on a comparable scale to place a local flora on gradients are the climatic profiles of the French SOPHY online database.{{Citation needed|date=December 2012}}
 
==Indicator Value of Dufrêne and Legendre==
 
This indicator value is an integral part of the indicator value analysis (IndVal), which quantifies the fidelity and specificity of species in relation to groups of sites in a user-specified classification of sites, and tests for the [[statistical significance]] of the associations by [[permutation]].<ref name="Dufrene1997"/><ref>De Caceres, M., and P. Legendre. 2009. Associations between species and groups of sites: indices and statistical inference. Ecology 90:3566-3574.</ref><ref>De Caceres, M., P. Legendre, and M. Moretti. 2010. Improving indicator species analysis by combining groups of sites. Oikos 119:1674-1684.</ref>
 
The indicator value of species ''i'' for class ''j'' is obtained with the equation
:<math>IndVal_{ij} = A_{ij} * B_{ij} * 100</math>
Here
:''A<sub>ij</sub>'' is fidelity, i.e. the proportion of the individuals of species ''i'' that are in class ''j''
:''B<sub>ij</sub>'' is specificity, i.e. the proportion of sites in class ''j'' that contain species ''i''
 
==References==
{{Reflist}}
 
{{DEFAULTSORT:Indicator Value}}
[[Category:Measurement of biodiversity]]

Revision as of 06:44, 22 January 2014

Indicator value is a term that has been used in ecology for two different indices. The older usage of the term refers to Ellenberg's indicator values, which are based on a simple ordinal classification of plants according to the position of their realized ecological niche along an environmental gradient.[1] More recently, the term has also been used to refer to Dufrêne & Legendre's indicator value, which is a quantitative index that measures the statistical alliance of a species to any one of the classes in a classification of sites.[2]

Ellenberg's Indicator Value

Ellenberg's indicator values[1] were the first model of bioindication proposed and applied to the flora of Germany, and they have a long tradition in interpretation and understanding of plant communities and their evolution. The latest edition of Ellenberg's indicator values applies a 9 point scale for each of six gradients: soil acidity, soil productivity or fertility, soil humidity, soil salinity, climatic continentality and light availability.[3] Indicator values also exist in Landolt's Flora of Switzerland[4] and some other floras. A substantial advance on a comparable scale to place a local flora on gradients are the climatic profiles of the French SOPHY online database.Potter or Ceramic Artist Truman Bedell from Rexton, has interests which include ceramics, best property developers in singapore developers in singapore and scrabble. Was especially enthused after visiting Alejandro de Humboldt National Park.

Indicator Value of Dufrêne and Legendre

This indicator value is an integral part of the indicator value analysis (IndVal), which quantifies the fidelity and specificity of species in relation to groups of sites in a user-specified classification of sites, and tests for the statistical significance of the associations by permutation.[2][5][6]

The indicator value of species i for class j is obtained with the equation

Here

Aij is fidelity, i.e. the proportion of the individuals of species i that are in class j
Bij is specificity, i.e. the proportion of sites in class j that contain species i

References

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  1. 1.0 1.1 Ellenberg H. Zeigerwerte der Gefässpflanzen Mitteleuropas / H. Ellenberg // Scripta geobotanica. Göttingen, 1974. – Vol. 9. – 197 p.
  2. 2.0 2.1 Dufrene, M., and P. Legendre. 1997. Species assemblages and indicator species: The need for a flexible asymmetrical approach. Ecological Monographs 67:345-366.
  3. Ellenberg H., Weber H.E., Dull R., Wirth V., Werner W., Paulisen D. Zeigerwerte von Pflanzen in Mitteleuropa [Indicator values of plants in Central Europe] / H. Ellenberg, H.E. Weber, R. Dull, V. Wirth, W. Werner, D. Paulisen // Scripta Geobotanics. – V. 18. – Verlag Erich Goltze KG, Göttingen, 1991. – 248 s.
  4. Landolt E. Okologische Zeigerwerts zur Schweizer Flora / E. Landolt // Veroff. Geobot. Inst. ETH. Zurich. – 1977. – H. 64. – S. 1-208.
  5. De Caceres, M., and P. Legendre. 2009. Associations between species and groups of sites: indices and statistical inference. Ecology 90:3566-3574.
  6. De Caceres, M., P. Legendre, and M. Moretti. 2010. Improving indicator species analysis by combining groups of sites. Oikos 119:1674-1684.