Index

Calculation

Explanation

Sörensen- (Jaccard-) Index

[Sørensen 1948]

        β = 1 / S_ø

a = common species  Arten, b = species in sample 1, c = species in sample 2

Whittaker

[Whittaker 1960,1977]

β = γ / α “       β = S_c  / S_(Ø)

S_(Ø) = average species number within samples, S_c = total number of speciesl

Species turnover in half changes

[Whittaker 1960,1977]

β = (log R₀  log R_n) / log 2

R₀ = Similarity of species inventories from one site, R_n = Similarity of species inventories of extreme for the respective gradient

ß-Turnover

[Wilson & Shmida 1984]

a, b = species number of sites to be compared; g, l = number of additional and lost“ species from one to the next site.