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Correlation between richness per unit area and the species pool cannot be used to demonstrate the species pool effect
Author(s) -
Herben Tomáš
Publication year - 2000
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.2307/3236783
Subject(s) - species richness , body size and species richness , correlation , species diversity , ecology , unit (ring theory) , positive correlation , statistics , biology , mathematics , geometry , mathematics education , medicine
. Significant correlation between the size of the species pool and richness per unit area is usually taken as a demonstration of the effect of the species pool on the species richness per unit area. This is not logically necessary. It has to be emphasized that such a correlation cannot be interpreted as a demonstration of the effect of species pool on the species richness per unit area. More generally, correlation cannot be used to demonstrate a one‐directional effect of one variable upon another, since several types of (functional) relationships could produce correlations between such variables; the same caution has to be taken when analysing the species pool vs. richness per unit area correlation. In this paper, a simple Monte Carlo simulation model is used to demonstrate that (1) statistical processes acting only at the local scale (such as competitive exclusion) can generate exactly the same correlation that has been used to infer the effect of the species pool on richness per unit area; (2) this correlation would be deemed significant even if the mathematical dependency between species pool and richness per unit area is taken into account; and (3) the strength of this relation depends on beta diversity within the contiguous area used to determine the species pool.