Preston diagram of an ecosystem
Gives a standard Preston diagram for an ecosystem.
- Ecosystem vector that is coerced to class
count, or a matrix whose rows are species counts
- An integer specifying the number of species abundance classes
to use, with default
NULLmeaning to use $1+log2(J)$. Must be greater than 1 if specified. If
xis a vector,
NULLis not acceptable as the program does not try to guess what is required
- Boolean, with default
FALSEmeaning to use the nonoverlapping technique discussed below, and
TRUEmeaning to use Preston's original formulation.
The Preston diagram is a table showing the number of species having
abundances in specified abundance classes. Consider the following
Preston diagram, created with
original = FALSE:
1 2 3-4 5-8 9-16 17-32 33-64 65-Inf number of species 10 5 7 5 1 5 4 0
This shows that there are 10 species with abundance 1 (that is, singletons); 5 species with abundance 2; 7 species with abudance 3-4; 5 species with abundance 5-8, and so on. This method is used by Hubbell (2001), and Chisholm and Burgman (2004).
TRUE means to follow Preston
(1948) and count any species with an abundance on the boundary between
two adjacent abundance classes as being split 50-50 between the classes.
Thus the fourth class would be
where $phi_i$ is the number of species with abundance
$i$ (given by
preston()returns an object of class
F. W. Preston 1948. The Commonness, and Rarity, of Species.
R. A. Chisholm and M. A. Burgman 2004. The unified neutral
theory of biodiversity and biogeography: comment. Ecology 85(11):
- S. P. Hubbell 2001. The Unified Neutral Theory of Biodiversity. Princeton University Press
preston(untb(start=rep(1,100), prob=0.01, gens=1000, keep=FALSE)) data(butterflies) preston(butterflies) preston(butterflies,original=TRUE) data(copepod) preston(copepod)