This function calculates percentage matrices based on a dataframe with species in columns and samples in rows.

Usage

percenta(x, first, last)

Arguments

x

Dataframe or matrix containing raw data with species in columns and samples in rows.

first

Number of first column in x (taxon) to be included in the sum that serves as basis for the percentage calculation (e.g. pollen sum, see Birks & Birks (1980)).

last

Number of last column in x (taxon) to be included in the sum that serves as basis for the percentage calculation (e.g. pollen sum, see Birks & Birks (1980)).

Value

The function returns a dataframe containing calculated percentages, with species in columns and samples in rows.

Details

Percentages can be calculated based on a selected group of columns or taxa (e.g. terrestrial taxa included in the pollen sum for palynological analyses, see Birks & Birks (1980) for illustration on pollen sum). For the rest of the columns (taxa) percentages are calculated based on totals from included columns (taxa), e.g. spores and aquatics.
The dataframe should be organized in such a way that taxa or columns to be included in the percentage calculation are contiguous. Percentages of other columns outside that range (first to last) are calculated based on the total sum of elements included (e.g. pollen sum).

References

Birks, H. J. B., and Birks, H. H. (1980). Quaternary Palaeoecology. University Park Press, Baltimore.