sgf.randarea {CTFS} | R Documentation

## Number of Species, Genera and Families for Randomly Selected Area

### Description

Counts the number of species, genera and families of the individuals found in a given single defined area of a plot. There area is defined by `quaddim` with a randomly selected initial corner. This function only identifies a randomly selected point and the corners of an area of given size starting from that point. It calls `sgf.area` to do the counting.

### Usage

    sgf.randarea(census1, spp.info, quaddim = c(100, 100),
            alivecode = c("A"), mindbh = NULL, plotdim = c(1000, 500),
            unidennames = c("**", "UNID", "uniden", "UNIDEN"))

### Arguments

`census1` | name of the datafame of a single census
`spp.info` | name of dataframe that contains each species and information about it, eg. `bcispp.info`
`quaddim` | dimensions (x,y) of the randomly selected area in meters
`alivecode` | character, codes of the variable `status` that indicate the tree is alive. The most general valid categories are: "A" and "AB" and "AS". The default for this function is "A"
`mindbh` | Minimum DBH for inclusion in computation
`plotdim` | plot dimensions, x,y lengths in meters
`unidennames` | vector of codes for unidentified species, codes vary among sites and datasets

### Details

Only one randomly selected area is subsetted and values computed with each run of this function. All areas are squares. For other shapes use `spp.randarea.range`

Pay attention to the default values of `alivecode` and `mindbh`. Any tree with `alivecode` not equal to “A” has a `dbh` = NA and so will not contribute to the results of this computation. Setting `mindbh` to some value other than NULL will affect the trees that are included in the calculation. Use `mindbh` to select trees larger than 10 mm dbh. Use `alivecode` to select trees to be counted as being alive but have no `dbh` measurement.

### Value

Returns a vector of the following information for the defined area.

`n.ind` | number of individuals
`n.spp` | number of species
`n.gen` | number of genera
`n.fam` | number of families
`r.sppgen` | ratio of number of species to number of genera
`r.sppfam` | ratio of number of species to number of families
`r.genfam` | ratio of number of genera to number of families

### Author(s)

Rick Condit, Suzanne Lao and Pamela Hall

### See Also

`CTFS.diversity`

### Examples

    ## Not run:
    1. default use gives the total number of species, genera, families for
    a randomly selected area of a given size.  Run multiple times to see
    that different values are computed each time.

    sgf.randarea(bci90.full,bcispp.info)

    ## End(Not run)

[Package CTFS version 1.00 Index]