abundance.change {CTFS}R Documentation

Annual Change in Population Size by Categories (User Defined Groups

Description

Computes annual change in population size for any user defined populations (groups). Any two census datasets can be provided in order of date of census. The rate of change and probability that the rate is = 0 is computed. For categories of DBH, use abundance.change.dbh since dbh must be determined independently for each census.

Usage

abundance.change(census1, census2, alivecode=c("A"),
        mindbh=10, split1=NULL, split2=NULL)

Arguments

census1 name of census datafile for first census, must be a dataframe, must be of same length as census2
census2 name of census datafile for second census, must be a dataframe, must be of same length as census1
alivecode character, codes of the variable status that indicate the tree is alive. The most general valid categories are: "A" and "AB" and "AS".
mindbh Minimum DBH for computing population size in each census
split1 a vector of categorical values of the same length as census which groups trees into classes of interest for which abundance values are computed. This vector can be composed of characters or numbers.
split2 a second vector of categorical values of the same length as census which groups trees into classes of interest for which abundance values are computed. This vector can be composed of characters or numbers.

Details

See CTFS.abundance for details on the computation of abundance and associated functions.

Two censuses must be used. They do not have to be sequential, only that census1 has to be before census2.

The vectors split1 and split2 must be of the same length as census1 and census2 but can contain NA.

If dbh class is one of the spilt vectors, use abundance.change.dbh instead. The dbh class of each tree is recalculated for each census in this function. No rate of change is calculated.

The inclusion of a tree is determined independently for each census. The user can only define status and mindbh once. These values are used for assessing a tree for inclusion for each census.

Value

abundance.change returns a list of arrays with the values of split1 as the first dimension and the values of split2 as the second dimension of the array. The array contains the following named components:

$N0 abundance in first census
$N1 abundance in second census
$S number of surviors from first census
$R number of recruits to second census
$rate annual rate of change in abundance
$prob probability that N0 == N1
$meanyrs mean number of years between census for trees used in mortality rate computation
$date0 mean date of first census
$date1 mean date of second census

Author(s)

Rick Condit, Suzanne Lao, Pamela Hall

See Also

CTFS.abundance

Examples

## Not run: 
# 1.  Default use of abundance.change
abund.ch.out <- abundance.change(tst.bci90.full,tst.bci95.full)

# 2.  Population change by species
spp.vct <- tst.bci90.full$sp
abund.ch.sp.out <-
abundance.change(tst.bci90.full,tst.bci95.full,split1=spp.vct)

## End(Not run)

[Package CTFS version 1.00 Index]