abundance.change {CTFS} | R Documentation |
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.
abundance.change(census1, census2, alivecode=c("A"), mindbh=10, split1=NULL, split2=NULL)
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. |
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.
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 |
$date1 |
mean date of second census |
Rick Condit, Suzanne Lao, Pamela Hall
## Not run: # 1. Default use of abundance.change abund.ch.out <- abundance.change(tst.bci90.full,tst.bci95.full) # 2. Population change by species spp.vct <- tst.bci90.full$sp abund.ch.sp.out <- abundance.change(tst.bci90.full,tst.bci95.full,split1=spp.vct) ## End(Not run)