Modelling Seedling Mortality
Seedling mortality in tree populations is important because it
limits population growth rates and controls the diversity of
forests. To learn about seedling mortality, ecologists return
regularly to forest quadrats to count the number of tree seedlings
that have survived from the previous census and to find new ones.
Typically, newly found seedlings are marked with flags. But
flagging is labor intensive and therefore limits the spatial and
temporal coverage of such studies. The alternative of not flagging
has the advantage of ease but suffers from two main disadvantages.
It complicates the analysis and loses information. The
contributions of this paper are (i) to introduce a method for using
unflagged census data to learn about seedling mortality and (ii) to
quantify the information loss so ecologists can make informed
decisions about whether to flag. Based on results presented here,
we believe that not flagging is often the preferred alternative.
The labor saved by not flagging can be used to better advantage in
extending the coverage of the study.
michael@stat.duke.edu
last updated 13 Sept. 2000
The manuscript is available in