Introduction - Genetic Diversity in Establishing Plant Populations: Founder Number and Geometry - page 3

2. Propagule storage or pre-germination treatment (e.g., cleaning the
seed of fruit, stratifi cation, scarifi cation).
3. Location of an introduction site, travel to and from the site, transport
of seeds or seedlings, and/or transport of harvesting or planting
equipment.
4. Site preparation, for example, opening of the canopy or soil
preparation.
5. Planting the species.
6. Provisioning the new plants (e.g., supplying fertilizer or water as
needed).
7. Protecting the initial plantings. Some plants require removal of pest
or weed species, or anti-herbivore protection (fencing, plastic stem-
protection tubing).
8. Post-planting monitoring.
9. Depending on the monitoring, the population may need to be
manipulated or supplemented (with additional plantings). Seeds may
need to be dispersed, plants may need to be pollinated. Competing
weeds, vines, or other pests or pathogens may need to be removed
at later stages or treated periodically. Enclosures may need to be
constructed as the stand develops.
10. Propagule harvesting for new plantings.
11. Introducing a species may involve disturbance of the habitat. For
example: unwanted seeds may be introduced on shoes or clothing; trail
or prepared site disturbance may occur; animal movement patterns
and other types of disturbance may modify portions of a preserve. In
some cases, there may be costs associated with such disturbance (e.g.,
removal of newly introduced alien species).
12. Genetic monitoring of the developing population to determine
whether genetic diversity retention is being optimized or requires
supplementation.
All of the above issues may involve expense in time, effort, and money.
What if, instead of introducing as many individuals as possible, we could
carry out more limited plantings that are just as effective, or almost as
effective, in establishing a population and maintaining its genetic diversity?
Suppose we have 20,000 seeds to be reintroduced. Should we introduce
200, 400, 6000, or 20,000 individuals per site? What are the comparative
consequences for population genetics of each of these types of introduction?
If introducing 500 individuals generally produces the same degree of
conservation of genetic diversity as introducing 1000, then obviously the
former is a less expensive option per site, and it permits introduction at two
different sites. With our 20,000 seeds, if we plant 500 seeds per site, we can
introduce the species at 40 different locations rather than 20, more broadly