Dispersal - Genetic Diversity in Establishing Plant Populations: Founder Number and Geometry - page 193

12.2. Information concerning trial populations m, n, and o is also included
in Table 12.2, but those trials (concerning varying offspring dispersal) will
be discussed in the next section.
Table 12.2 Percent of pollen dispersed from each zone for trials e, f, and g, or percent of
offspring dispersal to different zones for trials m, n, and o. There is no pollen dispersal from
beyond zone 4.

ZONE MINIMUM AND
MAXIMUM DISPERSAL
LIMITS

TRIALS e, m TRIALS f, n TRIALS g, o

ZONE 1: 0-5 grid units 45% 45% 25%

ZONE 2: 6-12 units 30% 30% 25%

ZONE 3: 13-21 units 20% 10% 25%

ZONE 4: 22-300 units 5% 15% 25%

Population e has a similar pollen shadow to population f, although f has
a fatter tail with more pollen dispersed to longer distances. Population g has
pollen more evenly dispersed across zones, and even greater percentages
dispersed to greater distances.
NEWGARDEN mean value output (30 runs per trial) for these trial
populations is depicted in Figs. 12.11 and 12.12. Increasing microgamete
dispersal distances increases population growth by approximately 7% after
14 rounds of mating, presumably because of an increased availability of
pollen donors for more isolated individuals. The different dispersal distance
schedules for populations e, f, and g do not seem to differ extensively in
population growth rates, however. These three populations with increased
microgamete dispersal have decreased loss of heterozygosity (10% or
greater) and F values (inbreeding and or Wahlund effect subdivision) at
the end of the trials. Further, the more evenly distant the microgamete
dispersal (e.g., population g), the greater the decreases. These results
demonstrate that increasing pollen dispersal distance promotes mixis
and decreases localized inbreeding even when offspring dispersal is kept
constant at 5 grid units. Population genetic diversity is also somewhat
promoted in terms of the number of unique alleles retained (Fig. 12.12B):
there is an approximately 4.5% increase with any of the explored increases
in microgamete dissemination over the trial with the most limited pollen
dispersal (trial N), although, as was shown with population growth, there is
little difference in retention across the trials with greater dispersal distance
schedules (trials e, f, and g). Under the given circumstances, increasing
microgamete dispersal appears to be an effective means of increasing the
genetic diversity of, and reducing inbreeding in, some populations.