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Comparing the “best” trials (those in which populations grew the
fastest and/or retained the most genetic diversity), g is the best trial for
those in which offspring dispersal is limited and microgamete dispersal is
variously distributed ( Figs. 12.13 and 12.14) . That trial g performed better
than the best trial when microgamete dispersal is limited and offspring are
variously dispersed (Figs. 12.13 and 12.14 trial m). In both trials g and m,
among their respective groups, the variously distributed dispersule was
most evenly dispersed (least leptokurtic). Compared to trial N, in which
both offspring and microgamete dispersal were limited to a maximum
of 5 grid point units, in terms of population growth and unique alleles
retained, all trials in which offspring dispersal was a maximum of 5 grid
units while microgamete dispersal ranged up to 300 grid points (trials e, f,
and g) were greater than trial N, whereas all trials in which microgamete
dispersal was limited to 5 units while offspring were dispersed up to 300
grid points (trials m, n, and o) were less than trial N. These results suggest
that establishing populations that differ in such characteristics as modeled
here will differ as to population growth rates and genetic diversity retention.
For restoration projects using species with these life history characteristics,
it may be more advantageous to expend effort on increasing microgamete
rather than offspring dispersal. Expending effort only on increased offspring
dispersal may reduce population growth and genetic diversity retention.
However, species with different life history characteristics or introduced
in different spationumeric patterns may exhibit different tendencies, and
NEWGARDEN can be used to explore such contingencies.
Increasing Offspring Dispersal when Microgamete Dispersal to
Four Different Zones Is Held Equal and Constant vs Increasing
Microgamete Dispersal when Offspring Dispersal to Four
Different Zones Is Held Equal and Constant
In the previous examples, the maximum distance of one type of dispersule
(either the offspring or the microgametes) was held constant to 5 units in
one zone while dispersal of the other dispersule was distributed to greater
distances with increasing evenness. In this section, we compare three types
of trials:
Type 1: In trial N, offspring and microgamete maximum dispersal distances
both = 5 grid units. This is the same population N as used in the previous
sections of this chapter.
Type 2: In trials g, h, i, and j, probability of dispersal of microgametes is
equally likely from each of four zones surrounding a randomly selected
offspring producer in each particular mating. In other words, 25% of the
successful microgametes across all of the matings for a given trial will
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