Corridors - Genetic Diversity in Establishing Plant Populations: Founder Number and Geometry - page 283

is approached. The greatest differences in population growth relative to
dispersal distance occur when the founders are split between preserves
(trials M and S, short- versus long-distance dispersal respectively). When
dispersal is short distance, splitting the founders (trial M) yields a 5.4%
larger population than when all 172 founders are placed in one preserve.
With long-distance dispersal, this relationship is reversed: trial R with
all founders placed in one preserve yields 7% greater growth than trial S
(founders split).
Turning to founding unique allele retention ( Fig. 17.5B) , short-distance
dispersal preserves more unique alleles, whether the founders are placed in
one (L) or two (M) preserves. Trials L and M are not statistically different,
but they do differ from trials R and S (long-distance dispersal) in unique
alleles retained by approximately 9.1% to 13%. Trials R and S are signifi cantly
different (p = .005), but R with founders placed in one preserve retains only
2.8% more unique alleles than trial S. Heterozygosity is in the range of 0.97
with a difference of only approximately 1%, those trials in which founders
are placed in one preserve (L and R) being slightly higher than trials in
which founders are split between preserves (M and S).
NEWGARDEN can also be used to examine population data for
separate subregions of the entire preserve-corridor-preserve system (see
the region and rectangle input statements given above when outlining the
input details for basic trial C). For example, in Fig. 17.6A, population growth
in the right preserve only is depicted for the short-distance dispersal trials
for which the results of the total preserve-corridor-preserve area are shown
in Fig. 17.3 (trials I and M, both with founders split into the left and right
preserves). Figure 17.6B shows population growth in the right preserve
only for the long-distance trials for which the total population growth
is depicted in Fig. 17.4. Notice that under short-distance dispersal (Fig.
17.6A), no offspring are found in the right preserve for the trials where all
founders are placed in only the right preserve (trials C and L). Only when
long-distance dispersal occurs is an incipient population seen in the right
preserve when the founders are placed in the left preserve only (Fig. 17.6B;
trials R and V).
Founding unique alleles retained in distinct areas can also be monitored.
Figure 17.7 graphs unique allele retention in the right preserve only for
trials C, I, R, and W. In trial C, after 12 generations, no alleles are retained
in the right preserve, since founders are placed on only one side of the
preserve and dispersal is relatively short. Although trial R also begins with
all 172 founders situated in the left preserve, as shown in Fig. 17.6, because
of further dispersal, some offspring are dispersed to the right preserve.
Thus, unique alleles in that preserve are seen to increase in number over
generations (Fig. 17.7). Even though only a few hundred individuals have
arrived in the right preserve after 12 generations, the unique alleles are