Input - Genetic Diversity in Establishing Plant Populations: Founder Number and Geometry - page 35

establishment at that grid point). In this way, individuals can persist on
the preserve grid blocking establishment even after they have become non-
reproductive. For example, reproduction (via micro- and/or megagametes)
can be assigned as 0 at a certain advanced age class after the mature
reproductive phase, with continuing degrees of mortality assigned to aging
individuals so that post-re productives will be randomly deleted until a
much, much older age for which mortality is set to 1 (all individuals of
an age class die). Varying rates of age-specifi c mortality across trials to
examine how mortality affects the retention of genetic diversity can aid in
assessing when, in the expansion of a population, reproductive or census
augmentation or attenuation is best provided.
Selfi ng Rate
The Selfi ng Rate command designates the amount of selfi ng that occurs in
each round of mating. Input values range from 0 (no selfi ng) to 1 (100%
selfi ng). Selfi ng rate can only be set when Dioecious = false (there is no
selfi ng for dioecious species). Even if the user sets pollen donation rate
to 0 for all generations, it is still possible to have pollen donation with
selfi ng rate set greater than 0. See also the section Random Mating. Eligible
reproductive individuals are randomly chosen to self according to the user-
specifi ed rate of selfi ng.
Selfi ng Rate: Some Theoretical Considerations
While some organisms are either obligate selfers or obligate outcrossers,
those that are intermediate between these extremes may exhibit pronounced
intraspecifi c variation in the degree of selfi ng. For example, interpopulation,
or year-to-year intrapopulation or even individual, variation in selfi ng
rates can be driven by several factors including varying growth resources
availability, weather variation effects on pollinator abundance, or Allee
effects (density of individuals affecting the ratio of outcrossing to selfi ng;
e.g., see Robledo-Arnuncio and Gil 2005). In one NEWGARDEN bout of
reproduction, the selection of individuals that engage in selfi ng is random
(according to the specifi ed rate), and thus a perennial individual may have
varying ratios of self-to-nonself offspring produced as it passes through
generations. While increasing the amount of selfi ng will increase the
amount of inbreeding in later generations not just because of the selfi ng
alone, but also because of the effect of increasing the number of closely
related individuals that can mate in the future, it does not immediately
drive increased inbreeding among relatively closely related individuals that
are not the products of selfi ng. As will be seen below, the latter effect can
be facilitated by spatial partitioning of the founders (subdivision). Varying