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

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individual seeds (not multiseeded cones or fruit). The input statement

takes the form:

where integer x is the generation class (by NEWGARDEN convention,

x = 0 designates founding individuals of the generation or age 0 class;

x = 1 is the fi rst generation produced by a bout of mating), and y is the

number of offspring produced per eligible female from matings (subject

to the other conditional constraints specifi ed—see below) that can go

on to survive, die (e.g., be distributed to points off the preserve grid), or

at least “vie” at one establishment grid point to be included in the next

generation. We use the term “vie” to indicate that, since each potential

offspring will be dispersed to a particular point, it is possible that two

or more potential offspring can be dispersed to the same point. In

creating the members of the next generation, NEWGARDEN randomly

selects only one of the potential offspring dispersed to the same point

to be included as a realized offspring in the next generation; other seeds

co-inhabiting the point then die before the next bout of reproduction. If an

offspring is the only individual dispersed to a particular unoccupied point

within the grid, it will automatically become an established offspring in

the next generation. Note that the input statement above designates the

offspring propagules produced per reproductive female as two. If both of

the offspring of a female are dispersed to points already occupied by an

existing individual established in an earlier generation, the newly dispersed

offspring die before the next round of mating. Such eliminated potential

offspring are tallied as part of the reproductive output of the generation

producing them, a female producing a potential offspring that dies because

of previous occupation of a point having 0 realized reproduction for that

one bout of mating even though reproduction rate (y) has been designated

as 2, and thus it has produced two propagules that do not survive. As

the density of points occupied by established individuals increases, the

relative contribution of eligible reproductive individuals will become more

variable, especially when offspring dispersal distances are low. Note also

that when reproduction rate y = 2, the two offspring of a given female are

still included in the tally of the reproductive output for that female in that

mating episode, even if the offspring are dispersed off the preserve grid

and thus die before establishing in the next cohort.

The user can alter age-specifi c offspring production. For example, the

statements

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