nelder_biculture: Create a Biculture Nelder Fan experimental design

In kevinwolz/sysdesign: An R Toolbox for Creating & Analyzing Systematic Experimental Designs in Biology

Description

Creates a Biculture Nelder Fan experimental design.

Usage

nelder_biculture(data, comps = NULL)

Arguments

data	An object of class nelder.
comps	An optional numeric vector containing the ratios of one species in each spoke. This can effectively be used to create non-standard bi-culture designs that deviate from the Goelz (2001) approach. If NULL, the default, then a linear gradient of speies composition is used between monoculture extremes for each species.

Details

The Nelder Fan or Nelder Wheel Type Ia experimental design (Nelder 1962) is an experimental design that systematically varies plant desnity within a single plot, where the growing area around each plant has a constant shape throughout the design but increases as radius increases. Goelz (2001) adapted this design to simultaneously study the effect of species composition by superimposing a species gradient along the arc (Figure 6 of Goelz, 2001). This function takes a Nelder Fan design from nelder and adds species identities to create the Goelz (2001) biculture version. For Nelder Fan designs with max.angle = 360, species monoculture are set to opposite poles of the circle, and the composition gradient occurs in two direction along either side of the circle in between. For Nelder Fan designs with max angle < 360, the composition gradient occurs in one direction between monoculture extremes at either edge of the design. This function does NOT robustly impose any conformity criterion to ensure that composition levels are tested evenly across all density levels. Species are assigned randomly to positions within each spoke of the design based on the probability of each species in that spoke. For a robust implementation of the composition-density conformity criterion that optimizes the rough initial approach of this function using an evolutionary algorithm, use nelder_biculture_optim.

Value

An object of classes sysd, nelder, and nelder-biculture. This is a list of 5 elements, the first 3 of which are the same as for nelder, and the last 2 of which are:

• "species.counts" - An abject of class "table" containing the total counts of each species in the design.

• "spoke.composition" - A data frame (tibble) containing the ratio and counts of each species by spoke.

Author(s)

Kevin J Wolz, [e-mail]

References

• Nelder JA (1962) New kinds of systematic designs for spacing experiments. Biometrics 18:283-307. http://www.jstor.org/stable/2527473

• Goelz J (2001) Systematic experimental designs for mixed species plantings. Native Plants Journal 2:90–96. http://npj.uwpress.org/content/2/2/90.short

See Also

Other definition functions: goelz_add_border(), goelz_corners(), goelz_guides(), goelz_mirror(), goelz_optim(), goelz_starts(), goelz(), nelder_biculture_competition(), nelder_biculture_optim(), nelder_decision(), nelder_interspoke_distance(), nelder(), select_optimal_goelz(), select_optimal_nelder_biculture()

Examples

nelder.design <- nelder(DN = 1000, D1 = 3000, N = 5)
dat <- nelder_biculture(data = nelder.design)

kevinwolz/sysdesign documentation built on June 13, 2020, 1:35 a.m.