# SI2: Flowering synchrony index of Augspurger (1983) In flower: Tools for characterizing flowering traits

## Description

It measures the extent of overlapping in the flowering periods among pairs of individuals in a population.

## Usage

 `1` ```SI2(dd, pop, ind) ```

## Arguments

 `dd` Flowering data. `pop` Research scale, such as Population, individual, inflorescence, single flowers. `ind` ID ofindividual or inflorescence.

## Details

si=(1/(n-1))*(1/fi)sum(ej);(j=1:n)

## Value

 `n` The number of individuals in the population. `fi` The number of days individual i was flowering. `ej` The number of days that individuals i and j are flowering synchronously, with j != i. `bij` Number of days on which at least one of them (j and/or i) is flowering. `si` Synchrony index,from 0 (total lack of synchrony) to 1 (perfect synchrony).

## Note

SI2 has been criticized for its dependence on flowering duration because the factor 1/fi increases the level of synchrony when flowering duration decreases.

WANG,XIE

## References

[1]Augspurger, C. K. (1983). Phenology, flowering synchrony and fruit set of six neotropical shrubs. Biotropica 15: 257~267.

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## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12``` ```a1=c(0,1,1,1,0,0,0) a2=c(0,1,0,1,1,0,0) a3=c(0,0,0,1,1,1,0) a4=c(1,0,0,1,1,0,1) a5=c(0,0,1,1,1,0,1) a6=c(0,0,0,1,1,1,1) pop=c("pop1","pop1","pop1","pop2","pop2","pop2") ind=c(1,2,3,1,2,3) dd=rbind(a1,a2,a3,a4,a5,a6) colnames(dd)=c("D5/1","D5/2","D5/3","D5/4","D5/5","D5/6","D5/7") C=SI2(dd,as.matrix(pop),as.matrix(ind)) C ```

### Example output

```[1] "pop1"
si
1 0.5000000
2 0.6666667
3 0.5000000
[1] "pop2"
si
1 0.75
2 0.75
3 0.75
n  min       max      mean         sd
pop1 3 0.50 0.6666667 0.5555556 0.09622504
pop2 3 0.75 0.7500000 0.7500000 0.00000000
```

flower documentation built on May 1, 2019, 9:27 p.m.