Hiho

I want to create a rarefaction curve using R i.e. vegan {rearecurve/speccaccum}.

This worked out quite well (please see here):

![][1])

Anyways, as you can see in the figures the curves don't reach saturation. So I know that i have to kind of fit or simulate the missing data but this is exactly the problem. How can I produce a fit or something similar that shows me how large my sample has to be to reach saturation in discovered species?

Thanks for your time and help!

ps. code:

    (raremax <- min(rowSums(t(species))))
    Srare <- rarefy(t(species), raremax)
    plot(specnumber(t(species)), Srare, xlab = "Observed No. of Species", ylab = "Rarefied No. of Species")
    abline(0, 1)
    rarecurve(t(species), step = 20, sample = raremax, col = "blue", cex = 0.6)

  [1]: https://i.imgur.com/7gPo7gv.png
My quite naive suggestion is to estimate the richness with some estimator like Chao1 (should be in Vegan package), then extrapolate your richness curve to get 90% of estimated diversity and check for the sample size. See [iNEXT R package][1] for details on extrapolating rarefaction curves.

 [1]: http://chao.stat.nthu.edu.tw/blog/software-download/inext-r-package/