sbdiv for methods rpht, tsht,
asht. Sums up species counts in each columns for every
treatment group and estimates Shannon's index with bias correction on
the resulting vectors of summed up species counts.
$$\widehat{HBC}_{i} = \hat{H}_{i} + (S_i -1)/(2N_{i\bullet}) -
(1-\sum(1/\hat{p}_{i\bullet s}))/(12N_{i\bullet}^2) -
\sum((1/\hat{p}_{i\bullet s})-(1/(\hat{p}_{i\bullet
s}^2)))/(12N_{i\bullet}^3);$$$i=1,...,k;s=1,...,S;p_{i \bullet s}=\frac{\sum_{j=1}^{n}x_{sj}}{N_{i\bullet}}$;
$$\hat{H}_i=(-1)\sum_{s=1}^{S}(\hat{p}_{i \bullet s} log(\hat{p}_{i \bullet s}))$$
$N_{i\bullet}= \sum_{j=1}^{n}N_{ij}$ Number of observed individuals in treatment $i$.
estShannonf(X, f)