Month,Zone,Replicate,SpeciesA,SpeciesB,SpeciesC
Sept,1,1,5,10,15
Sept,1,2,0,5,10
Sept,1,3,5,0,5
Sept,2,1,5,5,5
Sept,2,2,10,15,10
Sept,2,3,0,0,5

##</code><code>##

#!/usr/bin/env perl

use strict;
use warnings;

use Data::Table;
use Statistics::Lite qw(mean stddev);

my $dt = Data::Table::fromCSV("data.csv");

print "Original Data Table\n";
print "===================\n";
print $dt->tsv;
print "\n\n";

my $melt = $dt->melt(['Month', 'Zone', 'Replicate']);

print "Melt Table\n";
print "==========\n";
print $melt->tsv;
print "\n\n";

my $cast_mean = $melt->cast(
    ['Month', 'Zone'],
    'variable',
    Data::Table::STRING,
    'value',
    \&mean
); 

print "Cast (mean)\n";
print "===========\n";
print $cast_mean->tsv;
print "\n\n";

my $cast_stddev = $melt->cast(
    ['Month', 'Zone'],
    'variable',
    Data::Table::STRING,
    'value',
    \&stddev
); 

print "Cast (stddev)\n";
print "=============\n";
print $cast_stddev->tsv;

exit;

##</code><code>##

Original Data Table
===================
Month	Zone	Replicate	SpeciesA	SpeciesB	SpeciesC
Sept	1	1	5	10	15
Sept	1	2	0	5	10
Sept	1	3	5	0	5
Sept	2	1	5	5	5
Sept	2	2	10	15	10
Sept	2	3	0	0	5


Melt Table
==========
Month	Zone	Replicate	variable	value
Sept	1	1	SpeciesA	5
Sept	1	1	SpeciesB	10
Sept	1	1	SpeciesC	15
Sept	1	2	SpeciesA	0
Sept	1	2	SpeciesB	5
Sept	1	2	SpeciesC	10
Sept	1	3	SpeciesA	5
Sept	1	3	SpeciesB	0
Sept	1	3	SpeciesC	5
Sept	2	1	SpeciesA	5
Sept	2	1	SpeciesB	5
Sept	2	1	SpeciesC	5
Sept	2	2	SpeciesA	10
Sept	2	2	SpeciesB	15
Sept	2	2	SpeciesC	10
Sept	2	3	SpeciesA	0
Sept	2	3	SpeciesB	0
Sept	2	3	SpeciesC	5


Cast (mean)
===========
Month	Zone	SpeciesA	SpeciesB	SpeciesC
Sept	1	3.33333333333333	5	10
Sept	2	5	6.66666666666667	6.66666666666667


Cast (stddev)
=============
Month	Zone	SpeciesA	SpeciesB	SpeciesC
Sept	1	2.88675134594813	5	5
Sept	2	5	7.63762615825973	2.88675134594813