| Species and treatment | Oct-14 | Dec-14 | Feb-15 | Apr-15 | Jun-15 | Aug-15 | Oct-15 | ||||||||||||||||||||||
| Z. matrella | Wet | 1.15 | ± | 0.00 | bz | 0.94 | ± | 0.00 | by | 0.96 | ± | 0.00 | by | 1.03 | ± | 0.00 | by | 1.14 | ± | 0.01 | cy | 1.10 | ± | 0.01 | cy | 1.02 | ± | 0.01 | by |
| O. japonicus | Wet | 1.21 | ± | 0.00 | c | 1.16 | ± | 0.00 | c | 1.06 | ± | 0.01 | c | 1.06 | ± | 0.01 | c | 1.11 | ± | 0.00 | b | 1.19 | ± | 0.00 | d | 1.18 | ± | 0.00 | c |
| S. mexicanum | Wet | 1.04 | ± | 0.01 | a | 0.91 | ± | 0.00 | a | 0.92 | ± | 0.00 | a | 1.02 | ± | 0.00 | ab | 1.08 | ± | 0.01 | a | 1.04 | ± | 0.01 | b | 1.03 | ± | 0.01 | b |
| Dry | 0.91 | ± | 0.00 | a | 0.92 | ± | 0.00 | a | 1.01 | ± | 0.00 | a | 1.11 | ± | 0.01 | b | 0.95 | ± | 0.01 | a | 0.93 | ± | 0.00 | a | |||||