Table 1.
Characteristics of the studies from which data were taken
| Study name |
Reference |
Country |
No. of species |
Growth forms |
Device and rehydration procedure* |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| Original studies | ||||||||||
| FR-Med | France | 44 | Short-lived forbs (7) | Linear variable displacement transducer | ||||||
| Long-lived forbs (5) | 24 h in test tubes with deionized water in the dark at 4 °C | |||||||||
| Short-lived graminoids (2) | ||||||||||
| Long-lived graminoids (9) | ||||||||||
| Shrubs (17) | ||||||||||
| Trees (4) | ||||||||||
| Succulent (1) | ||||||||||
| SP-Med | Spain | 46 | Long-lived forbs (4) | Linear variable displacement transducer | ||||||
| Long-lived graminoids (6) | 24 h in test tubes with deionized water in the dark at 4 °C | |||||||||
| Shrubs (22) | ||||||||||
| Trees (14) | ||||||||||
| Succulent (1) | ||||||||||
| SA-Med | South Africa | 46 | Long-lived forbs (3) | Linear variable displacement transducer | ||||||
| Long-lived graminoids (3) | 24 h in test tubes with deionized water in the dark at 4 °C | |||||||||
| Shrubs (17) | ||||||||||
| Trees (7) | ||||||||||
| Not available (16)† | ||||||||||
| Succulents (4) | ||||||||||
| Published studies | ||||||||||
| EU-1 | Ryser and Urbas (2000) | Central Europe | 27 | Long-lived graminoids (27) | ID-C digimatic indicator (0·01 mm) | |||||
| One night rehydration | ||||||||||
| EU-2 | Wilson et al. (1999)‡ | Great Britain | 632 | Short-lived forbs (179) | Verdict analogue thickness gauge | |||||
| Long-lived forbs (331) | Hydrated over night in moist tissue paper in sealed polythene bags in a refrigerator (4 °C) | |||||||||
| Short-lived graminoids (10) | ||||||||||
| Long-lived graminoids (70) | ||||||||||
| Ferns (19) | ||||||||||
| Shrubs (18) | ||||||||||
| Tree (1) | ||||||||||
| Others (4) | ||||||||||
| Succulents (9) | ||||||||||
| AR-Cen | Vendramini et al. (2002) | Central Argentina | 55 | Short-lived forbs (3) | Cross-sectional observations under microscope | |||||
| Long-lived forbs (11) | No, but harvested after rainfall | |||||||||
| Trees (26) | ||||||||||
| Short-lived graminoids (2) | ||||||||||
| Long-lived graminoids (13) | ||||||||||
| Succulents (22) | ||||||||||
| CA-Qué | Shipley (1995) | Canada | 33 | Short-lived forbs (8) | Dial gauge micrometer | |||||
| Long-lived forbs (21) | Plants, harvested with roots, immediately brought back to the lab and given free access to water; measurements done within 3 h after harvest. | |||||||||
| Graminoids (2) | ||||||||||
| Shrubs (2) | ||||||||||
| AU-1 | Cunningham et al. (1999) | Australia | 37 | Shrub (1) | Cross-sections and image analysis | |||||
| Trees (36) | (2) 10-min hydration | |||||||||
| Succulent (1) | ||||||||||
| AU-2 | Roderick et al. (1999b) | Australia | 26 | Long-lived forbs (4) | Dial thickness gauge | |||||
| Shrubs (2) | Yes and no (no difference between the two) | |||||||||
| Trees (20) | ||||||||||
| AU-3 | Wright (2001) | Australia | 70 | Shrubs (53) | Dial gauge micrometer | |||||
| Trees (17) | Overnight between sheets of damp paper towel at 4 °C | |||||||||
| AU-4 | Prior et al. (2003) | Australia | 23 | Trees (23) | Dial gauge micrometer | |||||
| Overnight between sheets of damp paper | ||||||||||
For Tables 2–5 and Fig. 1, only laminar leaved species were considered (i.e. rolled and needle leaves were excluded); total species number is given in column 4 and detailed by growth forms in column 5. The number of succulent species used in Fig. 2 is added in column 5 (these species were not included in the calculation of total number of species shown in column 4).
Information about the ‘device’ which is the piece of equipment used to measure thickness is followed by the rehydration procedure of how leaves were rehydrated before the measurement of fresh mass.
These 16 taxa were not identified to the species level, and in the absence of unequivocal information, these were not assigned to a specific growth form.
Aquatics were removed from the original data set because their particular leaf anatomy confounds predictions of density.