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Table 2

Density of amphibian tail fin, and conversion into the fin surface required to produce 100 μg of freeze-dried matter (i.e. the minimum mass required for nitrogen-rich biological material for stable isotope measurements).

Species Number of individuals Freeze-dried matter density (µg mm−2) Fin surface required (mm−2)


  (fin samples) Mean ± SD Range Mean ± SD Range
Agile frog 17 (62) 13.7 ± 4.7 6.9–22.7 9.0 ± 2.8 5.5–16.7
European tree frog 10 (39) 7.9 ± 2.4 5.1–12.4 14.4 ± 4.1 9.0–20.8
Marbled newt 29 (139) 55.3 ± 9.1 23.1–89.4 2.0 ± 0.4 1.0–4.4
Palmate newt 7 (23) 37.7 ± 4.2 25.4–62.2 3.0 ± 0.2 1.8–4.0