Dear Gesine and Maria,

Sorry again that I took so long before decision. I ask one of the reviewers to read again the revised version of the manuscript. He said to me that your revised version is well reorganized, but he suggested a minor point. He suggested you to read a paper (Ishikawa et al., 2013, Ecological Research, 28, 759-, if you cannot access the paper, please contact me.) reporting a pitfall when estimating contribution based on d13C and D14C. Because D14C is, as definition, corrected with the d13C value, it needs a caution when applying a cross plot of d13C and D14C data for calculating the source contributions. This pitfall has generally been overlooked, but should not be neglected, theoretically speaking. Please look at the Appendix of the paper. As far as your data are concerned, it seems this correction is not a serious issue, but I ask you to check this, and mention this point in the revised manuscript.

Best,

Nao