Complex sentence: The non-transferability of the authorship means that there is no way to transfer several exploitation rights in whole but the possibility to grant rights of use to a utiliser, according to the § 31 UrhG.
Split into simpler sentences: The non-transferability of the authorship means that there is no way to transfer the exploitation rights on the whole. However, there is the possibility of granting certain rights of use to someone else, according to the § 31 UrhG.