Locomotion during digestion changes current estimates of seed dispersal kernels by fish

Dispersal of seeds by animals is an important mechanism regulating plant diversity, range expansions and invasions. Many birds, mammals, fish, and reptiles regularly ingest, transport and excrete viable seeds (known as endozoochory). The effectiveness of endozoochory is modelled in dispersal kernels: functions that describe seed shadows in the landscape by combining movement of animals with experimentally obtained seed retention times and survival. Currently, dispersal kernels use experimental data from resting animals, yet only moving animals disperse seeds. Although physical activity is known to affect digestive processes, little is known on how and to what extent this may influence current estimates of endozoochory. Activity may either prolong seed retention in the animal's gut (locomotion-priority mode hypothesis) or may not affect seed excretion rate (digestion-priority mode hypothesis), and may affect seed survival and germination positively or negatively. We tested how activity a...