Mesopredator frugivory has no effect on seed viability and emergence under experimental conditions

Members of the order Carnivora are a unique and important seed disperser who consume and deposit undamaged seeds while providing regular long-distance seed dispersal opportunities. Some members of Carnivora, such as coyotes (Canis latrans), are undergoing range expansions which may help the plant species they consume colonize new locations or replace dispersal services provided by recently extirpated species. In this study, we evaluated aspects of the seed dispersal effectiveness of coyotes and gut passage time to determine the potential dispersal distances for three commonly consumed and commonly occurring plant species (Amelanchier alnifolia, Celtis ehrenbergiana, and Juniperus osteosperma). We also investigated the potential effects of secondary dispersal of seeds away from scats by comparing seedling emergence from whole scats to those where seeds were first removed from scats. We found that seeds generally took between 4 and 24 h to pass through the digestive tract of coyotes, which could result in regular seed dispersal up to 7 km. Gut passage through coyotes had no effect on seed viability or emergence for any of the three plant species, including that gut passage for A. alnifolia and J. osteosperma does not replace cold stratification for breaking physiological dormancy. By simulating secondary dispersal, we found that 22% (+/- 8.2%) more C. ehrenbergiana seedlings emerged when seeds were removed from scats and those seedlings emerged 7 d earlier (+/- 5 d) compared to seeds that remained in the coyote scat. Coyotes are effective seed dispersers, with the potential for regular long-distance dispersal services and for providing opportunities for secondary seed dispersal, which could aid in climate migration or serve to replace extirpated dispersal mutualists.

Automated summary

Coyotes are effective seed dispersers, capable of providing regular long-distance dispersal services and opportunities for secondary seed dispersal, which could aid in climate migration or serve to replace extirpated dispersal mutualists.