It is good to be eaten by a bear: The implications of ingestion for the germination of berry producing species

The ability of seeds to germinate after ingestion is important to the population dynamics of some plant species and for understanding the relationships between consumers and producers.  Many studies have evaluated germinability after gut passage through birds.  However, grizzly bears and black bears also interact with many plant species.  Throughout the Rocky Mountain region, bears consume vast quantities of soft mast during late summer and early autumn.  For this reason, we evaluated the effect of gut passage on the ability of Vaccinium, Shepherdia and Amelanchier species to germinate.  Each species was evaluated over three treatments: 1) seed extracted from scat 2) seed mechanically separated from berry and 3) whole berry.  Furthermore, the viability of ungerminated seed was tested by tetrazolium treatment.  Across all species, gut passage appears to have positive effects on the percent germination.  For Vaccinium and Shepherdia species, the seed extracted from scat and the mechanically extracted seed exhibited similar germination percentages, suggesting a simple mechanistic relationship that requires little more than removing the seed from the berry.  The results imply that while bears may not be unique in their ability to increase germination, they do perform a function beneficial to the plants.