Masting benefits seedling recruitment of Armeniaca sibirica through directed dispersal by rodents

Abstract

In animal-dispersed plants, masting is often claimed to promote fitness through increasing seed survival (e.g., predator satiation hypothesis) and/or seed dispersal (e.g., predator dispersal hypothesis). Plant fitness is also enhanced when seeds are disproportionally deposited at the safe sites by animals in spatially heterogeneous environments (i.e., directed dispersal hypothesis). However, little is known about the relationship between masting and directed dispersal in animal-dispersed plants. Here, we tracked seed production, seed dispersal and seedling establishment of a rodent-dispersed plant (Armeniaca sibirica) from 2005 to 2017 in a warm-temperate forest in northern China. We hypothesized that masting would improve seed dispersal fitness through directed dispersal mediated by small rodents. Compared to the null model of random dispersal, more seeds were deposited at the safe sites and more seedlings were established from the safe sites in seed-rich years, indicating that directed dispersal occurred in the masting years. The proportions of seed deposition and seedling establishment at the safe sites were positively associated with seed abundance and seed-rodent ratio, suggesting that masting increased directed dispersal effects. Overall, seed abundance was better in predicting directed dispersal effects than rodent abundance or seed-rodent ratio. Beyond the most commonly considered advantages of predator satiation and predator dispersal, our results are the first to suggest that masting is beneficial for seed dispersal through directed dispersal mediated by animals. This finding might contribute to a better understanding of masting effects on plant recruitment.