Temporal consistency in the spatial pattern of seed predation across a forest - old field edge
2003
Meiners, S.J. | LoGiudice, K.
Seed predation is an important factor in determining the rate of tree establishment in abandoned agricultural land. Edges, through altered habitat use by small mammals, may influence the spatial pattern of forest regeneration in these successional sites. To determine the spatial pattern of seed predation across a forest-old field edge, we used a grid that began 30 m inside the forest and extended 60 m into the old field. Seed stations were placed at regular 10-m intervals and were monitored for removal of Acer rubrum seed for 50 d. This design was repeated over four years (1995-1998). Small mammal trapping was conducted in the final year of the study to determine the spatial pattern of seed predators within the site. Removal rates varied among the four years of the study with years of high and low removal rates. However, the spatial pattern of seed removal rate was similar in all years. Final survival ranged from 0.7-15.5% of seeds, with lower final survival in years with faster rates of seed removal (1996 and 1998). Seed removal rates and rates of discovery were greatest at the forest edge and decreased with distance into the old field. The number of seeds surviving to the end of the experiment also varied across the edge gradient, with highest survival at greater distances into the old field in low predation years. Seed removal rate covaried with spatial pattern of Peromyscus leucopus captures within the site. Seed removal and discovery was also higher under the exotic shrub Rosa multiflora, which may have provided cover for foraging seed predators. These indirect effects of edges on plant communities can potentially alter the rate and spatial pattern of tree invasion into disturbed lands and illustrate the importance of understanding plant-animal interactions in the context of habitat fragmentation.
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