Landscape Corridors Promote Long Distance Seed Dispersal by Birds During Winter but Not During Summer at an Experimentally Fragmented Restoration Site

In fragmented landscapes, plant population persistence and community
diversity can hinge upon plants dispersing seeds long distances
between isolated patches of habitat. Landscape corridors, which
connect otherwise isolated patches, have been shown to increase seed
dispersal by birds moving between patch fragments. However, because
bird behaviors change seasonally, the strength of this "corridor
effect" may also change. We assessed the utility of corridors for
promoting seed dispersal by birds during both summer and winter in a
well-replicated corridor experiment conducted in early successional
longleaf pine (Pinus palustris) savannah habitat at the Savannah River
Site in South Carolina, USA. We used a single species of
bird-dispersed fruiting plant, American black nightshade (Solanum
americanum), and controlled the timing and number of fruits available
to birds during summer and winter. Corridors increased long-distance
seed dispersal during winter but not during summer, indicating that
the effectiveness of corridors for promoting long-distance seed
dispersal can depend upon plant reproductive timing and seasonal
differences in bird movement. A better understanding of the
seasonality of plant-animal interactions will permit better
predictions about whether and how corridors provide connectivity for
plants.