Forest Restoration on a Closed Landfill: Rapid Addition of New Species by Bird Dispersal

Urban areas often contain sizeable pockets of de- graded land, such as inactive landfills, that could be re- claimed as wildlife habitat and as connecting links to en- hance remnant natural areas. In the northeastern US, many such lands fail to undergo natural succession to woodland, instead retaining a weedy, herbaceous cover for many years. We hypothesize that seed dispersal is a limiting factor, and that a form of secondary succession could be stimulated by introducing clusters of trees and shrubs to attract avian seed dispersers. As a direct test, we censused a 1.5-ha experimental plantation on the Fresh Kills Landfill (Staten Island, New York) one year after installation, in search of evidence that the plantation was spreading or increasing in diversity. The 1 7planted species, many from coastal scrub forests native to this region, were surviving well but contributed almost no seedlings to the area, in part because only 20% of the in- stalled trees or shrubs were reproductive. Of the 1079 woody seedlings found, 95% came from sources outside the plan- tation; most (71%) were from fleshy-fruited, bird-dispersed plants from nearby woodland fringes. Although the restora- tion planting itself had not begun to produce seedlings, it didfunction as a site for attracting dispersers, who enriched theyoung community with*20 new species. One-fourth of all new recruits were from nine additional wind-dispersed spe- cies. Locations with a high ratio of trees to shrubs had pro- portionately more recruits, indicating that plant size con- tributed to disperser attraction. The density of new recruits of each species was dependent on distance from the nearest potential seed source. Introducing native species with the capacity to attract avian dispersers may be the key to success