A Comparison of Plant Succession and Bird Utilization on Diked and Undiked Dredged Material Islands in North Carolina Estuaries.

摘要

This project consisted of a comparison of plant succession and bird utilization on diked and undiked dredged material islands in North Carolina estuaries. After a site is diked, deposition of dredged material may be delayed for several years or it may occur immediately. Unfilled diked islands that were studied had a complex topographic zonation. Plant succession was highly variable on these unfilled sites, with topography, substrate particle size, and availability of water being major causative factors. Plant succession on diked and filled sites was similar to that on undiked islands except that dikes tended to vegetate more quickly than did the deposits on outer portions of undiked sites. Only the least and gull-billed terns were found nesting predominantly on diked sites, with most nesting gulls and terns locating the majority of their breeding colonies on undiked sites. Fifteen to 30 years will be required for thickets suitable for wading bird colonies to develop on diked islands in North Carolina. Based on observations in New Jersey, it is expected that wading birds will use diked sites when appropriate habitat becomes available. No positive values of dikes relative to nesting colonial birds were discovered. One hundred forty-two species of shorebirds, waterfowl, and land birds were recorded on diked islands, while 94 species were found on undiked sites. Heaviest use was during fall migration. The increased avian diversity of diked over undiked sites paralleled the increased temporary diversity of habitats on diked sites.