Seabird Island Ecology

Abstract

Seabird islands house large colonies of seabirds that feed at sea but return to land to breed. Seabirds deposit large amounts of nutrients of marine origin onto islands; many species also disturb soil and vegetation during the building and maintenance of nests. Nutrient subsidies and physical disturbance by seabirds alter island soils and vegetation and modify plant and animal communities. Introduction of non‐native predators has resulted in population decreases or local extinction of many seabird species. Recent efforts at eradication of introduced seabird predators have been successful, but re‐establishment of seabirds and seabird island communities will likely take additional active restoration. Many other factors impact seabird populations such as overfishing, seabirds caught as by‐catch, increases in sea surface temperature, sea level rise, and various sorts of marine pollution, including plastics consumed by seabirds. These factors directly and indirectly affect the ecology of seabird islands. Key Concepts Seabirds deposit nutrients of marine origin in terrestrial environments. Seabirds impose physical disturbance on soils and vegetation in the process of building and maintaining nests. Seabird islands often house endemic and native plants and animals that are no longer found on the mainland. The presence of seabirds selects for plants that are tolerant of high‐disturbance and high‐nutrient (i.e. nitrogen and phosphorus) conditions and that increase primary and secondary productivity. Introduced mammalian predators have eradicated seabirds and other species on many seabird islands. The reduction of seabird populations by introduced predators alters plant and animal communities and nutrient cycling. Eradication of seabird predators is a necessary first step towards restoration of seabird islands. Restoration of seabird islands often requires active management of seabirds, other animals and plant populations. Protection of seabird islands will require international cooperation on land and at sea. Several marine environmental issues impact seabird populations and thus also the island communities that are tightly associated with seabird presence.

Transfer of nitrogen by migratory birds in the African-Western Eurasian Flyways

“…The movement of nutrients between ecosystems by migrating organisms has been well documented in fish [1,2], seabirds [3] and other taxa [4,5,6]. For example, the deposition of nitrogen (N) and phosphorus (P) in bird guano by migrating seabirds on islands increases primary productivity, changes soil characteristics, and affects organisms throughout food webs [7,8,9]. Migrating animals in some ecosystems represent a vital seasonal nutritional input that sustains ecosystems throughout the year [10], and nutrient transfer by migrating species changes ecosystem functions in complex ways [6,11,12].…”