Seabird Contributions to Island Ecosystem Dynamics

Seabirds act as pivotal engineers of island ecosystems by transporting nutrients, organic matter and, increasingly, contaminants from marine to terrestrial environments. Through annual deposition of guano, feathers and carcass remains, colonies enrich otherwise nutrient-poor soils with bioavailable nitrogen and phosphorus, triggering profound shifts in vegetation composition, productivity and successional trajectories. These ornitheutrophic inputs foster unique plant communities characterised by high biomass of specialised graminoids and forbs, while creating biogeomorphic feedbacks that can stabilise or reshape island topographies through altered sediment binding and root development. In polar and temperate regions, seabird-mediated fertilisation elevates microbial activity and alters soil pH, conductivity and trace-element profiles, with knock-on effects on invertebrate assemblages and food-web structure. Simultaneously, long-range foraging can introduce plastics and heavy metals, raising concerns over contaminant accumulation and ecosystem health. Understanding these dual roles of seabirds—as nutrient conveyors and vectors of pollution—is essential for effective conservation of breeding sites, the management of island habitats and the prediction of ecosystem responses to climate-driven shifts in seabird distributions.

Research from Nature Portfolio

Recent studies have deepened insight into how seabird colonies drive community segregation and global biogeochemical cycles. Work in high Arctic archipelagos has shown that faecal deposition by little auk colonies creates steep fertilisation gradients, leading to two distinct vegetation assemblages with differing niche overlap and facilitative interactions at community boundaries. This research highlights the mechanistic role of seabird-derived nitrogen in shaping plant diversity and inter-species competition under extreme nutrient limitation. Complementing this, a global inventory of seabird excretion has quantified annual fluxes of reactive nitrogen and phosphorus to islands and coastal waters, revealing that seabird contributions rival those of major terrestrial sources. These findings underscore the imperative to integrate seabird-mediated nutrient fluxes into models of island development, nutrient cycling and global marine-terrestrial connectivity.

Seabird Contributions to Island Ecosystem Dynamics publication trend

The graph below shows the total number of articles in seabird contributions to island ecosystem dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Guano: The excrement of seabirds, rich in nitrogen and phosphorus, which acts as a natural fertiliser when deposited on soil.

Ornitheutrophication: Nutrient enrichment of soils and water bodies resulting from bird-derived inputs, primarily guano deposition.

Biogeomorphic feedbacks: Interactions between biological processes (e.g. plant growth) and geomorphological changes (e.g. sediment stabilisation) that jointly shape landform evolution.

δ15N (delta-15-nitrogen): The ratio of stable nitrogen isotopes (^15N/^14N) used to trace the origin and cycling of nitrogen in ecological studies.

References

1. Birds influence vegetation coverage and structure on sandy biogeomorphic islands in the Dutch Wadden Sea. The Science of The Total Environment (2024).
2. Seabird transported contaminants are dispersed in island ecosystems. Chemosphere (2024).
3. Ecological niche overlap in the Arctic vegetation influenced by seabirds. Scientific Reports (2023).
4. Seabird colonies as important global drivers in the nitrogen and phosphorus cycles. Nature Communications (2018).