Seascape configuration determines spatial patterns of seabird-vectored nutrient enrichment to coral reefs (dataset)

Pelagic-feeding seabirds deliver nutrient subsidies that enhance the productivity, biodiversity, and resilience of terrestrial and marine ecosystems, particularly in nutrient-poor tropical environments. However, the biogeophysical variables governing the fluxes of these nutrients within and among interconnected ecosystems remain poorly understood. To address this, we examined the spatial distribution of seabird-vectored nutrients in the seascape of Tetiaroa, a semi-enclosed coral atoll in French Polynesia, where seabird populations and associated nutrient cycles are recovering after recent rat eradication. We focus on the nitrogen isotope (δ¹⁵N) signatures of a dominant marine alga as evidence of seabird-vectored nutrient uptake. Integrating stable isotope analysis within a seascape ecology framework, we show that breeding seabird biomass, depth, distance to land, geographic location within the atoll, and seafloor curvature drive spatial patterns of nutrient enrichment. Specifically, our models account for up to 88% of the variation in algal δ¹⁵N signatures and reveal peak enrichment in shallow, nearshore areas where water flow slows and converges due to localised seafloor curvature.