Seabird nutrient subsidies enrich mangrove ecosystems and are exported to nearby coastal habitats

In this study, we investigate how mangrove ecosystems respond to nutrient
subsidies supplied by nesting seabirds. We first quantify seabird guano
nutrient input and seabird guano nitrogen isotopes. We then assess the
influence of seabirds on mangroves by comparing nitrogen, phosphorus,
nutrient ratios and resoprtion efficiency in mangrove leaves sampled from
sites with nestings seabirds versus sites without nesting seabirds. We
trace the transfer of seabird-derived nutrients within the mangrove
ecosystems by comparing nitrogen isotope values in sediment, mangrove
leaves, gastropod and crabs at sites with nestings seabirds versus without
nesting seabirds. Lastly, we assess the export of seabird-derived
nutrients from mangrove ecosystems by comparing nitrate, nitrite and
phosphate levels in seawater, and nitrogen isotope values of macroalgae,
at sites with nestings seabirds versus without nesting seabirds.