https://doi.org/10.5061/dryad.0rxwdbs79

The dataset contains the following raw data : Seabird guano nutrients (3 files), Mangrove leaves nutrients (1 file), Mangrove foodweb nitrogen isotopes (1 file) and Seawater nutrient concentrations (1 file). The dataset also contains code for analyses (4 files).

Description of the data and file structure

Raw data files:

1. Seabird guano nutrients:
   • seabird_guano_nutrient_quantity.csv: nitrogen (N) and phosphorus (P) content of red-footed boobies and lesser frigatebird guano from samples collected in nests. N and P are in g/kg dry weight.
   • seabird_guano_nitrogen_isotope.csv: nitrogen isotope values (d15N) of red-footed boobies and lesser frigatebird guano from samples collected in nests. d15N values are in ‰.
   • seabird_guano_nutrient_total.csv: guano nutrient quantity and population metrics (number of breeding pairs, number of days of breeding period, proportion of time spent on nests, productivity [proportion of fledged chicks per breeding pair], defecation rate) for red-footed boobies and lesser frigatebird. Nutrient quantities are in g/kg dry weight, defecation rates are in g/bird/day.
2. Mangrove leaves nutrients:
   • mangrove_leaves_nutrients.csv: nitrogen isotope values (d15N), nitrogen (N), carbon (C) and phosphorus (P) concentration in green mangrove leaves (d15NG, NG, CG, PG) and senescent leaves (NB, CB, PB). Samples collected at 10 sites (5 seabird, 5 non-seabird sites) and within 8 quadrats at each site (suffix A-H). N, C and P are expressed as % composition, d15N values are in ‰.
3. Mangrove foodweb nitrogen isotope:
   • mangrove_foodweb_nitrogen_isotope.csv: nitrogen isotope values (d15N) of mangrove ecosystem compartments (leaves, sediment, littorinid gastropod, sesarmid crab, portunid crab, Halimeda macroalgae). Samples collected at 10 sites (5 seabird, 5 non-seabird sites) and within 8 quadrats at each site (suffix A-H). d15N values are in ‰.
4. Seawater nutrient concentrations:
   • seawater_nutrients_lagoon.csv: seawater nutrient concentrations (NOx and phosphate) collected at sites with seabird and without seabirds and during incoming and outgoing tide. NOx and phosphate are in µmol/L.

Code/Software

R scripts:

1. guano: Analyses for guano nutrients. Uses 'seabird guano nutrient' raw data files.
2. mangrove_nutrient: Analyses for mangrove nutrients, nutrient ratios and resorption efficiency. Uses 'mangrove leaves nutrients' raw data file.
3. foodweb_isotope: Analyses for mangrove foodweb isotopes. Uses 'mangrove foodweb nitrogen isotope' raw data file.
4. seawater: Analyses for seawater nutrient concentrations. Uses 'seawater nutrient concentrations' and 'mangrove foodweb nitrogen isotope' raw data file.

All codes are run with R software (version 4.3.0). R packages used include: dplyr, ggplot2, nlme, car, MuMIn, ggeffects, emmeans.