ecoteach (version 0.1.0)

vulture_diet: Gyps Vulture Stable Isotope Analysis - Feather Data (AR.feather subset)

Description

Stable isotope data (carbon, nitrogen, and sulfur) from Gyps vulture feathers collected in Tanzania for dietary analysis using stable isotope mixing models (SIMM). This dataset represents the AR.feather subset containing raw consumer isotope values from vulture feathers. Data was collected over 10 months from two protected areas: Serengeti National Park and Selous Game Reserve to analyze vulture dietary patterns across space and time using stable isotope analysis.

Usage

vulture_diet

Format

A data frame with 21 rows and 5 variables:

d13C

Numeric, delta 13C carbon isotope values per mill (‰)

d15N

Numeric, delta 15N nitrogen isotope values per mill (‰)

d34S

Numeric, delta 34S sulfur isotope values per mill (‰)

species

Factor, vulture species sampled (African white-backed or Rüppell's griffon)

tissue

Factor, tissue type analyzed (feathers)

Details

Vultures were captured using noose lines around provisioned or natural bait, processed, and released. Feather samples were analyzed for delta13C, delta15N, and delta34S using a PyroCube elemental analyzer at the NERC Life Sciences Mass Spectrometry Facility. The isotope signatures provide insights into vulture diet composition, with delta13C distinguishing between C3 and C4 plant consumers (browsers vs grazers), delta15N indicating trophic level, and delta34S helping separate geographic regions.

This subset was specifically prepared for use in stable isotope mixing models to estimate diet composition in Gyps vultures. The study found that vulture diet consisted primarily of grazing herbivores, with those in Serengeti National Park consuming higher proportions (>87%) of grazing species. Coordinates in the original study were denatured by +0.5 degrees to preserve geographic distribution while ensuring location confidentiality.

Collection period: August 18, 2018 to May 31, 2019 Study locations: Serengeti National Park (2.1540°S, 34.6857°E) and Selous Game Reserve (9.0000°S, 37.5000°E), Tanzania

Examples

# \donttest{
# Load the dataset
data(vulture_diet)
head(vulture_diet)
summary(vulture_diet)

# Examine isotope signatures by species
boxplot(d13C ~ species, data = vulture_diet,
        main = "Carbon Isotope Signatures by Vulture Species",
        xlab = "Species", ylab = "d13C (per mill)")

# Create isotope biplot
plot(vulture_diet$d13C, vulture_diet$d15N,
     col = as.numeric(vulture_diet$species),
     pch = 16, cex = 1.2,
     xlab = "d13C (per mill)", ylab = "d15N (per mill)",
     main = "Vulture Feather Isotope Signatures")
legend("topright", legend = levels(vulture_diet$species), 
       col = 1:nlevels(vulture_diet$species), pch = 16)

# Summary statistics by species
aggregate(. ~ species, data = vulture_diet[,1:4], FUN = mean)
# }