QFASA code (Fortran, R)

R and Fortran code used in quantitative fatty acid signature analysis (QFASA) robustness to assumption violations.

Categories: Software

QFASA Supplementary Data - Marine Mammal Fatty Acid Data

This dataset contains fatty acid (FA) data expressed as mass percent of total FA for bearded seals, ringed seals and walrus. This is one of many datasets used in Bromaghin et al., In press, Assessing the robustness of quantitative fatty acid signature analysis to assumption violations, Methods in Ecology and Evolution. These supplemental data were used in computer simulations to compare the bias of several quantitative fatty acid signature analysis (QFASA) estimators and develop recommendations regarding estimator selection. These data were collected to gain insights into the diet composition of Chukchi Sea polar bears.

qfasar (package of R functions)

An implementation of Quantitative Fatty Acid Signature Analysis (QFASA) in R. QFASA is a method of estimating the diet composition of predators. The fundamental unit of information in QFASA is a fatty acid signature (signature), which is a vector of proportions describing the fatty acid composition of adipose tissue. Signature data from at least one predator and from samples of all potential prey types are required. Calibration coefficients, which adjust for the differential metabolism of individual fatty acids by predators, are also required. Given those data inputs, a predator signature is modeled as a mixture of potential prey signatures and its diet estimate is obtained as the mixture that minimizes a measure...