qfasar: Quantitative Fatty Acid Signature Analysis in R

Knowledge of predator diets provides numerous insights into their ecology. Diet estimation therefore remains an active area of research in quantitative ecology. Quantitative Fatty Acid Signature Analysis (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 mass composition of lipids. For diet estimation, signatures from one or more predators and from samples of all types of prey potentially consumed by the predators 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 linear mixture of the mean prey-type signatures and diet composition is estimated as the specific mixture that minimizes a measure of distance between the observed and modeled predator signatures.