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Quantitative fatty acid signature analysis (QFASA) is a method of diet estimation introduced over a decade ago (Iverson et al. 2004). Even so, software implementing QFASA has only recently been publicly available. A new R package, called qfasar, provides the basic functionality to estimate diet composition in typical QFASA studies. In addition, the package provides more advanced functionality to evaluate and potentially improve the performance of a library of prey signature data, compute goodness-of-fit diagnostics that may be useful to assess the reliability of diet composition estimates, and perform various tasks to support simulation-based research. The package makes traditional estimation methods and several recently-published analytical techniques easily accessible to ecologists for the first time. qfasar is available on the CRAN website and from the US Geological Survey, Alaska Science Center products website.
Bromaghin, J. F. 2015. Simulating realistic predator signatures in quantitative fatty acid signature analysis. Ecological Informatics 30:68-71. doi:10.1016/j.ecoinf.2015.09.011
Bromaghin, J. F., S. M. Budge, and G. W. Thiemann. 2016. Should fatty acid signature proportions sum to 1 for diet estimation? Ecological Research 31:597-606. doi:10.1007/s11284-016-1357-8
Bromaghin, J. F., S. M. Budge, G. W. Thiemann, and K. D. Rode. 2016. Assessing the robustness of quantitative fatty acid signature analysis to assumption violations. Methods in Ecology and Evolution 7(1):51-59. doi:10.1111/2041-210X.12456
Bromaghin, J. F., K. D. Rode, S. M. Budge, and G. W. Thiemann. 2015. Distance measures and optimization spaces in quantitative fatty acid signature analysis. Ecology and Evolution 5(6):1249-1262. doi:10.1002/ece3.1429
Iverson, S. J., C. Field, W. D. Bowen, and W. Blanchard. 2004. Quantitative fatty acid signature analysis: a new method of estimating predator diets. Ecological Monographs 74:211–235. doi:10.1890/02-4105