qfasar: Quantitative Fatty Acid Signature Analysis in R

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 of distance between the observed and modeled signatures. A variety of estimation options, goodness-of-fit diagnostic procedures to assess the suitability of estimates, and simulation capabilities are implemented. Please refer to the package vignette and the documentation files for individual functions for details and references.

Data and Resources

Field Value
accessLevel public
bureauCode {010:12}
catalog_@context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
catalog_conformsTo https://project-open-data.cio.gov/v1.1/schema
catalog_describedBy https://project-open-data.cio.gov/v1.1/schema/catalog.json
datagov_dedupe_retained 20220725164314
identifier USGS:ASC64
metadata_type geospatial
modified 20201125
publisher U.S. Geological Survey
publisher_hierarchy Department of the Interior > U.S. Geological Survey
resource-type Dataset
source_datajson_identifier true
source_hash 8f20af253b5703c4b7a0272e7055fc6404ced98f
source_schema_version 1.1
theme {geospatial}
Groups
  • AmeriGEOSS
  • National Provider
  • North America
Tags
  • aitchison-distance-measure
  • amerigeo
  • amerigeoss
  • biota
  • bootstrap-sampling
  • chi-square-distance-measure
  • ckan
  • clustering
  • diet-composition
  • diet-estimation
  • distance-measure
  • geo
  • geoss
  • goodness-of-fit
  • kullback-leibler-distance-measure
  • linear-mixing-model
  • national
  • north-america
  • numerical-optimization
  • predator-prey
  • qfasa
  • quantitative-fatty-acid-signature-analysis
  • r_
  • rsolnp
  • simulation
  • united-states
  • usgs-asc64
isopen False
license_id notspecified
license_title License not specified
maintainer U.S. Geological Survey Alaska Science Center
maintainer_email ascweb@usgs.gov
metadata_created 2025-11-21T02:44:15.264714
metadata_modified 2025-11-21T02:44:15.264718
notes 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 of distance between the observed and modeled signatures. A variety of estimation options, goodness-of-fit diagnostic procedures to assess the suitability of estimates, and simulation capabilities are implemented. Please refer to the package vignette and the documentation files for individual functions for details and references.
num_resources 2
num_tags 27
title qfasar: Quantitative Fatty Acid Signature Analysis in R