Diet analysis using generalized linear models derived from foraging processes using R package mvtweedie.

Autor: Thorson JT; AFSC, NMFS, NOAA, Seattle, Washington, USA., Arimitsu ML; U.S. Geological Survey Alaska Science Center, Juneau, Alaska, USA., Levi T; Department of Forest Ecosystems and Society, Oregon State University, Corvallis, Oregon, USA., Roffler GH; Alaska Department of Fish and Game, Douglas, Alaska, USA.
Jazyk: angličtina
Zdroj: Ecology [Ecology] 2022 May; Vol. 103 (5), pp. e3637. Date of Electronic Publication: 2022 Mar 16.
DOI: 10.1002/ecy.3637
Abstrakt: Diet analysis integrates a wide variety of visual, chemical, and biological identification of prey. Samples are often treated as compositional data, where each prey is analyzed as a continuous percentage of the total. However, analyzing compositional data results in analytical challenges, for example, highly parameterized models or prior transformation of data. Here, we present a novel approximation involving a Tweedie generalized linear model (GLM). We first review how this approximation emerges from considering predator foraging as a thinned and marked point process (with marks representing prey species and individual prey size). This derivation can motivate future theoretical and applied developments. We then provide a practical tutorial for the Tweedie GLM using new package mvtweedie that extends capabilities of widely used packages in R (mgcv and ggplot2) by transforming output to calculate prey compositions. We demonstrate this approach and software using two examples. Tufted Puffins (Fratercula cirrhata) provisioning their chicks on a colony in the northern Gulf of Alaska show decadal prey switching among sand lance and prowfish (1980-2000) and then Pacific herring and capelin (2000-2020), while wolves (Canis lupus ligoni) in southeast Alaska forage on mountain goats and marmots in northern uplands and marine mammals in seaward island coastlines.
(© 2022 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America. This article has been contributed to by US Government employees and their work is in the public domain in the USA.)
Databáze: MEDLINE
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