A multi‐isotope (δ¹³C, δ¹⁵N, δ²H) feather isoscape to assign Afrotropical migrant birds to origins

Abstract

A universal challenge in methodology used to study the ecology, conservation and evolutionary biology of migratory species is the quantification of connectivity among breeding, wintering and stopover sites. For the avian Eurasian‐Afrotropical migratory system, knowledge of geographical wintering areas used by migrants that breed in Europe remains deficient, despite the advent of satellite transmitters and geolocators. Here we explored the use of theoretical plant δ13C and δ15N landscape distributions coupled with δ2H hydrologic models to construct multi‐isotopic avian foodweb clusters for Africa. The cluster analysis identified four distinct regions of Africa based on all three isotopes (13C, 2H, 15N), and five regions based only on 13C and 15N. We applied known isotopic diet‐tissue discrimination factors to map equivalent feather isotopic clusters for Africa. The validity of these feather isotopic clusters was tested by examining how well known‐ and unknown‐origin species were placed in regions of Africa using previously published feather isotope data. The success of this multi‐isotopic cluster model depended upon the species of interest and additionally on how well potential winter molt origins in Africa were constrained by prior information. Ground‐truthing data suggested this approach will be useful for first‐order approximation of overwintering regions for Afrotropical migrants and will be improved as our understanding of the nature of isoscapes for Africa is refined.

Reconstruction of the Gravettian food-web at Předmostí I using multi-isotopic tracking (13C, 15N, 34S) of bone collagen

“…Lateral view of the human mandible P26 from P redmostí I sampled for isotopic analysis. Riccialdelli et al, 2010;Hobson et al, 2012;Hückst€ adt et al, 2012;Madigan et al, 2012;Miller et al, 2013) but not so far in similar investigations using fossil material. In the present study, the pattern of distribution of individuals from herbivorous species on the one hand and carnivorous species on the other hand based on their d 13 C and d 15 N values was determined through a cluster analysis using the Ward's minimum variance method performed on stable carbon and nitrogen isotopic composition, with the software SAS JMP version 10.0, in order to identify trophic groups.…”

Matching geographical assignment by stable isotopes with African non-breeding sites of barn swallows Hirundo rustica tracked by geolocation

“…In a pioneering work, [21] proposed a detailed method for geographical assignments of Afrotropical migrant birds based on three natural stable isotopes, namely 2 H, 13 C and 15 N, wherein the baseline modelling is done by means of a multi-isotopic cluster model. This approach was refined, among others, by [4] by applying multivariate normal probability density functions for a spatially explicit assignment of the moult origin of birds.…”

“…The method is based on a high assignment resolution (e.g. 0.33° [4]) instead of the rather broad attribution to one of four or five isotopic similar regions (clusters) delineated by [21]. However, despite its increasing application, very few studies tested the assignment accuracy by matching assignment results with parallel direct tracking data such as geolocation [22, 23, 24].…”

Opportunism on the High Seas: Foraging Ecology of Olive Ridley Turtles in the Eastern Pacific Ocean

“…Nitrogen integrated into consumer tissues is enriched in 15 N relative to prey, such that top predators have the highest δ 15 N values (DeNiro and Epstein, 1981;Fry, 1988;Cabana and Rasmussen, 1996). Because the dominant nitrogen cycling regime in a region influences δ 15 N values at the base of the food chain (Hobson, 1999;Vander Zanden and Rasmussen, 2001), spatially discrete food webs with differing nutrient cycling offer distinct biogeochemical frameworks to study animal movement and trophic ecology (Hobson et al, 2012). In practice, measuring δ 15 N values of tissues from multiple individuals within a population can provide insights about local nitrogen sources, trophic level, and niche space (Thomas and Crowther, 2015).…”