FN Archimer Export Format PT J TI Isotopic Diversity Indices: How Sensitive to Food Web Structure? BT AF BRIND'AMOUR, Anik DUBOIS, Stanislas AS 1:1;2:2; FF 1:PDG-RBE-EMH;2:PDG-ODE-DYNECO-BENTHOS; C1 IFREMER, Fisheries Ecol & Modelling Dept, Nantes, France. IFREMER, DYNECO Benth Ecol Lab, Plouzane, France. C2 IFREMER, FRANCE IFREMER, FRANCE SI NANTES BREST SE PDG-RBE-EMH PDG-ODE-DYNECO-BENTHOS IN WOS Ifremer jusqu'en 2018 IF 3.534 TC 33 UR https://archimer.ifremer.fr/doc/00171/28270/26522.pdf LA English DT Article AB Recently revisited, the concept of niche ecology has lead to the formalisation of functional and trophic niches using stable isotope ratios. Isotopic diversity indices (IDI) derived from a set of measures assessing the dispersion/distribution of points in the δ-space were recently suggested and increasingly used in the literature. However, three main critics emerge from the use of these IDI: 1) they fail to account for the isotopic sources overlap, 2) some indices are highly sensitive to the number of species and/or the presence of rare species, and 3) the lack of standardization prevents any spatial and temporal comparisons. Using simulations we investigated the ability of six commonly used IDI to discriminate among different trophic food web structures, with a focus on the first two critics. We tested the sensitivity of the IDI to five food web structures along a gradient of sources overlap, varying from two distinct food chains with differentiated sources to two superimposed food chains sharing two sources. For each of the food web structure we varied the number of species (from 10 to 100 species) and the type of species feeding behaviour (i.e. random or selective feeding). Values of IDI were generally larger in food webs with distinct basal sources and tended to decrease as the superimposition of the food chains increased. This was more pronounced when species displayed food preferences in comparison to food webs where species fed randomly on any prey. The number of species composing the food web also had strong effects on the metrics, including those that were supposedly less sensitive to small sample size. In all cases, computing IDI on food webs with low numbers of species always increases the uncertainty of the metrics. A threshold of ~20 species was detected above which several metrics can be safely used. PY 2013 PD DEC SO Plos One SN 1932-6203 PU Public Library Science VL 8 IS 12 UT 000329323900053 DI 10.1371/journal.pone.0084198 ID 28270 ER EF