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| Jabot, Franck; Giraldo, Carolina; Lefebvre, Sebastien; Dubois, Stanislas. |
| Isotopic analyses are increasingly used to assess the structure of food webs and a series of isotopic functional indices have been proposed in the last decade to characterize this structure. These indices are based on the foundational assumption that proximity in the isotopic space informs on trophic similarity between species. While it has been recognized for long that this simplifying assumption should be used with caution, no formal evaluation of its domain of validity has been performed to date. We here simulate a large number (15,000) of food webs with varying characteristics to assess i) whether isotopic distance is a good proxy of trophic dissimilarity; ii) whether isotopic functional indices are good proxies of trophic functional properties; and... |
| Tipo: Text |
Palavras-chave: Connectance; Isotopic functional indices; Niche model; Omnivory; Virtual ecology. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00385/49596/50110.pdf |
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| Meynard, Christine N.; Kaplan, David; Leroy, Boris. |
| Liu et al. (2018) used a virtual species approach to test the effects of outliers on species distribution models. In their simulations, they applied a threshold value over the simulated suitabilities to generate the species distributions, suggesting that using a probabilistic simulation approach would have been more complex and yield the same results. Here, we argue that using a probabilistic approach is not necessarily more complex and may significantly change results. Although the threshold approach may be justified under limited circumstances, the probabilistic approach has multiple advantages. First, it is in line with ecological theory, which largely assumes non‐threshold responses. Second, it is more general, as it includes the threshold as a... |
| Tipo: Text |
Palavras-chave: ENM; Observation errors; Outliers; Prevalence; Probabilistic approach; Sample bias; Simulations; Species distribution models; Virtual ecology; Virtual species. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00501/61309/64868.pdf |
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| Kermorvant, Claire; Caill-milly, Nathalie; Bru, Nooelle; D'Amico, Franck. |
| Funding lake is one major issue in ecology, in particular at local scale. It is known that sustainable management of a natural population requires a good understanding of its functioning, itself dependent on a good long term monitoring program. Such programs are usually very difficult to implement, especially for resources characterized by high spatio-temporal variation in their distribution, resulting in a trade off between efficiency and costs. Today, thanks to rapidly evolving statistical theory, new survey designs are developed, some with the characteristic of well balancing samples in the study area. This paper aims at demonstrating that theses advanced sampling designs perform better than the usual ones for long term monitoring program of local... |
| Tipo: Text |
Palavras-chave: Arcachon bay; Balanced acceptance sampling; Spatial sampling; Spatial variation; Temporal variation; Virtual ecology. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00469/58064/60460.pdf |
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