Stable isotopes are increasingly being used to trace wildlife movements. A fundamental prerequisite of animal isotopic tracking is a good knowledge of spatial isotopic variations in the environment. Few accessible reference maps of the isotopic landscape ("isoscapes") are available for marine predators. Here, we validate for the first time an isotopic gradient for higher trophic levels by using a unique combination of a large number of satellite-tracks and subsequent blood plasma isotopic signatures from a wide-ranging oceanic predator. The plasma δ(13)C and δ(15)N values of wandering albatrosses (n = 45) were highly and positively correlated to the Southern Ocean latitudes at which the satellite-tracked individuals foraged. The well-defined latitudinal baseline carbon isoscapes in the Southern Ocean is thus reflected in the tissue of consumers, but with a positive shift due to the cumulative effect of a slight (13)C-enrichment at each trophic level. The data allowed us to estimate the carbon isotopic position of the main oceanic fronts in the area, and thus to delineate robust isoscapes of the main foraging zones for top predators. The plasma δ(13)C and δ(15)N values were positively and linearly correlated, thus suggesting that latitudinal isoscapes also occur for δ(15)N at the base of the food web in oceanic waters of the Southern Ocean. The combination of device deployments with sampling of relevant tissues for isotopic analysis appears to be a powerful tool for investigating consumers' isoscapes at various spatio-temporal scales.

How does an animal age in natural conditions? Given the multifaceted nature of senescence, identifying the effects of age on physiology and behavior remains challenging. We investigated the effects of age on a broad array of phenotypic traits in a wild, longlived animal, the wandering albatross. We studied foraging behavior using satellite tracking and activity loggers in males and females (age 6-48+ years), and monitored reproductive performance and nine markers of baseline physiology known to reflect senescence in vertebrates (humoral immunity, oxidative stress, antioxidant defenses, and hormone levels). Age strongly affected foraging behavior and reproductive performance, but not baseline physiology. Consistent with results of mammal and human studies, age affected males and females differently. Overall, our findings demonstrate that age, sex, and foraging ability interact in shaping aging patterns in natural conditions. Specifically, we found an unexpected pattern of spatial segregation by age; old males foraged in remote Antarctica waters, whereas young and middle-aged males never foraged south of the Polar Front. Old males traveled a greater distance but were less active at the sea surface, and returned from sea with elevated levels of stress hormone (corticosterone), mirroring a low foraging efficiency. In contrast to findings in captive animals and shortlived birds, and consistent with disposable soma theory, we found no detectable age-related deterioration of baseline physiology in albatrosses. We propose that foraging efficiency (i.e., the ability of individuals to extract energy from their environment) might play a central role in shaping aging patterns in natural conditions. senescence | foraging | immunity | oxidative stress | sex S enescence, a decline in fitness with advancing age, has been documented across a wide range of wild animals (1-3). There is an ongoing debate in the literature regarding the proximate mechanisms underpinning senescence. Age-associated immune dysfunction (referred to as immunosenescence) and increased susceptibility to oxidative stress are strong candidates as the major driving forces behind senescence in humans and laboratory animal models (4-6), but their relevance in natural populations remains unclear. Because of their generally longer lifespan compared with mammals, birds have emerged as predominant models for studying aging (7,8). The first studies on senescence were restricted almost entirely to investigations of age-dependent mortality or breeding performance (1). More recent pioneering studies that focused on proximal physiological patterns of aging in free-living birds yielded contrasting results; senescence was linked with decreased humoral immune response (9), increased oxidative stress (10), altered plasma levels of some hormones (refs. 2, 11; but see ref. 12), and decreased metabolic rate (ref. 13, but see ref. 14).Foraging behavior, the set of processes by which organisms acquire energy and nutrients (15), merits specific attention, because it may play a k...

We made a first descriptive study of weedy sunflowers infesting sunflower crop fields in one Spanish and three French regions. Overall, weedy sunflowers affected around 15% of sunflower fields. Infested fields were most often dispersed over the study areas without evident geographical clustering. In France, five weedy populations were surveyed more intensively. They were composed of a large diversity of morphotypes showing a combination of typical wild and domesticated traits in proportions that differed between populations. Yield losses reached 50% in heavily infested patches. Our results suggest that weedy sunflowers may have arisen through the hybridization of cultivated and wild sunflower, potentially during the seed production process. Such crop-wild hybrids would have been introduced recurrently into fields through the seed lots, where they evolved to locally invasive weedy populations.

Evidence of age-dependent changes in foraging behavior of free-ranging individuals is scarce, especially at older stages. Using the isotopic niche as a proxy of the trophic niche during both the breeding (blood) and inter-nesting (feather) periods, we report here empirical evidence for age-, gender-, and breeding status-dependent foraging ecology and examine its potential consequences on subsequent reproduction and survival in an extremely long-lived species, the Wandering Albatross (Diomedea exulans). Immature Wandering Albatrosses of both sexes forage in the subtropics (delta13C) and feed at the same trophic position (delta15N) as the adults. In contrast to immature birds, adult females forage, on average, at more northern latitudes than males, with both sexes feeding in the subtropics during the internesting period, and males, not females, favoring subantarctic waters during incubation. In contrast to adult females, males show a unique pattern among birds and mammals of a continuous change with age in their main feeding habitat by foraging progressively farther south in colder waters during both the breeding and inter-nesting periods. In males, foraging at higher latitudes (lower feather delta13C values) is associated with a lower probability of breeding during the following years compared to other birds, but with no effect on their probability of surviving. Foraging in cold and windy waters may be linked to foraging impairment that might explain different life history trade-offs and lower investment in reproduction with age. This key point requires further longitudinal investigations and/or studies examining foraging success and the energy budget of birds feeding in different water masses.

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Reproduction is a demanding activity for animals, since they must produce, and in some cases protect and provision, their young. It is often overlooked that demands of reproduction may also be exacerbated by exposure to contaminants. In this study, we make use of an exceptional long-term dataset to perform a cross-sectional study on the long-lived wandering albatross (Diomedea exulans) in order to test the effects of reproduction, persistent organic pollutants [POPs: pesticides and polychlorinated biphenyls (PCBs)], mercury, individual age (3-47 years), and sex on the levels of plasma oxidative damage and inflammation. The results of our study support the hypothesis that oxidative damage may be a physiological cost of reproduction and that individuals carrying higher levels of organic or non-organic contaminants have higher oxidative damage. Levels of the inflammatory protein haptoglobin were similar between breeding and non-breeding birds, with the exception of breeding males which had the lowest levels of haptoglobin. Our data also show an effect of age and of organic contaminants on the plasma oxidative damage level, but not on plasma haptoglobin. In addition, plasma oxidative damage level increased with red blood cell mercury concentration in females but not in males. Hence, our study highlights that the harmful effects of contaminants may come through interaction with factors like life stage or gender, suggesting potential for high variation in susceptibility to contamination among individuals.

Seabirds breeding on islands are vulnerable to introduced predators, such as rats and cats, and the removal of such predators is generally viewed as a priority for seabird conservation and restoration. However, multiple invasive mammal species interacting may generate unexpected outcomes following the removal (eradication) of one species. Generally these indirect interactions are not well understood or demonstrated. We propose and study a prey (seabird)mesopredator (rat)-superpredator (cat) model, taking into account the juvenile stages in the prey population, in order to direct conservation management for seabird conservation. We give a more biologically realistic differential system than those studied before (Courchamp et al. [1999]; Fan et al. [2005]), in particular for long-lived seabird species. We present a theoretical study and show existence and uniqueness of a positive solution as well as a qualitative study of the equilibria that may appear. Because standard numerical methods, usually implemented in scientific softwares, can fail to give the right biological approximations (Anguelov et al. [2009]), we propose a reliable algorithm that preserves most of the qualitative properties of the continuous system, using the theory of nonstandard finite difference methods. Finally, we use biologically realistic parameters available for the representative Barau's petrel (Pinet et al. [2008]), an endemic species from C opyright c 2010 W iley Perio d icals, In c. 381 382 Y. DUMONT ET AL.Réunion island, to present numerical simulations that support the theoretical study. Cats play the major role in seabird prey population dynamics. Seasonality in seabird breeding delays but does not prevent extinction. In all scenarios, cat control (or preferably eradication) is imperative to prevent extinction of vulnerable long-lived seabirds, like the Barau's petrel.

Soybean is cultivated in Europe as a GM free cultivation. In spite of a growing demand in identity preserved (IP) seeds and of the high environmental benefit of the soybean in the crop rotations, a great decrease of the soybean acreage has been observed in France and in Europe since 2002. That's why in 2007, Cetiom and Onidol, two bodies of the French oilseed crop organisation decided to carry out a comprehensive survey on the different actors of the soybean production chain from the farmers until the feed and food soybean users. The study showed that 12% of the total acreage is planted under organic farming and that most surfaces are still grown under IP process. It also highlighted that the decrease of soybean's surfaces till 2008 was mainly due to an insufficient economic competitiveness compared to other crops. The survey proved that the French production gained market shares between 2002 and 2007 for the soyfood industry supply (from 5 to 25% of the total acreage). The remaining production is processed in small or medium extrusion plants for the local animal raising. The needs of the industry were described in details showing that the main asset of the French production is the good control of the whole production chain, the high quality management by the farmers, the good protein content and shorter logistic chains compared to the imported soybean. For the future, the increasing environmental constraints and the larger demand of European soyfood industry but also of local high-quality feed and animal raising could lead soybean to recover between 100 000 and 150 000 hectares in France.