Michel Gauthier-clerc - Academia.edu (original) (raw)

Papers by Michel Gauthier-clerc

Emerging Infectious …, 2007

Wild birds share with humans the capacity for moving fast over large distances. During migratory ... more Wild birds share with humans the capacity for moving fast over large distances. During migratory movements, birds carry pathogens that can be transmitted between species at breeding, wintering, and stopover places where numerous birds of various species are concentrated. We consider the area of the Camargue (southern France) as an example to highlight how ad hoc information already available on birds' movements, abundance, and diversity can help assess the introduction and transmission risk for birdborne diseases in the western Mediterranean wetlands. Avian influenza and West Nile viruses are used as examples because birds are central to the epidemiology of these viruses.

The Condor, 2000

... We thank Luc Hoffmann, Jean-Paul Taris, and the Station Biologique de la Tour du Valat for ki... more ... We thank Luc Hoffmann, Jean-Paul Taris, and the Station Biologique de la Tour du Valat for kindly providing access to their estate, Vincent Boy for statistical advice, and Gérard Deswasmes for helpful comments on an earlier version of this ... In MH Kryger, T. Roth, WC Dement. ...

Canadian Journal of Zoology, 1998

... (Anas crecca crecca) Michel Gauthier-Clerc, Alain Tamisier, and Frank Cezilly ... Page 2. Tea... more ... (Anas crecca crecca) Michel Gauthier-Clerc, Alain Tamisier, and Frank Cezilly ... Page 2. Teals are gregarious by day and scatter at night for feeding (Tamisier 1974). During the day, Green-winged Teals concentrate on large open waters, where they sleep, preen, and rest. ...

Polar Biology, 2002

Sera from adult and chick king penguins were examined for antibodies to infectious bursal disease... more Sera from adult and chick king penguins were examined for antibodies to infectious bursal disease, in¯uenza A and Newcastle disease viruses. This study was completed by a 1-year survey of clinical signs of disease in the colony. About 4% and 1% of the birds were positive for serotypes 1 and 2, respectively, of infectious bursal disease virus. In 1996, two coughing peaks occurred in adults, during autumn and spring, and a peak of conjunctivitis occurred at the end of the winter. Although this showed the presence of infectious agents, it was not possible to be precise about whether the detected viruses were responsible for the clinical signs, or to assess if the infectious agents were native or introduced.

Aquatic Botany, 2010

The capacity of eight wetland seeds to be internally dispersed by common teal (Anas crecca L.) af... more The capacity of eight wetland seeds to be internally dispersed by common teal (Anas crecca L.) after a dry period typical of natural Mediterranean wetlands was experimentally quantified. These plant taxa (Chara spp., Echinochloa crus-galli (L.) P. Beauv., Eleocharis palustris (L.) Roem. & Schult, Polygonum lapathifolium L., Potamogeton nodosus Poir., Potamogeton pusillus L., Schoenoplectus mucronatus (L.) Palla, Scirpus maritimus L.) were frequently ingested by teal in the field. Captive teal were fed with known quantities of dry seeds and faecal samples were collected at intervals of 1-2 h for 48 h. The proportion of seeds retrieved after gut passage that germinated varied between taxa from 3% to 83%. From 2% to 63% of the seeds ingested were recovered intact, and 18-95% of these were still viable. Therefore, an overall 32% of the seeds ingested were evacuated in a viable condition, ranging from 0.2% for Chara spp. to 54% for S. mucronatus. Mean seed retention time was 3-5 h. Overall, 94% of seeds were evacuated within 12 h, but 2% were recovered after more than 24 h. Seed viability was reduced at longer retention times, although viable seeds of all taxa except Chara spp. were recovered 44-48 h after the experiment began. Germinability was increased by gut passage, although for some species this effect was only significant after stratification, indicating that they exhibit both mechanical and physical dormancy. Seed germination was accelerated by gut passage, especially at longer retention times. Gut passage increased the proportion of viable seeds, suggesting selective digestion of non-viable ones. Endozoochorous transport by teal appears to be a widespread dispersal mechanism among wetland plants.

Ambio, 2015

Winter-flooding of ricefields provides foraging habitat to waterfowl, which in return may bring a... more Winter-flooding of ricefields provides foraging habitat to waterfowl, which in return may bring agronomic benefits to farmers. Our study experimentally tested the effect of mallards (Anas platyrhynchos) on the standing stalks and weed seed bank in the Camargue (France), both of which present major challenges for farmers. Three duck densities were tested: (D1) 5 ducks ha(-1) (historical nocturnal density), (D2) 23 ducks ha(-1) (present nocturnal density), and (D3) 300 ducks ha(-1) (Asian rice-duck farming density). The ducks reduced the stalks significantly: -27 % (D1), -52 % (D2), and -91 % (D3). Conversely, they decreased the number of seeds by only 3 % (D3) and the seed mass by about 21 % (D1 and D3), which was not significant. Besides they had no effect on seed species richness. This study clearly demonstrates that the winter-flooding effect on straw decomposition can be enhanced by waterfowl foraging, hence showing an agronomic benefit from ducks to farmers. However, there was no clear effect in terms of seed bank reduction.

Polar Biology, 1999

The seabird tick Ixodes uriae (White) is common in subantarctic areas and is likely to be a vecto... more The seabird tick Ixodes uriae (White) is common in subantarctic areas and is likely to be a vector of pathogenic agents. This paper reports on the prevalence of tick-infested adult king penguins (Aptenodytes patagonicus) and on antibodies to the Lyme disease agent (Borrelia burgdorferi sensu lato) in adult and chick penguins. Fifteen percent of the adults of the colony studied were tick infested. B. burgdorferi antibodies were detected in 14% of tick-infested adults' and in 6% of chicks' sera. The percentage of tick-infested adults differed signi®cantly according to location in the colony, the highest density occurring on the upper slopes of the colony. The potential role of king penguins as B. burgdorferi reservoirs and the eect of this agent on king penguin populations remain unknown. The consequences for human health are discussed.

Journal of Field Ornithology, 2004

The double observer approach with marked nests was used in southern France for estimating the det... more The double observer approach with marked nests was used in southern France for estimating the detection probability of nests of the Squacco Heron (Ardeola ralloides), a cryptic species in its breeding behavior. Results indicate that the detection probability varied from 0.518 to 0.700 between observers. The overall detection probability, i.e., the probability that a nest was detected by at least one observer, was 0.856. Given a total of 66 nests found by both observers during the surveys, the breeding population was estimated at 77 nests. Since previous estimates of the Squacco Heron breeding population size did not take into account detection probability, we suggest that the breeding population is larger than previously thought in the Camargue and in other European breeding localities.

King penguins (Aptenodytes patagonicus) replace their complete plumage during a 3-to 4-week moult... more King penguins (Aptenodytes patagonicus) replace their complete plumage during a 3-to 4-week moulting fast on shore. After moulting, birds forage at sea for 2-3 weeks to store energy reserves for reproduction. Using an automatic identification and weighing system coupled with visual observations, we investigated the trade-off between the moulting fast and the following breeding attempt, in terms of body condition and in relation to time constraints, in free-living king penguins. King penguins reached their lowest body mass of the yearly cycle at the end of the moulting fast; this was lower than that at the end of the incubation fasts and not different from the body mass at egg desertion. Later in the season, the duration of the moulting fast became shorter and old feather loss occurred earlier after arrival ashore. Postmoulting foraging trips were shorter, but at the expense of body condition at the beginning of courtship. These results are discussed in relation to the synchronisation of the breeding cycle with food availability and mate choice.

Polar Biology, 2003

... Polar Biol (2003) 26: 587590 DOI 10.1007/s00300-003-0523-y Ce´line Le Bohec Æ Michel Gauthie... more ... Polar Biol (2003) 26: 587590 DOI 10.1007/s00300-003-0523-y Ce´line Le Bohec Æ Michel Gauthier-Clerc Jean-Paul Gendner Æ Nicolas Chatelain Yvon Le Maho ... Colon Waterbirds 15:5665 Martin GR (1998) Eye structure and amphibious foraging in albatrosses. ...

Polar Biology, 2004

Predation can have major effects on population dynamics, but predator–prey interactions in marine... more Predation can have major effects on population dynamics, but predator–prey interactions in marine ecosystems have rarely been studied. While the king penguin is one of the most studied seabirds, little is known about the impact of predation on its population dynamics. Here, we determine the impact of the main predators (giant petrels and skuas) on king penguin breeding success taking

PLoS ONE, 2012

Female birds transfer antibodies to their offspring via the egg yolk, thus possibly providing pas... more Female birds transfer antibodies to their offspring via the egg yolk, thus possibly providing passive immunity against infectious diseases to which hatchlings may be exposed, thereby affecting their fitness. It is nonetheless unclear whether the amount of maternal antibodies transmitted into egg yolks varies with female quality and egg laying order. In this paper, we investigated the transfer of maternal antibodies against type A influenza viruses (anti-AIV antibodies) by a long-lived colonial seabird, the yellow-legged gull (Larus michahellis), in relation to fluctuating asymmetry in females, i.e. the random deviation from perfect symmetry in bilaterally symmetric morphological and anatomical traits. In particular, we tested whether females with greater asymmetry transmitted fewer antibodies to their eggs, and whether within-clutch variation in yolk antibodies varied according to the maternal level of fluctuating asymmetry. We found that asymmetric females were in worse physical condition, produced fewer antibodies, and transmitted lower amounts of antibodies to their eggs. We also found that, within a given clutch, yolk antibody level decreased with egg laying order, but this laying order effect was more pronounced in clutches laid by the more asymmetric females. Overall, our results support the hypothesis that maternal quality interacts with egg laying order in determining the amount of maternal antibodies transmitted to the yolks. They also highlight the usefulness of fluctuating asymmetry as a sensitive indicator of female quality and immunocompetence in birds.

Ticks and Tick-borne Diseases, 2014

The hard tick Ixodes uriae parasitises a wide range of seabird species in the circumpolar areas o... more The hard tick Ixodes uriae parasitises a wide range of seabird species in the circumpolar areas of both Northern and Southern hemispheres and has been shown to be infected with Borrelia burgdorferi sensu lato, the bacterial agents of Lyme borreliosis. Although it is assumed that seabirds represent viable reservoir hosts, direct demonstrations of infection are limited to a single study from the Northern hemisphere. Here, the blood of 50 tick-infested adult king penguins (Aptenodytes patagonicus halli) breeding in the Crozet Archipelago (Southern Indian Ocean) was examined for B. burgdorferi sl exposure by serology and for spirochetemia by in vitro DNA amplification. Four birds were found positive by serology, whereas B. burgdorferi sl DNA was detected in two other birds. Our data therefore provide the first direct proof of Borrelia burgdorferi sl spirochetes in seabirds of the Southern hemisphere and indicate a possible reservoir role for king penguins in the natural maintenance of this bacterium. Although the bacterial genetic diversity present in these hosts and the infectious period for tick vectors remain to be elucidated, our results add to a growing body of knowledge on the contribution of seabirds to the complex epizootiology of Lyme disease and the global dissemination of B. burgdorferi sl spirochetes.

PloS one, 2009

Extended Spectrum beta-Lactamase (ESBL) producing Enterobacteriaceae started to appear in the 198... more Extended Spectrum beta-Lactamase (ESBL) producing Enterobacteriaceae started to appear in the 1980s, and have since emerged as some of the most significant hospital-acquired infections with Escherichia coli and Klebsiella being main players. More than 100 different ESBL types have been described, the most widespread being the CTX-M beta-lactamase enzymes (bla(CTX-M) genes). This study focuses on the zoonotic dissemination of ESBL bacteria, mainly CTX-M type, in the southern coastal region of France. We found that the level of general antibiotic resistance in single randomly selected E. coli isolates from wild Yellow-legged Gulls in France was high. Nearly half the isolates (47.1%) carried resistance to one or more antibiotics (in a panel of six antibiotics), and resistance to tetracycline, ampicillin and streptomycin was most widespread. In an ESBL selective screen, 9.4% of the gulls carried ESBL producing bacteria and notably, 6% of the gulls carried bacteria harboring CTX-M-1 grou...

Journal of Experimental Biology, 2014

Most studies analyzing the effects of global warming on wild populations focus on gradual tempera... more Most studies analyzing the effects of global warming on wild populations focus on gradual temperature changes, yet it is also important to understand the impact of extreme climatic events. Here we studied the effect of two cold spells (January 1985 and February 2012) on the energetics of greater flamingos (Phoenicopterus roseus) in the Camargue (southern France). To understand the cause of observed flamingo mass mortalities, we first assessed the energy stores of flamingos found dead in February 2012, and compared them with those found in other bird species exposed to cold spells and/or fasting. Second, we evaluated the monthly energy requirements of flamingos across 1980-2012 using the mechanistic model Niche Mapper TM . Our results show that the body lipids of flamingos found dead in 2012 corresponded to 2.6±0.3% of total body mass, which is close to results found in woodcocks (Scolopax rusticola) that died from starvation during a cold spell (1.7±0.1%), and much lower than in woodcocks which were fed throughout this same cold spell (13.0±2%). Further, Niche Mapper TM predicted that flamingo energy requirements were highest (+6-7%) during the 1985 and 2012 cold spells compared with 'normal' winters. This increase was primarily driven by cold air temperatures. Overall, our findings strongly suggest that flamingos starved to death during both cold spells. This study demonstrates the relevance of using mechanistic energetics modelling and body condition analyses to understand and predict the impact of extreme climatic events on animal energy balance and winter survival probabilities.

Vector-Borne and Zoonotic Diseases, 2007

An equine West Nile virus (WNV) outbreak occurred in 2004 in the Camargue, a wetland area in the ... more An equine West Nile virus (WNV) outbreak occurred in 2004 in the Camargue, a wetland area in the south of France where the virus was first reported in 1962 and re-emerged in 2000. WNV neutralizing antibodies were detected in resident birds and two isolates from a House Sparrow (Passer domesticus) and a Common Magpie (Pica pica) were completely sequenced. Phylogenetic analyses revealed that these isolates are closely related to strains previously found in horses in southern Europe and North Africa. More extensive investigation is required to determine whether WNV has been re-introduced or has become endemic in the Camargue.