References of "Denoël, Mathieu"
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See detailUsing sets of behavioral biomarkers to assess short-term effects of pesticide: a study case with endosulfan on frog tadpoles
Denoël, Mathieu ULg; D'hooghe, Bastien; Ficetola, G. Francesco et al

in Ecotoxicology (2012), 21(4), 1240-1250

Pesticides and other chemicals often have detrimental effects at environmental concentrations. Many amphibian species are particularly threatened because of their susceptibility but also because wetlands ... [more ▼]

Pesticides and other chemicals often have detrimental effects at environmental concentrations. Many amphibian species are particularly threatened because of their susceptibility but also because wetlands are often polluted. Behavioral assessments of toxicity have the advantage of showing sublethal effects but quantitative measures at varied scales of integrations are rarely considered together. In this study, we aimed at showing that these behavioral endpoints could be differently affected across time and concentrations, and be biomarkers of toxicity. To this end, we tested the effects of an organochlorine pesticide (endosulfan) on amphibians during a standard 96 h test. We evaluated possible lag effects in continuing the analyses after removal of the pesticide. The study was based on 240 tadpoles (4 pesticide treatments: 0.4, 3, 22, and 282 lg/l, 1 control and 1 solvent-control). Abnormal behaviors such as lying and swirling rapidly were exhibited only in the presence of the pesticide. Essential functions such as breathing and feeding were deeply affected by the pesticide: contaminated tadpoles breathed and fed less than control tadpoles. They also moved less and occupied a more central position in the aquariums in the presence of the pesticide. A higher mortality was only found at the highest concentration. These results suggest that endosulfan is toxic to amphibians at environmental concentrations. Behavioral markers showed potential as early warning systems. They should thus be used in complement to other markers to detect sublethal effects only a few days after application of the pesticide and at concentrations where mortality does not occur. [less ▲]

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See detailEffective conservation of an endangered newt species (Triturus cristatus): determinants from local to landscape scales
Denoël, Mathieu ULg; Perez, Amélie; Ficetola, Francesco

Conference (2011, December 07)

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See detailBehavioural ecotoxicology in amphibians: development of biomarkers
Denoël, Mathieu ULg

Conference (2011, October 25)

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See detailEffeti comportamentali dell'endosulfan su girini di Rana dalmatina
Lavorato, Manuela; Bernabé, I.; Tripepi, S. et al

Poster (2011, September)

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See detailAmphibia-Reptilia - 8 years on board: main changes and last figures
Denoël, Mathieu ULg; Ursenbacher, Sylvain; Harris, D. james et al

Conference (2011)

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See detailSex-specific effect of pool desiccation on the movement of Alpine newts, Mesotriton alpestris (Laurenti, 1768), among breeding sites (Caudata: Salamandridae)
Kopecky, Oldrich; Vojar, Jiri; Denoël, Mathieu ULg

in Herpetozoa (2011), 24(3/4), 127-134

In unpredictable habitats, it is advantageous to amphibians to reduce the risk of weather-induced offspring mortality by utilization of several reproductive patches. In european deciduous forest ... [more ▼]

In unpredictable habitats, it is advantageous to amphibians to reduce the risk of weather-induced offspring mortality by utilization of several reproductive patches. In european deciduous forest landscapes, ruts caused by vehicular traffic, typically comprising small vernal or ephemeral pools with variable hydroperiod, are at times used as breeding habitats by some species of amphibians. Previous research shows that in such systems newts move between ruts within a single reproductive season. The aim was to characterize such movements by means of a capture-mark-recapture study of the alpine Newt Mesotriton alpestris (laureNti, 1768), during two years differing in water availability, and to detect possible sex-specific differences. Movement between ruts differed between years according to sex. In the year with higher pool drying frequency, more females changed ruts than in the year when stable conditions prevailed. Among the adults that moved between ruts, however, the mean number of aquatic patches visited was higher in males. These results show that the sexes can react differently to environmental correlates and that alpine Newts are well adapted to utilize networks of temporary pools. [less ▲]

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See detailAmphibia-Reptilia - Editorial report 2010
Denoël, Mathieu ULg; Ursenbacher, sylvain; Harris, D. James

in Amphibia-Reptilia (2011), 32(4), 575-576

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See detailThe use of visual and automatized behavioral markers to assess methodologies: a study case on PIT-tagging in the Alpine newt
Winandy, Laurane ULg; Denoël, Mathieu ULg

in Behavior Research Methods (2011), 43(2), 568-576

Biomarkers are now widely used as tools in various research fields to assess individual integrity. The recent advances in quantification methods of behavioral patterns, such as computerized video-tracking ... [more ▼]

Biomarkers are now widely used as tools in various research fields to assess individual integrity. The recent advances in quantification methods of behavioral patterns, such as computerized video-tracking procedures, make them valuable biomarkers. However, the corollary of these novelties is that they remain relatively unknown and unused. In this study, we show that such tools can assess the validity of research methods, such as individual recognition. To demonstrate this we employed as a model a marking method (Passive Integrate Transponders: PIT-tagging) widely used in amphibians. Both detailed visual observations and video-tracking methods were complementary in highlighting components at different behavioral scales: locomotion, feeding, and breeding. We illustrate the scientific and ethical adequacy of the targeted marking method but also suggest that more studies should integrate behavioral analyses. Such biomarkers are a powerful tool to assess conservation concerns when other techniques cannot detect detrimental effects. [less ▲]

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See detailAmphibia-Reptilia - Editorial Report 2009
Denoël, Mathieu ULg; Ursenbacher, Sylvain; Harris, D. James

in Amphibia-Reptilia (2011), 32(1), 143

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See detailDermocystid infection and associated skin lesions in free-living palmate newts (Lissotriton helveticus) from Southern France
González-Hernández, M.; Denoël, Mathieu ULg; Duffus, A. J. L. et al

in Parasitology International (2010), 59(3), 344-350

Since the early 1900s, mesomycetozoan parasites have been reported in both European anuran and caudate species. These reports have primarily been descriptive, which has made assessing the impact of these ... [more ▼]

Since the early 1900s, mesomycetozoan parasites have been reported in both European anuran and caudate species. These reports have primarily been descriptive, which has made assessing the impact of these parasites on host populations difficult. Anecdotal reports of Dermocystidium-like parasites are becoming widespread across Europe, possibly indicating that these mesomycetozoan parasites are increasing in distribution and/or abundance. This highlights the need for further investigations into the occurrence, pathogenesis and effects on host health of these parasitic infections for free-living amphibian populations, particularly those which are already stressed or threatened by other factors. Here we report the results of pathological, microbiological and molecular investigations used to characterize unidentified skin lesions in palmate newts (Lissotriton helveticus) from Larzac, France. We confirm that the lesions are the result of infection with a novel dermocystidium-like parasite, which is related to Amphybiocystidium ranae. We also show that the same parasite is distributed across several newt breeding sites. The lesions that result from infection with this parasite range from single or few vesicular or nodular cutaneous lesions to multiple coalescing skin ulcers with extensive hemorrhages. The latter have not been previously described in amphibians due to mesomycetozoan parasitic infection. Dermocystid DNA was detected only in newts that showed lesions, providing comparative evidence of the parasite's pathogenicity. We discuss the potential significance of the presence of this pathogen in the context of the population health of palmate newts. [less ▲]

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See detailEcogeographical variation of body size in the newt Triturus carnifex: comparing the hypotheses using an information-theoretic approach
Ficetola, Gentile Francesco; Scali, Stefano; Denoël, Mathieu ULg et al

in Global Ecology & Biogeography (2010), 19(4), 485-495

Aim. Ecogeographical body size variation in vertebrates (e.g., Bergmann’s rule) has long been recognized. However, the patterns and causes of intraspecific ecogeographical body size variation in ... [more ▼]

Aim. Ecogeographical body size variation in vertebrates (e.g., Bergmann’s rule) has long been recognized. However, the patterns and causes of intraspecific ecogeographical body size variation in ectotherms, and in amphibians in particular, are strongly debated. We identified the relationship between bioclimatic variables and body size predicted a priori by alternative hypotheses (heat balance; endurance, seasonality, starvation resistance, water availability; primary productivity, parental investment) proposed to explain ecogeographical patterns of body size in ectotherms, and we evaluated the relative support of these hypotheses in explaining body size variation of the Italian crested newt, Triturus carnifex. Location Twenty-three populations covering the whole range of T. carnifex (Austria, Croatia, Italy and Slovenia) Methods. We obtained data on body size (SVL) of 2639 adult newts from direct measurements and the literature; we obtained high resolution environmental data for the sampled localities. We used an information-theoretic approach to evaluate the support of the different hypotheses, by the data. We also integrated information on population genetics in our models. Results. We observed strong geographic variation of body size. The best AIC models showed that populations with larger body size are associated with cold climates and secondarily with high primary productivity. Furthermore, sexual dimorphism increases in cold climates, as the increase in body size was stronger for females. When taking into account population genetics, we did not find support for relationships with the other variables. Main conclusion. Our results are consistent with three hypotheses proposed to explain ecogeographic variation in amphibians: heat balance, increased parental investment of females and productivity. Information theory provides the framework for comparing hypotheses rather than looking for patterns. We suggest that evaluating the support of mechanisms can provide better insights than simply assessing whether ecogeographical variation is in agreement with some ‘rule’. [less ▲]

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See detailMovements of Alpine newts (Mesotriton alpestris) between small aquatic habitats (ruts) during the breeding season
Kopecky, Oldrich; Vojar, Jiri; Denoël, Mathieu ULg

in Amphibia-Reptilia (2010), 31(1), 109-116

Many species with complex life cycles, such as caudate amphibians, migrate from terrestrial to aquatic habitats for reproduction. However, movements between reproductive ponds within a breeding season ... [more ▼]

Many species with complex life cycles, such as caudate amphibians, migrate from terrestrial to aquatic habitats for reproduction. However, movements between reproductive ponds within a breeding season have rarely been studied and are usually considered to be limited. Our aim was to determine whether this pattern occurs frequently in Alpine newts (Mesotriton alpestris) inhabiting complexes of small ruts on muddy forest tracks. We analysed capture-recapture data for individually marked newts as a function of locality, sex, body condition and hydroperiod throughout the breeding season. More than one third of the newts changed their ruts. Movements occurred more often towards ruts that did not dry during the breeding season. The body condition of males that changed ponds (but not that of females) was higher compared to that of resident newts in one of the studied populations. The relatively high frequency of movements between ruts can be seen as an adaptive strategy in unpredictable habitats which have a high probability of drying. The promiscuous pattern of newts also favours low site tenacity, because few sexual partners are available in each rut. Because of the broad occurrence of this kind of habitat, future studies should take into account these movements to better understand newt population dynamics and how to apply adequate conservation measures. [less ▲]

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See detailShort-term effects of an organochloride pesticide (endosulfan) on amphibian tadpoles
D'Hooghe, Bastien; Brasseur, Catherine ULg; Kestemont, Patrick et al

Poster (2010)

Detailed reference viewed: 44 (7 ULg)