Content uploaded by Christophe Eggert
Author content
All content in this area was uploaded by Christophe Eggert
Content may be subject to copyright.
A preview of the PDF is not available
Le déclin du Pélobate brun (Pelobates fuscus, amphibien anoure) : De la biologie des populations à la structuration génétique. [Decline of the Spadefoot toad (Pelobates fuscus): from population biology to genetic structure]
Abstract and Figures
Field studies of a remnant small Spadefoot toad population (Pelobates fuscus), a declining species, provided some new elements concerning its population biology. Many features were studied, such as habitat use, dispersal patterns and reproductive biology (behaviour and fecundity). Some life-history traits (longevity, age at sexual maturity) were asessed using the skeletochronological method, which allowed age structures to be studied. Genetic structure (mtDNA) were compared between populations from declining areas and from southern areas.[Text in French]
Figures - uploaded by Christophe Eggert
Author content
All figure content in this area was uploaded by Christophe Eggert
Content may be subject to copyright.
... The conservation status of the common spadefoot toad is the following: Law on biological diversity (Annex III), Habitat Directive 92/43/EEC (Annex IV), Bern Convention (Annex II), IUCN Red List (LC). It is a threatened European species (Eggert, 2002). Populations are declining in major part of their distribution area (Nöllert, 1997;Kuzmin, 1999;Eggert, 2002). ...
... It is a threatened European species (Eggert, 2002). Populations are declining in major part of their distribution area (Nöllert, 1997;Kuzmin, 1999;Eggert, 2002). ...
European common spadefoot toad (Pelobates fuscus) is a night active, very secretive species and the knowledge about it in Bulgaria is limited. The study in the area of the Zlatiya plateau was done with the aid of 100 pitfall traps, set to establish the common faunistic diversity.
Fixed and examined were 45 specimens. All important for the tailless amphibians morfometric indexes and values were measured and analysed. The animals were divided in 5 groups (juvenile, male subadult, female subadult, male mature adults and female mature adults). Statistical processing of the morphometric data showed that the sample as a whole can be considered homogeneous with weak variation of the signs.
The results were analysed and commented in a comparative aspect with similar studies in other parts of the geographic range of the species.
Morfometric data, in combination with the sex and size structure of the population, were indicative of its status and its trends, which was of great importance in determining the conservation significance and the favourable conservation status of the species. The results of this survey were useful for the preparation of a pack of conservation measures.
... En ce qui concerne les amphibiens, la prise de conscience du déclin des populations dans les années 1980 a soulevé la nécessité de mise en place de programmes internationaux de surveillance et de conservation [17]. C'est le cas du Pélobate brun (Pelobates fuscus), dont l'Alsace abrite un des trois noyaux de population qui subsistent en France [18][19][20]. Le Pélobate brun est classé parmi les espèces « en danger » sur la liste rouge des espèces menacées en France et cette espèce fait l'objet d'un plan de restauration. Le Pélobate brun est une espèce hivernante qui passe la majeure partie de l'année sous terre et ne remonte à la surface du sol que pendant la période de reproduction (de mars à juin). ...
... Un hydrophone relié à l'enregistreur et immergé dans l'eau a permis l'enregistrement de l'environnement sonore subaquatique pendant 10 minutes toutes les heures, et ce, entre 6h et 18h et trois fois par heure entre 18h et 6h. Les vocalisations du Pélobate brun se trouvant dans la bande de fréquences de 0.3 à 7 kHz [18], la fréquence d'échantillonnage des signaux a été fixée à 16 kHz, ce qui a permis l'enregistrement de sons jusqu'à une fréquence maximale de 8 kHz. Les enregistrements audio étaient au format WAV avec une résolution de 16-bits. ...
Un système de détection automatique pour le suivi d'un amphibien menacé, le Pélobate brun (Pelobates fuscus) Les enregistrements audio automatisés constituent un outil efficace et peu invasif pour le suivi d'espèces, permettant des acquisitions sur de longues périodes, mais implique le traitement d'un grand volume de données. Pour s'affranchir de l'écoute des enregistrements par un opérateur humain, nous avons développé un système de détection automatique dédié au suivi du Pélobate brun (Pelobates fuscus), une espèce d'amphibien menacée en France. La routine (Scilab) de détection repose sur i) l'inspection de la bande de fréquences où l'amplitude des vocalisations du Pélobate est la plus grande et, ii) le seuil d'émergence du niveau sonore dans cette bande de fréquences par rapport à celui du bruit résiduel. Sur la base d'une vérité-terrain, le détecteur a été optimisé et possède les caractéristiques suivantes : i) une bande de fréquence recherchée dans l'octave centrée sur 800 Hz ii) un seuil d'émergence d'au moins 14 dB par rapport au bruit résiduel. Ce détecteur obtient 52 % de bonnes détections et 5.4 % de fausses alarmes, apportant ainsi une méthode fiable comparée à d'autres détecteurs automatiques d'amphibiens.
... beschränkt; sie sprechen deshalb von einem "explosive breeder". P o p u l a t i o n s d y n a m i k : In den letzten 30 Jahren ist eine Vielzahl von Arbeiten mit Daten zur Populationsdynamik erschienen, von denen wir einige beispielhaft hier aufführen: Stöcklein (1980), Hildenhagen (1986), Endel (1987, Jahn (1994), Wiener (1997a,b), Kogoj (1997Kogoj ( , 2003, Baumann (1997), Tobias (2000), Eggert (2000), Hels (2002), Grosse (2008). ...
... Parmi toutes les espèces d'amphibiens de France, il a été signalé que le Pélobate brun (Pelobates fuscus) est probablement l'espèce la plus menacée (Dubois 1998), sa sauvegarde devant être une priorité (Lescure 1984). En effet sa disparision récente et rapide dans de nombreuses régions de France (Lescure 1984 ; Parent 1985) et son actuel déclin dans la zone ouest de son aire européenne de répartition (Eggert 2000Eggert , 2002a) sont autant de signaux alarmant concernant le statut à venir de cette espèce en France. Si des causes classiques de déclin des populations d'amphibiens ont été évoquées pour cette espèce -dégradation de l'habitat, introduction de poissons prédateurs etc. (Nöllert 1997 ; Kuzmin 1999), elles restent encore insuffisantes pour expliquer le déclin plus prononcé à l'ouest, et ce quelque fois malgré des efforts de gestion conservatoire de populations. ...
No Abstract. Publication in French.
We analyzed mitochondrial DNA variation in the Ringed Salamander, Ambystoma annulatum. Four of six populations studied were fixed for the same haplotype. We attribute this lack of detectable variation to recent colonization of this area, a hypothesis which is supported by paleoecological data and previous biogeographical analysis of the sympatric Spotted Salamander, Ambystoma maculatum. This study demonstrates the potential benefits of comparing biogeographical data across species and suggests that the Hypsithermal Interval may be an overlooked source of important historical impacts for species in the midwestern United States.
Maturation and growth were studied in two neighbouring lowland populations of Rana temporaria exhibiting a great difference in body size. This study took place in the southeast of France from 1986 to 1989. In this region, a local harvesting technique ensuring the release of tadpoles after intensive rearing results in regular genetic mixing between populations. Hence, only environmental influence on the growth rate could explain a difference in body size at maturation. The skeletochronological method was used to determine age. Most of the frogs in the two populations lived no longer than 3 years. The difference in body size between populations was reflected by a difference in age at maturity, which varied from 3 years at site 1 (where the frogs were larger) to 2 years at site 2. Newly metamorphosed froglets were larger at site 1 than at site 2. Back-calculated sizes of 1-year-old individuals did not differ between sites. Size was always greater for age-classes 2, 3, and 4 at site 1. We conclude that, relative to size at metamorphosis, faster growth at site 2 enables maturation to occur earlier and at a smaller size than at site 1. The significance of closer lines in bone cross sections as an indication of age at first reproduction is questioned.
Age structure of a Pelobates fuscus population portion, which visits ponds during the 1996 breeding period, was studied using skeletochronological methods. The studied population lives in northeast France, in the western border of the species area. The age distributions were strongly different between the sexes : males were represented mainly by the two_ and three-years-old individuals, when females were older. A lack of three-years-old migrating females was observed and discussed.
Although there is growing concern that amphibian populations are declining globally1±3, much of the supporting evidence is either anecdotal4,5 or derived from short-term studies at small geographical scales6±8. This raises questions not only about the dificulty of detecting temporal trends in populations which are notoriously variable9,10, but also about the validity of inferring global trends from local or regional studies11,12. Here we use data
from 936 populations to assess large-scale temporal and spatial variations in amphibian population trends. On a global scale, our
results indicate relatively rapid declines from the late 1950s/early 1960s to the late 1960s, followed by a reduced rate of decline to the present. Amphibian population trends during the 1960s were negative in western Europe (including the United Kingdom) and
North America, but only the latter populations showed declines from the 1970s to the late 1990s. These results suggest that while large-scale trends show considerable geographical and temporal variability, amphibian populations are in fact declining-and that this decline has been happening for several decades.
During a long-term study of the amphibian fauna on an artificial island near Vienna (Austria), one isolated site was completely encircled with a permanent drift fence and pitfall traps. Eleven amphibian species occurred at the study site. For the Common Spadefoot Toad (Pelobates fuscus) and for the Danube Crested Newt (Triturus dobrogicus). individuals could be recognized by photographing the highly variable dorsal/ventral patterns. Daily patrols of the drift fence, for 6 years since 1986, enabled us to monitor the demography and dynamics of these two species. For T. dobrogicus, the adult part of the censused population decreased from 207 to 87 individuals during the first 2 years of investigation and then remained stable. Pelobates fuscus showed a constant decrease over 6 years, from 626 to 62 individuals. Juveniles were produced annually; a massive increase in this age class was observed for both species during the period of investigation. Triturus dobrogicus showed higher adult survival than P. fuscus. The constancy of several population parameters of both species may reflect the stability of the cultured parkland habitat in which the study site is located.
-Sea-level change along the French Atlantic Channel coasts since the time of the Last Glacial Maximum
LAMBECK K. (1997).-Sea-level change along the French Atlantic Channel coasts since the time of the
Last Glacial Maximum. Palaeogeography, Palaeoclimatology, Palaeoecology., 129, 1-22.
Quantitative evidence for global amphibian declines
- Houlahan J E S Findlay C
- Meyer R A H Schmidt B
- L Kuzmin S
HOULAHAN J.E., FINDLAY C.S., SCHMIDT B.R., MEYER A.H. & KUZMIN S.L. (2000).-
Quantitative evidence for global amphibian declines. Nature, 404, 752-755.
-Two complementary methods to study the terrestrial movements of the Spadefoot toad (Pelobates fuscus Laur.) In: Current Study in Herpetology
- Eggert C H P Peyret P
- Guyetant R
EGGERT C., PEYRET P.H.P. & GUYETANT R. (1999).-Two complementary methods to study the
terrestrial movements of the Spadefoot toad (Pelobates fuscus Laur.). In: Current Study in
Herpetology., 95-97, Miaud & Guyétant (eds), Le Bourget du Lac.
-The amphibians of the former soviet union
KUZMIN S.L. (1999).-The amphibians of the former soviet union. Pensoft (ed.), Sofia, Moscou, 538 p.