56 research outputs found
Le Robert â Grotte de lâĂlet Chancel
La grotte de lâĂźlet Chancel avait Ă©tĂ© identifiĂ©e comme prĂ©sentant un potentiel intĂ©rĂȘt archĂ©ologique et palĂ©ontologique dans le cadre dâune opĂ©ration de prospection et dâinventaire du karst martiniquais conduite en 2013. Cette hypothĂšse sâappuyait sur la configuration de ce site qui sâavĂšre ĂȘtre idĂ©ale : une grotte sĂšche Ă configuration de piĂšge sĂ©dimentaire situĂ©e Ă faible distance de la mer. Dans le but de tester cette hypothĂšse, une opĂ©ration de sondage archĂ©ologique a Ă©tĂ© conduite en nove..
La TrinitĂ© â Morne Castagne
Lâobjectif de cette opĂ©ration Ă©tait de tester le potentiel archĂ©ologique et palĂ©ontologique des abris du Morne Castagne via la conduite dâun sondage dans un de ces abris. Ce morne Ă©tant lâun des rares contextes calcaires de lâĂźle de la Martinique, il reprĂ©sentait une opportunitĂ© unique de pouvoir dĂ©couvrir des accumulations de restes de vertĂ©brĂ©s anciens bien prĂ©servĂ©s dans un contexte naturel. Un sondage dâun mĂštre carrĂ© a Ă©tĂ© pratiquĂ©, sous le grand abri du Morne Castagne. Ce sondage a pu ĂȘ..
The recent history of an insular bat population reveals an environmental disequilibrium and conservation concerns
With the global pandemic of Covid-19, the putative threats related to the increasing contact between wild animals, including bats, and human populations have been highlighted. Bats are indeed known to carry several zoonoses, but at the same time, many species are currently facing the risk of extinction. In this context, being able to monitor the evolution of bat populations in the long term and predict future potential contact with humans has important implications for conservation and public health. In this study, we attempt to demonstrate the usefulness of a small-scale paleobiological approach to track the evolution of an insular population of Antillean fruit-eating bats (Brachyphylla cavernarum), known to carry zoonoses, by documenting the temporal evolution of a cave roosting site and its approximately 250 000 individuals bat colony. To do so, we conducted a stratigraphic analysis of the sedimentary infilling of the cave, as well as a taphonomic and paleobiological analysis of the bone contents of the sediment. Additionally, we performed a neotaphonomic study of an assemblage of scats produced by cats that had consumed bats on-site. Our results reveal the effects of human-induced environmental disturbances, as well as conservation policies, on the bat colony. They also demonstrate that the roosting site is currently filling at a very fast pace, which may lead to the displacement of the bat colony and increased contact between bats and human populations in the near future. Our research outcomes advocate for a better consideration of retrospective paleobiological data to address conservation questions related to bat populations
Squamate of the Late Pleistocene and Holocene of the Guadeloupe archipelago : evolution of biodiversity and interactions with human populations
Lâimpact actuel de lâHomme sur la biosphĂšre affecte lâensemble des organismes vivants et des milieux. Il est souvent considĂ©rĂ© comme Ă©tant Ă lâorigine de la 6Ăšme crise dâextinction de masse. La quantification des effets de ce phĂ©nomĂšne est cependant complexe car certains ont dĂ©butĂ© bien avant que les scientifiques ne sâintĂ©ressent Ă ces questions et ne produisent des donnĂ©es de rĂ©fĂ©rence. Ce problĂšme est tout particuliĂšrement manifeste dans les milieux les plus fragiles, telles que les Ăźles, dont les Ă©cosystĂšmes ont pu ĂȘtre bouleversĂ©s par lâHomme de maniĂšre trĂšs rapide et cela avant que leur biodiversitĂ© nâait Ă©tĂ© documentĂ©e. Dans ce cas, les ossements fossiles sâavĂšrent ĂȘtre les uniques vestiges tĂ©moignant de lâexistence passĂ©e de faunes parfois Ă©teintes. Ils deviennent donc lâunique fenĂȘtre permettant dâentrevoir la biodiversitĂ© ancienne de ces milieux. Mon travail de thĂšse se questionne sur la biodiversitĂ© passĂ©e au sein de lâarchipel de la Guadeloupe (Antilles françaises) Ă travers lâexemple des reptiles squamates (lĂ©zards et serpents). LâĂ©tude de prĂšs de 40 000 ossements issus de 31 sites archĂ©ologiques et palĂ©ontologiques datant de la fin du PlĂ©istocĂšne (30 000 B.P.) Ă nos jours, a permis de mettre en Ă©vidence lâĂ©volution de la diversitĂ© de ces vertĂ©brĂ©s dans le temps ainsi que de leurs relations avec les diffĂ©rentes populations humaines. Ces rĂ©sultats ont Ă©tĂ© obtenus grĂące Ă lâutilisation de diverses mĂ©thodes (anatomie comparĂ©e, morphomĂ©tries traditionnelle et gĂ©omĂ©trique, palĂ©ohistologie et archĂ©ozoologie, rĂ©cits des premiers voyageurs) et grĂące au dĂ©veloppement dâapproches mĂ©thodologiques spĂ©cifiques aux squamates. Les donnĂ©es obtenues font Ă©tat de lâimpact limitĂ© sur les faunes par les populations humaines amĂ©rindiennes ayant occupĂ© la Guadeloupe pendant plus de 4000 ans jusquâau 17Ă©me siĂšcle. En effet, bien quâayant chassĂ© certains squamates (iguanes et amĂ©ives) et probablement participĂ© Ă un enrichissement de la faune, les AmĂ©rindiens ne semblent pas avoir contribuĂ© Ă appauvrir la biodiversitĂ© des squamates guadeloupĂ©ens. En revanche, les donnĂ©es fossiles plus rĂ©centes dĂ©montrent un fort impact sur les faunes de squamates exercĂ© par les populations europĂ©ennes qui colonisent ces Ăźles Ă partir du XVIIĂšme siĂšcle. Lâeffet de cette seconde vague de colonisation se manifeste par la transformation morphologique de certains taxons (rĂ©duction de taille, rĂ©duction de variabilitĂ© morphologique) et par une sĂ©rie dâextinctions totales ou partielles dâespĂšces (restriction dâaire gĂ©ographique). Ainsi, le taux dâextinction des squamates de Guadeloupe est estimĂ© entre 47 et 56% depuis 300 ans. Cette vague dâextinctions sâoppose Ă lâapparente stabilitĂ© de la faune des squamates que rĂ©vĂšle le registre fossile du PlĂ©istocĂšne et de la premiĂšre moitiĂ© de lâHolocĂšne. Ces rĂ©sultats dĂ©montrent lâintĂ©rĂȘt de lâĂ©tude minutieuse des faunes fossiles rĂ©centes pour une meilleure comprĂ©hension de lâimpact de lâHomme sur son milieu au cours du temps, un domaine encore relativement peu dĂ©veloppĂ©, tout particuliĂšrement pour ce qui concerne les squamates.Current human impact on the biosphere affects all living organisms and environments. This global phenomenon is often considered as the origin of the 6th mass earth extinction crisis. Yet, the quantification of the effects of this crisis can be problematic because it started long before scientists started to investigate it and to produce reference data. This issue is especially obvious in fragile ecosystems, like islands, which environments could have been quickly modified in relation with anthropogenic phenomena before their biodiversity can have been described. In this case, fossil bones are often the sole remaining remains of past ecosystems and the only possibility to study them. My PhD work is interested in squamate (snakes and lizards) past biodiversity of the Guadeloupe Islands (French West Indies). I studied more than 40 000 fossil bones of squamates from 31 archaeological and paleontological deposits dated from Late Pleistocene (40 000 B. P.) to nowadays. My study reveals the evolution of the diversity of these reptiles along with their relations with past human populations. The results are obtained using several methods (comparative anatomy, traditional and geometric morphometrics, paleohistology and zooarchaeology) and thanks to new methodological tools I developed dedicated to the study of squamate bone remains. My results show the limited impact on squamate faunas of Amerindian human populations who inhabited Guadeloupe islands during more than 4 000 years. Indeed, although these populations seem to have hunted some squamates (iguanas and ameivas) and slightly contributed to enrich squamate diversity, they do not seem to be the cause of any extinction event. At the opposite, European populations who colonized Guadeloupe Islands since the XVIIth century strongly impacted the native squamate biodiversity. These effects take the forms of morphological modification of some taxa (size reduction, reduction of morphological variability) and partial (decrease of geographic distribution) or total extinction of many taxa. Indeed, the extinction rate of squamates species in Guadeloupe during the last 300 years is estimated between 47 and 56%. This recent mass extinction phenomenon strongly contrasts with the apparent stability of the squamate diversity between Pleistocene and the first half of Holocene revealed by fossil data. These results show the interest of studying late quaternary fossil faunas to better understand the impact of Human on its environment, a field of research still largely underdeveloped especially concerning squamates
RĂ©sumĂ© de diplĂŽme - Squamates du PlĂ©istocĂšne supĂ©rieur et de lâHolocĂšne de lâarchipel guadeloupĂ©en : Ă©volution de biodiversitĂ© et interactions avec lâHomme
International audienc
Nouvelles donnĂ©es archĂ©ozoologiques sur lâoppidum de Corent: RĂ©sultats de la campagne de fouille 2010
International audienc
Describing Archaeological Iguana Laurenti, 1768 (Squamata: Iguanidae) Populations: Size and Skeletal Maturity
International audienc
Reconstructing the body sizes of Quaternary lizards using Pholidoscelis Fitzinger, 1843, and Anolis Daudin, 1802, as case studies
International audienc
Analyse taphonomique dâun assemblage dâossements subfossiles dâherpĂ©tofaune caribĂ©enne (Ăźle de Marie-Galante, Petites Antilles)
Les analyses taphonomiques sont indispensables Ă la comprĂ©hension des processus dâaccumulation des assemblages fossiles dâossements de vertĂ©brĂ©s. Ces approches sont fondamentales dans les contextes archĂ©ologiques, oĂč le rĂŽle des humains dans la constitution de lâassemblage doit ĂȘtre Ă©tudiĂ© en dĂ©tail. Cependant, les Ă©tudes taphonomiques se sont jusquâĂ prĂ©sent concentrĂ©es sur les rĂ©gions tempĂ©rĂ©es et les restes de mammifĂšres et peu dâĂ©tudes concernent les autres groupes de vertĂ©brĂ©s, notamment lâherpĂ©tofaune, ainsi que les aires tropicales. Cela rĂ©sulte en un important biais dans la littĂ©rature scientifique qui impacte fortement les Ă©tudes palĂ©oĂ©cologiques et archĂ©ozoologiques dans les aires gĂ©ographiques oĂč les squamates et amphibiens sont bien reprĂ©sentĂ©s. Dans cet article, nous prĂ©sentons une analyse taphonomique de prĂšs de 11â000 ossements dâherpĂ©tofaune collectĂ©s dans lâabri Cadet 3 sur lâĂźle de Marie-Galante et datĂ©s entre le dĂ©but de lâHolocĂšne et la pĂ©riode amĂ©rindienne. Les rĂ©sultats obtenus ne supportent pas lâhypothĂšse du rĂŽle des populations humaines dans la constitution de lâassemblage, malgrĂ© la prĂ©sence de niveaux stratigraphiques archĂ©ologiques bien caractĂ©risĂ©s dans le site. Lâagent accumulateur le plus probable est un petit rapace nocturne (i.e., Athene cunicularia guadeloupensis (Ridgway, 1874) ou Tyto insularis (Pelzeln, 1872)). Nous effectuons Ă©galement une comparaison avec les autres sites fossiles de Marie-Galante et mettons en Ă©vidence la diversitĂ© des modes dâaccumulations dans les diffĂ©rentes grottes voisines de Cadet 3, mais Ă©galement le manque dâĂ©tudes taphonomiques dĂ©taillĂ©es qui seraient nĂ©cessaires pour pouvoir interprĂ©ter ces diffĂ©rences.Taphonomic analyses are of primary importance to understand the accumulation processes of fossil vertebrate bone assemblages. These approaches are fundamental in archaeological contexts in which the role of humans in the formation of an accumulation must be investigated in detail. However, taphonomic works have so far focused on temperate regions and mammals and few studies extensively deal with other vertebrates, especially the herpetofauna, and tropical areas. This results in an important gap in the scientific literature, which has a strong impact on the paleoecological and zooarchaeological research in the areas where squamates and amphibians are well-represented. In this paper, we present a detailed taphonomic study of a large herpetofaunal assemblage of nearly 11â000 bones collected in the Abri Cadet 3, on Marie Galante Island, and dated from the beginning of the Holocene to the Amerindian period. Obtained results donât support the role of humans in the constitution of the assemblage despite the occurrence of clear archaeological layers in the site. The most-likely culprit for the creation of the bone assemblage is a small nocturnal raptor (i.e., Athene cunicularia guadeloupensis (Ridgway, 1874) or Tyto insularis (Pelzeln, 1872)). We also conduct a comparison with the other available deposits from Marie Galante, highlighting the diversity of accumulation processes in the different nearby cave sites but also the lack of detailed taphonomic studies which would be needed to explain this diversity.</p
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