Search results for "FOS"
showing 10 items of 15075 documents
Hierarchical log Gaussian Cox process for regeneration in uneven-aged forests
2021
We propose a hierarchical log Gaussian Cox process (LGCP) for point patterns, where a set of points x affects another set of points y but not vice versa. We use the model to investigate the effect of large trees to the locations of seedlings. In the model, every point in x has a parametric influence kernel or signal, which together form an influence field. Conditionally on the parameters, the influence field acts as a spatial covariate in the intensity of the model, and the intensity itself is a non-linear function of the parameters. Points outside the observation window may affect the influence field inside the window. We propose an edge correction to account for this missing data. The par…
Environmental factors responsible for the gyrogonite formation by an endangered macroalga, Lychnothamnus barbatus, a fertility indicator of past and …
2019
Abstract Gyrogonites (calcified oospores) of charophytes are commonly used in palaeoecology. Although, the study of morphometry and gyrogonite production by extant charophytes is limited. This concerns the genus Lychnothamnus , frequent in the past but contemporarily represented only by L. barbatus , the rare and endangered species applied in assessment of water quality as a bioindicator of oligo-mesotrophic lakes. In this study two hypotheses were verified: (1) the length and width of L. barbatus gyrogonites increase with increasing depth; (2) at the deeper sites, L. barbatus produces more numerous gyrogonites compared to shallower lake areas. Gyrogonites were picked from L. barbatus thall…
Why all vole molars (Arvicolinae, Rodentia) are informative to be considered as proxy for Quaternary paleoenvironmental reconstructions.
2013
13 pages; International audience; Rodents are considered as a good model and as a good proxy to characterise Quaternary environments. Molars and incisors are the best-preserved remains and are found in abundance in the fossil record. Since several decades, the lower molars are mostly used for specific determinations. Instead of using qualitative and descriptive characters, morphometric methods provide now a general quantitative description of shape. Applying these new morphometric methods (outline analysis), we demonstrate that lower as well as upper molars are useful and efficient for palaeontological analyses within voles (Arvicolinae). Herein it is made evident that except the first lowe…
Trophic ecology of a Late Pleistocene early modern human from tropical Southeast Asia inferred from zinc isotopes
2021
Tam Pà Ling, a cave site in northeastern Laos, has yielded the earliest skeletal evidence of Homo sapiens in mainland Southeast Asia. The reliance of Pleistocene humans in rainforest settings on plant or animal resources is still largely unstudied, mainly due to poor collagen preservation in fossils from tropical environments precluding stable nitrogen isotope analysis, the classical trophic level proxy. However, isotopic ratios of zinc (Zn) in bioapatite constitute a promising proxy to infer trophic and dietary information from fossil vertebrates, even under adverse tropical taphonomic conditions. Here, we analyzed the zinc isotope composition (66Zn/64Zn expressed as δ66Zn value) in the en…
Molecular phylogeny of the extinct giant deer, Megaloceros giganteus.
2006
a Centre de Genetique Moleculaire et Cellulaire (CGMC), CNRS UMR 5534, Universite Claude Bernard Lyon 1, Villeurbanne, France b Laboratoire d’Anthropologie des Populations du Passe, CNRS UMR 5199 PACEA, Universite Bordeaux 1, Talence, France c UCD School of Biology and Environmental Science, UCD, BelWeld, Dublin 4, Ireland d Laboratoire d’Ecologie des Hydrosystemes Fluviaux, CNRS UMR 5023, Universite Claude Bernard Lyon 1, Villeurbanne, France e Biogeosciences-Dijon, CNRS UMR 5561, Universite de Bourgogne, Centre des Sciences de la Terre, Dijon, France f Department of Palaeontology, Royal Belgian Institute of Natural Sciences, Brussels, Belgium g Department of Biology, University College Lo…
New insight into the colonization processes of common voles: inferences from molecular and fossil evidence.
2008
Biologie et Gestion des Populations, Campus International de Baillarguet, Montferrier/Lez, FranceElucidating the colonization processes associated with Quaternary climatic cycles is important in order to understand the distribution of biodiversity and the evolutionary potential of temperate plant and animal species. In Europe, general evolutionary scenarios have been defined from genetic evidence. Recently, these scenarios have been challenged with genetic as well as fossil data. The origins of the modern distributions of most temperate plant and animal species could predate the Last Glacial Maximum. The glacial survival of such populations may have occurred in either southern (Mediterranea…
Ticket to spawn: Combining economic and genetic data to evaluate the effect of climate and demographic structure on spawning distribution in Atlantic…
2019
Abstract Climate warming and harvesting affect the dynamics of species across the globe through a multitude of mechanisms, including distribution changes. In fish, migrations to and distribution on spawning grounds are likely influenced by both climate warming and harvesting. The Northeast Arctic (NEA) cod (Gadus morhua) performs seasonal migrations from its feeding grounds in the Barents Sea to spawning grounds along the Norwegian coast. The distribution of cod between the spawning grounds has historically changed at decadal scales, mainly due to variable use of the northern and southern margins of the spawning area. Based on historical landing records, two major hypotheses have been put f…
Fossorial but widespread: the phylogeography of the common spadefoot toad (Pelobates fuscus), and the role of the Po Valley as a major source of gene…
2007
International audience; Pelobates fuscus is a fossorial amphibian that inhabits much of the European plain areas. To unveil traces of expansion and contraction events of the species' range, we sequenced 702 bp of the mitochondrial cytochrome b gene. To infer the population history we applied phylogeographical methods, such as nested clade phylogeographical analysis (NCPA), and used summary statistics to analyse population structure under a neutral model of evolution. Populations were assigned to different drainage systems and we tested hypotheses of explicit refugial models using information from analysis of molecular variance, nucleotide diversity, effective population size estimation, NCP…
Adaptive radiation in the fossil record: a case study among Jurassic ammonoids
2013
15 pages; International audience; Evolutionary radiations have been extensively studied especially in the fossil record and in the context of postcrisis recoveries. The concept of adaptive radiation that emerges from this very broad topic explicitly involves the effect of adaptation driven by ecological opportunity and is considered to be of the foremost importance. It is essential to be able to detect adaptive radiation because it points up factors that predispose a clade to radiate. Adaptive radiation has received much attention in recent decades based mostly on studies dealing with recent clades, but data from the fossil record are still scarce. This study begins to fill this gap with th…
The Strategic Reference Gene: an organismal theory of inclusive fitness
2019
How to define and use the concept of inclusive fitness is a contentious topic in evolutionary theory. Inclusive fitness can be used to calculate selection on a focal gene, but it is also applied to whole organisms. Individuals are then predicted to appear designed as if to maximise their inclusive fitness, provided that certain conditions are met (formally when interactions between individuals are 'additive'). Here we argue that applying the concept of inclusive fitness to organisms is justified under far broader conditions than previously shown, but only if it is appropriately defined. Specifically, we propose that organisms should maximise the sum of their offspring (including any accrued…