Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
See detailEvolution régressive récente de la végétation des tourbières hautes à sphaignes en Haute Ardenne (Hautes-Fagnes, Belgique)
Hindryckx, Marie-Noëlle ULg

Doctoral thesis (1999)

In temperate Europe, intact raised bogs from Northern Germany to the French Massif Central are part of rare postglacial ecosystems that one can consider as natural or very close to the natural state ... [more ▼]

In temperate Europe, intact raised bogs from Northern Germany to the French Massif Central are part of rare postglacial ecosystems that one can consider as natural or very close to the natural state. Unfortunately, many of them have been degraded or highly disturbed by intense human activities. Some of them, however, kept a subintact central part. This is the case for the three big raised bogs situated in the Hautes-Fagnes plateau in Belgium: the fagne Wallonne, the fagne de Clefaye and the Misten raised bogs. Their vegetation belongs to the Vaccinio oxycocci-Sphagnetea magellanici Br.-Bl. & Tx. 43 and Eriophoro vaginati-Sphagnetalia papillosi Tx. 70. But the legal conservation measures are not sufficient to guarantee their protection : in the course of the last 30 years, 10 to 25% of the area covered with intact raised bogs of the Hautes-Fagnes plateau have been degraded, mainly invaded by Molinia caerulea. Although it is important to bring forward such alarming observations, it is more essential to understand exactly the origin of the factors causing the degradation, if suitable measures to thwart the factors that condition them, and try to attenuate if not suppress their harmful effects, and thereby restore the conditions that will enable the natural vegetation from these environments to recover the lost areas. Here are the main objectives of this work: • To highlight the current and recent ecological and phytodynamic consequences of the degradation of the raised bogs; • To identify and date the causes of the degradation that struck the intact parts of the raised bogs present on the Hautes-Fagnes plateau; • To examine the practical management measures in the short-, medium-, and long-term taken in Belgium and abroad in order to restore the natural evolution of the peatlands. Studies of the vegetation The vegetation maps, on a scale of 1/250, indicate that, despite some differences, the degradation phenomenon seems to begin in the same way in the three bogs. We can notice: • an invasion by Molinia caerulea of the intact peat areas (in sometimes very high tussocks) but also its presence, in a more diffuse form, within the -narrowzones of transition and even among typical bog species; • a soil draining, resulting in the proliferation of Ericaceae, especially around relatively intact zones; • the existence of Deschampsia flexuosa, which seems to be linked to rather steep slopes at the edge of zones exclusively colonised by Molinia caerulea,; • the poor representation, both in terms of quality as quantity, of bryophytes; fewer than 10 species of peatmosses occur in these peatlands, where they are often little or ill-developed; • the occupation of peat bogs by relatively exclusive species (Empetrum nigrum, Molinia caerulea and other very thick Ericaceae bushes) which prevent other peat forming communities from developing. The analysis of the vegetation releves taken along three transects shows that the Misten bog appears as the most intact one (or the best preserved one) based on the cover, distribution and vitality of peatmosses, although as indicated by the vegetation map, Molinia caerulea surrounds this raised bog. The fagne de Clefaye peat bog seems much drier and the percentage of peatmosses cover is lower compared to the Misten bog. Some Empetrum nigrum clumps no longer contain any mosses. On the other hand, this bog holds more Sphagnum species than either of the other two bogs investigated. The raised bog of the fagne Wallonne is the most degraded one (at least the north-west part of it). The complexity of the problem composed already the focus of several studies as part of a graduate work. In order to have some idea of the evolution of the vegetation, all the releves which have been carried out along the transects of the three bogs have been the subject of an observation follow-up. Even if six or seven years between the vegetation releves is too short a time to show some significant evolution in a peat bog, the results nonetheless enable to bring to the fore some trends in the evolution of the vegetation present in the main bogs of the haut-plateau, Along the itemised transect, the vegetation of the peat bog seems to be stable and optimal for a peat forming activity typical of an ombrotrophic raised bog, to develop. The northern part of the fagne Wallonne bog shows much more worrying signs of evolution (heaths developing quickly) or signs of degradation of its vegetation (reduction of the number of peatmosses, increasing density of Molinia caerulea, and invasion by Betula alba subsp. glutinosa). The vegetation of the fagne de Cléfaye bog clearly evolves towards a drier phase (high intensification of heaths development) without leading to the rarefaction of peatmosses. We wanted to put these evolutional studies in a broader context and take advantage of previous studies carried out on the haut-plateau in similar conditions. Despite the interpretation difficulties that were met, the different studies allow to assert that there has been a quick change in the vegetation of the raised bogs in the last forty years. Are we in the presence of a Natural evolution or a degradation process? The ground cover in the northern part of the fagne Wallonne bog shows obvious signs of degradation. The southern part of it as well as the fagne de Cléfaye bog show instead an evolution of the vegetation towards a stage heavily composed of heaths, with, however, a strong reduction of peatmosses. The Misten bog seems to experience the slowest evolution: is this a former evolution stage of the vegetation or is the balance achieved? Hydrological studies In natural conditions, the fluctuations of the water table of an ombrotrophic bog on a one-year scale remain modest: about 10 centimetres from one season to the other. It is thus interesting to check if the variations of the water table level are of the same nature in different spots of the three studied bogs or if the alteration phenomena, that are visible at the vegetation level and are present on the three bogs also appear in the behaviour of water tables at the surface of these bogs. Based on the follow-up of the 148 dip wells scattered on the three peat bogs, it appears that the Misten bog water table level is the most stable one. This means that the peat forming species, present on the fagne de Clefaye and especially in the studied part of the fagne Wallonne, are constantly subjected to fluctuations (which are sometimes significant) of the water table level. Now, if the peatmosses usually spread according to a humidity gradient, some of them tolerating a greater distance of the water table level than others, it does not mean however that a same species can survive such variations. The dip wells maps and the 3-dimensional representations of the water table enable to better understand the spreading of the vegetation at the surface of the bog. But these measures also reveal the presence of pedological phenomena, natural or not, such as drainage ditches, outlet, exploitation scar, fissures in the peat mass and others, that very much influence the variation of the water table level and thereby the surface vegetation in the short-, medium-, and long-term Paleo-ecological studies In order to better understand the evolution of raised bogs and especially try to find signs of their degradation, it is essential to investigate the peat lying right under the present vegetation. All the steps that have been set about within this context tried to answer the following questions: Is there a link between the vegetation present at the surface and the recent peat composition lying right under? Is there a link between the recently formed peat composition and the water table level observed on the peat bog? Are the microfossils, that are contained in the peat, affected by variations of the water table? Can we draw differences in the composition of the peat according to how far the boring has been carried out from the current active central zone of the peat bog? It clearly appears that the composition of the peat varies according to the type of present vegetation under which the sample was taken and the range of fluctuations of the water table level recorded on this spot. On the Misten peat bog, the palynological study of peat borings 10 m away from one another allowed to show that peat layers representing the same paleobotanical event(s) do not have the same thickness in each boring and can even be absent. In the same way, at a constant rate of pollen, the accumulation speed of the peat is higher in the bog centre compared to its margins. If one considers a same paleo-botanical event, and thus a same period of time, one can see that the pollen concentration is inversely proportional to the thickness of the peat. Two distinct parts are visible on the borings of the Misten peat bog surface: the upper part, the most recent one, characterised by the influence of the topographic position of the boring on the peat forming speed; the lower part, the oldest one, in which the influence is less pronounced. Thanks to different dating techniques (l4C, pollen concentrations and reference borings), this boundary between the two parts can approximately be dated back to the middle of the 14th century. This phenomenon should be related to an anthropogenic phenomenon rather than to a climatic one, given the short distance separating the borings. It would rather be the result of the manual exploitation of the peat than the harmful effects of the Eupen ditch which was dug much later (1774). A lot of microfossils, identifiable or not, present in the borings (rhizopodes, conidia ...) can doubtless be used as degradation indicators. Of course, these studies need to be deepened and systematised before going any further. What emerges especially from these studies is that when one undertakes regeneration attempts on a peat bog, one should not only take the present vegetation and hydrological parameters into account, but also the peat structure and composition, in at least the upper part of the deposits. Research and management Although acting on the current evolution of the Belgian bogs appears essential in order to prevent them from disappearing, it is clear that restoration measures that were appropriate elsewhere, cannot be applied to other areas without some thorough knowledge of the ecological parameters that govern them. The obvious result of this work is that the scientific follow-up of the management measures that have been taken is not only imperative, but that prior study measures of the sites and their characteristics are indispensable. This type of study is heavy because it requires an important investment from the researcher and often causes a lot of damage to the studied flora and fauna. However, these studies are necessary to understand the peatland systems and should even be complemented by further studies (lysimetric, structural or chemical...) . The standardisation of the data gathering system, the improvement of the information techniques and the management of the results organised in a way that allows all the researchers to consult them should contribute towards some lightening of the work. The computer science and the miniaturised electronic technology could improve the efficiency of the measures implemented, thereby benefiting the researcher and the reserve. Given the implied advanced technologies, these modern studies and data gathering processes would be expensive but it is cheap in comparison to the costs of the heavy works that are to be undertaken in the hope of preserving the raised bogs. Moreover, such a preparation of management measures can only improve their efficiency. If, despite all the efforts, the preservation of the jewels of the state nature reserve of the Haute-Fagnes is jeopardised, these studies will at least allow to go further in the understanding of the raised bogs systems. [less ▲]

Detailed reference viewed: 121 (11 ULg)
Full Text
Peer Reviewed
See detailL'Evolution saisonière de la teneur en CO2 de l'air de deux grottes belges : Ste-Anne et Brialmont, Tilff
Gewelt, Michel; Ek, Camille ULg

in Paterson, K.; Sweeting, M.M. (Eds.) New directions in Karst (1983, September)

Detailed reference viewed: 20 (2 ULg)
See detailThe evolution stages of a local agro-production: The cases of cider and syrup in East Belgium
Schmitz, Serge ULg

in Bryant, Christopher; Grilloti Di Giacomo, Maria (Eds.) Quality Agriculture: Historical Heritage and Environmental Resources for the Integrated Development of Territories (2007)

Relating the history of cider and syrup from the “Pays de Herve” (East of Belgium), the paper underlines the vicissitude of a local production. What remains local in these traditional products? Which ... [more ▼]

Relating the history of cider and syrup from the “Pays de Herve” (East of Belgium), the paper underlines the vicissitude of a local production. What remains local in these traditional products? Which component should remain local in traditional product? [less ▲]

Detailed reference viewed: 38 (13 ULg)
Full Text
Peer Reviewed
See detailEvolution sur deux ans des capacités fonctionnelles et motrices de sujets âgés résidant en maison de repos
Buckinx, Fanny ULg; Beaudart, Charlotte ULg; Slomian, Justine ULg et al

in Gériatrie et Psychologie Neuropsychiatrie du Vieillissement (2014), 12(1), 57-58

Detailed reference viewed: 12 (2 ULg)
Full Text
Peer Reviewed
See detailÉvolution technique au Paléolithique ancien de Karain (Turquie)
Otte, Marcel ULg; Yalçinkaya, Isin; Kozlowski, Janusz et al

in Anthropologie (L') (1995), 99(4), 529-561

The Karain Cave, in Southern Turkey, provided a long sequence pf Lower and Middle Palaeoliothic. A "Clactonian" type flake industry is present at the basis, with numerous denticulates and notches. The ... [more ▼]

The Karain Cave, in Southern Turkey, provided a long sequence pf Lower and Middle Palaeoliothic. A "Clactonian" type flake industry is present at the basis, with numerous denticulates and notches. The evolution is marked by the development of the elaborated preparation of flakes leading to the Levallois technology. Four climatic cycles were recognized, each with an alternance of a long cold phase and thinner tempered deposits. The now available radiometric datations place the last tempered phase around 120 to 100,000 years. [less ▲]

Detailed reference viewed: 102 (0 ULg)
See detailEvolution typologique des cercueils/sarcophages privés de l'époque ramesside
Gohy, Stéphanie ULg

Master's dissertation (2004)

Detailed reference viewed: 14 (3 ULg)
See detailL'évolution urbaine de 1945 à nos jours
Merenne-Schoumaker, Bernadette ULg

in Stiennon, Jacques (Ed.) Histoire de Liège (1991)

Analyse de l'évolution urbaine de la Ville de Liège depuis 1950

Detailed reference viewed: 31 (0 ULg)
See detailEvolution végétale: points de vue récents sur deux périodes-clés de l'histoire des plantes.
Meyer-Berthaud, Brigitte; Gerrienne, Philippe ULg

Conference (2004)

Detailed reference viewed: 8 (0 ULg)
Full Text
See detailÉvolution(1979-2008)des services d'hospitalisation en Belgique. Quel(s) liens avec la hiérarchie urbaine?
Trotta, Marie ULg

Conference (2010, February 24)

L'organisation de l'offre hospitalière ainsi que sa planification se voient aujourd'hui bouleversées par les logiques de marché ou d'efficience progressivement introduites dans le système hospitalier en ... [more ▼]

L'organisation de l'offre hospitalière ainsi que sa planification se voient aujourd'hui bouleversées par les logiques de marché ou d'efficience progressivement introduites dans le système hospitalier en Belgique comme dans les pays voisins. Ce bouleversement n’est pas sans impact sur l’organisation spatiale des services de soins. Toutefois, si certains auteurs y voient un renforcement de la relation à la hiérarchie urbaine, d’autres soutiennent l’hypothèse de l’émergence d’un tout autre modèle organisationnel : le réseau. L’objectif de cette recherche était de comparer l'organisation spatiale des services d’hospitalisation juste avant l’introduction d’un moratoire stoppant la croissance hospitalière (année 1979) avec la situation actuelle (année 2008) au travers de leur relation à la hiérarchie urbaine sur le territoire belge afin de soutenir l’une ou l’autre hypothèse. Si un renforcement de la relation n’apparaît que très légèrement, on a surtout pu démontrer un comportement différencié selon le type de services analysés et leur place dans la pyramide des soins. Promoteur du Mémoire : Bernadette Mérenne-Schoumaker. [less ▲]

Detailed reference viewed: 75 (20 ULg)
Peer Reviewed
See detailEvolution, en fonction de l'age et du sexe, de l'uree, de la creatinine et de la clairance de la creatinine.
El Allaf, Dia ULg; Marchal, C.; El Allaf, M. et al

in Archives Internationales de Physiologie et de Biochimie (1984), 92(3), 249-54

Serum urea and creatinine concentrations were determined in 150 healthy subjects. The formula of Cockcroft and Gault was used in order to calculate creatinine clearance. Such estimation of creatinine ... [more ▼]

Serum urea and creatinine concentrations were determined in 150 healthy subjects. The formula of Cockcroft and Gault was used in order to calculate creatinine clearance. Such estimation of creatinine clearance is widely used as a parameter for individualization of dosage of drugs secreted primary via the kidneys. The effects of age and sex were then assessed on serum urea, serum creatinine and on creatinine clearance. [less ▲]

Detailed reference viewed: 86 (5 ULg)
Peer Reviewed
See detailThe evolutionarily conserved Kruppel-associated box domain defines a subfamily of eukaryotic multifingered proteins
Bellefroid, Eric J.; Poncelet, Dominique A; Lecocq, Pierre J et al

in Proceedings of the National Academy of Sciences of the United States of America (1991), 88(9), 3608-12

We have previously shown that the human genome includes hundreds of genes coding for putative factors related to the Kruppel zinc-finger protein, which regulates Drosophila segmentation. We report herein ... [more ▼]

We have previously shown that the human genome includes hundreds of genes coding for putative factors related to the Kruppel zinc-finger protein, which regulates Drosophila segmentation. We report herein that about one-third of these genes code for proteins that share a very conserved region of about 75 amino acids in their N-terminal nonfinger portion. Homologous regions are found in a number of previously described finger proteins, including mouse Zfp-1 and Xenopus Xfin. We named this region the Kruppel-associated box (KRAB). This domain has the potential to form two amphipathic alpha-helices. Southern blot analysis of "zoo" blots suggests that the Kruppel-associated box is highly conserved during evolution. Northern blot analysis shows that these genes are expressed in most adult tissues and are down-regulated during in vitro terminal differentiation of human myeloid cells. [less ▲]

Detailed reference viewed: 24 (1 ULg)
Full Text
Peer Reviewed
See detailEvolutionary affiliation of the marine nitrogen-fixing cyanobacterium Trichodesmium sp. strain NlBB 1067, derived by 16s ribosomal RNA sequence analysis
Wilmotte, Annick ULg; Neefs, Jean-Marc; De Wachter, Rupert

in Microbiology (1994), 140

The 165 rRNA sequence of Trichodesmium sp. strain NlBB 1067 was determined and used for the construction of a distance tree and bootstrap analysis. The tree shows that, among the available cyanobacterial ... [more ▼]

The 165 rRNA sequence of Trichodesmium sp. strain NlBB 1067 was determined and used for the construction of a distance tree and bootstrap analysis. The tree shows that, among the available cyanobacterial 165 rRNA sequences, Trichodesmium NlBB 1067 has Oscillatoria PCC 7515 as its closest relative, presenting 94.9% of sequence similarity with the latter strain. This is in contrast to a difference of 9 mol O/O G + C in mean genomic DNA base composition between the two organisms. Nevertheless, the genotypic heterogeneity presented by a number of strains assigned to the genus Oscillatoria hinders a taxonomic decision on the separate existence of the genera Trichodesmium and Oscillatoria. The sequence of the internal transcribed spacer (ITS) between the 165 and 23s rRNA genes was also determined, as a possible marker to study inter- and intraspecif ic variability. The ITS contains the genes coding for tRNA1Ie and tRNAAia and its total length is 547 nucleotides. In six out of eight sequenced clones, there is a duplication of 29 nucleotides, surrounding the 5' end of the tRNA1Ie. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
See detailEvolutionary analysis of a complex multigene family by semi-automated mining of public sequence databases
Baurain, Denis ULg

Conference (2012, June 19)

Eukaryotic genes have a mosaic structure of exons and introns. After transcription, precursor mRNAs have to be spliced to yield mature mRNAs suitable for protein synthesis. This process is termed splicing ... [more ▼]

Eukaryotic genes have a mosaic structure of exons and introns. After transcription, precursor mRNAs have to be spliced to yield mature mRNAs suitable for protein synthesis. This process is termed splicing and is carried out by a complex known as the spliceosome. Serine/arginine-rich (SR) proteins play essential roles in splicing. They have a modular organization featuring at least one RNA recognition motif (RRM) domain and a carboxyl-terminal RS region enriched in arginine/serine dipeptides. However, their architectures are quite diverse, which has so far complicated their evolutionary analysis. To investigate the origin and evolution of SR splicing factors, we inferred phylogenies for more than 12,000 RRM domains representing more than 200 broadly sampled organisms. Our results show that all SR proteins share a single ancient origin. Based on refined analyses, we propose a scenario for their diversification into four natural families and a dozen subfamilies. Altogether, this work confirms the homogeneity and antiquity of SR splicing factors while establishing robust phylogenetic relationships between animal and plant proteins. In this talk, I will focus on the bioinformatics approaches required to carry out such a large-scale phylogenetic analysis. [less ▲]

Detailed reference viewed: 20 (3 ULg)
Full Text
Peer Reviewed
See detailEvolutionary conserved role of ptf1a in the specification of exocrine pancreatic fates
Zecchin, E.; Mavropoulos, A.; Filippi, A. et al

in Developmental Biology (2004), 268(1), 174-184

We have characterized and mapped the zebrafish ptf1a gene, analyzed its embryonic expression, and studied its role in pancreas development. In situ hybridization experiments show th at from the 12-somite ... [more ▼]

We have characterized and mapped the zebrafish ptf1a gene, analyzed its embryonic expression, and studied its role in pancreas development. In situ hybridization experiments show th at from the 12-somite stage to 48 hpf, ptf1a is dynamically expressed in the spinal cord, hindbrain, cerebellum, retina, and pancreas of zebrafish embryos. Within the endoderm, ptf1a is initially expressed at 32 hpf in the ventral portion of the pdx1 expression domain; ptf1a is expressed in a subset of cells located on the left side of the embryo posteriorly to the liver primordium and anteriorly to the endocrine islet that arises from the posterodorsal pancreatic anlage. Then the ptf1a expression domain buds giving rise to the anteroventral pancreatic anlage that grows posteriorly to eventually engulf the endocrine islet. By 72 hpf, ptf1a continues to be expressed in the exocrine compartment derived from the anteroventral anlage. Morpholino-induced ptf1a loss of function suppresses the expression of the exocrine markers, while the endocrine markers in the islet are unaffected. In mind bomb (mib) mutants, in which delta-mediated notch signalling is defective [Dev. Cell 4 (2003) 67], ptf1a is normally expressed. In addition, the slow-muscle-omitted (smu) mutants that lack expression of endocrine markers because of a defective hedgehog signalling [Curr. Biol. 11(2001) 1358] exhibit normal levels of ptf1a. This indicates that hedgehog signaling plays a different genetic role in the specification of the anteroventral (mostly exocrine) and posterodorsal (endocrine) pancreatic anlagen. (C) 2004 Elsevier Inc. All rights reserved. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailEvolutionary ecology of facultative paedomorphosis in newts and salamanders
Denoël, Mathieu ULg; Joly, Pierre; Whiteman, Howard H.

in Biological Reviews (2005), 80(4), 663-671

Facultative paedomorphosis is an environmentally induced polymorphism that results in the coexistence of mature, gilled, and fully aquatic paedomorphic adults and transformed, terrestrial, metamorphic ... [more ▼]

Facultative paedomorphosis is an environmentally induced polymorphism that results in the coexistence of mature, gilled, and fully aquatic paedomorphic adults and transformed, terrestrial, metamorphic adults in the same population. This polymorphism has been of interest to scientists for decades because it occurs in a large number of caudate amphibian taxa as well as in a large diversity of habitats. Numerous experimental and observational studies have been conducted to explain the proximate and ultimate factors affecting these heterochronic variants in natural populations. The production of each alternative phenotype is based on a genotype x environment interaction and research suggests that differences in the environment can produce paedomorphs through several ontogenetic pathways. No single advantage accounts for the maintenance of this polymorphism. Rather, the interplay of different costs and benefits explains the success of the polyphenism across variable environments. Facultative paedomorphosis allows individuals to cope with habitat variation, to take advantage of environmental heterogeneity in the presence of open inches, and to increase their fitness. This process is expected to constitute a first step towards speciation events, and is also an example of biodiversity at the intraspecific level. The facultative paedomorphosis system is thus ripe for future studies encompassing ecology, evolution, behaviour, endocrinology, physiology, and conservation biology. Few other systems have been broad enough to provide varied research opportunities on topics as diverse as phenotypic plasticity, speciation, mating behaviour, and hormonal regulation of morphology. Further research on facultative paedomorphosis will provide needed insight into these and other important questions facing biologists. [less ▲]

Detailed reference viewed: 245 (18 ULg)
Full Text
Peer Reviewed
See detailEvolutionary ecology of paedomorphosis in the Alpine newt Triturus alpestris
Denoël, Mathieu ULg

Conference (2003)

Paedomorphosis, in which individuals retain ancestral characteristics in the adult stage, is widespread in newts and salamanders and is suspected to play an important role in evolution. In some species ... [more ▼]

Paedomorphosis, in which individuals retain ancestral characteristics in the adult stage, is widespread in newts and salamanders and is suspected to play an important role in evolution. In some species, paedomorphosis is facultative with some individuals skipping the metamorphic stage. Dimorphic populations of the Alpine newt inhabit a large variety of aquatic habitats such as permanent lakes and temporary ponds. The aim of this study was to determine the benefits of the alternatives in these different habitats. To this end, I focused on resource partitioning, energy intake, body condition and age structures in different populations composed of the two morphs. In deep lakes, there was a substantial trophic differentiation between morphs. Paedomorphs primarily preyed on plankton whereas metamorphs foraged on terrestrial invertebrates that fell to the water surface. By reducing competition, resource partitioning may contribute to the coexistence of the alternative morphs in heterogeneous habitats. On the contrary, in a small pond, resource use was similar in the two morphs. Maturity is reached earlier in the paedomorphs from this small pond than in metamorphs (progenetic process), favoring then a rapid turn-over of the population, while similar gonadal development was observed in one of the deep lakes (neotenic process). Body condition was generally higher in paedomorphs than in metamorphs in each studied population. These results show that facultative paedomorphosis is adaptive in varied habitats, but that different factors may favor it depending of the characteristics of the environment. Paedomorphic phenotypes can thus be selected in low altitude productive ponds and high altitude oligotrophic lakes. [less ▲]

Detailed reference viewed: 15 (2 ULg)
Full Text
See detailEvolutionary history of Leopoldamys neilli, a karst endemic rodent in Southeast Asia, and implications for its conservation
Latinne, Alice ULg; Waengsothorn, Surachit; Michaux, Johan ULg

Conference (2013, August 15)

In this study, we have investigated the phylogeography of Leopoldamys neilli, a Murinae rodent species endemic to limestone karsts in Southeast Asia, on the basis of mitochondrial and nuclear markers ... [more ▼]

In this study, we have investigated the phylogeography of Leopoldamys neilli, a Murinae rodent species endemic to limestone karsts in Southeast Asia, on the basis of mitochondrial and nuclear markers. Both mitochondrial and nuclear markers support a large-scale population structure of four main groups within L. neilli and a strong finer structure within each of these groups. A deep genealogical divergence among geographically close lineages is observed and denotes a high population fragmentation. Our findings suggest that the current phylogeographic pattern of this species results from the fragmentation of a widespread ancestral population and that vicariance has played a significant role in the evolutionary history of L. neilli during Plio-Pleistocene. This study revealed an unexpected high level of intraspecific diversity within L. neilli. Consequently, the four main L. neilli population groups should be considered as four distinct Evolutionarily Significant Units (ESUs) and require appropriate management and conservation plans. [less ▲]

Detailed reference viewed: 19 (4 ULg)
Full Text
Peer Reviewed
See detailEvolutionary history of the bank vole Myodes glareolus: a morphometric perspective
Ledevin, Ronan; Michaux, Johan ULg; Deffontaine, Valerie et al

in Biological Journal of the Linnean Society (2010), 100(3), 681-694

The bank vole experienced a complex history during the Quaternary. Repeated isolation in glacial refugia led to the differentiation of several lineages in less than 300 000 years. We investigated if such ... [more ▼]

The bank vole experienced a complex history during the Quaternary. Repeated isolation in glacial refugia led to the differentiation of several lineages in less than 300 000 years. We investigated if such a recent differentiation led to a significant divergence of phenotypic characters between European lineages, which might provide insight into processes of intraspecific differentiation. The size and shape of the first and third upper molars, and first lower molar, of bank voles genetically attributed to different lineages were quantified using an outline analysis of their occlusal surface. The three teeth present similar trends of decreasing size towards high latitudes. This trend, the inverse of Bergmann's rule, is interpreted as the result of a balance between metabolic efficiency and food availability, favouring small body size in cold regions. Molar shape appeared to differ between lineages despite genetic evidence of suture zones. A mosaic pattern of evolution between the different teeth was evidenced. The analysis of such phenotypic features appears as a valuable complement to genetic analyses, providing a complementary insight into evolutionary processes, such as selective pressures, that have driven the differentiation of the lineages. It may further allow the integration of the paleontological dimension of the bank vole phylogeographic history. (C) 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 681-694. [less ▲]

Detailed reference viewed: 67 (1 ULg)