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En el NW de Burgos (España) la unidad geomorfológica de las Loras es un espacio de transición entre la Montaña Cantábrica y las llanuras de Castilla. Su relieve es morfoestructural. Alternan elevaciones, llamadas loras (sinclinales colgados de culminación plana) y valles (combes labradas en los anticlinales). La estructura es de relieve plegado, pero está alterado por fallas. El paisaje es fundamentalmente geológico., The geomorphological unity of the Loras –NW of Burgos (Spain)– is a sort of transitional space from the Cantabrian mountains and the plains of the Castille. The relief is morphological- structural. Alternating elevations brain –Loras– and valleys –combes–. The topography of the region presents a mountainous terrain with folds and the faults. The Loras its wonderful geological landscape.

Biostratigraphy and paleoenvironments at the onset of the recent Würm as inferred from the large mammals from Le Flageolet I (Dordogne, France). The analysis of the large mammals represented in the Aurignacian and Perigordian assemblages of Le Flageolet I was undertaken in part to increase our understanding of the biostratigraphy and paleoenvironments of this part of southwestern France. The work presented here has three goals, the initial aim being to describe the taxa identified from these assemblages. Nine different taxa of carnivores are present, none of which are abundant : only 1.3% of the combined ungulate and carnivore specimens are from carnivores, and over half of these are of foxes ( Vulpes vulpes and Alopex lagopus). The ungulate component of the large mammal fauna is dominated by reindeer and red deer, with smaller numbers of horses and large bovids. Since most of the large bovids could only be identified to the genus level, our analysis emphasizes Rangifer tarandus, Cervus elaphus, and Equus caballus. This analysis allows us to compare the Le Flageolet I assemblages to other early Recent Würm sites, to revisit a series of questions related to the evolution of Cervus elaphus and Equus caballus, and to discern possible environmental causes of both morphological and biometric variability within these three species. The second part of our analysis is dedicated to a biostratigraphic analysis of two additional sites of comparable age, sites which have also provided large mammal assemblages from well-controlled and reasonably homogeneous stratigraphic contexts. This set of assemblages allows us to define eight "biozones" at the beginning of the Recent Würm, each of which appears restricted to a relatively brief period of time. Of these eight, six are represented at Le Flageolet I. The third part of the analysis, directed toward understanding the past climates of this region, is based primarily on the modern climatic correlates of the taxa represented in these "biozones". The period between about 34000 radiocarbon years BP and 26000 BP was marked by contrasting warmer and colder climatic conditions; after 26000 BP, climates increasingly approached those that marked the glacial maximum. Early Würm climates during the time of accumulation of strata XI of Le Flageolet I, K5-7 of La Ferrassie, and 7 of Roc de Combe, on the one hand, and strata IV and V of Le Flageolet I, on the other, were extremely cold. In contrast, markedly temperate climates were in place during the accumulation of strata I to K1-3 at La Ferrassie, and of strata VII of Le Flageolet I and D2 to F of La Ferrassie. These inferred climatic extremes match, and presumably explain, the low taxonomic richness values that mark the ungulate assemblages of Le Flageolet strata XI, VII, V, and IV (cf. Grayson and Delpech 1998), and are supported by the probable presence of both large and small reindeer in these strata. In contrast, Le Flageolet strata IX, VIII, and VI show both greater richness values and contain only large reindeer., L'étude des grands mammifères représentés dans le gisement aurignacien et périgordien du Flageolet I a été menée dans le but de préciser la biostratigraphie et les paléoenvironnements du début du Wiirm récent dans la région concernée. Ce travail se divise en trois parties, la première vise à caractériser les taxons présents. Les carnivores sont assez nombreux ( 9 taxons différents) mais peu abondants : le nombre de leurs vestiges ne représente que 1 ,3 % du nombre de restes déterminés (ongulés et carnivores) et, parmi ces vestiges, plus de la moitié se rapportent au Renard qui est représenté à la fois par Vulpes vulpes et par Alopex lagopus. Les ongulés sont largement dominés par le Renne et le Cerf, le Cheval et les grands Bovidés arrivant respectivement en troisième et quatrième position. Si les recherches sur les grands Bovidés n'ont permis qu'une détermination des genres ( et des espèces) représentées dans le site, celles portant sur Rangifer tarandus, Cervus elaphus et Equus caballus ont conduit à caractériser les populations représentées relativement à celles d'autres sites wùrmiens, à remettre en cause certaines vues concernant l'évolution de Cervus elaphus et Equus caballus et à percevoir de possibles causes environnementales aux variations morphologiques ou (et) biométriques rencontrées sur les éléments squelettiques de ces trois espèces. La deuxième partie consacrée à l'étude biostratigraphique prend en compte les ensembles fauniques de deux autres sites du début du Wùrm récent, le Roc de Combe ( couches 8 et 7) et La Ferrassie qui, comme ceux du Flageolet I, forment des échantillons homogènes stratigraphiquement c'est à dire composés de spécimens dont l'origine stratigraphique a été critiquée et contrôlée. Une biozonation a pu être établie pour le début du Wùrm récent ; elle comporte huit horizons, chacun d'eux correspondant à une période de temps relativement brève. Six d'entre eux sont représentées au Flageolet I. La troisième partie de notre analyse qui vise à retracer les climats passés se fonde essentiellement sur la signification climatique actuelle des taxons représentés dans ces horizons. De 34000 BP jusque vers 26000 BP environ, le début du Wùrm récent apparaît comme une période aux climats contrastés, après quoi le climat évoluerait de façon plus régulière vers les conditions du dernier maximum glaciaire. La courbe climatique du début du Wùrm récent passerait par des " extrêmes froids " lors des périodes de formation des couches XI du Flageolet I, K5-7 de La Ferrassie et 7 du Roc de Combe d'une part, IV et V du Flageolet I d'autre part, et par des " extrêmes tempérés " durant la formation des couches I à K1- 3 de La Ferrassie d'une part, VII du Flageolet I et D2 à F de La Ferrassie d'autre part. Les " extrêmes climatiques " inférés vont avec, et sans doute expliquent, les faibles valeurs de la richesse taxonomique des assemblages d'ongulés des couches XI, VII, V et IV du Flageolet l( cf. Grayson et Delpech, 1998). L'hypothèse de l'établissement de ces extrêmes climatiques est soutenue par la présence probable de Rennes de grande taille et de petite taille dans ces mêmes couches. Dans les autres ensembles (IX, VIII et VI), au contraire, la richesse taxonomique est plus forte et le Renne paraît être toujours de grande taille., Delpech Françoise, Grayson Donald K., Rigaud Jean-Philippe. Biostratigraphie et paléoenvironnements du début du Würm récent d'après les grands mammifères de l'Abri du Flageolet I (Dordogne, France) / Biostratigraphy and paleoenvironments at the onset of the recent Würm as inferred from the large mammals from Le Flageolet (Dordogne, France). In: Paléo, n°12,2000. pp. 97-126.

A trapoeraba (gênero Commelina) é planta daninha-problema em cafezais devido à sua capacidade de sobreviver nas mais diversas condições e tolerância ao herbicida glyphosate. O objetivo deste trabalho foi avaliar a eficiência do herbicida 2,4-D, em doses crescentes, aplicado isoladamente ou em mistura com o glyphosate, no controle de Commelina benghalensis e Commelina diffusa. Para isso, foi conduzido um experimento para cada espécie, em vasos, em casa de vegetação, no delineamento inteiramente casualizado, com cinco repetições. Foram comparados dez tratamentos, que consistiram da combinação de cinco doses de 2,4-D (0; 167,5; 335; 670; e 1.005 g ha-1) e duas doses de glyphosate (0 e 720 g ha1). Avaliou-se a eficácia dos tratamentos pela porcentagem de controle, avaliada em cinco épocas, em relação à testemunha. Em C. benghalensis, 2,4-D proporcionou controle excelente (>91%) aos 33 DAT (dias após tratamento) a partir de 167,5 g ha-1 na presença de glyphosate e a partir de 335 g ha-1 na ausência de glyphosate. Em C. diffusa, 2,4-D proporcionou controle excelente aos 33 DAT a partir de 670 g ha-1, tanto na presença quanto na ausência de glyphosate. No entanto, somente a mistura de 2,4-D + glyphosate a 1.005 + 720 g ha-1 provocou 100% de controle desta espécie, verificando-se rebrota das plantas nos outros tratamentos. Nas condições dos experimentos, C. benghalensis mostrou-se mais suscetível que C. diffusa ao herbicida 2,4-D aplicado isoladamente ou em mistura com o glyphosate. Portanto, a identificação da espécie de trapoeraba presente na área a ser tratada e o conhecimento de sua biologia auxiliam na escolha do melhor produto e da dose ideal a ser aplicada, ou mesmo na escolha da mistura adequada, garantindo menor custo e melhor controle, com menores riscos para a cultura e o meio ambiente. The dayflower (genus Commelina) is a problem weed in coffee plantations due to its capacity to survive in diversified conditions and tolerance to glyphosate herbicide. The objective of this work was to evaluate the efficiency of increasing doses of 2,4-D herbicide, applied alone or in mixture with glyphosate, in controlling Commelina benghalensis and Commelina diffusa. Thus, two experiments (one for each species) were conducted in pots, in a randomized complete design, with five replications, under greenhouse conditions. Ten treatments consisting the combination between five 2,4-D rates (0.0, 167.5, 335.0, 670.0 and 1,005.0 g ha-1) and two glyphosate rates (0.0 and 720.0 g ha-1) were compared. The efficacy of the treatments was evaluated through the percent of weed control, in five evaluation times, in relation to the control treatment (herbicide absence). In C. benghalensis, 2,4-D provided excellent control (> 91%) at 33 days after treatments (DAT), starting from 167.5 g ha-1 in the glyphosate presence and starting from 335 g ha-1 in glyphosate absence. In C. diffusa, 2,4-D provided excellent control at 33 DAT starting from 670 g ha-1 in the glyphosate presence and absence. However, only the mixture of 2,4-D + glyphosate at 1,005 + 720 g ha-1 provided 100% of control of that species, with the occurrence of plant growth in the other treatments. In the experimental conditions, C. benghalensis was more susceptible than C. diffusa to 2,4-D herbicide, applied alone or in mixture with glyphosate. Thus, identifiying dayflower species present in the area and understanding its biology can help to choose a better herbicide and the ideal rate to be applied, or even an adequate mixture, warranting better control and lower cost, with lower risks for the culture and the environment.

O conhecimento dos mecanismos de reprodução de uma espécie de planta daninha, principalmente em relação à dormência e germinação de suas sementes, é de grande importância na determinação do método e da época ideal de seu controle. Com o objetivo de avaliar a germinação de sementes aéreas e subterrâneas de Commelina benghalensis, plantas desta espécie foram cultivadas em vasos, em casa de vegetação, nas condições de Viçosa, Estado de Minas Gerais, Brasil. Semente subterrânea grande (SSG) e semente aérea pequena (SAP) apresentaram o maior e o menor peso (8,81 e 1,90 mg/semente, respectivamente). Semente aérea grande (SAG) e semente subterrânea pequena (SSP) apresentaram pesos intermediários (3,65 e 3,51 mg/semente, respectivamente), porém semelhantes entre si. A data de coleta das sementes aéreas influenciou seu peso, observando-se, nas condições do experimento e no intervalo considerado (setembro a dezembro), maior peso de semente na primeira coleta (24/9/1999). A germinação das sementes aéreas não foi influenciada pelo tempo de armazenamento. Sementes aéreas pequenas germinaram melhor a 20-35 ºC, e as grandes, a 25 ºC. A germinação de sementes aéreas recém-colhidas variou de 7,50% em SAP a 21,67% em SAG/E (semente aérea grande com envoltório). O armazenamento por quatro meses aumentou a porcentagem de germinação de SAG e não alterou a de SAG/E e SAP. Sementes subterrâneas pequenas e grandes armazenadas por três meses apresentaram 32,5 e 92,5% de germinação, respectivamente. O aumento do tempo de armazenamento de três para seis meses diminuiu a porcentagem de germinação de SSG e SSP. O calor seco aumentou a porcentagem de germinação de SAG/E e SSP, não alterou a de SAG e SAP e diminuiu a de SSG. O grau de dormência diferiu muito entre os quatro tipos de sementes. A produção de sementes polimórficas com grandes diferenças no grau de dormência permite que C. benghalensis germine e se estabeleça nos mais diversificados ambientes e épocas do ano, o que dificulta o manejo desta espécie daninha. Understanding the reproductive mechanisms of a weed species, mainly concerning to its seeds' dormancy and germination is of great importance for determining the method and right time for its control. To evaluate the germination of aerial and underground seeds of Commelina benghalensis. plants were grown in pots under greenhouse conditions in Viçosa, Minas Gerais, Brazil. The large underground seed (SSG) and the small aerial seed (SAP) had the largest and the smallest seed weight of 8.81 and 1.90 mg/seed, respectively. Large aerial seed (SAG) and small underground seed (SSP) had similar intermediate weights (3.65 and 3.51mg/seed, respectively). The aerial seed harvest date influenced their weight, with a production of heavier seeds in the first harvest (September, 24 1999) being observed during the experimental period and interval studied (September to December). Aerial seed germination was not influenced by storage time. SAP showed better germination percent at 20-35 ºC and SAG at 25 ºC. Germination of freshly harvested aerial seeds varied from 7.50% for SAP to 21.67% for SAG/E (large aerial seed with covering). Four-month storage increased SAG germination percent without altering it in SAG/E and SAP. Small and large underground seeds stored during three months showed 32.5 and 92.5% of germination, respectively. Increasing storage time from three to six months decreased SSG and SSP germination percent. Germination percent was increased by dry heat in SAG/E and SSP, had no alteration in SAG and SAP, and decreased in SSG. The degree of dormancy differed among the four seed types. The production of polymorphic seeds showing great differences in dormancy degree allows C. benghalensis to germinate and establish in the most diversified environments and seasons of the year, making difficult the management of this weed species.