Intraspecific genome size variation and morphological differentiation of Ranunculus parnassifolius (Ranunculaceae), an Alpine–Pyrenean–Cantabrian polyploid group

The aim of this study was to assess genome size variation and multivariate morphometric analyses to ascertain cytotype distribution patterns and the morphological differentiation within the Ranunculus parnassifolius group in the Pyrenees and the Alps. Although divergences in nuclear DNA content among different species within a genus are widely acknowledged, intraspecific variation is still a somewhat controversial issue. Holoploid and monoploid genome sizes (C‐ and Cx‐values) were determined using propidium iodide flow cytometry in 125 plants of R. parnassifolius s.l. distributed across four European countries. Three different DNA ploidy levels were revealed in the study area: diploid (2n ～ 2x, 57.14%), triploid (2n ～ 3x, 1.19%), and tetraploid (2n ～ 4x, 41.67%). The mean population 2C‐values ranged from 8.15 pg in diploids to 14.80 pg in tetraploids, representing a ratio of 1 : 1.8. Marked intraspecific/interpopulation differences in nuclear DNA content were found. Diploid populations prevail in the Pyrenees, although tetraploid cytotypes were reported throughout the distribution area. In general, mixed‐cytotype populations were not found. The Spearman correlation coefficient did not reveal significant correlations between genome size and altitude, longitude, or latitude. Morphometric analyses and cluster analyses based on genome size variation revealed the presence of three major groups, which exhibited a particular biogeographical pattern. A new cytotype, DNA triploid, was found for the first time. Tetraploid populations showed constant nuclear DNA levels, whereas diploid populations from the Pyrenees, in which introgressive hybridization is suggested as a presumable trigger for genome size variation, did not. Scenarios for the evolution of geographical parthenogenesis in R. parnassifolius s.l. are discussed. Finally, the different levels of effectiveness between plant and animal reference standards are analysed. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 251–271.     

Use of Camera-Trapping to Estimate Puma Density and Influencing Factors in Central Brazil

Abstract: We used remotely triggered cameras to collect data on Puma (Puma concolor) abundance and occupancy in an area of tropical forest in Brazil where the species' status is poorly known. To evaluate factors influencing puma occupancy we used data from 5 sampling campaigns in 3 consecutive years (2005 to 2007) and 2 seasons (wet and dry), at a state park and a private forest reserve. We estimated puma numbers and density for the 2007 sampling data by developing a standardized individual identification method. We based individual identification on 1) time-stable parameters (SP; physical features that do not change over time), and 2) time-variable parameters (VP; marks that could change over time such as scars and botfly marks). Following individual identification we established a capture-recapture history and analyzed it using closed population capture-mark-recapture models. Puma capture probability was influenced by camera placement (roads vs. trails), sampling year, and prey richness. Puma occupancy was positively associated with species richness and there was a correlation between relative puma and jaguar (Panthera onca) abundance. Identifications enabled us to generate 8 VP histories for each photographed flank, corresponding to 8 individuals. We estimated the sampled population at 9 pumas (SE = 1.03, 95% CI = 8–10 individuals) translating to a density of 3.40 pumas/100 km². Information collected using camera-traps can effectively be used to assess puma population size in tropical forests. As habitat progressively disappears and South American felines become more vulnerable, our results support the critical importance of private forest reserves for conservation.     

Sett density as an estimator of population density in the European badger Meles meles

• 1 Estimations of European badger population density in the UK are usually based on surveys of numbers of main setts. However, this approach cannot be used in low‐density areas, such as the Mediterranean region, where no main setts can be defined. Therefore, an alternative method is needed to estimate badger density over large areas.
• 2 We reviewed the existing published information to evaluate whether badger density is correlated to the density of all setts in an area (not only the main setts) and to ask whether badger density can be predicted from total sett number throughout the geographical range of the species.
• 3 In multiple regression analysis, badger density and the size of the study area explained 73% of the variance in sett density. Badger density had a significant positive effect on sett density, while the effect of study area size was not significant. Therefore, total sett density can be used to obtain an estimation of relative badger density in all habitats and regions throughout the badger's geographical range, allowing comparative research.

     

Changes in the Molecular Weight Distribution of the Hemicellulosic Polysaccharides from Rice Coleoptiles Growing Under Different Conditions

The changes in the molecular weight distribution of water-solubleand water-insoluble hemicelluloses from the cell walls of ricecoleoptiles growing in air and under water were studied. Thegrowth of rice coleoptiles was remarkably enhanced by growingunder water. Water-insoluble hemicellulose, mainly constitutedby xyloglucan, suffered an important depolymerization duringcoleoptile growth. On the other hand, ß-glucan andarabinoxylan, the two main polysaccharides of the water-solublehemicelluloses showed different changes during coleoptile growth.ß-glucan showed an increase in its degree of polymerizationduring the coleoptile fast growth phase and it decreased beforecoleoptile growth ceased. Arabinoxylan did not show importantdifferences in its mass-average molecular weight. Thus, xyloglucanand ß-glucan are the two hemicellulosic polysaccharidesinvolved in the cell wall loosening mechanism during coleoptilegrowth under both culture conditions. Key words: Arabinoxylan, cell wall, ß-glucan, xyloglucan