The increased population of the Wild Boar (Sus scrofa L.) in Europe

In this paper the recent population changes of the Wild Boar in different European countries is analysed through the study of hunting statistics. A simultaneous increase in numbers is observed throughout the whole area during the period 1965–1975. From 1975 onwards the population stabilizes itself apart from in peripheral areas like Finland. Potentially favourable factors which play a part in this process are discussed and certain reproductive and dispersive characteristics which favour its invasive behaviour are discussed.     

Waterlogging responses in dune,swale and marsh populations of Spartina patens under field conditions

Summary Soil waterlogging responses were examined in three Spartina patens populations along a steep flooding gradient in coastal Louisiana. Root anatomy and physiological indicators of anaerobic metabolism were examined to identify and compare flooding responses in dune, swale and marsh populations, while soil physicochemical factors were measured to characterize the three habitats. Soil waterlogging increased along the gradient from dune to marsh habitats and was accompanied by increases in root porosity (aerenchyma). Aerenchyma in marsh roots was apparently insufficient to provide enough oxygen for aerobic respiratory demand, as indicated by high root alcohol dehydrogenase activities and low energy charge ratios. Patterns of root metabolic indicators suggest that dune and swale roots generally respired aerobically, while anaerobic metabolism was important in marsh roots. However, in each population, relatively greater soil waterloging was accompanied by differences in enzyme activities leading to malate accumulation. In dune and swale roots under these circumstances, depressed adenylate energy charge ratios may have been the result of an absence of increased ethanol fermentation. These trends suggest that: 1) Aerenchyma formation was an important, albeit incomplete, long-term adaptation to the prevalent degree of soil waterlogging. 2) All populations adjusted root metabolism in response to a relative (short-term) increase in soil waterlogging.     

Potential of restoration and phytoremediation with Juncus roemerianus for diesel-contaminated coastal wetlands

Oil spills may considerably damage sensitive coastal wetlands. In this study, the tolerance limits of a dominant coastal salt marsh plant, Juncus roemerianus, to diesel oil and its phytoremediation effectiveness in wetland environments were investigated in the greenhouse. J. roemerianus was transplanted into salt marsh sediment contaminated with diesel fuel at concentrations of 0, 20, 40, 80, 160, 320, and 640 mg diesel g^?1 dry sediment. Plant stem density, shoot height, aboveground biomass and belowground biomass were detrimentally impacted at high oil dosages even 1 year after transplantation. Tolerance limits were estimated between 160 and 320 mg g^?1 based on various plant variables. Importantly, J. roemerianus enhanced oil degradation; at the 40 mg/g diesel dosage, concentrations of residual total petroleum hydrocarbons (TPH) in the sediment planted with J. roemerianus were significantly lower than those of unplanted sediments 1 year after treatment initiation. Furthermore, concentrations of total targeted polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in the J. roemerianus planted treatment were, respectively, about 3% and 15% of the unplanted treatment. Concentration reduction in all categories of hydrocarbons suggested that J. roemerianus effectively phytoremediated the diesel-contaminated wetlands.     

Chromosome numbers in Brazilian species of Crotalaria (Leguminosae, Papilionoideae) and their taxonomic significance

Chromosome numbers were counted for 23 species of Crotalaria native to Brazil. Among these data there were new counts for 15 taxa, and some confirmed previous reports or represented numbers that were different from those cited previously. The chromosome numbers most frequently found were 2 n  = 16 and 2 n  = 32. Only C. incana L. had 2 n  = 14 and C. tweediana Benth. had 2 n  = 54. The counts 2 n  = 32 and 54 were found in species of section Calycinae and 2 n  = 16 and 14 in species of section Chrysocalycinae . The data revealed the importance of chromosomal parameters in the characterization of sections Calycinae and Chrysocalycinae in Brazil. We discuss the systematic significance and evolutionary aspects for the genus, comparing the results with the two sections that are native in Brazil.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 271–277.     

Chromosome numbers and meiotic analysis in the pre-breeding of <Emphasis Type="BoldItalic">Brachiaria decumbens</Emphasis> (Poaceae)

A total of 44 accessions of Brachiaria decumbens were analysed for chromosome count and meiotic behaviour in order to identify potential progenitors for crosses. Among them, 15 accessions presented 2n = 18; 27 accessions, 2n = 36; and 2 accessions, 2n = 45 chromosomes. Among the diploid accessions, the rate of meiotic abnormalities was low, ranging from 0.82% to 7.93%. In the 27 tetraploid accessions, the rate of meiotic abnormalities ranged from 18.41% to 65.83%. The most common meiotic abnormalities were related to irregular chromosome segregation, but chromosome stickiness and abnormal cytokinesis were observed in low frequency. All abnormalities can compromise pollen viability by generating unbalanced gametes. Based on the chromosome number and meiotic stability, the present study indicates the apomictic tetraploid accessions that can act as male genitor to produce interspecific hybrids with B. ruziziensis or intraspecific hybrids with recently artificially tetraploidized accessions.     

Patterns of genetic variability at individual minisatellite loci in minke whale Balaenoptera acutorostrata populations from three different oceans

The genetic variability at six cloned minisatellite loci was analyzed in minke whale populations from the North Atlantic, North Pacific, and Antarctic Oceans. Three loci displayed only a few different alleles in each of the three populations, with heterozygosity ranging from 0.00 to 0.47, and three loci revealed many different alleles in at least two fo the three populations, with heterozygosity ranging up to 0.98. Using small sample sizes, samples from two adjacent Antarctic Management Areas were not found to differ significantly in allele frequencies at any of the six loci. The use of principal coordinate analysis to detect multilocus disequilibria was explored. No significant evidence was found of intrapopulation heterogeneity within the pooled Antarctic sample. Pronounced interoceanic differences were observed at every locus, confirming the existence of genetic isolation found earlier using more conventional marker systems. The populations from the three oceans appear to have diverged to such a degree that the hypervariable loci have had time to evolve independently and arrive at different evolutionary stages in different populations. The frequency of undetected "null" alleles is remarkably high in minke whale populations compared to human populations and is probably a result of the cloning protocol used. Minisatellite loci are shown to provide a powerful population genetic tool, supplying levels of resolution appropriate to different degrees of evolutionary divergence.      

Recovery of freshwater marsh vegetation after a saltwater intrusion event

Greenhouse mesocosms of freshwater marsh vegetation were exposed to a simulated saltwater intrusion event followed by a recovery period during which water levels and interstitial water salinity were adjusted over a range of conditions. Virtually all above-ground vegetation, including the three dominant species, Sagittaria lancifolia L., Leersia oryzoides (L.) Swartz, and Panicum hemitomon Schultes, was killed by the initial saltwater intrusion event. P. hemitomon did not recover, but S. lancifolia and L. oryzoides, as well as many of the other species initially present, exhibited some ability to recover depending on post-saltwater intrusion conditions. Increasingly harsh recovery conditions (for freshwater marsh vegetation), including more reduced soil conditions, higher interstitial salinities, and higher interstitial sulfide concentrations were associated with decreased live above-ground biomass and species richness. The effect of elevated salinity on vegetative recovery became more pronounced under flooded conditions. This experiment illustrates that the response of a freshwater marsh community to the long-term disturbance effect of a transient saltwater intrusion event will be strongly influenced by post-intrusion salinity and water levels.