Weed species diversity and community composition in cropping practices at two intensity levels – a six-year experiment

Alternative cropping practices can be expected to increase the diversity and change the species composition of weed communities. In a six-year field experiment we compared species diversity and species composition in the weed community of cereal fields cultivated by conventional and by low-input cropping methods. In the conventional cropping both mineral fertilizers and herbicides were applied but in the low-input cropping the fertlizer was manure and herbicides were avoided altogether. The level of nitrogen fertilization was higher in conventional cropping. A five-year crop rotation comprising rye, oat-pea, barley and two-year grasslands was used in both cropping methods. We found that the species pool was larger (42 vs 35 species) and the average number of species higher (20.2 vs 13.1 species) in low-input than in conventional cropping. This was the case both in the data pooled across crops and in each crop separately. Herbicides affected species diversity and species composition more than did nitrogen fertilization. Species susceptible to the herbicides applied declined in abundance, which resulted in more skewed dominance patterns in the communities of conventional fields than in those of low-input fields. The crop affected the species composition of weed communities more than did the cropping method. Our results suggest that weed species diversity could be promoted by using low-intensity cropping practices.     

Prostaglandin biosynthesis inhibitors and endometriosis

The prostaglandin biosynthesis inhibitors ketoprofen and indomethacin were compared in the treatment of primary dysmenorrhea in a double-blind, cross-over trial involving 23 patients. Each drug was used for 2–4 days during 3 consecutive menstruations in randomized order. Good or moderate overall relief was obtained in 60 of the 68 ketoprofen-treated menstruations (88 %) and in 60 of the indomethacin-treated cases (90 %). A dysmenorrhea score, based on subjective estimations of 8 symptoms, similarly decreased from a mean (±S.E.M.) basal level of 9.6 ± 0.6 to 3.6 ± 0.3 during ketoprofen treatment and to 4.0 ± 0.3 during indomethacin. Both drugs relieved pelvic and lower back pains and eliminated vomiting and diarrhea in 82–97 % of the cycles whereas headache, fatigue and nervousness were less frequently alleviated (40–67 %). Eighteen of the 23 women (78 %) had been unable to work during the first day of menstruation, the rate of working days lost was reduced to 4 % with ketoprofen and 9 with indomethacin. Mild side-effects occurred during 12 ketoprofen and 14 indomethacin therapies. Ketoprofen thus seems to be as effective and tolerable as indomethacin in the treatment of primary dysmenorrhea.     

Hormone response of diabetic patients to exercise at cool and warm temperatures

Both exercise and high ambient temperatures stimulate the secretion of counterregulatory hormones which can change glucose homeostasis. We studied whether in diabetic patients there are any differences in the hormonal response to exercise performed at cool or warm ambient temperatures. A study was performed on eight male insulin-dependent patients at rest and during exercise at +10 degrees C and +30 degrees C. Exercise consisted of three consecutive 15-min periods at 60% of maximal aerobic capacity. The concentrations of plasma lactate and counterregulatory hormones at rest were similar at warm and cool temperature, whereas prolactin concentration was higher (P less than 0.01) at +30 degrees C. Exercise resulted in an increase in noradrenaline, growth hormone and prolactin (P less than 0.01), prevented the diurnal decrease in cortisol, but had no effect on glucagon. Hormone responses to exercise were similar at +10 degrees C and at +30 degrees C, except for cortisol and noradrenaline which showed greater responses at warm than at cool temperatures. This may have been due to the higher relative work load at warm compared to cool temperatures as suggested by the higher heart rate and greater increase of lactate at +30 degrees C. These data indicate that within a range of ambient temperatures commonly occurring in sports, the response of counterregulatory hormones is largely independent of ambient temperature in insulin-dependent diabetic patients.     

Development and fate of Eutreptiella gymnastica bloom in nutrient-enriched enclosures in the coastal Baltic Sea

Response of the phytoplankton community to bottom-up (nutrients,organic carbon source) and top-down (fish) manipulations, bothsingly and together, were studied daily during a 3 week periodin July 1993 by using eight 50 m³ mesocosms in the coastal northernBaltic Sea. Nutrient additions (once per week) invoked a seriesof blooms of Eutreptiella gymnastica Throndsen (Euglenophyceae)(up to 13 x 10³ cells ml^–1) which formed the major part(60–90%) of the total autotrophic biomass. After rapiddepletion of nutrients (2–3 days) from the surface layer(0–6 m) downwards migration and a subsequent peak of E.gymnasticain the lower part of the water columns (6–12 m) followed.Settled material collected from the bottom of the enclosurescontained a considerable amount of E.gymnastica cells and restingcysts. Nevertheless, sinking loss rates of E.gymnastica wereestimated to be less than 1% day^–1 of the suspended cellnumbers. The fate of E.gymnastica blooms was estimated to begrazing through mesozooplankton. However, provided the nutrientsare plentiful in the water column, the growth potential of E.gymnasticaappears to exceed the ambient grazing pressure. If the nutrientsbecome depleted, it seems to be effectively controlled by mesozooplanktongrazing, which is probably limiting the likelihood of massiveE.gymnastica blooms in the coastal Baltic Sea. Our study suggeststhat E.gymnastica appears to be a fast-growing fugitive (bloom)species with flexible behavioural (vertical migration) and lifehistory (cyst formation) adaptations which is able to exertdominant role and direct trophic relations similar to otherbloom species adapted for decaying turbulence and high nutrientenvironments.     

Human dimensions of wolf (<Emphasis Type="Italic">Canis lupus</Emphasis>) conflicts in Finland

The growth of the Finnish wolf (Canis lupus) population during the last years has highlighted people’s contradictory attitudes toward wolves. The supranational conservation objectives brought on by Finland’s membership in the European Union (EU) and the regional application of the official policy on wolves have led to conflicts. This article is based on the preparation process of the wolf management plan in Finland. As a part of the process, a nationwide hearing was arranged in 2004. Fear of wolves is widespread and even more common in areas with low wolf population. People living in areas where wolves occur feel that they can no longer influence decision making which affects them and that the authorities, conservationists, and the EU do not listen to their opinions. Numerous requests have been made for the legislation and its interpretation, and concessions to these requests would promote consensus and increase tolerance for wolves. Proposed changes include reforming the damage compensation system and formulating a clearer interpretation of the conservation status of wolves. However, it seems impossible to create a policy that would be universally supported. As the wolf question has become more central in environmental policy, the conservation and management of the species have become more complicated, and the cooperation between various interest groups has declined. The wolf conflict could be mitigated by compromises, but because the conflict is value-based, solutions are illusive.     

Evidence of dietary differentiation among late Paleocene–early Eocene plesiadapids (Mammalia,primates)

Plesiadapis cookei is an extinct relative of extant euarchontans (primates, dermopterans; scandentians), which lived in North America during the late Paleocene. P. cookei body mass has been estimated to be ～2.2 kg, making it large compared with other species of its genus from North America, but similar to some from Europe. In particular, size as well as dental form similarities to P. russelli have been noted. However, it is thought that P. russelli evolved from P. tricuspidens, and into Platychoerops daubrei. Dental similarities among P. cookei, P. russelli, and P. daubrei have been hypothesized to reflect a more folivorous diet than utilized by P. tricuspidens. Here we test the hypothesis that P. cookei is more dietarily specialized than P. tricuspidens by quantifying functionally significant aspects of molar, premolar, and incisor forms. Casts of M₂s and P₄s of P. tricuspidens, P. cookei, and P. daubrei were microCT‐scanned. We measured the relief index and/or the complexity from surface reconstructions of scans. Results show that P. cookei has higher M₂ relief and complexity than P. tricuspidens; P. daubrei exhibits the highest relief and complexity. Similarly, P. cookei has a more complex P₄ than P. tricuspidens, whereas that of P. daubrei exhibits the highest complexity. Finally, the I¹ of P. cookei resembles more the incisor of P. daubrei than that of P. tricuspidens. Because high relief and complexity of dentitions are related to fibrous plant diets in living mammals, these findings support the hypothesis that previously identified similarities among P. cookei, P. russelli and P. daubrei reflect a folivorous diet. Am J Phys Anthropol, 2010. © 2009 Wiley‐Liss, Inc.     

Genetic variation of the Siberian tit Parus cinctus populations at the regional level: a mitochondrial sequence analysis

We studied the matrilinear genetic structure of the Siberian tit Parus cinctus by sequencing 911 bp of the mitochondrial control region of 56 birds from Fennoscandia and 3 from Yakutia, central Siberia, representing subspecies P. c. lapponicus and P. c. cinctus , respectively. One major haplotype comprised 35.7% of all birds and was present in all Fennoscandian populations. Sequence variation of 5 museum specimens from Norway fitted with the pattern of the present-day birds. The nucleotide diversity was 0.00205±0.00025 in the Fennoscandian population and no population structuring was detected. The star-like phylogeny suggests a recent expansion of the population size in the evolutionary time scale. A modern decline of the population size from 200 000 pairs to 50 000 pairs in Finland has resulted from cutting and fragmentation of old-growth forests, but the effects of this could not yet be detected in the mtDNA pattern. However, the nucleotide diversity differed among populations being the highest at Kuusamo, close to the Russian border. Conceivably, the gene flow maintained by the substantial migration of Siberian tits is sufficient to prevent differentiation of local populations in Fennoscandia. Presumably the large conservation areas in NE Finland and on the Russian side of the border contribute to the high genetic variation observed in the Kuusamo population. Comparison of the mtDNA phylogeny of the Siberian tit with the phylogenies of the great tit, the blue tit and the willow tit showed that the Siberian tit and some other non-migratory species of the foliage gleaning guild share similar post glacial histories in the western palaearctic.     

Differentiation in parasitism among ecotypes of whitefish segregating along depth gradients

Parasitism is a potential mechanism initiating or facilitating ecotypic differentiation and speciation in freshwater fish. While recent studies have begun to explore this question, there are no empirical studies of parasitism in evolutionary replicates of ecotype‐pairs at variable stages of speciation. Such comparative studies of parasitism along continuums of host differentiation are needed as a first step towards testing the role of parasites in ecological speciation. We explored parasitism of whitefish Coregonus lavaretus in four pre‐alpine lakes in Switzerland that hold replicate species radiations of whitefish. We sampled shallow and deep‐spawning ecotypes on their breeding grounds. We found significant and consistent differences in infection between the ecotypes so that the shallow‐spawning fish had more trematode infections, whereas the deepspawning fish had more cestodes. The magnitude of these differences correlated positively with the degree of the genetic differentiation among the ecotypes and negatively with the extent of eutrophication of the lakes. Although the overall diversity of infections was low, some parasite species with potential effects on fish showed marked differences in infection between the ecotypes, suggesting that parasitism may have a role in maintaining ecotype differentiation in this system. Our results also indicate previously unknown habitat segregation of the better differentiated ecotypes, i.e. species, along the depth gradient outside the breeding season. Moreover, oligotrophic lakes tended to have higher parasite species richness and higher abundances of infection, than mesotrophic and eutrophic lakes, suggesting that the history of eutrophication affects parasite diversity.