Changes in local species richness of farmland birds in relation to land-use changes and landscape structure

It has been suggested that an increase in the area of low-intensity land-use on arable land (e.g. set-aside fields and short-rotation coppice), and high or increased farmland habitat heterogeneity, may halt or reverse the observed population decline of farmland birds. We tested these hypotheses by undertaking farmland bird censuses during two contrasting periods of agricultural policies and land-use (i.e. 1994 and 2004) in a farmland region covering a gradient of forest- to farmland-dominated landscapes in Sweden. Local species richness (i.e. at 3 hectare sites) declined significantly between 1994 and 2004. Local species richness was positively related to habitat heterogeneity in both years of study whereas temporal change in species richness was not. Local change in species richness was positively associated with a change in the proportion of non-rotational set aside and short-rotation coppice (i.e. low-intensity land-use forms), but also to changes in the amount of spring-sown crops. However, the effect of low-intensity land-use was significantly dependent on the amount of forest in the surrounding landscape. An increase in low-intensity land-use was linked to an increase (or less marked decrease) in species richness at sites located in open farmland surroundings but to a decrease in richness at sites located in forest surroundings. This interaction between amount of forest and low-intensity land-use could be interpreted as a “rare habitat effect”, where an increase in a farmland habitat only positively affects biodiversity when it was originally uncommon (i.e. open farmland areas). Our results suggest that conservation measures of farmland biodiversity have to be put in a landscape context.     

The obesity-associated FTO gene encodes a 2-oxoglutarate-dependent nucleic acid demethylase

Variants in the FTO (fat mass and obesity associated) gene are associated with increased body mass index in humans. Here, we show by bioinformatics analysis that FTO shares sequence motifs with Fe(II)- and 2-oxoglutarate-dependent oxygenases. We find that recombinant murine Fto catalyzes the Fe(II)- and 2OG-dependent demethylation of 3-methylthymine in single-stranded DNA, with concomitant production of succinate, formaldehyde, and carbon dioxide. Consistent with a potential role in nucleic acid demethylation, Fto localizes to the nucleus in transfected cells. Studies of wild-type mice indicate that Fto messenger RNA (mRNA) is most abundant in the brain, particularly in hypothalamic nuclei governing energy balance, and that Fto mRNA levels in the arcuate nucleus are regulated by feeding and fasting. Studies can now be directed toward determining the physiologically relevant FTO substrate and how nucleic acid methylation status is linked to increased fat mass.     

Landscape characteristics explain large-scale variation in demographic traits in forest grouse

The effects of landscape composition on species and populations have become increasingly important due to large and rapid habitat changes worldwide. In particular, concern is raised for several forest-dwelling species such as capercaillie and black grouse, because their habitats are continuously changing and deteriorating from human development. Conservation of these species is linked to sustainable forest management that seeks to benefit multiple species, which demands knowledge about demographic rates in relation to forest composition and structure. We related the spatial variation in adult density and chick production of capercaillie and black grouse to landscape characteristics from 13 areas within the boreal forest of Norway. Linear mixed effects models showed that black grouse and capercaillie had similar associations to landscape characteristics. Adult density of both species was positively related to the proportion of old forest (>80 years), but only if the area had large proportions of mid to high productive forests. Chick production was negatively related to the proportion of old forest, but positively to habitat diversity and more so for black grouse compared to capercaillie. However, the result for chick production suggest that other forest types also are important, and that forest grouse needs a variety of habitats during their life history stages. Management that seeks to simultaneously conserve populations of black grouse and capercaillie needs to ensure a matrix of various forest types. A special focus must be on the critical life history of local populations to successfully preserve viable populations, for black grouse and capercaillie this implies protection of old and mid to high productive forest while keeping a heterogeneous landscape.     

Finishing feeding strategy as an instrument for modification of fatty acid composition of brook char (<Emphasis Type="Italic">Salvelinus fontinalis</Emphasis>)

This study investigated the possibility of using a finishing feeding strategy and to apply a dilution model for the calculation of the content of fatty acids (FA) in farmed brook char (Salvelinus fontinalis). Four duplicate groups of fish with an initial weight 153.3 ± 4.9 g^?1 were kept in a flow-through system for 135 days, during which they more than triplicated their weight. Control groups were fed the same unmodified commercial diet with 100 % fish oil (FO) or with 60 % fish oil and 40 % rapeseed oil (RO) mixture. Two groups were fed by RO diet followed by 45 (RO:45FO) and 90 (RO:90FO) days of FO diet, respectively, at the end of the growing period. The fillet FA composition at the end of the experiment corresponded with the FA composition of the lipid source in the diet for the tested groups. A significant (p < 0.05) impact on FA composition with a decreasing tendency in the representation of n-3 HUFA with a prolonged feeding period with the RO diet was observed. The application of a dilution model enabling the prediction of the content of a given fatty acid in a given time was successfully performed.     

Tree layer dynamics of the Cahnov–Soutok near-natural floodplain forest after 33 years (1973–2006)

The paper deals with the issue of the spontaneous development of Central-European floodplain forests. The research object was the Cahnov–Soutok National Nature Reserve situated on the confluence of Dyje R. and Morava R. in the Czecho–Slovak-Austrian borderland area. This locality has been left to spontaneous development since the beginning of the 1930s. In the years 1973, 1994 and 2006, the surveyed site was subjected to the measurement of standing and lying, live and dead trees reaching a diameter at breast height of 10 cm and the whole area regeneration of woody species. The work objective is to describe the most pronounced trends in tree layer changes having occurred in the period of study and to capture changes in the total tree volume and production of dendromass during the disintegration of the old grazing oak layer. The survey into the near-natural floodplain forest of Cahnov–Soutok showed that (1) the most significant trend is a decreased representation of Quercus robur in all monitored indicators and conversely an expanding representation of Acer campestre, Carpinus betulus and Tilia cordata and (2) that the floodplain forest ecosystem demonstrates a high-level stability in the total volume of tree biomass with an essential change in the tree species composition, spatial structure and average stem volume of individual trees.     

Standard Probability Density Functions of Characterizing Water Quality Variables in Dimictic Glacial/Boreal Lakes

With the secure supply of healthy fresh water being a threatened essentiality for the global society, compatibility among scientists working with water quality issues must be considered as highly prioritized. To achieve this, a standard that facilitates compatible comparisons between statistical models that describe and/or predict lake water quality should contribute. A large population of dimictic glacial/boreal lakes – with variable ranges wide enough to represent a majority of such lakes – is therefore analyzed with respect to probability density functions of the seven characterizing water quality variables pH, alkalinity, conductivity, hardness, color, Secchi depth, and total phosphorus concentration. With the lakes being limestone treated, the primary variables are transformed to normal distribution in cases: 1; ‘Before limestone treatment’, 2; ‘After limestone treatment’, and 3; ‘The entire database’ (case 1 + case 2). It is concluded that the transformation functions derived in case 3 are sufficiently valid as optimal transformation functions in all three cases. This suggests that the transformation functions derived approximate the probability density functions of these important water quality variables in the generic class of dimictic glacial/boreal lakes, and that they should be well suited as transformation standards in natural, as well as in limestone treated lakes. It also implies that limestone treatment does not significantly alter the shape of the probability density functions analyzed.     

基于ALR-GMM的群养猪攻击行为识别算法研究

群养猪攻击行为是评估猪群对微环境适应性的重要指标.活动指数模型能够描述猪群行为模式,已经在群养猪攻击行为识别研究中得到初步验证.然而,养殖设施的差异性和动态背景环境等因素所导致的环境适应性差是限制其商业化应用的主要障碍.本文基于递归背景建模思想,在高斯混合模型(GMM)中引人双曲正切函数,提出了一种自适应学习率GMM的...     

Effect of combined nitrogen and sulphur fertilization on yield and qualitative parameters of Camelina sativa [L.] Crtz. (false flax)

Abstract

Camelina (Camelina sativa (L.) Crtz., false flax) is described as a species requiring fewer inputs than other oilseed crops thus making it an interesting alternative in sustainable cropping systems. As information on the combined effects of nitrogen and sulphur on camelina yield and quality parameters is meagre, a pot fertilization experiment was carried out with nitrogen applied as NH₄NO₃ at three increasing rates equivalent to a range from 63 up to 127 kg ha^?1. These treatments were combined with sulphur additions applied as (NH₄)₂SO₄ to achieve a soil sulphate content of 25 or 45 mg kg^?1, respectively (equivalent to 75 and 135 kg S ha^?1). The medium and high nitrogen rates combined with the low sulphur fertilization level increased the number of branches per plant compared with the lowest nitrogen fertilization at the same sulphur rate. Camelina seed yield increased with increasing nitrogen doses at the same low sulphur level, whereas straw yield increased only at the highest rate of nitrogen. Thousand-seed mass increased at the highest nitrogen dose and with the low sulphur application rate. In addition, the increase in nitrogen fertilization reduced seed oil content from 39.8% to 37.1%. A highly negative correlation was observed between oil and protein content of seeds. Nitrogen fertilization increased total oil yield and total protein yield. Differences in crop parameters between the sulphur treatments were not significant statistically, although the higher sulphur treatment tended to increase seed yield as well as oil and protein content compared with the low sulphur treatment. Thus, the combined application of N and S as mineral fertilizers is only recommended when growing camelina on sulphur-deficient soils if the aim is to achieve both high oil and protein production.