Migration strategies of brown trout (Salmo trutta) in a subarctic river system as revealed by stable isotope analysis     

Timo J. Ruokonen  Mikko Kiljunen  Jaakko Erkinaro  Panu Orell  Olli Sivonen  Eero Vestola  Roger I. Jones 《Ecology of Freshwater Fish》2019,28(1):53-61

We estimated the proportions of anadromous and freshwater‐resident brown trout (Salmo trutta) in different parts of the subarctic River Näätämöjoki/Neidenelva system (Finland and Norway) using carbon, nitrogen and hydrogen stable isotope analyses of archived scales as identifiers of migration strategy. Our results showed that carbon stable isotope values were the best predictor of migration strategy. Most individuals fell into two clearly distinct groups representing anadromous (47%) or freshwater‐resident (42%) individuals, but some fish had intermediate carbon values suggesting repeated movement between freshwater and the sea. The proportion of anadromous individuals decreased steadily with distance from the sea forming a spatial continuum in migration strategies which is probably maintained by the combination of several factors such as divergent availability of food resources, variable migration costs and genetic differences. These within‐catchment differences in migration strategies should be taken into account in fisheries management practices.  相似文献   

Influence of mycotoxin producing fungi (Fusarium, Aspergillus, Penicillium) on gluten proteins during suboptimal storage of wheat after harvest and competitive interactions between field and storage fungi     

Prange A  Modrow H  Hormes J  Krämer J  Köhler P 《Journal of agricultural and food chemistry》2005,53(17):6930-6938

Cereals contaminated by Aspergillus spp., Penicillium spp., and Fusarium spp. and their mycotoxins, for example, ochratoxin A (OTA) and deoxynivalenol (DON), are not only a risk to human and animal health but can also show poor technological properties and baking quality. The influence of these genera on the sulfur speciation of low molecular weight (LMW) subunits of glutenin was characterized by investigating suboptimally stored wheat samples in situ by X-ray absorption near edge structure (XANES) spectroscopy and baking tests. Field fungi of the genus Fusarium have hardly any influence on both the sulfur speciation of wheat gluten proteins and the baking properties, whereas storage fungi of the genera Aspergillus and Penicillium have a direct influence. An increased amount of sulfur in sulfonic acid state was found, which is not available for thiol/disulfide exchange reactions in the gluten network, and thus leads to a considerably reduced baking volume. From changes of the composition of the mould flora during suboptimal storage of wheat and from the mycotoxin contents, it can be concluded that microbial competitive interactions play an important role in the development of the mould flora and the mycotoxin concentrations during (suboptimal) storage of wheat.  相似文献   

Effects of forest inventory errors on the area and spatial layout of harvest blocks     

Md. Nurul Islam  Timo Pukkala  Mikko Kurttila  Lauri Mehtätalo  Tero Heinonen 《European Journal of Forest Research》2012,131(6):1943-1955

  相似文献   

Growth and yield models for uneven-sized forest stands in Finland   总被引：1，自引：0，他引：1  

Timo Pukkala  Erkki Lähde  Olavi Laiho 《Forest Ecology and Management》2009

Uneven-sized forestry is gradually gaining popularity and acceptability also in the Nordic countries. This is because of the willingness of the public and some forest owners to avoid clear-fellings and pursue more near-nature forest structures. It has also been realized that the profitability of uneven-sized forestry may be competitive with even-aged forestry. In Finland, management of uneven-sized stands is hampered by the lack of information about the dynamics of such stands, and about the yield and profitability of uneven-sized forestry. This study developed models which allow managers to simulate the growth and yield of uneven-sized stands in Finland, making it possible to predict the yield and analyze the sustainability of different management options. The model set consists of individual-tree diameter increment, height and survival models, and a model for ingrowth. The modeling data consisted of two long-term field experiments of uneven-sized forest management, a set of temporary sample plots measured earlier for growth modeling purposes, and the sample plots of the third National Forest Inventory of Finland. The application area of the models covers all growing sites, all main tree species, and the whole surface area of Finland. According to the models, the sustainable harvest of a fertile (Oxalis-Myrtillus site) uneven-sized Norway spruce forest varies between 5.5 and 7 m³ ha⁻¹ a⁻¹ in Central Finland, depending on the length of the cutting cycle, stand density, and shape of the diameter distribution. It is profitable to harvest large diameter classes more heavily than small ones. Due to the large amount of data the models for diameter increment are highly significant and reliably show the growth level of trees in uneven-sized stands. The weakest models are the ingrowth models, which are based on a clearly smaller data set than the other models.  相似文献   

Effects of early cleaning on young Picea abies stands     

Karri Uotila  Timo Saksa 《Scandinavian Journal of Forest Research》2014,29(2):111-119

Young Norway spruce stands (Picea abies [L.] Karst) are typically cleaned of non-crop species on one or several occasions during young stand stage. In order to objectively evaluate the perceived benefits of early cleaning (EC), we studied the effects of EC on three study sites 2–2.5 years after receiving the treatment. Experiments were established as a randomised complete block design with a total of 40 blocks. Although height growth and mortality were not significantly affected, we found that EC substantially reduced canopy competition and, consequently, the mean diameter of released spruce grew 21–32% faster depending on the site. Furthermore, non-crop trees that were cleared during EC had fewer sprouts in two of the three sites and the sprouts were substantially smaller than the corresponding non-crop trees on control in all sites. EC can reduce the cost of pre-commercial thinning because EC reduced the estimated time needed for subsequent management by 18–49%. Thus, EC offers forest owners and managers an economically viable young stand management option.  相似文献   

Spatial variability of organic matter degradability in tidal Elbe sediments     

Zander  Florian  Heimovaara  Timo  Gebert  Julia 《Journal of Soils and Sediments》2020,20(6):2573-2587

Purpose

The microbial turnover of sediment organic matter (OM) in ports and waterways impacts water quality, sonic depth finding and presumably also rheological properties as well as greenhouse gas emissions, especially if organic carbon is released as methane. As a consequence, sediment management practices as a whole are affected. This study aimed to discern spatial OM degradability patterns in the Port of Hamburg and investigated correlations with standard analytical properties as a basis for future predictive modelling.

Materials and methods

Sediments in the Port of Hamburg were repeatedly sampled at nine locations along an east-west transect using a 1-m corer. In a stratified sampling approach, layers of suspended particulate matter (SPM), fluid mud (FM), pre-consolidated sediment (PS) and consolidated sediment (CS) were identified and individually analysed for long-term aerobic and anaerobic degradation of organic matter, DNA concentration, stable carbon isotope signature, density fractions and standard solids and pore water properties.

Results and discussion

The investigation area was characterised by a distinct gradient with a 10-fold higher OM degradability in upstream areas and lower degradability in downstream areas. Concomitantly, upstream locations showed higher DNA concentrations and more negative δ¹³C values. The share of bulk sediment in the heavy density fraction as well as the proportion and absolute amount of organic carbon were significantly larger at downstream locations. A depth and hence age-related gradient was found at individual locations, showing higher degradability of the upper, younger material, concomitant with higher DNA concentration, and lower OM turnover in the deeper, older and more consolidated material. Deeper layers were also characterised by higher concentrations of pore water ammonium, indicative of anaerobic nitrogen mineralisation.

Conclusions

Organic matter lability is inversely linked to its stabilisation in organo-mineral complexes. The observed degradability gradient is likely due to the different OM quality in relation to its origin. Downstream OM enters the system with the tidal flood current from the direction of the North Sea whereas upstream locations receive OM originating from the catchment, containing more autochthonous, plankton-derived and more easily degradable components. At individual sampling points, depth-related degradability gradients reflect an age gradient, with easily degradable material in top layers and increasing stabilisation of OM in organo-mineral compounds with depth.

  相似文献   

Veterinary medicine of the GDR in strained relations between technical instructions and political guidelines     

Prange H  Azar J 《Schweizer Archiv für Tierheilkunde》2003,145(1):26-39

The development of Veterinary Medicine in the Soviet Occupation Zone in Germany and the former German Democratic Republic (GDR) is sketched in highlights. After the collectivization of agriculture (1960) a centralistically controlled national veterinary system was established. It was suited to the requirements of the industrially organized animal production. The successive classification of socialistic veterinary administration was associated with the following matters: the extension of veterinary subject matters, a vertical division of work with the aid of newly created technical veterinary professions, and a penetration of the profession with political guidelines. As the professional level of the veterinary system in the GDR was relatively high the reflection in retrospective needs to be evaluated in a differentiated way considering the textual and social conditions. In spite of centralism and indoctrination the veterinary system remained professionally autonomous with islands of political independence, which sustained the identity of this profession. The latter formed the base for self renewal of the East German veterinary system at the end of the socialistic area 1989/1990.  相似文献   

Parasites of the common crane Grus grus (L.) in Europe     

Gottschalk C  Prange H 《Berliner und Münchener tier?rztliche Wochenschrift》2002,115(5-6):203-206

28 species of parasites (8 coccidia, 6 trematodes, 1 cestode, 6 nematodes, 1 tick, 6 mallophages) were found at the Common Crane. After presenting the interconnection of parasites with different carriers as vectors, intermediate and several final hosts in the biocoenosis of Common Cranes, the results of parasitological examination of 421 samples of cranes resulted in varying parasitization at different seasons and flyways. Further studies are needed to interprete these facts correctly. Changes of presented localities of diverted feedings and their parasitological and bacteriological control at resting places may avoid concentration of pathogens in soil, intermediate hosts and carriers.  相似文献   

Predicting regeneration establishment in Norway spruce plantations using a multivariate multilevel model     

Jari Miina  Timo Saksa 《New Forests》2006,32(3):265-283

This study predicts the regeneration establishment on 3-year-old Norway spruce (Picea abies (L.) Karst.) plantations in southern Finland using regeneration survey data. Regeneration establishment was described by seven response variables: number of planted spruces, natural Scots pines (Pinus sylvestris L.), natural spruces, natural seed-origin birches (Betula pubescens Ehrh. and B. pendula Roth.) and other broadleaves (i.e. sprout-origin birches and other broadleaves than birch), as well as height of crop-tree spruce and dominant height of broadleaves. Due to the multivariate (several responses for each plot) and multilevel (plot, stand, municipality, forest centre) structure, regeneration establishment was modelled by fitting a multivariate multilevel model with explanatory variables such as temperature sum, site fertility, soil quality and method of site preparation. In the model, the numbers of tree seedlings were modelled using over-dispersed Poisson distributed equations, and the tree heights were modelled using normally distributed linear equations. The estimated fixed and random parameters of the equations were logical, and there was no serious bias in predicting the regeneration establishment in the independent test data set. This modelling approach can be used to predict the regeneration establishment stochastically by taking into account the large unexplained variation in regeneration models.  相似文献   

Biodiversity policies in commercial boreal forests: Optimal design of subsidy and tax combinations     

Erkki Koskela  Markku Ollikainen  Timo Pukkala 《Forest Policy and Economics》2007,9(8):982-995

This paper examines the first-best instruments for biodiversity maintenance in commercial boreal forests when landowners behave either in Faustmannian or Hartmanian way. Using an extended Hartman model, we show that biodiversity conservation requires both prolonged rotation age and leaving retention trees. While the former promotes some old growth species, the latter create new structural elements of decaying and dead wood, which can sustain a variety of saprolyxic species. A fully synchronized combination of retention tree subsidy and tax instrument is needed both to lengthen the privately optimal rotation period and to provide an incentive to leave retention trees. Using Finnish data we illustrate empirically the sizes of instruments. When combined with a harvest tax, the retention tree subsidy is 1000 and 750 € in the Faustmann and in the Hartman model, respectively. When used with a timber subsidy or a site value tax, the retention tree subsidy is 1700 €/ha in both models. The harvest tax rate varies over the range 40–65% in the Faustmann model and 20–40% in the Hartman model, while timber subsidy is between 0.5–1.0% and site value tax is about 1.75%.  相似文献