A redescription of Arostrilepis beringiensis (Kontrimavichus et Smirnova, 1991) and descriptions of two new species from Palaearctic microtine rodents, Arostrilepis intermedia sp. n. and A. janickii sp. n. (Cestoda: Hymenolepididae)     

Makarikov AA  Kontrimavichus VL 《Folia parasitologica》2011,58(4):289-301

Arostrilepis beringiensis (Kontrimavichus et Smirnova, 1991) is redescribed on the basis of its type specimens from Lemmus trimucronatus (Richardson) and material from the collections of the Institute of Systematics and Ecology of Animals, Novosibirsk from the lemmings Myopus schisticolor (Lilljeborg) and Lemmus sibiricus (Kerr) from the Asian part of Russia. Specimens previously identified as Arostrilepis horrida (Linstow, 1901) from voles are revised and newly collected materials are addressed. Two new species of the genus Arostrilepis Mas-Coma et Tenora, 1997, A. intermedia sp. n. from red-backed voles (Myodes Pallas) from the Asian part of Russia and A. janickii sp. n. from Europe, are described. These species are clearly distinguished from congeners by form and size of the cirrus and its armature as well as the type of arrangement for the testes, position of the cirrus-sac with regard to poral ventral osmoregulatory canals, and host specificity.  相似文献   

Crop stand density enhances competitive ability of spring barley (Hordeum vulgare L.)     

Vytautas Pilipavicius  Regina Romaneckiene  Kestutis Romaneckas 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(7):648-660

Abstract

The aim of the research was to establish weediness, competitive ability and productivity of the crop. The experimental object was agrophytocenoses of spring barley – Hordeum vulgare L. – crop of spring barley ‘Aura’ and unsown soil, and weeds growing in them. The crop was formed sowing 0, 120, 200 and 280 kg ha^?1 (0, 2.7, 4.5 and 6.2 million seeds per ha^?1 respectively) seeds of spring barley ‘Aura’. Spring barley crop was not harrowed and herbicides were not applied. In the field experiment estimates were made of changes of weeds and spring barley inter- and within- species competition optimizing crop density. During three years of field experiment in the crop of spring barley annual weeds prevailed at 88–99%, such as Chenopodium album, Stellaria media, Erysimum cheiranthoides. Perennial weeds formed 1–12% of the crop weeds, such as Sonchus arvensis, Cirsium arvense, Equisetum arvense. General number of weed species in spring barley crops varied from 13 to 21. Weed abundance proportionally declined in the crops of higher density, hence, higher seed rate should be recommended for organic agriculture where weeds are controlled in non-chemical ways. Consistently increasing barley stand density, the competition between species (spring barley with weeds) gradually turned into competition within species (between barley plants) when a higher number of weaker and non-productive stems started forming. Spring barley yield did not significantly depend on the stand density. Increasing stand density enhanced cultivated crop yield to a certain level (200 kg ha^?1), since an increase in spring barley plant number resulted in the reduction in weight per plant and 1000 grain weight, which was compensated by an increase in the number of spring barley plants. Different spring barley density had an essential influence on the chemical composition of weeds which was similar to that of spring barley. Weeds accumulated the greatest amount of crude proteins, crude fat and crude fibre growing without spring barley.  相似文献   

Soil pore-water environment and CO2 emission in a Luvisol as influenced by contrasting tillage     

Virginijus Feiza  Dalia Feiziene  Irena Deveikyte  Vytautas Seibutis  Sarunas Antanaitis  Virmantas Povilaitis 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(4):350-359

Little is known how contrasting tillage (deep ploughing, top- and sub-soil loosening with straight or bent leg cultivator [BLC], direct drilling [DD]) affect important soil physical properties (total porosity [TP], pore size distribution [PSD], water release characteristics [WRC]) and CO₂ emissions from a Luvisol. The study was aimed to alleviate compaction on land that had been under reduced tillage for 4 successive years. Undisturbed core samples were collected from 5–10, 15–20 and 25–30 cm depths for soil WRCs, TP and pore-size distribution determination. A closed chamber method was used to quantify the CO₂ emissions from the soil. Soil loosening with straight or BLC produced the highest total soil porosity (on average 0.48 m³ m^?3) within 5–30 cm soil layer, while conventional tillage (CT) gave 6%, DD up to 25% reduction. Sub-surface loosening with a BLC was the most effective tool to increase the amount of macro- and mesopores in the top- and sub-soil layers. It produced 21% more macro- and mesopores within 25–30 cm soil layer as compared to the soil loosened with a straight leg cultivator. Plant available water content under CT and DD was lower as compared to that under deep loosening with straight or BLC (23% and 18%, respectively). DD produced 12% lower soil surface net carbon dioxide exchange rate than CT and by 25–28% lower than deep soil loosening with straight or BLC. The increase in micropores within 25–30 cm soil layer caused net carbon dioxide exchange rate reduction. The amount of mesopores within the whole 5–30 cm soil layer acted as a direct dominant factor influencing net CO₂ exchange rate (NCER) (Pxy = ?3.063; r = 0.86).  相似文献   

Soil sustainability changes in organic crop rotations with diverse crop species and the share of legumes     

Dalia Feiziene  Virginijus Feiza  Virmantas Povilaitis  Agne Putramentaite  Daiva Janusauskaite  Vytautas Seibutis 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2016,66(1):36-51

There have been few long-term field studies on greenhouse gases measurement in organic crop rotations under temperate climatic conditions. Little is known about the extent to which the share of legumes in a crop rotation of organic farming affects the potentials for CO₂ emission and soil organic carbon sequestration. The current study was aimed to investigate soil physicochemical state and soil net CO₂ exchange rate in diverse organic crop rotations with different crop species and proportions of legumes. Four 5-year duration crop rotations were investigated. The best soil sustainability of the arable layer was found in a crop rotation enriched with red clover (Trifolium pratense L.). This rotation resulted in the highest soil mesoporosity and the lowest microporosity, ensured the best supply of plant-available water and revealed high soil resistance to dry conditions. Red clover secured the highest soil organic C sequestration, caused the increase in reserves of total N and available K, and slackened the decrease of soil-available P sources. Red clover-based cropping system exhibited the highest soil net CO₂ exchange rate during five experimental years. The effect of crop rotation, consisting of phacelia (Phacelia tanacetifolia Benth.), peas (Pisum sativum L.) and yellow lupin (Lupinus luteus L.), on soil sustainability was weaker than the effect of rotation with red clover. Non-legume rotations, i.e. binary (two-crop) rotation and the crop rotation involving four spring and one winter species, can be regarded as miners of soil nutrient resources rather than contributors. These rotations did not promote soil sustainability because the soil lost large amounts of macronutrients and caused 26–33% lower soil net CO₂ exchange rate, compared with leguminous rotations. For future, it could be recommended for ecological farming to rely more on crop rotations with red clover to improve ecosystems functioning.  相似文献   

Analysis of the genetic structure of the European eel Anguilla anguilla using the mtDNA D-loop region molecular marker     

Adomas Ragauskas  Dalius Butkauskas  Aniolas Sruoga  Vytautas Kesminas  Isaak Rashal  Wann-Nian Tzeng 《Fisheries Science》2014,80(3):463-474

Sequence variation of the mtDNA D-loop region was analyzed in order to investigate the intraspecific evolution and the population genetic structure of the critically endangered European eel Anguilla anguilla. An additional attempt was made to collect information on the genetic characteristics of groups of eels representing naturally recruited eels to Lithuania and Latvia and introduced into Lithuanian lakes. A total of 148 eels were investigated, and 107 different haplotypes attributed to 39 haplogroups were determined during the study. A dataset comprising 229 sequences was created using the data from both this study and from earlier studies (n = 81). Analysis of this dataset revealed that haplotype diversity was 0.99567, the average number of nucleotide differences was 12.50544, there were 145 polymorphic sites and nucleotide diversity was 0.02426. No significant genetic differentiation was detected between different combinations of samples. However, the population genetic structure of this species could be characterized as a genetic mosaic formed due to the existence of reproductively isolated groups. The existence of a genetic mosaic in this species could be explained by the different evolutionary lineages found in the eel population.  相似文献   

A redescription of Arostrilepis horrida (Linstow, 1901) and descriptions of two new species from Palaearctic microtine rodents, Arostrilepis macrocirrosa sp. n. and A. tenuicirrosa sp. n. (Cestoda: Hymenolepididae)     

Makarikov AA  Gulyaev VD  Kontrimavichus VL 《Folia parasitologica》2011,58(2):108-120

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Effect of clear-cutting on the understory vegetation,soil and diversity of litter beetles in scots pine-dominated forest     

Laima Česonienė  Remigijus Daubaras  Vytautas Tamutis  Vilma Kaškonienė  Paulius Kaškonas  Vidas Stakėnas 《Journal of Sustainable Forestry》2013,32(8):791-808

Currently, the aim of modern forest management is not only timber production but also the protection of biodiversity. The initial effects of clear-cut logging on forest understory vegetation, soil and the diversity of litter beetles have been studied. We examined unstudied effects of clear-cutting disturbance on understory vascular plant species abundance, forest soils, and understory vegetation nutrients as well as beetle diversity one year after clear-cutting. Substantial changes in the prominence values and above-ground mass of forest-related vascular plant and moss species were detected. Clear-cuttings resulted in fast appearance of new light-loving plant species. The significant decrease in understory plant biomass influenced the reduction of nutrient pools in clear-cut areas after one year. The clear-cut logging negatively influenced the richness of species and the number of individuals of stenobiontic forest-related beetles in the forest litter. However, forest clear-cuttings were beneficial for eurytopic and open land species.  相似文献