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Environmentally friendly management as an intermediate strategy between organic and conventional agriculture to support biodiversity
No full textVäetamise ja pestitsiidide kasutamise mõju mesilaselaadsetele (Apoidea) suvirapsil
Full text linkSpring oilseed rape is an important oilseed crop, the area of which has increased significantly in northern Europe, including Estonia. Spring oilseed rape is predominantly autogamous but cross-pollination can have several positive effects, including higher seed yield and better quality. Hence, it is profitable to encourage high number of bees as the main pollinators in oilseed rape fields. On the other hand the expansion of oilseed rape growing area in Europe has increased the number of pests. This has resulted in the need to use more pesticides which have negative effects also on useful organisms, including pollinators. The aims of the current thesis were from one side to study the impact of oilseed rape (as crop which has high nutrient demand) foliar fertilization with different microfertilizers on the number of flower visiting bees (honey bees, bumble bees and solitary bees) and on the other hand the repellency of insecticide Fastac 50 EC on honey bees and the effect of sub-lethal doses of insecticide on respiratory pattern of bumble bees as it is a good indicator of their physiological state.
The results of the study showed that to secure a higher number of pollinators for achieving higher seed yield and other benefits deriving from cross-pollination spring oilseed rape should receive proper complex fertilization. Applied microfertilizers turned out to be useless in terms of increasing the number of pollinators. In addition, the study tended to confirm that Fastac 50 EC does not show repellency for honey bees in field conditions. Flower density seemed to be the main signal for bees and might override the repellent effect. Even solutions with ten times lower concentrations of Fastac 50 EC than registered field rate in Estonia affected significantly the respiratory patterns of bumble bees and decreased the longevity.
The study shows that as in field conditions additional factors may affect the choices of bees, laboratory and semi-field studies often do not reflect the situation in field conditions. The sub-lethal doses of pesticides bees encounter do affect the physiological state of the pollinators, being thus one possible reason for global pollination crisis. At the same time the application of pesticides is quite new phenomenon from the evolutionary perspective and pollinators have not learned to recognize the hazards. Pesticides should not be used routinely and prophylactically without regard to pest incidence but the need for the application should be previously monitored. The protection of pollinators against negative effects of pesticides should also be supported by the policies (e.g. through the environmental measures of the European Union common agricultural policy). In addition, further research on the ecotoxicity of pesticides is needed and more environmentally friendly growing technologies should be worked out (e.g. entomovector-technology and biopesticides).Suviraps on oluline õlikultuur, mille kasvupind on Põhja-Euroopas, k.a Eestis, oluliselt suurenenud. Raps on peamiselt isetolmlev, kuid risttolmlemisel on mitmeid eeliseid, sh tõstab seemente kvaliteeti ja kvantiteeti. Seetõttu on mesilaselaadseid kui rapsi peamisi tolmeldajaid igati kasulik soodustada. Teisest küljest on rapsi kasvupinna suurenemine toonud kaasa ka kahjurite arvukuse tõusu, mistõttu on vaja kasutada rohkem pestitsiide. Viimased avaldavad aga negatiivset mõju ka kasulikele organismidele, sh tolmeldajatele. Käesoleva doktoritöö eesmärgiks oli ühelt poolt uurida rapsi kui suure toitainetevajadusega kultuuri lehekaudse mikroväetistega väetamise mõju õisi külastavate mesilaselaadsete (meemesilaste, kimalaste ja erakmesilaste) arvukusele ning teiselt poolt repellentse insektitsiidi Fastac 50 EC eemalepeletavat toimet meemesilastele ja sub-letaalsete dooside mõju kimalaste hingamisrütmidele, mis on heaks füsioloogilise seisundi näitajaks.
Uurimus näitas, et tolmeldajate arvukuse soodustamiseks on rapsi vaja kõrgema saagi ja teiste risttolmlemisest tulenevate eeliste tagamiseks kompleksväetisega väetada. Katses kasutatud lehekaudsed mikroväetised aga tolmeldajate arvukust enam täiendavalt ei suurendanud. Lisaks leiti, et põllu tingimustes ei avaldunud Fastac 50 EC väidetavalt repellentne toime meemesilastele – kõige olulisemaks signaaliks osutus õite tihedus, mis võis üle kaaluda insektitsiidi väidetavalt eemalepeletava toime. Katse põhjal selgus, et isegi kümme korda madalama kontsentratsiooniga Fastac 50 EC lahus kui on Eestis tegelik registreeritud põllul kasutatav doos, mõjutas oluliselt kimalaste hingamisrütme ja vähendas nende eluiga.
Antud uurimustöö tulemused näitavad, et labori- ja väikeseskaalaliste põldkatsete tulemused ei peegelda tihti tegelikku olukorda põllu tingimustes. Sub-letaalsed pestitsiidi doosid mõjutavad tolmeldajate füsiloogilist seisundit ning võivad seega olla üheks globaalse tolmeldamiskriisi põhjuseks. Seejuures on pestitsiidide kasutamine evolutsioonilisest vaatepunktist küllaltki uus nähtus ja tolmeldajad ei ole veel õppinud riske ära tundma. Pestitsiide ei tohiks kasutada rutiinselt ja lihtsalt profülaktika mõttes, vaid vajadust selle järele tuleks põllul eelnevalt seirata. Tolmeldajate kaitsmist pestitsiidide negatiivsete mõjude eest tuleks toetada ka läbi erinevate poliitikate (sh läbi Euroopa Liidu ühise põllumajanduspoliitika keskkonnameetmete). Vajalikud on täiendavad uurimused pestitsiidide toksilisusest elusorganismidele ning välja tuleks töötada keskkonnasõbralikumaid kasvatustehnoloogiaid (nt entomovektor-tehnoloogia ja biopestitsiidid).Publication of this thesis is supported by the Estonian University of
Life Sciences and by the Doctoral School of Earth Sciences and Ecology
created under the auspices of European Social Fund
Crop rotation and agri-environment schemes determine bumblebee communities via flower resources
Full text link<p>The biodiversity (flower cover and bumblebees) and environmental data used in the analyses.</p>
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Estonian bumblebees
Full text linkBumblebees – who are they and what do they look like? Bumblebees are insects with a burly, furry and colourful appearance. They are members of the bee genus Bombus in the family Apidae. People have given them different names and they can be met in forests, fields, meadows and gardens, both in the countryside and in towns. Bumblebees can be found throughout the world except for Australia and the Tropics. There are over 250 species of bumblebees in the world of which 68 species can be found in Europe. Bumblebees can be divided into true bumblebees and their nest parasites, known as cuckoo bumblebees. In Estonia 21 species of true bumblebees and 8 species of cuckoo bumblebees are found – 18 species of the true bumblebees belong to the species of the conservation category III of the Nature Conservation Act. This publication focuses mainly on true bumblebees (henceforth referred to a bumblebees)
Eesti kimalased
No full textKes on kimalased ja millised nad välja näevad? Kimalased on kogukad, karvased ja värvilised kiletiivaliste seltsi mesilaslaste sugukonda kuuluvad putukad. Nad on rahva seas tuntud kui maamesilased, metsmesilased ja kumalased, keda võib kohata metsas, põllul, niidul, aias, nii maal kui ka linnas. Kimalased võib jagada päriskimalasteks ja nende pesaparasiitideks – kägukimalasteks. Kimalasi leidub peaaegu kõikjal maailmas – kokku on teada vähemalt 265 liiki, sh Euroopas vähemalt 66 liiki (nii päris- kui ka kägukimalasi kokku). Eestis võib kindlasti kohata 20 liiki päriskimalasi ning 8 liiki kägukimalasi. Enamus päriskimalaste liikidest kuuluvad looduskaitseseaduse alusel III kaitsekategooriasse. Antud trükis keskendub peamiselt päriskimalastele (edaspidi kimalased).Kaasrahastanud Euroopa LiitKaasrahastanud Euroopa Lii
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