Šio darbo tikslas buvo išanalizuoti literatūros šaltinius ir kitus prieinamus duomenis apie akumuliuotos taršos kiekius ir galimą jos genotoksinį poveikį paukščiams (individai, populiacijos), ir įvertinti atliktus tiriamųjų rūšių konkrečius citogenetinius tyrimus, aplinkos taršos ir citotoksinių efektų atskiruose individuose kontekste. Atlikus citogenetinius tyrimus, pateikti rezultatų analizės ir statistinio apdorojimo metodus. Mikrobranduolių analizės metodas sėkmingai taikytas skirtingų sistematinių taksonų gyvūnams- moliuskams, žuvims ir žinoma paukščiams. Taigi, šiame darbe tiriamų paukščių populiacijų tyrimams buvo taikytas mikrobranduolių analizės metodas. Didžiausias mikrobranduolių dažnis konstatuotas, P. major 10,5%, o mažiausias A. arundinaceus 0,55% individuose. Tai gali rodyti skirtingą rūšių jautrumą citotoksiniam ir genotoksiniam aplinkos poveikiui. Didžiausia tikimybė, kad tokius mikrobranduolių skaičiaus eritrocituose skirtumus tarp rūšių nulemia didžiąją dalimi skirtinga mityba, skirtinga maisto objektų akumuliuojama tarša. / The purpose of this diploma paper was to analyse the sources of literature and other available materials (reports of monitoring, data bases), valuating investigative birds species organisms' impurity and possible genotoxic effect of this. And finally to exercise methods of cytological micronuclei experiments and adduce results analysis and statistical processing methods. Cytogenetic experiments (micronuclei test) were made in distinct species in Paridae and Sylviidae families. The highest frequency of micronuclei was found in populations of Parus major – 10,5%, the lowest – in populations of A. arundinaceus 0,55% micronuclei. This can show different species sensitivity to cytogenetic and genetic environmental influence. The highest possibility that the distinctions of micronuclei frequency in erythrocytes between species are mostly determined by the difference of nourishment and the accumulative pollution of nutrition objects. It particularly depends on the quality conditions in their ecological niches.

In this thesis, I try to proceed one step further towards an understanding of the biogeographic processes forming the distribution patterns of organisms that we see today. Babblers and warblers are diverse groups of passerines that are phylogenetically intermixed with other groups in the superfamily Sylvioidea. First, the gross phylogeny of the babblers and associated groups was estimated. Five major lineages of a well-supported monophyletic babbler radiation were recovered, and we proposed a new classification at family and subfamily level. Further, the genus Pnoepyga was excluded from Timaliidae, and we proposed the new family Pnoepygidae fam. nov. Second, the systematic position was investigated for the Albertine Rift taxon Hemitesia neumanni, which was found to be nested within the almost entirely Asian family Cettidae, and possible biogeographical scenarios were discussed. We concluded that the most plausible explanation involved late Miocene vicariance in combination with local extinctions. Third, the historical biogeography of a Leiothrichinae subclade, the Turdoides babblers and allies, was inferred. We concluded that the Middle East region probably played an important role in the early history of this clade, followed by local extinctions in this region. Fourth, a Bayesian method to reconstruct the historical biogeography under an event-based model was proposed, where the total biogeographic histories are sampled from its posterior probability distribution using Markov chains. In conclusion, I believe that, especially with more sophisticated methods available, we will see an increasing number of studies inferring biogeographic histories that lead to distribution patterns built up by a combination of dispersals and vicariance, but where these distributions have been extensively reshaped, or litterally demolished, by local extinctions. Therefore, my answer to the frequently asked question dispersal or vicariance? is both, but not the least: extinctions. / At the time of the doctoral defence the following papers were unpublished and had a status as follows; Papers 3 and 4: Manuscripts