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Annual adjusted mean from ANCOVA analyses of absolute individual fecundity (AF × 1000) of Saaremaa-Ventspils autumn spawning herring. Repeated measure ANCOVA with individual total length, total weight, and age as covariates was used. The vertical lines give approximation for the 95% confidence interval of repeated measures test of ANCOVA with covariates.
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The analysis of the abundance and distribution of the early life-history stages of the western Baltic spring-spawning herring population, spanning 23 yr, revealed that the abundance of yolk-sac larvae was strongly spatially structured and significantly more abundant during the optimal temperature window for viable hatch of herring larvae (9 C to 13...
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... a1, a2, b0, and b1 are regression parameters. Meanwhile the shift detection algorithm has been successfully applied in different studies [7], [38], [39] and can be summarized as follows: while iteratively moving a potential shift point t 0 over the TS (by incrementing t 0 by 1 year each step), using a specifically defined structural break model, per each iteration relevant decision criteria described below are recorded. These results are displayed in a compound diagrammatic illustration that is termed as a ''shiftogram'' [37]. ...
... From the (a) shiftogram it is obvious that a rather strong shift occurred around 1989 in the BSI time series. This shift corresponds well with observations of other authors [38], [39], [7]. However, given the different length and starting dates of the two corresponding time series it is obvious that during the overlapping time span of years 1992 to 2010 two rather weak shifts only occurred in the WBSS recruitment time series (being centred around years 1994 and 1999), but without synchronous shock signals in the BSI time series. ...
Climate forcing in complex ecosystems can have profound implications for ecosystem sustainability and may thus challenge a precautionary ecosystem management. Climatic influences documented to affect various ecological functions on a global scale, may themselves be observed on quantitative or qualitative scales including regime shifts in complex marine ecosystems. This study investigates the potential climatic impact on the reproduction success of spring-spawning herring (Clupea harengus) in the Western Baltic Sea (WBSS herring). To test for climate effects on reproduction success, the regionally determined and scientifically well-documented spawning grounds of WBSS herring represent an ideal model system. Climate effects on herring reproduction were investigated using two global indices of atmospheric variability and sea surface temperature, represented by the North Atlantic Oscillation (NAO) and the Atlantic Multi-decadal Oscillation (AMO), respectively, and the Baltic Sea Index (BSI) which is a regional-scale atmospheric index for the Baltic Sea. Moreover, we combined a traditional approach with modern time series analysis based on a recruitment model connecting parental population components with reproduction success. Generalized transfer functions (ARIMAX models) allowed evaluating the dynamic nature of exogenous climate processes interacting with the endogenous recruitment process. Using different model selection criteria our results reveal that in contrast to NAO and AMO, the BSI shows a significant positive but delayed signal on the annual dynamics of herring recruitment. The westward influence of the Siberian high is considered strongly suppressing the influence of the NAO in this area leading to a higher explanatory power of the BSI reflecting the atmospheric pressure regime on a North-South transect between Oslo, Norway and Szczecin, Poland. We suggest incorporating climate-induced effects into stock and risk assessments and management strategies as part of the EU ecosystem approach to support sustainable herring fisheries in the Western Baltic Sea.
... Kotta & Kuprijanov, 2012) with one new abundant polychaete species of the genera Potamilla/Pseudopotamilla still to be identified. This all suggests that recent human activities have opened, modified, or intensified the vector(s) responsible for the transfer of the large mobile invertebrates into the north-eastern Baltic Sea, potentially accompanied by recent abrupt changes in environmental conditions (Arula, 2012;ICES, 2012a). ...
The aim of this paper was to report the arrival and rapid colonization of the nektobenthic crustacean Rhithropanopeus harrisii in the shallow north-eastern Gulf of Riga. The crab was found for the first time from the Estonian coastal sea in Pärnu Bay in August 2011. In 2012, during targeted sampling efforts, different life-history stages of the species (larvae, juveniles, and adults) were observed all over Pärnu Bay with some sporadic findings at the open coast of the Gulf of Riga. These observations, together with a successful breeding, confirm that R. harrisii is established in the study area. Provided the high density of R. harrisii and the lack of such functional trait in the study area and in the north-eastern Baltic Sea range in general, this invasion is likely to cause significant repercussions on the structure and functioning of soft- and hard-bottom benthic macrophyte and invertebrate communities in the near future.
Fungi represent one of the largest and diverse kingdoms of eukaryotes, and Basidiomycota is the second most species-rich group within Fungi. Despite the ecological importance of basidial fungi, i.e., their leading role in decomposition of wood in terrestrial ecosystems, their diversity and taxonomy are insufficiently known. Fulfilling this knowledge gap, the thesis presents taxonomic studies in a class of basidal fungi called Dacrymycetes. Dacrymycetes occur only on dead wood and produce either of the two types of fruitbodies: gelatinous voluminous yellow or dry flat bleak-coloured. The latter type, also called corticioid fruitbodies, is the primary focus of this thesis. Traditionally, such corticioid fruitbodies in dacrymycetes were strictly associated with the family Cerinomycetaceae and its only genus Cerinomyces. This emphasis on a single character led to inclusion of dissimilar species into Cerinomyces, and over the time the genus became overly broad and polyphyletic. Thus, aim of the present thesis was to revise Cerinomyces and related taxa on a basis of DNA sequence-based phylogenetic analyses and morphological studies. As a result, Cerinomyces was reshaped to a more natural scope and became monophyletic. Priority for the corticioid morphology was abandoned, and gelatinous members were introduced to the genus. Instead of fruitbody type, the genus is now united by a set of microscopic characters: simple clamps, thin-walled aseptate basidiospores, and low amount of carotenoid pigments. Moreover, investigating taxa morphologically similar to Cerinomyces, the rest of dacrymycetes was partially revised. Special attention was paid to notable morphological structures called “dendrohyphidia” that are common in Cerinomyces, but were also found in other dacrymycetes. To accommodate such taxa in the Dacrymycetaceae family, a new genus Dendrodacrys was raised. In total, the thesis proposes 42 nomenclatural novelties to science, including one new genus, 27 new species, and 14 new combinations.
Modern day human genomes are mixtures of ancient components. Thanks to advancements in ancient DNA (aDNA) research, we can detect the origins of these components and study them. However, aDNA might either not be available or be of low quality in many situations due to DNA structure being subject to degradation related to time and different environmental factors. Thankfully, we can identify and extract these ancient layers also from contemporary human genomes with local ancestry inference methods. With this approach, we can study admixed populations, which have highly divergent ancestral components, in terms of demography and functional analyses. This thesis particularly focuses on two such groups: South Asian populations, which are composed of West Eurasian and South Asian ancestries, and Ethiopian populations, which are composed of Eurasian and African ancestries. In the first part, past demographic events, diverse genomic variation and post-admixture natural selection in South Asia are investigated by generating surrogates for the two main ancestral components of contemporary South Asian genomes. In the second part, a local ancestry inference-based method is evaluated for improving selection detection in ancestral components of admixed genomes and it is applied on South Asian genomes. In the third and the last part, a similar approach to the first part is conducted for Ethiopian genomes to pinpoint the source of Eurasian ancestry in contemporary Ethiopians.
Eurasian wild boar is the most widespread species of the Suidae family and its populations increased significantly in the second half of the 20th century – a change that has been largely associated with the continuing spread of agriculture, as well as the widespread practice of supplementary feeding. However, due to its omnivorous diet, high population density of wild boar can have disastrous effects on other animals, particularly on ground-nesting birds, whose populations have suffered from loss of habitat as well as predation.Wild boar can also play an important role in disease outbreaks as a reservoir of various pathogens shared between wildlife and domestic animals. The purpose of this thesis was to examine the potential consequences of supplementary feeding of wild boar for ground-nesting birds and wild boar infection with endoparasites, because increased overall abundance of wild boar and increased contact rates at feeding sites can promote the spread of various diseases.
In this study, supplementary feeding had a key role in determining wild boar abundance and grain from feeding sites constituted a major food category even in the warm season, when food availability was not hindered by low temperatures and deep snow. However, despite having access to supplemental food, wild boar acted as a predator of nests and chicks of forest grouse and the concentration of wild boar and other predators near feeding sites resulted in locally increased predation risk for ground-nesting birds. What is more, the novel molecular method applied in this study revealed that faecal diet analysis based on morphology, which is still a popular method in diet studies, underestimates the proportion of bird in wild boar diet, indicating that previous studies might suffer from the same error. In addition to its contribution to increased predation of ground-nesting birds, supplementary feeding was shown to influence endoparasite infection in wild boar both directly and indirectly through increased abundance. Supplementary feeding sites had become hot-spots for acquiring lungworm infection and parasites with a direct life cycle benefited from the overall high host abundance. These unwanted effects should be reckoned with in wild boar management.
Forests provide habitat for a huge variety of fungi that, in turn, play key roles in several forest ecosystem processes. The fungal biota is increasingly affected by human-caused transformation of forests, i.a., significant declines in the amount of coarse dead wood and large old trees. My thesis concentrates on fungi inhabiting such structures. My main focus is on polypores that belong to the dominant dead-wood composers in the forests, but I also explore lichenised fungi. Many polypores and lichens are nowadays found mainly in the remaining old-forest patches, and the occurrence of several species is thought to indicate ecological value of a forest. My general aim was to assess the forest conservation and management practices from the perspective of the fungi inhabiting dead wood and old living trees. The main method in polypore studies was fruit-body based species-inventory. In the stand scale, I found this method efficient: while all polypore species inhabiting a tree-trunk (as revealed by their DNA in the wood samples) may not produce fruit-body on the same tree, conspecific fruit-bodies can be usually found on other trunks in close vicinity. Differently from the intensively managed Fennoscandia, the old-forest associations of polypores were relatively weak in Estonia, as revealed by a comparison of old-growth, mature managed and harvested forests. Thus, fungal habitat associations and indicator value depend on regional landscape context. For the few species that were confined to old -growths, specific substrate requirements (notably large spruce trunks) were the reason. I also show that interpreting species habitat associations may me confused by “cryptic species” that have similar morphology, but differ by genetics and ecology. Thus, conservation practices might benefit from fewer, but better supported, fungal indicators. I demonstrate that fungi inhabiting dead wood and old living trees (including putative old-forest specialists) may form species-rich assemblages also in managed forests. This is possible if these forests are diverse in terms of tree species, dead-wood structures, and successional stages, including old stands. My general conclusion is that there are many possibilities for adjusting forest management to better address the fungal diversity that depends on dead wood and old living trees.
