Challenges for Diadromous Fishes in a Dynamic Global Environment

<em>Abstract</em>.-Diadromy is a life history attribute in a small number of fish species, and also some decapod crustaceans and gastropod mollusks, involving regular migrations at defined life history stages between freshwaters and the sea. Despite the relatively few species known to be diadromous, these are often of high fisheries importance owing in part to their migratory movements being spatially and temporally concentrated, making them vulnerable to exploitation. These migrations have important implications for a diverse array of aspects of biology: evolutionary, genetic, biogeographical, ecological, community, and conservation. There are also implications for the acclimatization of species into novel habitats, and deriving from these implications, diadromous fishes introduced into natural ecosystems may have seriously adverse impacts on the receiving ecosystems. As well, diadromy provides some species with the capacity to facilitate restoration of populations caused by adverse impacts on aquatic ecosystems across a broad range of spatial and temporal scales, from the effects of volcanism and glaciation to those of polluting discharges with anthropogenic sources. Allied with these questions is that relating to the importance of habitat connectivity and the vulnerability of diadromous species to events that interfere with up- and downstream migrations in fluvial ecosystems.

The National Unity of the Romanians and the Breakup of the Austro-Hungarian Empire

Both in their scholarly writings and at conferences such as those at Indiana University in 1966 and Bratislava in 1967, historians have expressed the opinion, which has been unanimously accepted, that the breakup of the Austro-Hungarian empire must be mainly ascribed to the centrifugal role of the non-German and non-Magyar nationalities in that empire. Relegated to the rank of second-class subjects of the Habsburg emperor by the privileged classes of the dominant German and Magyar nations, the Slavic and Latin nationalities enjoyed fewer political privileges than the Germans and Hungarians, suffered from discriminations that impeded the growth of their cultural potentialities, and were subjected to various economic measures that handicapped the development of their economies. Historians are also agreed that the lack of economic unity of the Dual Monarchy was another important reason for the collapse. Furthermore, the majority of specialists on Habsburg history attribute a considerable portion of the blame for the dissolution of the Habsburg realm to the nationality policies pursued by the government in the Transleithanian half of the monarchy. The repression of the non-Magyar nationalities by the privileged classes in Hungary stimulated the growth of national liberation movements among the oppressed nationalities and prompted them to intensify their struggle, first, for equal rights, then for national autonomy, and, finally, for self-determination.