Martin Culek

Geological And Morphological Evolution of The Socotra Archipelago (Yemen) from the Biogeographical View

Abstract Some misunderstandings persist in the biological literature, concerning the geological evolution of the Socotra Archipelago. The aim of this paper is to interpret new information about the Gulf of Aden geology, from the view of possible methods of terrestrial biota species migration to the Socotra Islands. An overview of the Socotra Platform with the Socotra Archipelago topography is given. Present-day geological publications are mostly oriented towards tectonic structure of the Gulf and its tectonic evolution, and thus information concerning the elevation of the land surface and the sea level was necessary to deduce. The first biogeographically relevant emergence of a land mass in the area of present-day Socotra Archipelago commenced during the late Eocene Epoch (38-34 Ma BP). Some islands persisted after later transgressions of the sea, before the time of the opening of the Gulf of Aden rift (ca 20-17 Ma), accompanied by substantial uplift and large-scale uplift of the land. This was the last time when terrestrial biota could, relatively easily, reach the area of the Socotra Archipelago on land from the African mainland, and also with medium probability from present-day Arabia. The total evaporation of the Red Sea from 11-5 Ma BP enabled the migration of terrestrial species from and to Arabia via Somalia. Nevertheless, channels in Guardafui and Brothers basins made important, but perhaps nonfatal, barriers. The last and most important uplift of Haggier Mts. on Socotra occurred at the end of the Miocene Epoch (9-6 Ma BP). That was probably the time of the last Tertiary emergence of the Socotra Platform, potentially enabling some species to migrate across narrowed abovementioned channels. Great changes in sea level occurred during the Quaternary Period, periodically exposing the surface of the Socotra platform. Two channels persisted, preventing the invasion of modern species onto the Socotra Archipelago. Channels within the Brothers basin between Abd al-Kuri Isl. and other islands of the Archipelago formed some barriers to dispersal, and probably led to important biota differences in the scope of the Archipelago. Finally, a scenario of the “facilitation” provided by tsunami and sea currents for the immigration of biota onto the Archipelago is presented.

Biogeographical patterns in vertebrate assemblages of the Czech Republic: regional division in the context of species’ distributions in Europe

Abstract. This study attempts to explore biogeographical patterns in vertebrate assemblages of the Czech Republic and to delineate faunal biogeographical regions of the country. We focused on native terrestrial species and first explored main gradients in the composition of their assemblages. The first gradient revealed by Principal Coordinate Analysis was best correlated with climatic variables, whereas the second gradient can be ascribed rather to longitude and to the associated habitat change. Using the spatially constrained clustering, the Czech Republic was divided into five cohesive regions and species above-average associated with these regions showed distinct distributions within the European continent. Delineated regions also significantly differed at least in three considered environmental variables. We provided clear evidence that species distribution data gathered by national mapping support main biogeographical patterns suggested by previously published expert-based classifications of the country. We also demonstrated that the fauna of the Czech Republic shows a biogeographical pattern very similar to that showed by natural habitats defined in terms of plant communities. This indicates that both fauna and flora of the Czech Republic yield to the same environmental forces and biogeographical processes such as spreading of faunistic and floristic elements from the adjacent Carpathian Mountains and the Pannonian Basin.

Biogeografické regiony České republiky

Kniha podrobně charakterizuje vsechny ctyři biogeograficke podprovincie a take 91 bioregionů CR. Každý bioregion je popsan z hlediska polohy, plochy, hornin, reliefu, půd, podnebi, aktualniho stavu krajiny, flory a fauny, vegetace potencialni i aktualni, dale pak dle geobiocenologicke typizace a kontrastů k okoli. Uvedena jsou i klicova chraněna uzemi. Soucasti publikace je podrobna mapa biogeografickeho cleněni CR v měřitku 1:500 000.

Biogeographical provinces, subprovinces and bioregions of the Czech Republic

ABSTRACT Presented biogeographical division of the Czech Republic was elaborated initially for purposes of national and supra-national Ecological Networks. This division has its own hierarchy, consisting of both individual and typological biogeographical units. Higher units (biogeographical province, subprovince, and bioregion) are of individual character. Within the territory of the Czech Republic, two biogeographical provinces, four biogeographical subprovinces and 91 biogeographical regions have been distinguished. Hierarchically lower biogeographical units (biochora, group of geobiocoene types) have typological character; their characteristics in English are intended to be published later. All of the biogeographical units - with the exception of the group of geobiocoene types - are elaborated in maps of scale 1:50 000.