Zoogeographical classification of the macroparasite faunas of four flatfish species from the northeastern Atlantic

The macroparasite faunas of four righteye flounder species (flounder Platichthys flesus, witch flounder Glyptocephalus cynoglossus, American plaice Hippoglossoides platessoides and Atlantic halibut Hippoglossus hippoglossus) caught off the northern Norwegian coast at 70°N, were classified zoogeographically. The parasite faunas of all four host species were dominated by boreal parasites. This appears to be the situation with the entire area of distribution of these flatfish species. The relationship between the extension of the range of the host species towards the Arctic and the proportion of parasites belonging to the arctic group is indicated.     

Distribution patterns and chorological analysis of fish fauna of the Arctic Region

Chorological structure of ichthyofauna of the Arctic Region is described. Distribution patterns of 504 fish-like vertebrates and fish species are characterized. One hundred and eighty-nine range types are defined, which are combined into eight main categories: 1—Arctic; 2—Atlantic-Arctic; 3—transitional subarctic zone of Atlantic sector; 4—Pacific-Arctic; 5—transitional subarctic subarctic zone of Pacific sector, 6—Pacific-Atlantic (amphiboreal); 7—bipolar; 8—continental (fresh and brackish waters). Arctic and boreal regions are bordered by transitional (subarctic) zones, which are the areas of intermutual penetration of faunas. The distribution of most fish species that penetrate into to the Arctic Region from the southern areas is limited by these transitional zones. The benthic fish species prevail in the group of autochthonous Arctic species (which includes 64 species or 14% of marine fauna). The demersal fauna of the Arctic preudoabyssal is presented by endemic species. Ten variations of amphiboreal distribution patterns are revealed. Three areas may be defined within the Atlantic-subarctic zone in regard to the fish fauna and range types, i.e., Labrador-Greenland region, the Barents Sea region, and Icelandic (transitional) region.     

Butterflies (Lepidoptera, Rhopalocera) in the Arctic fauna

The Arctic fauna includes 106 species of diurnal butterflies: Papilionidae (6 species), Pieridae (20), Lycaenidae (18), Nymphalidae (30), Satyridae (27), and Hesperiidae (5). Among them, representatives of the family Nymphalidae predominate as to the features characterizing the biological progress in the Arctic, as well as to the number of the most strongly pronounced arctic forms. The family Satyridae shares the first place with Nymphalidae by the number of species, but differs from the latter in the uneven or local distribution. The family Pieridae demonstrates a wide distribution of polyzonal and boreal species in the tundra zone. The distribution patterns of Lycaenidae are different in the Eurasian and Beringian-American sectors. Species of Papilionidae and Hesperiidae occur only in the southern part of the tundra zone. Each family is characterized by specific distribution in the Arctic subzones and landscapes and by latitudinal trends in its specific ratio in the faunas. There are 30 to 40 arctic species, including arctic proper (euarctic and hemiarctic) and hypoarctic, arctoalpine, arctomontane, and arctoboreal species. The species developing successfully under high-latitude conditions are Boloria chariclea, B. polaris, B. improba, Colias nastes, C. hecla, and Erebia fasciata; the first two species can be considered true euarctic forms. Specific features of the latitudinal and longitudinal distribution of the butterfly species in different parts of the Arctic are discussed.     

Patterns of formation of island fauna of butterflies (Lepidoptera, Diurna) at the northern forest boundary in the region of pleistocene continental glaciation (by the example of White Sea islands)

Patterns of formation of island butterfly fauna at the northern forest boundary in the region of Valdai inland ice were analyzed by the example of White Sea islands. The ecotone effect, typical for northernmost taiga and forest-tundra and introducing the transitional butterfly fauna in near-tundra forest between the boreal and hypoarctic zones, was not observed on the White Sea islands. Island isolation provided for the absence of some Arctic species, entering near-tundra forest from the North, in the island fauna. Island butterfly faunas represent poor variants of the northern taiga fauna lacking some polyzonal and temperate species and having a reduced set of Arctic boreal species.     

THE BIOGEOGRAPHIC ORIGIN OF ARCTIC ENDEMIC SEAWEEDS: A THERMOGEOGRAPHIC VIEW1

The Arctic is geologically and biogeographically young, and the origin of its seaweed flora has been widely debated. The Arctic littoral biogeographic region dates from the latest Tertiary and Pleistocene. Following the opening of Bering Strait, about 3.5 mya, the “Great Trans‐Arctic Biotic Interchange” populated the Arctic with a fauna strongly dominated by species of North Pacific origin. The Thermogeographic Model (TM) demonstrates why climate and geography continued to support this pattern in the Pleistocene. Thus, Arctic and Atlantic subarctic species of seaweeds are likely to be evolutionarily “based” in the North Pacific, subarctic species are likely to be widespread in the warmer Arctic, and species of Atlantic Boreal or warmer origin are unlikely in the Arctic and Subarctic. Although Arctic seaweeds have been thought to have a greater affinity with the North Atlantic, we have reanalyzed the Arctic endemic algal flora, using the Thermogeographic Model and evolutionary trees based on molecular data, to demonstrate otherwise. There are 35 congeneric species of the six, abundant Arctic Rhodophyta that we treat in this paper; 32 of these species (91%) occur in the North Pacific, two species (6%) occur in the Boreal or warmer Atlantic Ocean, and a single species is panoceanic, but restricted to the Subarctic. Laminaria solidungula J. Agardh, a kelp Arctic “endemic” species, has 18 sister species. While only eleven (61%) occur in the North Pacific, this rapidly dispersing and evolving genus is a terminal member of a diverse family and order (Laminariales) widely accepted to have evolved in the North Pacific. Thus, both the physical/time‐based TM and the dominant biogeographic pattern of relatives of Arctic macrophytes suggest strong compliance with the evidence of zoology, geology, and paleoclimatology that the Arctic marine flora is largely of Pacific origin.     

Leptostraca,Mysidacea, Isopoda,and Decapoda (Anomura) (Crustacea,Malacostraca) of the Chukchi Sea and Adjacent Waters: Biogeography and Fauna Formation

Data on the distribution of 72 species of Leptostraca, Decapoda: Reptantia: Anomura, Mysidacea, and Isopoda in the northern Bering Sea, the Chukchi and East Siberian seas, and the adjacent areas of the continental slope in the Arctic basin at depths less than 500 m were used for biogeographic analysis. According to distribution, these species can be united into 15 biogeographic groups. The hydrological regime, primarily, the distribution of waters of different origin in the investigated regions, governs the distribution of different biogeographic groups of crustaceans. Pacific boreal and subtropic-boreal species mostly inhabit the southern part of the Chukchi Sea, coastal waters off Alaska to Point Barrow, and the central region of this sea to the Herald Bank. For these taxa, the boundary between the Pacific and Arctic faunas is in the Chukchi Sea crossing from Cape Serdtse Kamen and Point Barrow to the area west of the Herald Bank. Possible pathways and the major stages of formation of the fauna of the investigated crustaceans for the last 18000 years are discussed.     

Springtails (Hexapoda,Collembola) of Tundra Landscapes of the Kola Peninsula

A quantitative study of collembolan assemblages on the Barents Sea coast of the Kola Peninsula was performed. Altogether, 104 collembolan species of 55 genera and 16 families were found. Analysis of the faunal composition revealed its high similarity to that of the faunas of the neighboring regions of Norway as well as a marked decline in species richness as compared to the Siberian analogues. A high share of littoral forms with increased vagility and the predominance of species with “southern” (= boreal) and “western” distribution patterns are the main characteristics of the fauna studied; only a few true arctic forms were found, always with low abundance and occurrence levels. Most of the studied collembolan assemblages are characterized by the dominance of a few species which inhabit a part of or the entire range of plant communities. As a result, collembolan assemblages under various types of vegetation cover in different landscape elements often show only insignificant differences.     

Floristic division of the Arctic

Abstract: The progress in the floristic study of the circumpolar Arctic since the 1940s is summarized and a new floristic division of this region is presented. The treeless areas of the North Atlantic and North Pacific with an oceanic climate, absence of permafrost and a very high proportion of boreal taxa are excluded from the Arctic proper. It is argued that the Arctic deserves the status of a floristic region. The tundra zone and some oceanic areas are divided into subzones according to their flora and vegetation. Two groups of subzones are recognized: the Arctic group (including the Arctic tundras proper and the High Arctic) and the Hypoarctic group. The Arctic phytochorion is floristically divided into sectors: 6 provinces and 20 subprovinces reflecting the regional features of each sector in connection with flora history, physiography and continentality-oceanity of the climate. Each sector is described and differentiated by a set of differential and co-differential species. The peculiarities of the Arctic flora are manifest in different ways in the various sectors, and endemism is not the universal criterion for subdivision.     

The structure and spatial organization of the butterfly fauna (Lepidoptera,Rhopalocera) of the Ural Mountains

The butterfly fauna of the Ural Mountains contains 233 species: Papilionidae (6 species), Pieridae (23), Lycaenidae (64), Nymphalidae (60), Satyridae (57), and Hesperiidae (23). The number of butterfly species in seven regional and 29 local faunas generally increases gradually from north to south. The mean number of species in the local butterfly faunas is 127 in the southern Urals and slightly over 50 in the Polar Urals. The arealogical structure of the fauna is determined by the distribution of species recorded in 24 meridional and 19 latitudinal groups which together result in 80 distribution patterns. Based on comparison of the local butterfly faunas of the Urals, two large, historically formed faunistic complexes are distinguished: southern and northern. Either complex contains two faunistic complexes of the second order, hypoarctic and boreal in the former, and southern boreal and subboreal in the latter. The faunas of the Kazakhstan part of the Urals form a separate subboreal semi-arid complex, whereas the extreme boreal fauna of Pay-Khoy forms an independent arctic complex.     

The dominant fish fauna in the North Sea and its determination

The 224 species of fish reported from the North Sea are regarded as being composed of elements of three faunas—Boreal, Lusitanian and Atlantic, and they can be grouped accordingly on both a number of species and a biomass basis. The estimation of biomass of more than 10 important species is based on stock estimates obtained from population data. For 65 non-standard species the estimate is based on a comparison of catch rates for 'standard'and non-standard species from groundfish survey data. This involves assumption about the relative catchability of different sets of species. For the other species the biomass are computed in different ways. An analysis of the dominant fish fauna in the North Sea is attempted. The fish fauna in the area is analysed in two ways: by the conventional total number of species from each zoogeographic area, and by the biomass of the representatives of each fauna. It is concluded that for establishing the dominant faunal element of fish, biomass is a better index than is the number of species. The dominant faunal element of fish in the North Sea is Boreal.     

Springtails (Collembola) of eastern Chukotka: Characteristics of the fauna and species assemblages

A total of 139 collembolan species from 55 genera were found in coastal tundra near the settlement of Lavrentiya in the eastern part of the Chukchi Peninsula. The local fauna of the region is quite “Beringian” in species composition but its structure appears to be in full agreement with the known characteristics of southern tundra faunas of other sectors in the Arctic. The specificity of collembolan complexes of the main plant associations in the studied area is not very high because the predominant collembolan species usually inhabit a wide range of communities. The performed study on Collembola fails to confirm the conventional view of a significantly higher diversity of northeastern Palaearctic faunas. Despite the rather southern position of the studied coastal tundra, the species richness of its collembolan fauna seems to be the same as or only slightly higher than that of analogous landscapes in the other Arctic sectors. The apparent discrepancy between relatively low diversity of Collembola at the local level as shown herein and its rich regional fauna may be the result of increased differentiation of the collembolan fauna of the region characterized by very complex orography and extremely contrasting climatic conditions.     

Demersal fish assemblages and spatial diversity patterns in the Arctic-Atlantic transition zone in the Barents Sea

Direct and indirect effects of global warming are expected to be pronounced and fast in the Arctic, impacting terrestrial, freshwater and marine ecosystems. The Barents Sea is a high latitude shelf Sea and a boundary area between arctic and boreal faunas. These faunas are likely to respond differently to changes in climate. In addition, the Barents Sea is highly impacted by fisheries and other human activities. This strong human presence places great demands on scientific investigation and advisory capacity. In order to identify basic community structures against which future climate related or other human induced changes could be evaluated, we analyzed species composition and diversity of demersal fish in the Barents Sea. We found six main assemblages that were separated along depth and temperature gradients. There are indications that climate driven changes have already taken place, since boreal species were found in large parts of the Barents Sea shelf, including also the northern Arctic area. When modelling diversity as a function of depth and temperature, we found that two of the assemblages in the eastern Barents Sea showed lower diversity than expected from their depth and temperature. This is probably caused by low habitat complexity and the distance to the pool of boreal species in the western Barents Sea. In contrast coastal assemblages in south western Barents Sea and along Novaya Zemlya archipelago in the Eastern Barents Sea can be described as diversity "hotspots"; the South-western area had high density of species, abundance and biomass, and here some species have their northern distribution limit, whereas the Novaya Zemlya area has unique fauna of Arctic, coastal demersal fish. (see Information S1 for abstract in Russian).     

Biogeography of the octocorallian coelenterate fauna of southern Africa

The geographical and bathymetric distribution of southern African octocorals is analysed. Of the over 200 estimated species of regional octocorals, 81 confirmed and adequately described species are studied using a radial sector method. Two primary faunal components are recognized–endemic (53.3% of the fauna by numbers of species) and Indo-Pacific (39.4%). An Atlantic component contributes only minimally (about 1.7%), while the remaining fauna is made up of cosmopolites (2.8%) and scattered species (2.8%). A subantarctic component is not evident for the present-day, although evidence for previous contact is presented. A sister-group analysis using genera as a guide to sister species, shows the biogeographic affinities for the present-day fauna as a whole to be 45% Indo-Pacific, 31% cosmopolitan, 10% endemic, 10% Atlantic and 4% southern oceans (subantarctic). Applying the same method to only those genera with endemic species shows the affinities of the present-day endemic fauna to be 27.5% Indo-Pacific, 27.5% endemic, 24% cosmopolitan, 14% Atlantic and 7% subantarctic. Clearly defined boundaries for west, south, and east coast faunas (as recognized by previous authors in describing various intertidal faunas) are found not be present with regard to the octocoral fauna (largely due to its overwhelmingly subtidal nature). Instead two primary zoogeographic provinces are recognized–the Cape Endemic Province (extending from Liideritz to Inhaca Island) and the south-western fringe of the Indo-Pacific Province from East London north-eastwards. An overlap zone between these two is recognized between East London and Inhaca Island, with the region in the vicinity of Richards Bay having an essentially evenly mixed fauna (roughly 50% Cape Endemic Province and 50% Indo-Pacific). Of the 84 octocoral genera recorded for the region, seven (or 8.3%) are endemic, and of these, five are monotypic while two are ditypic. The fauna is shown to be predominantly sublittoral (about 95% by numbers of species), the shallow sublittoral (< 100 m in depth) being the region with highest species richness. Pennatulaceans are eurybathic (intertidal to 4756 m) and clearly show a high proportion of cosmopolites (20% of presently identified species). Soft corals are stenobathic and restricted to the intertidal, continental shelf and uppermost portion of the continental slope (<500m), while gorgonians are intermediate in depth distributon (intertidal to 1200 m). No cosmopolitan alcyonaceans are presently recorded. The centre of the Cape Endemic Province is the Agulhas Bank–an extensive region of shallow continential shelf (< 200 m in depth) between Cape Town and East London. Two regions of octocoral radiation for southern Africa are postulated–the Agulhas Bank and the western Indian Ocean.     

Biogeography of Eocene bryozoans from the St Vincent Basin, South Australia

The first extensive and stratigraphically detailed taxonomic study of the Middle to Late Eocene Bryozoa of the St Vincent Basin has identified more than 200 species of Cheilostomata and 50 species of Cyclostomata. There are three biogeographic groups: basin endemic, Australian and global. Two-thirds (116) of the cheilostome species and seven genera are currently considered endemic to this basin. Most species are endemic to Australia and similar to those found in the Oligo-Miocene of Victoria. The Cellariidae are a common component of most Australian Cainozoic deposits, but the species are highly dissimilar, with 13 of the 17 species here being new. The global component indicates that biogeographic links with regions outside Australia still existed in the Eocene. The cyclostome genus Reticrescis is only known from the Australian and Antarctic Eocene. Ten genera have their first occurrence in the Eocene St Vincent Basin. The Phidoloporidae and Smittinidae represent the most diverse and ubiquitous groups at a geological time close to their time of origination. Contemporaneous sediments in Antarctica, eastern Europe and North America also have a diverse fauna of this family, pointing to a strong Tethyan link. Rhamphosmittina lateralis (MacGillivray) is still extant in New Zealand, having an exceptionally long time range of 40 million years. Overall, the fauna has a distinct Late Cretaceous character. A new genus of Onychocellidae appears similar to genera that were common in Cretaceous Tethyan faunas but rare during the Cainozoic. This similarity ends in the Oligocene, after which the Australian bryozoan became endemic     

Pathways of formation of the fauna of the Solovetsky Archipelago,the White Sea,Northwest Russia

The fauna of the Solovetsky Archipelago represents an extremely depleted and reduced variant of the continental northern boreal one. The level of its depletion roughly corresponds to the latitudinal shift by one or two biomes, that is, by the number of species it is comparable to the mainland concrete faunas of the forested or hypoarctic tundra. Only very few arctic species, let alone more southern (nemoral) faunal elements, occur on the archipelago. The compositions of the basic fauna groups and their dominant species are determined there by three main factors: a wide distribution of intrazonal ecosystems (coastal wastelands and grasslands, birch sparse forests, peat bogs), limited living space, and extreme climatic conditions. Among the dominants are eurytopic polyzonal and, to a lesser degree, hypoarctic species. The isolation of the Solovetsky Islands is no significant barrier to the dispersal of numerous animal species, but these islands form a highly specific environment that strongly prevents the invasion of new species lacking relevant preadaptations to the local habitat and climatic conditions. The effect of “density compensation” of lower taxonomic diversity is revealed on the archipelago in many taxa, the range of abundant species being able to vary considerably in time depending on the climatic conditions. The Solovetsky Islands’ fauna is continental by origin, having been mainly formed in the Late Pleistocene and Early Holocene (～9–10 ka before the present).     

Arctic biogeography: The paradox of the marine benthic fauna and flora

The marine benthic fauna and flora that inhabit the shallow arctic sublittoral zone comprise a relatively young marine assemblage characterized by species of either Pacific or Atlantic affinity and notably few endemics. The young character of nearshore arctic communities, as well as their biogeographical composition, is largely a product of the Pleistocene glaciation. However, analysis of more recent collections and comparison between the origins of the benthic fauna and flora present some interesting paradoxes to biogeographers. One enigma is the low frequency of algal species with Pacific affinities in the Arctic, especially in the Chukchi, Beaufort and East Siberian Seas of the Eastern Arctic, which receive direct inputs of northward-flowing Pacific waters. In contrast, animal species with Pacific affinities are found throughout the nearshore regions of the Arctic, reaching their highest frequency in the marginal seas between the New Siberian Islands and the Canadian Archipelago. Organization of published and unpublished data, additional field collections, and the use of cladistics and molecular DNA techniques by systematists are a high priority for future research in reconstructing the evolution of the arctic biotic assemblage.     

Biogeography of the phoracanthine beetles (Coleoptera: Cerambycidae)

Six biogeographic subregions of the phoracanthine beetles are proposed on the basis of 136 valid species in all eleven genera of this Australasian group of insects: the Kosciuskan, Western, Eyrean, Torresian, Timorian and New Guinean. Both phenetic and cladistic approaches are employed in the biogeographic study of these beetles. Phenetically, the Kosciuskan and Torresian fauna are the most similar and the least faunal similarity occurs between the New Guinean subregion and all others. Cladistically, two distinct peripheral faunas are divided: the southern Western+Kosciuskan and the northern New Guinean+Torresian+Timorian. The Eyrean fauna in the central Australian continent is more distantly related to the remainder than the latter are to each other. Biogeographic history of the phoracanthine beetles is discussed extensively.     

A molecular analysis of relationships and biogeography within a species complex of Holarctic fish (genus Osmerus)

Episodes of trans-Arctic faunal exchange and isolation between the north Pacific and Atlantic ocean basins have been implicated as important historic geological events contributing to extant patterns of genetic diversity and structure in Holarctic faunas. We made a further test of the significance of such biogeographic events by examining mitochondrial DNA (mtDNA) restriction fragment length and cytochrome b sequence polymorphism among north Pacific and Arctic, north-western Atlantic (north-eastern North American), and north-eastern Atlantic (European) regional forms of the boreal smelt, genus Osmerus. Our analyses also assessed whether the regional forms within this ‘species complex’: (i) represent a single widely distributed and polytypic species, or is composed of three geographically distinct species, and (ii) resulted from a single split from north Pacific ancestral Osmerus or two independent Pacific-Atlantic divergences. MtDNA sequence divergence estimates among forms ranged from 5.6–8.9% and from 6.1–8.5% based on restriction fragment and 300 base pairs of cytochrome b sequencing, respectively. Divergence within forms averaged less than 0.5% for fragment analysis and no differences were detected from sequence analysis. Provisional dating of lineage separations in Osmerus based on our sequence divergence estimates suggested a mid-Pliocene to early Pleistocene time frame for diversification among the forms. These estimated lineage separation dates support the idea that geological events in ‘Beringia’ and the surrounding trans-Arctic area (e.g. opening of the Bering Seaway, Pleistocene glacial advances), occurring over a similar time frame, have influenced radiation in Osmerus. Phenetic and parsimony analyses of the sequence divergence estimates and of sequence polymorphisms suggested that the north Pacific/Arctic form and the northwestern Atlantic form shared a common ancestor more recently than either has with the north-eastern Atlantic form, thus supporting the hypothesis that the species complex has arisen from two independent Pacific-Atlantic divergences probably beginning during the mid-Pliocene.     

Biogeography and history of the Mediterranean bird fauna

With 366 species of breeding birds, the Mediterranean region is a "hot spot" of species diversity. Many biogeographic realms contributed to the establishment of the extant fauna, which makes this region a crossroads for birds, but the two most important realms are the large forest blocks that extend today over Eurasia and the semi-arid belts of the southern and southwestern Palaearctic. The few groups that presumably differentiated within the Mediterranean basin are mostly birds of open habitats and shrublands (e.g. Sylvia spp.), whereas few species evolved in Mediterranean forests dominated by sclerophyllous evergreen tree species. We suggest this results from the history of vegetation belts and their associated faunas during the Pleistocene. On the whole, in contrast to other groups of vertebrates, the bird fauna is fairly homogeneously distributed all over the basin although there are some regional-specific trends in species assemblages, mostly on the basis of habitat selection and biogeographic origin. Many species of eastern and southeastern origin invaded the Mediterranean basin on the northern side of the sea up to the Balkan peninsula and the southern side to the Atlantic coast. The extant biogeographic patterns of the Mediterranean bird fauna are interpreted in the light of the Quaternary history shared by the biotas of the western Palaearctic in relation to the cycle of climatic changes which produced periodic huge spatiotemporal migrations of communities and populations. The severe human impact that started c. 8000-10,000 years ago resulted not so much in species extinctions as in dramatic changes in distributional patterns, complicating the reconstruction of biogeographic scenarios.     

The springtail (Hexapoda,Collembola) fauna of Wrangel Island

Analysis of the collembolan fauna of Wrangel Island based on published data and recent sampling was performed. The species richness of springtails on the island (89 species from 41 genera and 12 families) exceeds the levels characteristic of most other insular territories of the Arctic Ocean, except for Greenland and some small islands located within the southern tundra belt. The specificity of the species composition of the springtail fauna on the island depends on a high proportion of species with amphi-Pacific ranges, reflecting its formation within the Beringian Arctic sector. At the same time, the structure of the springtail fauna of the island is rather similar to those of the known tundra faunas of the Siberian sector, with no anomalies being detected.