Biogeographic Units Research Articles

Evaluation of Biogeographic Classification Schemes for Conservation Planning: Application to New Zealand's Coastal Marine Environment

For many regions worldwide, multiple and often contrasting biogeographic classifications exist that are derived from a variety of taxa and techniques. This presents a challenge for managers who must choose appropriate large-scale spatial frameworks for systematic conservation planning. We demonstrate how systematically collected community data can be used to evaluate existing biogeographic classifications, identify the most appropriate metric for biogeographic patterns seen in other taxonomic groups, and develop an independent biogeographic classification scheme for systematic conservation planning. We evaluated 6 existing biogeographic classifications for New Zealand's nearshore marine environment with community-similarity metrics derived from abundance and presence-absence data for macroalgae (107 species) and mobile macroinvertebrates (44 species). The concordance between community metrics and the previous classifications was high, as indicated by a high multivariate classification success (CS) (74.3-98.3%). Subsequently, we carried out an independent classification analysis on each community metric to identify biogeographic units within a hierarchical spatial framework. The classification derived from macroalgal presence-absence data achieved the highest CS and could be used as a mesoscale classification scheme in which 11 regional groupings (i.e., bioregions) (CS = 73.8-84.8%) are nested within northern and southern biogeographic provinces (CS = 90.3-98.7%). These techniques can be used in systematic conservation planning to inform the design of representative and comprehensive networks of marine protected areas through evaluation of the current coverage of marine reserves in each bioregion. Currently, 0.22% of the territorial sea around mainland New Zealand is protected in no-take marine protected areas in which 0-1.5% of each bioregion represented.

Iberian–Balearic fern regions and their explanatory variables

This article delineates the compositional regions present in the Iberian–Balearic fern flora and compares these regions to previously proposed biogeographic units. It also assesses the extent to which environmental variables could explain the regions and the fern species richness gradients found within them. A combination of 40 previously published and new maps were used to compile the distribution of 123 pteridophytes on a 50 × 50 km UTM grid. Cluster analysis of the resulting 257 squares was used to classify 10 regions based on fern species assemblages. Discriminant function analysis identified the environmental variables that best explained these fern composition regions. Using generalized linear models; the number of species in each square was regressed against topography, climate, geology, environmental diversity, land use and spatial variables within each region. Two main latitudinal pteridophyte zones can be recognized in the Iberian Peninsula. These two zones are longitudinally subdivided into two sub zones. The 10 regions established significantly differ both in species richness and influential environmental variables. Climatic variables discriminate the most among regions, followed by topography, heterogeneity and geology. Pteridophyte richness varies, with richer areas being located along the coast and the main mountain ranges and the poorest areas being in the central plateaus and some north eastern and south western river basins. Species richness variation in Iberia is positively correlated with altitude range, precipitation, maximum altitude and area with siliceous soils. It is negatively correlated with the total annual days of sun, however. The fact that species richness is explained by different variables within each of the 10 regions indicates that the specific factors determining the spatial distribution of species richness vary from region to region. Some coastal regions are poorly explained by the model, and display a negative correlation with the selected causal factors. This finding suggests that persistent historic effects might play a local role in determining species assemblages in these regions.

Análise biogeográfica da avifauna da região oeste do baixo Rio Negro, amazônia brasileira

Neste estudo é realizada uma análise biogeográfica detalhada da avifauna da Amazônia Central a oeste do Rio Negro, região onde está localizado o Parque Nacional do Jaú (PNJ). As distribuições geográficas de 383 táxons (espécies e subespécies) de aves registradas no PNJ foram analisadas através de métodos biogeográficos qualitativos e quantitativos (análise de agrupamento e análise de parcimônia de endemismo). A avifauna do PNJ é fortemente influenciada pelas regiões noroeste e oeste da bacia amazônica. Foram identificadas três unidades biogeográficas e o PNJ se agrupa com sítios localizados no alto Rio Orinoco e na Guiana. De modo similar, o PNJ se agrupa com o sítio do alto Rio Orinoco tendo a Guiana como grupo-irmão no cladograma de área com maior suporte. Diferentes sub-grupos de espécies revelaram cladogramas de áreas com variadas topologias, sugerindo complexos cenários de diversificação da avifauna amazônica. Estes cenários biogeográficos podem ter sido influenciados por eventos geológicos ocorridos durante o Mioceno e Pleistoceno. Neste estudo foi identificada uma área de endemismo não descrita para a Amazônia - a área de endemismo Rio Negro. A avifauna da região do PNJ, além de ser representativa dos setores noroeste e oeste da Amazônia, possui táxons de distribuição restrita à região central da Amazônia, reforçando ainda mais sua importância na proteção da biodiversidade amazônica.

Endemic insects from the Yungas of Argentina

Until now, biogeographic unit of the Yungas was almost exclusively characterized by its floristic taxa. Presence of other taxonomical groups, in this case arthropods, were poorly recorded besides implicit mention of arthropods to characterizeYungas as a natural region. We present herein a species checklist of the holometabolous insects considered as endemics of the Yungas in Argentina. This checklist is a result of a rigorous endemicity analysis (Navarro et al, en prep.) Comments about altitudinal gradients of distribution for these endemic species are made. Results reveal a total of 23 endemic insects species of Yungas, representing 13 families of Lepidoptera, Diptera and Hymenoptera。

Does Macaronesia exist? Conflicting signal in the bryophyte and pteridophyte floras

Macaronesia, which includes five mid-Atlantic archipelagos (Azores, Madeira, Selvagems, Canaries, and Cape Verdes), has been traditionally recognized as a distinct biogeographic unit whose circumscription has been intimately associated with the hypothesis that the flora is a relict of a formerly broadly distributed subtropical Tertiary flora. The concept of Macaronesia is revisited here using parsimony and Bayesian analyses of floristic data sets for the moss, liverwort, and pteridophyte floras. All analyses reject the monophyly of Macaronesia s.l., resolving the Cape Verdes with tropical Africa. Of the other Macaronesian archipelagos, the liverwort and pteridophyte analyses support, or could not reject, an Azorean-Madeiran-Canarian clade (hereafter Macaronesia s.s.), but the moss analysis resolves the Canary Islands as sister to North Africa, thus rejecting the concept of Macaronesia s.s. for this group. Dynamic interchange of taxa with neighboring continental areas rather than relictualism best explains the relationships of the Cape Verde cryptogamic flora and the Canary Island moss flora. In contrast, relictualism is consistent with a monophyletic Macaronesia s.s. for liverworts and pteridophytes. However, from the limited information available on relationships of endemic cryptogams, this explanation alone may be unsatisfactory. Spatially congruent patterns may, in fact, conceal a complex mixture of relictual distributions and more recent speciation and dispersal events.

Assessment of diversity, distribution, conservation status and preparation of management plan for medicinal plants in the catchment area of parbati hydroelectric project stage — III in Northwestern Himalaya

The developmental activities, particularly the construction of hydroelectric projects are causing a great loss of biodiversity in the Indian Himalayan Region. The Himachal Pradesh, a part of IHR is well known for the development of hydroelectric projects. The Parbati H.E. Project is amongst the major projects of the State. The different stages of the project are all causing loss of biodiversity of the area. Stage III of the Parbati H.E. Project is a run of the river scheme on the Sainj River downstream of Power House of Parbati H.E. Project Stage II. The project shall utilize regulated discharge of Parbati H.E. Project Stage II and inflow of River Sainj for power generation, and has been contemplated as a peaking station operating in tandem with Stage II. The present study has been undertaken to see the impact of hydroelectric project on the biodiversity, particularly on medicinal plants. A total of 104 species of medicinal plants, belonging to different life forms, i.e., trees (23 spp.), shrubs (22 spp.), herbs (57 spp.) and ferns (2 spp.) were recorded. The species have been analyzed and studied for their distribution, classification, altitudinal zones, part (s) used, indigenous uses, nativity, endemism and rarity. DDifferent parts of these species, such as whole plants, roots (including rhizomes and tubers), leaves, flowers, fruits, seeds, stems, barks, spikes, nuts and insect galls are used by the inhabitants for curing various diseases and ailments. 30 species are native to the Himalayan region, 9 species native to the Himalayan region and adjacent countries also and 65 species are non-natives. 9 species are near endemics. Considering the whole Himalaya as a biogeographic unit (sensu lato), the near endemics are endemic to the Himalaya. Among these species, Zanthoxylum armatum is categorized as Endangered and Valeriana wallichii as Vulnerable. Hedychium spicatum, Rhus javanica, Berberis lycium, Thalictrum foliolossum, Salvia lanata, Rubia cordifolia and Bergenia ligulata may be considered as threatened species due to their over exploitation for trade. 90 species are propagated by seeds, 8 species by seeds and rhizomes/roots/tubers, 4 species by seeds and cuttings, and 2 species by sori. A management plan for the cultivation and conservation of the medicinal plants in the dam submergence area, and the commercially viable medicinal plants with high value in the catchment area is suggested.

Does the Trans‐mexican Volcanic Belt represent a natural biogeographical unit? An analysis of the distributional patterns of Coleoptera

AbstractAim We analysed the geographical distribution of beetle species of the families Buprestidae, Cerambycidae, Dryophthoridae, Melolonthidae, Passalidae and Staphylinidae from the Trans‐mexican Volcanic Belt (TVB) through a track analysis and a parsimony analysis of endemicity (PAE), in order to test its naturalness and determine its affinities.Location The area analysed corresponds to the TVB, which is a biogeographical province of the Mexican Transition Zone.Methods The panbiogeographical analysis was based on the comparison of the individual tracks of 299 species of Buprestidae, Cerambycidae, Dryophthoridae, Melolonthidae, Passalidae and Staphylinidae (Coleoptera). The TVB was divided into 1o × 1ogrid cells and we also included in the analysis the remaining Mexican biogeographical provinces. Parsimony analysis of endemicity with progressive character elimination (PAE‐PCE) was applied to classify areas by their shared taxa according to the most parsimonious cladograms. The nested sets of areas were represented as generalized tracks.Results Three generalized tracks were obtained: (1) grid cells 9C, 9D, 10D, 10E, Sierra Madre Oriental, Chiapas, Mexican Gulf and the Sierra Madre del Sur; (2) grid cells 3B, 3C, 4B, 4C, 5C, 6C, 7C, Sierra Madre Occidental, Sierra Madre del Sur, Balsas Basin and the Mexican Pacific Coast, and (3) grid cells 8D, 9C, 9D, 10D, 10E, Yucatán Peninsula, Chiapas, Sierra Madre Oriental and the Mexican Gulf.Main conclusions We conclude that the TVB does not represent a natural biogeographical unit because it shows different relationships with other biogeographical provinces, being clearly transitional between the Nearctic and Neotropical provinces. Some parts of the TVB are related to Neotropical provinces (Chiapas, Mexican Gulf and Mexican Pacific Coast) and others to the remaining provinces of the Mexican Transition Zone (Sierra Madre Oriental, Sierra Madre del Sur, Sierra Madre Occidental and Balsas Basin).

Late Würm and early Holocene in the mountains of northwest Iberia: biostratigraphy, chronology and tree colonization

Northwest Iberia (Spain and Portugal) is a large and complex territory which is currently considered a contact border between two different biogeographical regions, the Eurosiberian and the Mediterranean. Such complexity is clearly influenced by several main factors, namely the winding mountain ranges of this region and their position on the peninsula, which result in several markedly different environments coexisting within distances of only a few kilometres apart, such as extremely oceanic or continental climates and high mountain areas or inland basins. This intricacy might also be reflected in the postglacial palaeoecological reconstructions which have been made for different mountain areas of northwest Iberia. Several isolated pollen diagrams from key sites in the area which have been published during the last decades have been questioned, because they show tendencies or chronologies apparently incompatible with global dynamics affecting the North Atlantic. In this paper we explore the possible integration of the biostratigraphies and chronologies of several selected pollen sites in this region. Northwest Iberia as a whole has been firstly divided into several more homogeneous biogeographical units, and high quality pollen sequences from each unit were selected to obtain reconstructions of local dynamics at each site and also approximations of the regional tendencies in each unit. Subsequently, the correlation between the different regional tendencies and their coherence in relation to the global climatic models performed for the North Atlantic is discussed.

Water Availability: An Overview of Issues and Future Challenges for the St. Lawrence River

For some years now, water availability in the St. Lawrence River has been an inherent part of the larger issues threatening the integrity of its aquatic ecosystems. The St. Lawrence system (including the Great Lakes) is among the three largest in North America, alongside the Mackenzie and Mississippi rivers, in terms of basin size and flow rate. Located downstream of the international section (Kingston to Cornwall, Ontario), the Quebec portion of the St. Lawrence comprises four major bio-geographic units: the fluvial section, which is primarily influenced by Great Lakes inflows, the freshwater tidal portion of the fluvial estuary, the saltwater transition located in the upper estuary and the lower estuary, which widens up to become the Gulf of St. Lawrence (SLC 1996). Despite its large size, the St. Lawrence is subject to a range of anthropogenic pressures including variations in water availability, which reveal its vulnerability to hydrological and climatic factors. To fully appreciate the issues at stake in the fluvial section, we must first examine the context in which the Great Lakes-St. Lawrence was transformed. Specific aspects relating to fluvial integrity will then be described using the case of Lake St. Pierre, a designated Biosphere Reserve (UNESCO) and Ramsar site, as an example. Lastly, we will examine the current pressures on the ecosystem and future risks to water availability.

The Hydradephaga of the Segura basin (SE Spain): twentyfive years studying water beetles (Coleoptera)

We present the results of 25 years of study of the faunistics, biogeography, ecology and conservation of the Hydradephaga of the Segura river basin. Eighty one species have been recorded from the area, ca. 45% of the total of species found in the Iberian peninsula. Six of them are Iberian endemics, and fourteen are considered to be rare within the basin, although most of these are not rare in an Iberian context. The phenetic hierarchy of relationships among the western-Palaearctic regions considered shows a clear similarity of the fauna of the Segura basin with that of the Maghreb, which, together with the rest of the Iberian fauna form a well defined group isolated from the rest of the European areas. Within the Iberobalear region, there is also a clear north-south division, with a secondary classification into western and eastern basins. The Balearic islands seem to be a relatively independent biogeographical unit, although more related with the southern cluster. The environmental characteristics determining the distribution of the Hydradephagan fauna in the study area, as determined by Correspondence Analysis, are altitude, degree of mineralization of the water, and amount and type of riparian vegetation. Using a semi-quantitative scoring system to evaluate the vulnerability of the species only <em>Hydroporus decipiens</em> had a vulnerability value considered to be high (9), due to its rarity within the basin and to its general restricted distribution, although the incomplete knowledge of its distribution and taxonomy could be a distorting factor. With a similar value (8), <em>Nebrioporus baeticus</em> is a typical inhabitant of saline running waters, highly endangered habitat due to the increasing use of irrigation in the surrounding fields. The stations with the highest conservation interest were mountain streams in the NW of the basin, which are also of high conservation interest for other aquatic Coleoptera (e.g. Hydraenidae). A disadvantage of the index applied (IC, “conservation interest”) is the lack of reference to the conservation interest of habitats outside the study area. Thus, the saline or hypersaline streams, which are extremely rare in an European (or even global) context, are not considered of particular relevance due to the poor species richness and local abundance. The use of other criteria for the selection of sites of conservation value, such as complementarity, could overcome this limitation.

Forty years since Boucot, Johnson and Staton's seminal paper “On some atrypoid, retzioid, and athyridoid Brachiopoda”

The rate at which new spire-bearing brachiopods, exclusive of spiriferids, have been described, their temporal and geographic diversity, and their grade of endemism through time are reviewed. There has been an almost four-fold increase in the number of spire-bearing brachiopod genera (spiriferids excluded) included in the revised edition of the Treatise compared with those recognized in the first edition. Many of these genera were based on specimens from previously poorly known geologic successions, especially in Russia and China where Chinese and Russian colleagues had undertaken admirable and hard research. Even assuming a relatively high proportion of invalid or synonymous genera, the annual rate of creation of genera has been five to seven times that prior to publication of the first edition. Spire-bearing brachiopod genera erected after the first edition of the Treatise show a greater degree of endemicity than those erected prior to its appearance, with endemism displayed by the athyridids being greater than for the atrypids. No correlation seems to exist between degree of endemicity and generic diversity at any specific time. Endemic spire-bearers are of great value in discriminating biogeographic units. Spire-bearing genera with cosmopolitan tendencies did not evolve rapidly, so their value for global stratigraphic correlations is generally poor. The large increase in generic-level taxa appears to have resulted in a cascading expansion in numbers of higher taxa. In addition to the remarkable increase in the number of taxa during the last four decades, there has been an obvious shift in brachiopod research with increasing integration of other disciplines (biological, palaeontologic, mineralogic), which is improving our understanding of spire-bearers, and of the phylum as a whole in time and space.

Centers of marine fauna redistribution

The concepts of centers of biota origin and centers of biota accumulation are usually regarded as mutually exclusive. In this paper, they are analyzed within the framework of a unified concept of centers of biota redistribution. Such a center is a biogeographic unit that has three developmental stages: accumulation, diversification, and dispersal. At the accumulation stage, the taxonomic capacity of the corresponding biogeographic district drastically increases and its species richness becomes higher owing to in-migration of species from other regions. At the diversification stage, the species richness continues to increase owing to speciation, and a unified succession system develops. At the dispersal stage, the biotic boundaries of the region act as efficient barriers to species invasion, and the species of the redistribution center gain an advantage over the species of adjacent regions when colonizing new habitats. In the Neogene, the main shallow-water centers of marine fauna redistribution were located in the Indo-Malayan triangle, the western Atlantic, and the northern Pacific. The role of redistribution centers in deep-ocean areas belonged to the Antarctic and the western Pacific. The possibility of using an ecosystem approach to the study of redistribution centers is discussed.

Differentiation of tetrapod communities and some aspects of biotic events in the early triassic of Eastern Europe

The patterns of spatial differentiation of the Early Mesozoic terrestrial biota in Eastern Europe and Australia-Tasmania demonstrate that the tetrapod faunal recovery following the Permian extinction was characterized by both global and regional heterogeneity. Local distinctions observed in the development of Early Triassic tetrapod assemblages of European Russia allow the recognition of the following realms: (1) the central and northern regions of the East European Platform (Moscow-Mezen Syncline) and the Timan-North Ural Region; (2) the southern Fore-Urals, including the Obshchii Syrt Plateau; and (3) the southern regions of the East European Platform (the slope of the Voronezh Anticline). Climatic conditions at the initial stage of the development of local communities were characterized by an increase in aridity and seasonal contrasts of climate. Therefore, terrestrial assemblages mostly concentrated in the aquatic and coastal biotopes. Accordingly, vertebrate assemblages of the region were dominated everywhere by aquatic amphibians and semiaquatic reptiles, while the accompanying palynomorph assemblages show the predominance of hygrophilous vegetation indicative of swampy mangrove setting. With respect to amphibians, a peak of local biogeographic differentiation falls on the onset of the Early Triassic and, in the case of reptiles, on the end of this time span. This change conforms to the increasing role of reptiles in the overall taxonomic diversity with time. Among the three main biogeographic units of the region, the Southern Fore-Ural Realm is distinguished by the maintenance of distinct faunal links with Gondwanan regions. The Southern Realm shows a connection with the Germanic Basin and more western Euramerican areas, which is documented for the Late Olenekian and occurred under influence of coastal marine conditions.

Du comportement symbolique des derniers chasseurs Mechta-Afalou d'Afrique du Nord

The symbolic behaviour of the latter Mechta-Afalou hunters of northern Africa. The symbolic universe of Mechta-Afalou’s men is very little known, as Prehistory was mostly interested in reconstituting industrial assemblages and technological modes of their obtention. We will try in this paper, on the basis of the last works of Afalou Bou Rhummel, to accede to some of those activities indirectly bound to subsistence. We will first focus on the longevity of the human occupation of this important rock shelter and of the neighbouring shelters inscribed within the bio-geographical unit of the coastal mountainous massif of the Babors. The territory has been occupied continuously by Iberomaurisian populations during more than eight millennia, just before Holocene. Access to food resources, requesting the numerous strata of nature, departing from fishing art possibilities and going through the universe of molluscs and different varieties of vertebrates, seems to have been controlled by those populations that have, nonetheless, shown a particular preference to the wild ship ( Ammotragus lervia). Populations have invested the different areas of the territory with different significance. To grasp each subtlety, far from it, is still not yet possible. Nevertheless, we ought to seek for the significance of choosing the Afalou Bou Rhummel shelter for the establishment of a necropolis gathering several tens of individuals, such as the westward and almost contemporary necropolises of Columnata and Taforalt. Those places were certainly meaningful enough for everyone to have wished to get buried there or at least not elsewhere, in other habitats even occupied at the same epoch. It happens that the shelter has also given, in the form of backed clay statuettes, the oldest artistic manifestations known up to now in northern Africa. This second fact represents the meeting point, in a living place, of two prominent facts of recent prehistory both characterising modern Men: the metaphysical fact and the aesthetic fact. To cite this article: S. Hachi, C. R. Palevol 5 (2006) .

Molecular systematics of the trans‐Pacific alpine genusOreomyrrhis(Apiaceae): phylogenetic affinities and biogeographic implications

The alpine ecosystem is the only terrestrial biogeographic unit that is distributed globally. Studying phylogenetics of the plant species in this widespread ecosystem can provide insights into the historical biogeographic processes that have shaped the global biodiversity. The trans-Pacific disjunct alpine genus Oreomyrrhis (Apiaceae) was investigated using nrDNA ITS sequences to test the taxonomic and biogeographic hypotheses. Phylogenetic analyses using maximum parsimony, maximum likelihood, and Bayesian inference revealed that species of Oreomyrrhis form a weakly supported monophyletic clade that is nested within Chaerophyllum sect. Chaerophyllum (subtribe Scandicinae, tribe Scandiceae). The optimal solutions of dispersal-vicariance analysis indicate that the ancestor of Chaerophyllum sect. Chaerophyllum (including Oreomyrrhis) was distributed in Eurasia and subsequently dispersed to North America and southern Pacific Rim. Based on dating using ITS sequence variation, these dispersal events were most likely recent, probably during late Tertiary to Quaternary. The structure of the ITS haplotype network suggests that a rapid range expansion via long-distance dispersal had been crucial in generating the trans-Pacific disjunction of Oreomyrrhis. Furthermore, evolution toward smaller mericarp size and a transition from outcrossing to selfing during Oreomyrrhis's evolution might have increased the chances for long-distance dispersal, facilitating its range expansion and occupation on alpine environments.

The ‘landscape scale’ in planning: Recent experience of bio-geographic planning units in Britain

Landscape-scale mapping is becoming more widely used as an approach to identifying ‘characteristic’ units of countryside for information gathering and policy delivery purposes. A number of innovative approaches currently being developed and applied in Britain are reviewed. The justifications for producing these methods, as reflected in published sources, are analysed. Interviews with selected professionals, who identify various benefits for more effective policy delivery, integrated planning, partnership formation and public engagement, are reported on. Most of the approaches also override administrative boundaries, which enables a more naturalistic reflection of environmental systems, whilst also creating some political difficulties. Other problems are associated with cost and subjectivity. Overall, the methods are likely to improve joined-up rural decision making, but further research into their effectiveness is needed.

Zoogeography of the shallow‐water holothuroids of the western Indian Ocean

AbstractAim To analyse the zoogeography of the shallow‐water holothuroids of the western Indian Ocean (WIO). Based on this analysis we ask to what extent differences in species’ ability to disperse across potential barriers provide an explanation for holothuroid zoogeography.Location Shallow‐waters (50 m isobaths) of the WIO, extending from Suez to Cape Town and from the coastline of East Africa upward to 65° E.Methods Data for the analysis were obtained from Samyn's (2003) monograph on the shallow‐water sea cucumbers of the WIO. A species presence/absence matrix with a resolution of 1° latitude/longitude was constructed. These cells were assigned to eight coarser operational geographical units, which were delimited on the basis of published faunistic and geological borders. The analytical zoogeographical methods employed were cluster analysis on several β‐diversity coefficients and parsimony analyses of endemicity. The influence of life‐history strategies on the distribution pattern was analysed through examination of latitudinal and longitudinal gradients, and by plotting cumulative curves for species number against range size.Results The shallow‐water holothuroid fauna of the WIO can be split into several biogeographical units. To the north, we found evidence that the northern Red Sea holothuroid fauna differs from that of the southern Red Sea. The latter has closest affinity with south‐east Arabia and the Persian Gulf, and thus the biogeographical barrier of Bab‐el‐Mandab nowadays seems to be of minor importance. The cold upwelling at the east coast of Somalia forms an effective barrier for holothuroids and especially those with lecitothrophic (short‐lived) larvae. Even though the circumtropical biogeographical pattern is not well resolved, important taxonomic turnovers suggest that it is composed of several distinct subprovinces. Taxonomic turnover is at least partially dictated by the dispersion capacity of the different orders.Main conclusions This study concludes that the WIO is best split into at least three biogeographical realms: (1) the Red Sea and associated Arab Basin, (2) the asymmetrical circumtropical region stretching from the horn of Africa to southern Mozambique, and (3) southern Africa. Conspicuous differences in dispersal abilities of the three dominant orders are identified. The biogeography of the WIO is best explained by: (1) species’ dispersion ability, (2) the prevalent current patterns, and (3) to a lesser, geographically limited extent, recent geological history. As a serendipitous discovery, we found that Rapoport's rule does not hold in the WIO.

Biogeographical patterns and Rapoport's rule in southeastern Pacific benthic polychaetes of the Chilean coast

Recently three biogeographical units were identified along the Chilean coast (the Magellanic Province, an Intermediate Area, and the Peruvian Province), however few studies have focused on the factors and dynamic processes that formed these spatial units (e.g. Rapoport's rule and its causal mechanisms). In this study we used benthic polychaetes of the Chilean coast to evaluate patterns of latitudinal distribution and species richness, and the existence of the three main biogeographical provinces described for the Chilean coast. Additionally, we evaluated the latitudinal Rapoport effects and geometric constraint as a null hypothesis explaining the species richness distribution. We found that benthic polychaete diversity increased towards southern latitudes. The cluster and ordination (non‐metric MultiDimensional Scaling, nMDS) analyses of the distribution data, presented only two statistically significant (bootstrapping techniques) biogeographic provinces along the Chilean coast, with a break occurring between 41° and 42°S. While, our results did not support a latitudinal Rapoport effect, they did support the view that latitudinal Rapoport effects are a local phenomenon, occurring only for the Northeastern Pacific marine taxa. The relationship between latitudinal range extent and mean latitude indicated the existence of two hard boundaries at either extreme of the Chilean coast, limiting the geographical ranges of the species. However, geometric constraints tested using a Monte Carlo simulation approach showed a weak level of mid‐domain effect on species richness. Finally, we propose that geometric constraint together with the geomorphology and historical characteristics of the Chilean coast explain the biogeographical patterns of benthic polychaete taxa in Chile.

EXCEPTIONAL TARDIGRADE-DOMINATED ECOSYSTEMS IN ELLSWORTH LAND, ANTARCTICA

We describe a terrestrial faunal community including only Tardigrada and Rotifera, present on inland nunataks of Ellsworth Land, Antarctica (∼75°–77° S, 70°–73° W). The fauna is exceptional in its simplicity, including five tardigrade species (three new to science) and at least two rotifer species, which comprise two consumer trophic levels. Nematode worms, the most important element of the simplest faunal communities previously reported worldwide (from the Ross Sea Dry Valley region of continental Antarctica), and microarthropods, otherwise represented in all known Antarctic terrestrial communities, are absent. The tardigrade community composition shows affinity with the continental Antarctic fauna, with which it shares three species. The remaining two species are unique to Ellsworth Land and may suggest a prolonged existence as a distinct biogeographical unit.

Distributional patterns of the neotropical fly genus Polietina Schnabl & Dziedzicki (Diptera, Muscidae): a phylogeny-supported analysis using panbiogeographic tools

Over the last decades, Neotropical region has been subdivided into smaller units (areas of endemism), yet these subdivisions were not necessarily based on an evolutionary perspective. Consequently, these areas of endemism may be biogeographic units that do not actually represent natural historical units. Here, the distributional patterns of the genus Polietina Schnabl & Dziedzicki, 1911 (Diptera, Muscidae; including 15 species) are analysed by applying panbiogeographic tools to recognise and propose primary homologous areas within the Neotropical region. The analysis and discussion of the results obtained here will be reconciled to the information provided by the phylogenetic hypothesis available for the genus.