Biotic Regions Research Articles

Amphibians and reptiles in North Sweden: distribution, habitat affinities, and abundance (Classes: Amphibia and Reptilia).

North Sweden ('Norrland' in Swedish) covers 243000 km2 and lies mainly in the boreal biome. The herpetofauna comprises five amphibian and four reptile species: Lissotriton vulgaris, Triturus cristatus, Bufo bufo, Rana temporaria, Rana arvalis, Zootoca vivipara, Anguis fragilis, Natrix natrix, and Vipera berus. Successful conservation and management of amphibians and reptiles depend on accurate information about distribution, habitat affinities, and abundance. Such knowledge is also essential as a benchmark to assess changes in distribution and abundance that may come about as a result of climate change and human habitat alteration. This paper aims to present accurate distribution maps, describe habitat affinities, and provide abundance estimates for the herpetofauna of North Sweden for the period 1970-2022. Distribution data are presented by traditional faunistic provinces, as well as by biotic regions and alpine life zones. Separate sections address post-glacial colonization and a herpetological perspective on anthropogenic changes in relation to species´ present status. Bufo bufo, Rana temporaria, Rana arvalis, Zootoca vivipara, and Vipera berus are widely distributed throughout the boreal sub-regions. Rana temporaria, Zootoca vivipara, and Vipera berus also extend into the alpine region. Triturus cristatus, Anguis fragilis, and Natrix natrix occur mainly in the coastal parts of the Southern Boreal region. There are no signs of recent changes in distribution range, but Lissotriton vulgaris, Triturus cristatus, and Rana arvalis have been largely overlooked in the past and have a much wider occurrence than previously recognized. Most species are found in habitats usually not described in all-European field guides. Nearly all anurans hibernate in water. Abundance estimates suggest that some species are more common in the boreal than thought, supporting the notion that a large share of their total European population occurs there. Although local extinctions and declines are known, there are no signs of widespread population decline for any species during the study period.

A New Genus for Euschoengastia chisosensis Wrenn, Baccus, and Loomis, 1976 (Trombidiformes: Trombiculidae)

The trombiculid genus Euschoengastia Ewing, 1938 is currently comprised of species from all biotic regions giving the genus a worldwide distribution. In North America, there are 60 described species. One species, Euschoengastia chisosensis Wrenn, Baccus, and Loomis, was collected parasitizing cricetid rodents in Texas, USA. In the present study, a new genus is proposed for this species, Jumanoacarus Bassini-Silva, Jacinavicius, and Welbourn.

An analytically derived delineation of the West African Coastal Province based on bivalves

AbstractAimTo assess the pattern of biotic regions (BR) and their boundaries, to detect chorotypes and to relate these patterns to key environmental factors.LocationEastern Atlantic Ocean.Time periodRecent.Taxon studiedBivalvia.MethodsDistributions were scored for 595 species. Operational geographical units are classified hierarchically using Baroni‐Urbani & Buser similarity index, clusters were assessed for statistical significance with the ‘RMacoqui 1.0’ software using G tests of independence, and chorotypes were inferred likewise from similarity between species distributions.ResultsThree strong biotic boundaries delimit four BR: (1) European Atlantic and Mediterranean; (2) West African, from western Sahara to southern Angola; (3) Baia dos Tigres/Namibia; and (4) Saint Helena/Ascension. The West African BR is subdivided by two weak boundaries into three subordinate BR: the tropical region proper, the north‐western African transition zone and the cluster (southern Angola/São Tomé/Cape Verde Islands). Of the 429 species present in West Africa, 261 (60.7%) are endemic, and 19 genera (7.2%) are endemic. Sixteen chorotypes were identified; the European BR is correlated with chorotypes C5 (149 species mostly European and Mediterranean) and C3 (38 species mostly in northern Europe), whereas the West African BR is mainly characterized by chorotype C6 (221 species). Some discontinuous distribution patterns of tropical West African species were identified as chorotypes, but subordinate to chorotype C6. The West African BR is mainly characterized by sea surface temperature and chlorophyll; characterization without the islands also involved the extensive sandy coast. The north‐western African transition region is characterized by an arid climate and few rivers and influenced by seasonal upwelling. The cluster of southern Angola, Sao Tomé and Cape Verdes contrasts with the remainder of West Africa in having a predominantly rocky shore.Main conclusionsThe present analyses provide an objective regionalization based on species occurrences, which supports the traditional recognition of West Africa as a major biotic region with a high level of endemism. Attention is called on that the unique endemic component is insufficiently represented in current marine protected areas.

Floristic composition in ecotone forests in northern Brazilian Amazonia: preliminary data.

BackgroundEcotone has been defined as “a multi-dimensional environmentally stochastic interaction zone between ecological systems with characteristics defined in space and time, and by the strength of the interaction” (Hufkens et al. 2009). This is a known concept to define transitional zones between two or more ecological communities, ecosystems or biotic regions. Ecotone forests, dispersed in northern Brazilian Amazonia, are natural formations which have been largely affected by anthropogenic impacts, such as deforestation and fire. Maracá Ecological Station, State of Roraima, Brazil, is a protected area with extensive representations of ecotone forests in this region of the Amazonia. Forest inventories and floristic surveys are important as they extend our knowledge (1) of forest structure and tree species composition and (2) of tree and palm species ecology in this region of the Amazonia. Both improve our ability to predict changes in plant diversity, considering the future scenarios of climate change in comparison with previous surveys performed in Maracá.New informationWe present a forest inventory carried out in 129 plots (10 m x 50 m; 6.45 ha in total) dispersed in a grid (5 km x 5 km) located in a forest zone ecotone in the eastern part of Maracá Ecological Station. All stems (tree + palm) with diameter at breast height ≥ 10 cm were recorded, identified and measured. A total of 3040 stems were recorded (tree = 2815; palm = 225), corresponding to 42 botanic families and 140 identified species. Seven families and 20 genera contained unidentified taxa (12.2%). Sapotaceae (735 stems; 10 species), Leguminosae (409; 24) and Rubiaceae (289; 12) were the most abundant families. Peltogyne gracilipes Ducke (Leguminosae), Pradosia surinamensis (Eyma) T.D.Penn. (Sapotaceae) and Ecclinusa guianensis Eyma (Sapotaceae) were the species with the highest importance value index (~ 25%). The dominance (m2 ha-1) of these species corresponds to > 36% of the total value observed in the forest inventory. Our dataset provides complementary floristic and structure information on tree and palm in Maracá, improving our knowledge of this Amazonian ecotone forest.

Fish assemblage convergence along stream environmental gradients: an intercontinental analysis

Species that pass through similar environmental filters, regardless of geographic proximity or evolutionary history, are expected to share many traits, resulting in similar assemblage trait distributions. Convergence of assemblage trait distributions among different biotic regions would indicate that consistent ecological processes produce repeated patterns of adaptive evolution. This study analyzes trait–environment relationships across multiple stream fish assemblages representing evolutionarily divergent faunas. We hypothesized that trait–environment patterns converge across regional faunas in response to a common set of environmental filters acting on functional traits. One hundred and ninety‐seven species and forty streams were sampled from five regions: Belize, Benin, Brazil, Cambodia and USA. By examining trait–environment plots, multiple congruent trait–environment patterns were found across all regions, indicative of a consistent set of environmental filters acting on local community assembly. The consistency of these patterns strongly suggests that water velocity and habitat structural complexity function as universal environmental filters, producing similar assemblage trait distributions in streams across all regions. Bivariate relationships were not universal, and only one of the associations between a single functional trait and single environmental variable was statistically significant across all five regions. Strong phylogenetic signal was found in traits and habitat use, which implies that niche conservatism also influenced assemblage trait distributions. Overall, results support the idea that habitat templates structure trait distributions of stream fish assemblages and do so in a consistent manner.

Do phytogeographic patterns reveal biomes or biotic regions?

We present the largest comparative biogeographical analysis that has complete coverage of Australia's geography (20 phytogeographical subregions), using the most complete published molecular phylogenies to date of large Australian plant clades (Acacia, Banksia and the eucalypts). Two distinct sets of areas within the Australian flora were recovered, using distributional data from the Australasian Virtual Herbarium (AVH) and the Atlas of Living Australia (ALA): younger Temperate, Eremaean and Monsoonal biomes, and older southwest+west, southeast and northern historical biogeographical regions. The analyses showed that by partitioning the data into two sets, using either a Majority or a Frequency method to select taxon distributions, two equally valid results were found. The dataset that used a Frequency method discovered general area cladograms that resolved patterns of the Australian biomes, whereas if widespread taxa (Majority method, with >50% of occurrences outside a single subregion) were removed the analysis then recovered historical biogeographical regions. The study highlights the need for caution when processing taxon distributions prior to analysis as, in the case of the history of Australian phytogeography, the validity of both biomes and historical areas have been called into question.

Conceptual and empirical advances in Neotropical biodiversity research.

The unparalleled biodiversity found in the American tropics (the Neotropics) has attracted the attention of naturalists for centuries. Despite major advances in recent years in our understanding of the origin and diversification of many Neotropical taxa and biotic regions, many questions remain to be answered. Additional biological and geological data are still needed, as well as methodological advances that are capable of bridging these research fields. In this review, aimed primarily at advanced students and early-career scientists, we introduce the concept of “trans-disciplinary biogeography,” which refers to the integration of data from multiple areas of research in biology (e.g., community ecology, phylogeography, systematics, historical biogeography) and Earth and the physical sciences (e.g., geology, climatology, palaeontology), as a means to reconstruct the giant puzzle of Neotropical biodiversity and evolution in space and time. We caution against extrapolating results derived from the study of one or a few taxa to convey general scenarios of Neotropical evolution and landscape formation. We urge more coordination and integration of data and ideas among disciplines, transcending their traditional boundaries, as a basis for advancing tomorrow’s ground-breaking research. Our review highlights the great opportunities for studying the Neotropical biota to understand the evolution of life.

Long-term changes in composition and distribution patterns in the Iberian herpetofaunal communities since the latest Pleistocene

The climate has undergone significant changes since the end of the Last Glacial Maximum and in the course of the Holocene, parallel to important cultural transformations and migrations in the human communities. The faunal record has also suffered the effects of climate change. Amphibians and reptiles in particular have been shown to be highly sensitive because they are very susceptible to temperature alterations due to their ectothermy. This research presents the first approach to the Iberian paleobiogeography of the different species of amphibians and reptiles from the Late Pleistocene (MIS3) to present times, based on a comparative synthesis of the latest research published in recent years and the fossil record of the 58 archaeo-paleontological sites with significant assemblages. The paleoherpetofaunal associations make it possible to establish two major biotic regions during the Late Pleistocene. The first biotic region was located in the center and south of the Iberian Peninsula, with thermophilic species as the most representative taxa. The second biotic region was formed by the Atlantic-Cantabrian facade and the northeast Iberian area, dominated by hygrophilous and Euro-Siberian species, with an absence of Mediterranean species. After the Last Glacial Maximum there was an unprecedented concurrence in the northern Iberian Peninsula of autochthonous taxa from that area with thermophilic species. In the early Holocene, new species with no previous record in the Iberian Peninsula entered northern Iberia from eastern Mediterranean refugia. Finally, the introduction of North African species was the last significant biogeographical change during the Middle-Late Holocene.

PLANT DIVERSITY AND ENDEMISM IN THE CALIFORNIA FLORISTIC PROVINCE

Abstract The California Floristic Province (CFP) is an area of high biodiversity and endemism corresponding roughly to the portion of western North America having a Mediterranean-type climate. High levels of diversity and endemism in the CFP are attributed to the unique geo-climatic setting of the region. In recent years, much has been learned about the origins of plant diversity in western North America. This work, however, has been hindered by a focus on political rather than biotic regions, such that much more is known about diversity and endemism in the state of California than the natural biotic region represented by the CFP. Here we present a preliminary list of native land plants (vascular plants and bryophytes) found in the CFP, as well as an analysis of diversity and endemism patterns at the level of both species and minimum rank taxa (MRT; species and infraspecific taxa). A total of 6,927 MRT are native to the CFP, including 6,143 vascular plants and 784 bryophytes. Of these, 2,612 vascular plan...

Dispatches

Dispatches

The imbalance of nature: revisiting a Darwinian framework for invasion biology

AbstractAimA major implication of natural selection is that species from different parts of the world will vary in their efficiency in converting resources into offspring for a given type of environment. This insight, articulated by Darwin, is usually overlooked in more recent studies of invasion biology that are often based on the more modern Eltonian perspective of imbalanced ecosystems. We formulate a renewed Darwinian framework for invasion biology, the evolutionary imbalance hypothesis (EIH), based only on the action of natural selection in historically isolated populations operating within a global network of repeated environments. This framework predicts that successful invaders are more likely to come from biotic regions of high genetic potential (with independent lineages of large population size), experiencing a given environment for many generations and under strong competition from other lineages.LocationGlobal.MethodsWe test the predictive power of this framework by examining disparities in recent species exchanges between global biotic regions, including patterns of plant invasions across temperate regions and exchanges of aquatic fauna as a result of modern canal building.ResultsOur framework successfully predicts global invasion patterns using phylogenetic diversity of the world's biotic regions as a proxy that reflects their genetic potential, historical stability and competitive intensity, in line with the Darwinian expectation. Floristic regions of higher phylogenetic diversity are more likely to be source areas of invasive plants, and regions of lower phylogenetic diversity are more likely to be invaded. Similar patterns are evident for formerly isolated marine or freshwater assemblages that have been connected via canals.Main conclusionsWe advocate an approach to understanding modern species invasions that recognizes the potential significance of both the original Darwinian explanation and the more modern view that emphasizes novel ecological or evolutionary mechanisms arising in the introduced range. Moreover, if biological invasions are a natural outcome of Darwinian evolution in an increasingly connected world, then invasive species should continue to displace native species and drive widespread shifts in the functioning of ecosystems.

Common distribution patterns of marsupials related to physiographical diversity in Venezuela.

The aim of this study is to identify significant biotic regions (groups of areas with similar biotas) and biotic elements (groups of taxa with similar distributions) for the marsupial fauna in a part of northern South America using physiographical areas as Operational Geographical Units (OGUs). We considered Venezuela a good model to elucidate this issue because of its high diversity in landscapes and the relatively vast amount of information available on the geographical distribution of marsupial species. Based on the presence-absence of 33 species in 15 physiographical sub-regions (OGUs) we identified Operational Biogeographical Units (OBUs) and chorotypes using a quantitative analysis that tested statistical significance of the resulting groups. Altitudinal and/or climatic trends in the OBUs and chorotypes were studied using a redundancy analysis. The classification method revealed four OBUs. Strong biotic boundaries separated: i) the xerophytic zone of the Continental coast (OBU I); ii) the sub-regions north of the Orinoco River (OBU III and IV); and those south to the river (OBU II). Eleven chorotypes were identified, four of which included a single species with a restricted geographic distribution. As for the other chorotypes, three main common distribution patterns have been inferred: i) species from the Llanos and/or distributed south of the Orinoco River; ii) species exclusively from the Andes; and iii) species that either occur exclusively north of the Orinoco River or that show a wide distribution throughout Venezuela. Mean altitude, evapotranspiration and precipitation of the driest month, and temperature range allowed us to characterize environmentally most of the OBUs and chorotypes obtained.

Between warm and cold: Impact of the Younger Dryas on human behavior in Central Europe

Following a thorough review of high-resolution environmental archives, this paper aims at discriminating the factors determining the heterogeneous repercussion of the Lateglacial Younger Dryas in Central Europe. When examining the archaeological implications of human adaptation to the subsequent changes in the natural environment two divergent biotic regions are of special interest: the North European Plain and adjacent areas; and the Alpine foothills and surrounding mountain ranges. In these regions, two different archaeological technocomplexes (traditions) are found: the Tanged Point Complex and the Curve-Backed Point Groups. Considering the distribution of the archaeological sites witnessing changes in the material culture and subsistence pattern, the intensity of the environmental changes caused by the Younger Dryas is a decisive element. Settlement discontinuity during the Younger Dryas is questioned. Moreover, the potential existence of established social networks between the two regions expressed by comparable developments such as microlithization is considered. Finally, the authors assess whether the Younger Dryas acted as an accelerator or a brake in the process of regional diversification prior to the Early Mesolithic.

Diverse bacteria inhabit living hyphae of phylogenetically diverse fungal endophytes.

Both the establishment and outcomes of plant-fungus symbioses can be influenced by abiotic factors, the interplay of fungal and plant genotypes, and additional microbes associated with fungal mycelia. Recently bacterial endosymbionts were documented in soilborne Glomeromycota and Mucoromycotina and in at least one species each of mycorrhizal Basidiomycota and Ascomycota. Here we show for the first time that phylogenetically diverse endohyphal bacteria occur in living hyphae of diverse foliar endophytes, including representatives of four classes of Ascomycota. We examined 414 isolates of endophytic fungi, isolated from photosynthetic tissues of six species of cupressaceous trees in five biogeographic provinces, for endohyphal bacteria using microscopy and molecular techniques. Viable bacteria were observed within living hyphae of endophytic Pezizomycetes, Dothideomycetes, Eurotiomycetes, and Sordariomycetes from all tree species and biotic regions surveyed. A focus on 29 fungus/bacterium associations revealed that bacterial and fungal phylogenies were incongruent with each other and with taxonomic relationships of host plants. Overall, eight families and 15 distinct genotypes of endohyphal bacteria were recovered; most were members of the Proteobacteria, but a small number of Bacillaceae also were found, including one that appears to occur as an endophyte of plants. Frequent loss of bacteria following subculturing suggests a facultative association. Our study recovered distinct lineages of endohyphal bacteria relative to previous studies, is the first to document their occurrence in foliar endophytes representing four of the most species-rich classes of fungi, and highlights for the first time their diversity and phylogenetic relationships with regard both to the endophytes they inhabit and the plants in which these endophyte-bacterium symbiota occur.

Multi‐scale determinants of dung beetle assemblage structure across abiotic gradients of the Kalahari–Nama Karoo ecotone, South Africa

AbstractAim Changing conditions across spatial gradients are primary determinants of biotic regions, local habitats, and distributional edges. We investigate how a climatic gradient and edaphic mosaic interact as multi‐scale drivers of spatial patterns in scarabaeine dung beetles. The patterns are tested for congruency with ecoregion and floral boundaries over the same gradient, as responses to physical factors often differ among higher taxa.Location Southern Africa and the Nama Karoo–Kalahari ecotone, Northern Cape, South Africa.Methods Data consisted of the climatic distributions of 104 species and their abundances at 223 sites in two ecoregions/floral biomes, four bioregions, and 13 vegetation units. Factor analyses determined the biogeographical composition of the species, and regional‐ to local‐scale patterns in species abundance structure. Hierarchical analysis of oblique factors determined the proportional contribution of spatial variance to patterns. One‐wayanovawas used to test for significant separation of patterns along factor axes. Stepwise multiple regression was used to determine correlations of five physical attributes with species richness, Shannon‐Wiener diversity, and factor loadings for the study sites.Results Four biogeographical influences overlap in the study region, although rank contribution declines from south‐west arid through north‐east savanna to widespread and south‐east highland taxa. Species abundance structure comprises five subregional patterns, two centred to the north‐east (Kalahari, Isolated Kalahari Dune) dominated by Kalahari influence, and three to the south‐west (Nama Karoo subdivisions: Bushmanland, ‘Upper’, ‘Stony Prieska’) dominated by south‐west arid influence. Kalahari deep sands are characterized especially by a warmer, moister climate, whereas the Nama Karoo mosaic of deep or stony soils is characterized especially by north‐west aridity (Bushmanland), south‐east cooler temperatures (‘Upper’), or excessively stony soils (‘Stony Prieska’). Four of the subregional patterns each comprised three localized patterns related primarily to relative stoniness, edge effects from geographical position, or incidence of rainfall. Species richness and diversity declined with decreasing rainfall and increasing stoniness.Main conclusions Climatic and edaphic factors are important multi‐scale determinants of spatial patterns in dung beetle assemblage structure, with edaphic factors becoming more important at local spatial scales. The patterns are roughly congruent with the Kalahari Savanna–Nama Karoo ecotone at the floral biome or ecoregion scale, but show limited coincidence with finer‐scale floral classification.

Biogeographical patterns of Chinese spiders (Arachnida: Araneae) based on a parsimony analysis of endemicity

AbstractAim The distributions of Chinese spiders are used to form biotic regions and to infer biogeographical patterns.Location China.Methods China was initially divided into 294 quadrats of 2° latitude by 2° longitude. The distributions of 958 species of spiders were summarized for each quadrat. Subsequently, these quadrats were pooled into 28 areas based on topographical characteristics and to a lesser extent on the distributions of spiders. Parsimony analysis of endemicity (PAE) was used to classify the 28 areas based on the shared distributional patterns of spiders.Results China was found to have seven major biogeographical regions based on the distributional patterns of spiders: Western Northern region (clade B2: Tibetan Plateau and Inner Mongolia‐Xinjiang subregions), Central Northern region (clade B3), Eastern Northern region (clade B4), Central region (clade C2), Eastern Southern region (clade C3), Western Southern region (clade C4), and Central Southern region (clade C5).Main conclusions The distributional patterns of Chinese spiders correspond broadly to geological provinces. A comparison of the geological provinces and the distributional patterns of spiders reveals that the spiders occur south of the geological provinces. Furthermore, a general biogeographical classification with five natural areas is suggested as follows: Tibetan Plateau, Central Northern, Eastern Northern, Western Northern (excluding Tibetan Plateau), and Southern regions.

Phylogenetic relationships and historical biogeography of tribes and genera in the subfamily Nymphalinae (Lepidoptera: Nymphalidae)

We infer for the first time the phylogenetic relationships of genera and tribes in the ecologically and evolutionarily well-studied subfamily Nymphalinae using DNA sequence data from three genes: 1450 bp of cytochrome oxidase subunit I (COI) (in the mitochondrial genome), 1077 bp of elongation factor 1-alpha (EF1-α) and 400–403 bp of wingless (both in the nuclear genome). We explore the influence of each gene region on the support given to each node of the most parsimonious tree derived from a combined analysis of all three genes using Partitioned Bremer Support. We also explore the influence of assuming equal weights for all characters in the combined analysis by investigating the stability of clades to different transition/transversion weighting schemes. We find many strongly supported and stable clades in the Nymphalinae. We are also able to identify ‘rogue’ taxa whose positions are weakly supported (the different gene regions are in conflict with each other) and unstable. Our main conclusions are: (1) the tribe Coeini as currently constituted is untenable, and Smyrna, Colobura and Tigridia are part of Nymphalini; (2) ‘Kallimini’ is paraphyletic with regard to Melitaeini and should be split into three tribes: Kallimini s.s., Junoniini and Victorinini; (3) Junoniini, Victorinini, Melitaeini and the newly circumscribed Nymphalini are strongly supported monophyletic groups, and (4) Precis and Junonia are not synonymous or even sister groups. The species Junonia coenia, a model system in developmental biology, clearly belongs in the genus Junonia. A dispersal-vicariance analysis suggests that dispersal has had a major effect on the distributions of extant species, and three biotic regions are identified as being centres of diversification of three major clades: the Palaearctic for the Nymphalis-group, the Afrotropics for Junoniini and the Nearctic for Melitaeini.

Spatial analysis of taxonomic and genetic patterns and their potential for understanding evolutionary histories

AbstractAim The aim of this research is to develop and investigate methods for the spatial analysis of diversity based on genetic and taxonomic units of difference. We use monophyletic groups of species to assess the potential for these diversity indices to elucidate the geographical components of macro‐scaled evolutionary processes.Location The range occupied byPultenaeaspecies in temperate and sub‐tropical eastern Australia, extending from western South Australia (133° E–32° S) to Tasmania (146° E–43° S) to coastal central Queensland (148° E–20° S).Methods We applied a series of both spatially explicit and spatially implicit analyses to explore the nature of diversity patterns in the genusPultenaea, Fabaceae. We first analysed the eastern species as a whole and then the phylogenetic groups within them. We delineated patterns of endemism and biotic (taxon) regions that have been traditionally circumscribed in biogeographical studies of taxa. Centres of endemism were calculated using corrected weighted endemism at a range of spatial scales. Biotic regions were defined by comparing the similarity of species assemblages of grid cells using the Jaccard index and clustering similar cells using hierarchical clustering. On the basis that genetically coherent areas were likely to be more evolutionary informative than species patterns, genetic indices of similarity and difference were derived. A matrix of similarity distances between taxa was generated based on the number of shared informative characters of two sections oftrnL‐FandndhFchloroplast nuclear regions. To identify genetically similar areas, we clustered cells using the mean genetic similarities of the species contained within each pair of cells. Measures of the mean genetic similarity of species in areas were delineated using a geographically local multi‐scalar approach. Resultant patterns of genetic diversity are interpreted in relation to theories of the evolutionary relationships between species and species groups.Results Centres ofPultenaeaendemism were defined, those of clades 1 congruent with the spatially separated centres of clades 2 and 3. The taxonomic classification analysis defined cells with shared groups of species, which in some cases clustered when plotted in geographic space, defining biotic regions. In some instances the distribution of biotic regions was congruent with centres of endemism, however larger scale groupings were also apparent. In clade 1 one set of species was replaced by another along the extent of the range, with some connectivity between some geographically disjunct regions due to the presence of widespread species. In the combined analysis of clade 2 and 3 species the major biotic (taxonomic) groups with geographic coherence were defined by species in the respective clades, representing the geographic separation of these clades. However distinctive biotic regions within these main groupings of clades 2 and 3 were also apparent. Clustering cells using the mean genetic similarities of the species contained within each pair of cells indicated that some of the taxonomically defined biotic boundaries were the result of changes in composition of closely related species. This was most apparent in clades 1 and 2 where most cells were highly genetically similar. In clade 3 genetically distinct groups remained and were in part defined by sister taxa with disjunct distributions. Gradients in mean genetic similarity became more apparent from small to larger scales of analysis. At larger scales of analysis, regions of different levels of genetic diversity were delineated. Regions with highest diversity levels (lowest level of similarity) often represented regions where the ranges of phylogenetically distinctive species intergraded.Main conclusions The combined analysis of diversity, phylogeny and geography has potential to reveal macro‐scaled evolutionary patterns from which evolutionary processes may be inferred. The spatial genetic diversity indices developed in this study contribute new methods for identifying coherent evolutionary units in the landscape, which overcome some of the limitations of using taxonomic data, and from which the role of geography in evolutionary processes can be tested. We also conclude that a multiple‐index approach to diversity pattern analysis is useful, especially where patterns may be the result of a long history of different environmental changes and related evolutionary events. The analysis contributes to the knowledge of large‐scale diversity patterns ofPultenaeawhich has relevance for the assessment of the conservation status of the genus.

A biogeographical analysis of the genera Audouinella (Rhodophyta), Cystoseira (Phaeophyceae) and Cladophora (Chlorophyta) in the western Mediterranean Sea and Adriatic Sea

We carried out a biogeographical analysis of the genera Audouinella (Rhodophyta), Cystoseira (Phaeophyceae) and Cladophora (Chlorophyta), as well as the species in the three genera pooled together, in the western Mediterranean Sea and Adriatic Sea. For this purpose, the continental shelves close to 13 hydrographical watersheds were used as operational geographical units. The analysis was performed in accordance with a hypothetical–deductive approach. Four weak boundaries and five biotic regions were obtained for Audouinella; one strong and two weak boundaries, separating four biotic regions, were found for Cystoseira; two weak boundaries delimiting three biotic regions were obtained for Cladophora. The species of the three genera pooled together allowed us to separate three biotic regions delimited by two weak boundaries. The environmental factors that can explain the presence of the boundaries between biotic regions were run-off, distance of a given region from the Strait of Gibraltar following the course of the main current of the Mediterranean Sea, current flow, and salinity. The characterization of each biotic region and the relationships with the environmental factors that could explain the biotic boundaries are discussed.

Testing for inter-drainage connections on the basis of the distribution pattern of endemic freshwater fishes

We classified the secondary rivers of the Duero and Tagus drainages on the basis of the presence or absence of native freshwater fishes in order to analyse hypothetical interconnections between them and to survey intra-drainage biogeographical complexity. Except for a few rivers with low diversity, the tributaries were classified into two main biogeographical areas (Duero and Tagus basins), which were subdivided into different biotic regions delimited by significant boundaries. In the Duero basin, in particular, three regions were identified. One corresponds to a large and homogeneous group of tributaries, containing species not shared with the Tagus basin. Two other small regions, at the south-western border of the Duero basin, were characterized by the presence of a local endemic species and by a fauna related to that of the Tagus basin. Similarly, three biotic regions were found in the Tagus basin. The middle-upper basin plus the Alagon River was defined by the presence of S. trutta and Ch. arcasii. The other two regions, located in the lower basin, were both characterized by the presence of Ch. lemmingii; but were differentiated on the basis of the distribution patterns of their lentic species. The internal biogeographical complexity detected in the Duero and Tagus drainages showed both geographical and historical components. Our data support the existence of interconnections between the basins during the Cenozoic period, and we postulate the existence of an ancient endorheic basin connecting the south-western part of the Duero and the north-west of the Tagus basin, as a historical explanation for translocation of fauna.