Biogeographic Classification Research Articles

Biogeographical synthesis of Andalusia (southern Spain)

Andalusia is a large territory of almost 90,000 km 2 in the south of Spain. The marked heterogeneity of its orographic, lithological and climatic features affords its plants and vegetation a high degree of biodiversity. A biogeographical classification for Andalusia is proposed, based on studies of the physical environment, bioclimatic and analysis of the endemic taxa, series and plant communities found in the territory.

Phytogeographical relationships among high mountain areas in the Baetic Ranges (South Spain)

ABSTRACTThe Mediterranean area is regarded nowadays as one of the hot‐spots of world biodiversity. The Baetic ranges in Spain have such a large number of endemic plant taxa that the territory has been recognized as a well‐defined biogeographical unit. These endemic taxa tend to concentrate on disjunct highland areas that have been described consequently as ‘highland islands’. Despite the importance and complexity of these sites, the research carried out so far has produced only descriptive classifications. These approaches overlook the relationships between the sites and do not serve to identify the main centres of endemism. Herein, multivariate analysis techniques (cluster analysis and reciprocal averaging) and the parsimony analysis of endemicity (PAE), applied to the 222 orophilous endemic taxa of the Baetic ranges, have been used to reveal the floristic similarities between the areas involved, to identify the centres of endemism and to re‐assess the previous classifications. Four centres of endemism are defined, one siliceous and three calcareous. The most outstanding feature in the Baetic ranges is precisely the floristic difference between siliceous and calcareous mountains. Calcareous territories extend along a SW–NE axis in line with the oceanic–continental gradient. The nature of the soil in the vast siliceous and calcareous–dolomitic territories of the Sierra Nevada is probably the cause of the remarkable floristic diversity. Not surprisingly, in our analysis these areas stand out as centres of endemism. We conclude that previous biogeographical classifications of the ranges are too rigid and do not properly reflect the floristic similarities of the area under study.

A comparison of different biogeographical classifications of Europe, Great Britain and Spain

Various biogeographical and bioclimatic classifications of a number of regions, countries and continents have been created to meet diferent objectives. A policy maker might ask the question ‘why is there no single accepted classification and how do the different classifications compare with one another?’ In order to answer these two questions three classifications created by different methods for Great Britain and two for Spain are compared using the Kappa statistic. All of the classifications were created from data on cellular grids with a set window size. Further non-statistical comparisons are made with other classifications. The biogeographic classifications studied in this paper produced three different types of zone: those that were always identified whatever the method; those that were broadly similar but where the boundaries differed; and those that were unique to a particular classification. These different types of zone are likely to exist for any comparison between classifications of a particular region. The extent of the geographic window from which data were obtained had a major effect on the classification of grid cells at the edges of the window. For example, the few grid cells in the south of England, with characteristics of continental Europe, are not detected if data from Great Britain alone are used for the classification. We conclude that the data window should always be larger than the area for which the classification is being made. The objective Kappa statistic, although useful, was not capable of discerning similarities and dissimilarities that appear obvious to the subjective human eye. Although the details of the classifications differed there were broad similarities between the classifications and these differences reflect important divisions along major environmental axes that have been inferred by earlier biogeographers. As the divisions are real there is a sound basis for their use in future land use or environmental policy.

Marine faunal realms of the Mesozoic: review and revision under the new guidelines for biogeographic classification and nomenclature

Consensus among the Friends of Paleobiogeography produced tentative guidelines to the classification and nomenclature of marine biogeographic units, i.e. biochores. Based on these loose ‘rules’, the present paper is a critical review of all published Mesozoic marine Realms, Subrealms, and ?Superrealms (formerly called ‘climatic belts’).Biochores are defined by the overall endemism within geographic and time envelopes that include choro- and chrono-types, without consideration of facies or climate. The hierarchy of ranks or tiers is: ?Superrealm, Realm, Subrealm, Province, Subprovince (only ranks in italics are obligatory); ‘region’ is informal. These ranks scale with endemism, geographic range, and persistence in time. Biochores are named geographically, following nomenclatural guidelines (not strict rules) of synonymy and homonymy, with priority beginning with Uhlig's paper of 1911. Uhlig's two ‘climatic belts’ are tentatively accepted as optional, top-ranking ‘Superrealms’ for times of exceptional global endemism; available names for them are ‘Euroboreal’ (or ‘Panboreal’, new) and ‘Tethys–Panthalassa’. The validity of the 29 existing names for realm-group biochores (Realms, Subrealms and Superrealms) in the marine Mesozoic is discussed; 19 names are rejected for a variety of reasons, including synonymy, homonymy and usefulness. The most important realm-group biochores are: Arctic and Boreal– Atlantic in the Boreal/? Euroboreal Realm or ?Superrealm; and Tethyan, Mediterran– Caucasian, Indo-Pacific (Jurassic–Early Cretaceous) and Austral (Middle–Late Cretaceous) in the ? Tethys– Panthalassa ?Superrealm.

Global model of vegetation migration: incorporation of climatic variability

Climate change induced by increasing concentrations of greenhouse gases in the atmosphere is expected to transform global distribution of terrestrial vegetation. The analysis of global vegetation distributions determined by earth’s climates is usually based on biogeographical classifications. These classifications assume that flora in any location is predetermined by certain parameters of climate, and that change in these parameters will produce instant changes in plants composition. Application of the models employing biogeographical classifications to different scenarios of climate change is generally limited with the hypothesis of ‘dynamic equilibrium’: the rate of climate change should be comparable with the rate of vegetation response. The estimated rate of hypothesized global warming is now considered to be fast enough to fall outside these limits. Therefore, an alternative assumption that the forests will be extirpated, but will not migrate to the new territory within the time limits of CO 2 doubling, can be considered a better approximation of future vegetation dynamics. We propose a model to study the effect of native variability of input data on model prediction, portraying vegetation migration as a stochastic process. We included into analysis only variability of climate and assumed that the only process affected by changing climate variability is vegetation mortality (i.e. regional extirpation). Our simulations show that the probabilistic approach can significantly change the forecasts of global vegetation redistribution. The predicted by the model extirpation area for boreal forests is significantly less, than the area predicted by the equilibrium model without forest in-migration.

Panbiogeography: tracking the history of life

1. Introduction: What is Panbiogeography? 2. Life as Geological Layer: Panbiogeography and the Earth Sciences 3. Mapping the Trees of Life: Panbiogeography, Phylogenetic Systematics and Evolutionary Processes 4. Tracking the Trees of Life: Lines, Map, and Matrix 5. Towards a New Regional Biogeography: The Revival of Biogeographical Classification 6. Tracks, Nodes, Biodiversity and Conservation 7. Glossary

Interpreting biogeographical boundaries among Afrotropical birds: spatial patterns in richness gradients and species replacement

Summary Aim We analyse the geographical distribution of 1911 Afrotropical bird species using indices of three simple biogeographic patterns. The first index, the frequency of species with range edges (Te), is formulated to map directly the density of species distribution limits, for comparison with the results of traditional biogeographical classification and ordination procedures, in order to show variations in the strength and breadth of transition zones. The other two indices are formulated to seek to distinguish as directly as possible between two components within these transition‐zone patterns: contributions from gradients in species richness (Tg); and contributions from replacements among species (Tr). We test the ability of these indices to discover the same boundaries among Afrotropical bird faunas as one popular procedure for classifying areas (TWINSPAN) and then use them to look for geographical trends in the different kinds of transition zones. Location The analysis is restricted to the sub‐Saharan or Afrotropical region, excluding the Arabian Peninsula, Madagascar and all offshore islands. Methods We record the presence of each species in 1961 1°×1° grid cells of the map. To apply the three indices, each (core) grid cell in turn is compared with its neighbouring eight cells in the grid. The range edges index (Te) counts the number of species with range edges between the core cell and the surrounding cells. The richness gradients index (Tg) counts the largest difference in species richness measured diametrically across the core cell in any direction when there is a consistent trend in richness along this line of three cells. The species replacements index (Tr) counts the number of species pairs recorded within a nine‐cell neighbourhood that are not corecorded within any of the cells. Values for each of the 1961 grid cells are calculated and used to produce colour‐scale maps of transition zones. Results Large‐scale spatial patterns of variation in density of range edges (Te) are consistent with classifications of the same data and with most previous biogeographical classifications proposed for the region. Variation in richness gradients (Tg) and species replacements (Tr) explain different parts of this pattern, with transition zones around humid forests in the equatorial region being dominated by species replacement, and transition zones around deserts (most extensive in the north and south) being dominated by richness gradients. Main conclusions The three indices distinguish the spatial arrangement and intensity of different kinds of transition zones, thereby providing a first step towards a more rigorous mechanistic understanding of the different processes by which they may have arisen and are maintained. As an example of one such pattern shown by our analyses of Afrotropical birds, there is evidence for a broad latitudinal trend in the nature of transition zones in faunal composition (following the latitudinal distribution of the different kinds of habitat transitions), from being dominated by species replacements near the equator to being dominated by richness gradients further from the equator.

Marine Conservation Initiatives in Australia: Their Relevance to the Conservation of Macroalgae

The world's oceans have been widely regarded as the source of inexhaustible abundance and the need to conserve the Earth's largest biotic realm has only recently been recognised. Consequently, studies of marine conservation have lagged behind comparable studies of terrestrial biomes. Compiling inventories, monitoring ecological communities, detecting and monitoring rare and threatened species, devising biogeographic classification schemes, declaring protected areas (reserves) and reporting to government on the state of the environment are strategies thought effective for the conservation of biodiversity. There is no comprehensive inventory of Australian marine macroalgae, although 'The Australian Marine Algal Name Index' stores data on species names and species distribution patterns for the continent. No Australian marine macroalgal species is currently included on any 'Rare and Threatened' species list, but this reflects only our inability to detect these species. Biogeographic classification schemes have been devised for Australian coastal waters, but little is known of the macroalgae in many of the bio-regions identified. Many marine protected areas (MPAs) have been declared in Australia, but the macroalgae protected in the reserves are generally poorly known and the effects of protection on macroalgal biodiversity has not been evaluated. Furthermore, many MPAs are zoned as multi-use areas, and the actual areas of MPAs zoned as 'conservation zone', offering strict protection, are very small. The greatest impediment to developing effective strategies for the conservation of Australian marine macroalgae is the lack of detailed knowledge on taxonomy, population size, life history characteristics, habitat specificity and geographic distribution of species and on the structure and function of macroalgal communities. In order to gain this knowledge, priority should be given to research programs directly relevant to the inventorying, monitoring, protection and management of marine macroalgal biodiversity. It is essential that conservation and management of the marine environment are based on scientific knowledge.

The distribution patterns of reptiles in the Riff region, northern Morocco

Summary A biogeographical classification of reptiles in the RiVregion (northern Morocco, Africa) was carried out to look for shared distribution patterns, here termed chorotypes. Baroni-Urbani & Buser’s similarity index was applied to the presence/absence data of reptiles in 10#10 km UTM (Universal Transverse Mercator) squares, and then UPGMA (Unweighted Pair-Group Method using arithmetic average) was used to classify the species. A probabilistic method was employed to assess the statistical significance of the groups obtained. An ordination method, the Canonical Correspondence Analysis, was also used to study the distribution of the reptiles within a continuous framework. A gradual longitudinal replacement of reptile species was found throughout the RiV, with no sharp discontinuities for the distributions of most of the species. This may be due to the biogeographical northward movement of the Saharan boundaries, which have not yet reached biogeographical equilibrium. Thus, Saharan reptiles enter the RiV region from the east, through the lower basin of the River Moulouya. Seven reptile chorotypes were identified in the RiV, and these comprise Mediterranean species and others endemic to the Maghreb (the region that spans most of North-western Africa, excluding the Sahara). These chorotypes have a western distribution, and are segregated from one another according to altitude. Historical and ecological processes can account for the distributions shared by these species, which have inhabited the RiV for longer than eastern reptiles.

Phytosociological, bioclimatic and biogeographical classification of woody climax communities of western North America

Abstract. In this study, combining the Braun‐Blanquet phytosociological approach with numerical methods (cluster analysis and principal coordinate ordination), woody climax associations of western North America are described, ranging from NW Baja California (Mexico) to Alaska (USA), and including some interior zones of Idaho and Montana (USA), Alberta, British Columbia and the Yukon Territory (Canada). 95 floristic associations are identified, and each is characterized by floristic combination, biogeographical range, and bioclimatic conditions.

A New Biogeographical Classification of the Scottish Uplands. I. Descriptions of Vegetation Blocks and Their Spatial Variation

A vegetation survey of 88 Scottish upland sites (mainly designated as Sites of Special Scientific Interest) was carried out between 1981 and 1988. Vegetation stands were classified in the field into 90 previously defined types, equivalent to 65 communities in the National Vegetation Classification. Vegetation maps were drawn for each site and measured to give quantitative data on the occurrence and extent of the communities. Two-way indicator-species analysis, used to classify the sites and communities, gave nine geographical groups of sites, each defined by blocks of indicator communities. These nine groups remained stable when the analysis placed varying degrees of emphasis on communities which are rare and restricted (in area) or on extensive communities which make up the major components of the upland landscape (...)

A New Biogeographical Classification of the Scottish Uplands. II. Vegetation--Environment Relationships

1. This paper describes vegetation-environment relationships in the mountains, moorland and peatlands of upland Scotland. The analysis involves 48 environmental variables, covering location. topography, climate, geology, geomorphology and land-use, and 65 plant communities mapped for 88 sample sites. These environmental variables account for much of the variation in assemblages of plant communities within nine major biogeographical groups of sites.2. Correlations between environmental variables were investigated independently of the vegetation using principal components analysis (PCA). The first axis defines a gradient of increasing oceanicity from east to west (21.3% variance) and the second axis contrasts high sites forming extensive montane summits with somewhat warmer lower-altitude sites with little or no montane ground (17.5% variance). Precipitation has strong correlations with both axes. Grouse-moor management and small-patch burning are strongly correlated with the least oceanic areas.3. Site-community data were ordinated without any environmental variables using detrended correspondence analysis (DCA), and then with the environmental variables included using canonical correspondence analysis (CCA). Direct gradient ordination of the vegetation data by CCA shows that these environmental variables are sufficient to account for nearly all of the community variation that can be represented on the first three DCA axes. Species-environment correlations are between 0.91 and 0.93, with a close similarity between the CCA axes and those of the unconstrained DCA.4. The first 2 CCA axes explain 18% of the total variance in the vegetation with a clear pattern of geographical separation of sites separated on the axes. Axis 1 is strongly correlated with oceanicity (r = 0.68) and the number of wet days (r = 0.80). Axis 2 is strongly correlated with maximum altitude (r = -0.75). Axis 3 is correlated with latitude (r = 0.78) and summer temperature (r = -0.56), and gives a north-south division based on the extent of anthropogenic vegetation, showing that secondary changes have occurred regionally as well as locally.5. Geology appears to have little influence on the broad-scale pattern of vegetation with the exception of the geologically well-defined Breadalbane hills.6. The biogeographical analysis described here can be used to evaluate and then select sites of nature conservation interest. The CCA ordination-space can be used to detect sampling bias in groups of sites in relation to environmental variables and to show gaps in their geographical coverage.

New Zealand biogeography: A panbiogeographic approach

Abstract The history of biogeography is briefly reviewed in relation to the dispersal/vicariance controversy. A cladistic analysis of known good dispersers, the admiral butterflies (Bassaris and Vanessa), provides a basis to assess the relative roles of dispersal and vicariance in generating geographic distribution patterns. Cladistic parsimony analyses of geographic distribution and phylogenetic data for Gondwanic and circum-antarctic taxa are used to appraise some of the varied views on the biogeographic classification and relationships of New Zealand. The new panbiogeographic approach to New Zealand’s biogeographic classification is outlined and its conceptual links with geology reviewed. New models and explanations for two classic problems in New Zealand biogeography, the origin of the Chatham Islands biota and the mid-South Island glacial gap, are presented. These are based on track and cladistic analyses.

Biogeographic classification of the Neotropical Leptophlebiidae (Ephemeroptera) based upon geological centers of ancestral origin and ecology

Thirty‐four genera belonging to the Gondwanian subfamily Atalophlebiinae are known from the Neotropics. Development of the lower Central American isthmus was marked only by dispersal of Gondwanian Atalophlebiinae from South America into Central America. No member of the Laurasian subfamily, the Leptophlebiinae, has dispersed from North America into Central or South America. The Antilles were colonized entirely by Atalophlebiinae from South and Central America. Genera of Neotropical Atalophlebiinae are placed into one of two faunal components: either the Patagonian Shield, South Andean, Cold‐Adapted Genera; or the Guiana & Brazilian Shields, Warm‐Adapted Genera. The 10 Patagonian Shield Genera are primarily associated with cold‐water streams of southern South America. Secondary diversification has occurred in the southern coastal mountains of Brazil, and at high elevations in the central and northern Andes. Phylogenetically, Patagonian Shield Genera are related to diverse genera on several Gondwanian conti...

Plankton Biogeography of the Indian Ocean

AbstractKnowledge of plankton biogeography for the Indian and adjacent seas is necessary for an understanding of the regional characteristics and changes in the plankton composition. Some of the plankters will serve as good biogeographical indicator species. Some phytoplankters and tintinnids among zooplankton are promising for use as such labels for the presence of different waters in the Porto Novo (Coromandel coast, Bay of Bengal) region. A biogeographical classification of the local phytoplankton and peculiarities in the distribution of some rare tintinnids occurring there are discussed.