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Geographic Scales (geographic + scale)
Kinds of Geographic Scales Selected AbstractsGEOGRAPHIC SCALE AND FUNCTIONAL SCOPE IN METROPOLITAN GOVERNANCE REFORM: THEORY AND EVIDENCE FROM GERMANYJOURNAL OF URBAN AFFAIRS, Issue 2 2006Joachim K. Blatter New dichotomies emerge, for example, "jumping of scale" versus "relativation of scales"; "deterritorializiaton" versus "reterritorialization"; "spaces of place" versus "space of flows." These dichotomies can be interpreted as different proposals and/or diagnoses in respect to the geographic scale and functional scope of emerging institutions of metropolitan governance. The paper aims to trace the empirical question of which direction we are heading by analyzing recent metropolitan governance reforms in six West German metropolitan areas. The findings show that there is a general trend to create soft institutions of governance on a larger scale as a reaction to global competition and continental integration. Beyond this commonality, we discover quite different institutional trajectories. The regions which are strongly embedded in the global economy tend toward a "deterritorialized" form of metropolitan governance with rather weak institutions characterized by large geographic scales and functional specialization. In contrast, the regions which are not as much embedded in the global economy have been able to create strong governance institutions on a regional level characterized by a rather small geographic scope and based on a territorial logic of functional integration and geographic congruence. [source] Geographic Scale and Grass-Roots Internationalism: The Liverpool Dock Dispute, 1995,1998,ECONOMIC GEOGRAPHY, Issue 3 2000Noel Castree Abstract: In the context of ongoing debates over the effects of "globalization" on organized labor and, specifically, recent experiments in labor internationalism, this paper examines the geography of the Liverpool dock dispute, 1995,98. The dispute has rarely been subject to a serious analysis of its causes and trajectory. This is surprising since it was not only the most protracted industrial dispute in recent British history but also the hub of a relatively novel form of transnational labor organizing: namely, a form of grass-roots internationalism organized largely outside the formal apparatuses of national and international unionism. In the paper I focus on the nature and dynamics of this "grass-roots internationalism" with a view to making two claims that have a wider thematic and theoretical relevance to the study of labor geographies. First, contrary to an emerging new orthodoxy in labor geography (and labor studies more generally), the Liverpool case in fact suggests that the necessity for labor to "up-scale" solidarity and struggle in the 1990s is much overstated. Second, the Liverpool case suggests that international labor organizing is only efficacious when considered in relation to two scales of struggle often thought increasingly irrelevant or ineffectual in a globalizing world: the local and the national. Thus, while those few analysts who have cited the Liverpool dispute, basing their assessments on secondhand knowledge, have held the dockers up as exemplars of a new form of labor internationalism, in this paper I suggest the need for a more complex and contingent appreciation of the multiscalar dynamics of labor struggles. In short, we have not yet reached the stage, even in a globalizing world, where labor's "spatial fixes" must be preeminently supranational. [source] LAND RICH AND DATA POOR: MODELLING REQUIREMENTS IN AUSTRALIA'S FAR NORTHECONOMIC PAPERS: A JOURNAL OF APPLIED ECONOMICS AND POLICY, Issue 3 2005Natalie Stoeckl Economic models have long been used as a way of organising and presenting information for policy makers interested in large regions,e.g. nations,and recent advances in information technology make the goal of developing models for decision makers in other locales a realistic one. The research on which this paper focuses was part of large project investigating the feasibility and desirability of developing a multi-disciplinary computer model of the Australian Savannas. In the large project, researchers were broken in to three teams: those considering the biophysical, demographic, and economic aspects of the modelling problem. This paper presents findings from part of the economic component of the investigation: that which sought information from key local ,stakeholders' about the type of information that would be useful to them. Responses indicate that many of Australia's existing economic models are capable of providing the ,right' type of information; but at too coarse a geographic scale for those in remote regions. Evidently, there is a need for developing other models. [source] Comparative population genetic structures of the fruit fly Urophora cardui and its primary parasitoid Eurytoma robustaENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 3 2003Jes Johannesen Abstract The interaction between two species may depend on geographic scale and this in turn can affect co-evolution among them. The present study comparatively examines population genetic structures of the tephritid gall fly Urophora cardui and its primary ectoparasitoid Eurytoma robusta for inference of relative dispersal patterns and host-parasitoid specificity. Genetic differentiation patterns indicated two levels of hierarchical structure in both species: locally similar distance-dependencies but globally differences. Locally, both species showed isolation by distance and a high correlation between host and parasitoid FST for the same population-pairs was found. At the local level, E. robusta populations were most structured. These findings suggest that locally E. robusta is tracking behind its host, U. cardui, and that colonisation of new patches by both species underlie a stepping-stone dispersal process. The investigation as a whole showed that U. cardui populations were hierarchically structured across a genetic-geographical cline. There was no sign of a comparable cline in E. robusta where populations globally became independent of one another and of the host. The different degree of hierarchical genetic structure of the two species suggests that dispersal processes or interactions differ relative to geographical scale and population history. [source] Variation in leaf functional trait values within and across individuals and species: an example from a Costa Rican dry forestFUNCTIONAL ECOLOGY, Issue 1 2010Catherine M. Hulshof Summary 1.,Patterns of species co-existence and species diversity in plant communities remain an important research area despite over a century of intensive scrutiny. To provide mechanistic insight into the rules governing plant species co-existence and diversity, plant community ecologists are increasingly quantifying functional trait values for the species found in a wide range of communities. 2.,Despite the promise of a quantitative functional trait approach to plant community ecology, we suggest that, along with examining trait variation across species, an assessment of trait variation within species should also be a key component of a trait-based approach to community ecology. Variability within and between individuals and populations is likely widespread due to plastic responses to highly localized abiotic and biotic interactions. 3.,In this study, we quantify leaf trait variation within and across ten co-existing tree species in a dry tropical forest in Costa Rica to ask: (i) whether the majority of trait variation is located between species, within species, within individuals or within the leaves themselves; (ii) whether trait values collected using standardized methods correlate with those collected using unstandardized methods; and (iii) to what extent can we differentiate plant species on the basis of their traits? 4.,We find that the majority of variation in traits was often explained by between species differences; however, between leaflet trait variation was very high for compound-leaved species. We also show that many species are difficult to reliably differentiate on the basis of functional traits even when sampling many individuals. 5.,We suggest an ideal sample size of at least 10, and ideally 20, individuals be used when calculating mean trait values for individual species for entire communities, though even at large sample sizes, it remains unclear if community level trait values will allow comparisons on a larger geographic scale or if species traits are generally similar across scales. It will thus be critical to account for intraspecific variation by comparing species mean trait values across space in multiple microclimatic environments within local communities and along environmental gradients. Further, quantifying trait variability due to plasticity and inheritance will provide a better understanding of the underlying patterns and drivers of trait variation as well as the application of functional traits in outlining mechanisms of species co-existence. [source] CULTURAL ECONOMY AND THE CREATIVE FIELD OF THE CITYGEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 2 2010Allen J. Scott ABSTRACT. I begin with a rough sketch of the incidence of the cultural economy in US cities today. I then offer a brief review of some theoretical approaches to the question of creativity, with special reference to issues of social and geographic context. The city is a powerful fountainhead of creativity, and an attempt is made to show how this can be understood in terms of a series of localized field effects. The creative field of the city is broken down (relative to the cultural economy) into four major components, namely, (a) intra-urban webs of specialized and complementary producers, (b) the local labour market and the social networks that bind workers together in urban space, (c) the wider urban environment, including various sites of memory, leisure, and social reproduction, and (d) institutions of governance and collective action. I also briefly describe some of the path-dependent dynamics of the creative field. The article ends with a reference to some issues of geographic scale. Here, I argue that the urban is but one (albeit important) spatial articulation of an overall creative field whose extent is ultimately nothing less than global. [source] Comparative mtDNA sequence (control region, ATPase 6 and NADH-1) divergence in Hucho taimen(Pallas) across four Siberian river basinsJOURNAL OF FISH BIOLOGY, Issue 4 2005E. Froufe Hucho taimen from eight populations spanning four drainage basins (Amur, Lena, Enisei and Khatanga) were analysed for nucleotide sequence variation across three mitochondrial genes (ATP6, NADH-1 and control region). Samples of H. hucho, Brachymystax lenok(sharp-snouted and blunt-snouted forms) and Parahucho perryi were also included for comparison. Nucleotide variation across a total of 1826 base pairs in H. taimen revealed shared haplotypes between the Amur and Lena basins, further supporting a previous hypothesis of late to post-Pleistocene hydrological exchange between these now disjunct basins. In contrast to an earlier study using the control region alone, clear phylogeographic structure was seen at a large geographic scale, reflected by two phylogroups, one corresponding to the Amur and Lena basins, and the other to the Enisei and Khatanga basins. Comparative rates of divergence revealed considerably faster and less heterogeneous substitution rates for the two coding genes, especially at interspecific levels compared to the mtDNA control region. [source] GEOGRAPHIC SCALE AND FUNCTIONAL SCOPE IN METROPOLITAN GOVERNANCE REFORM: THEORY AND EVIDENCE FROM GERMANYJOURNAL OF URBAN AFFAIRS, Issue 2 2006Joachim K. Blatter New dichotomies emerge, for example, "jumping of scale" versus "relativation of scales"; "deterritorializiaton" versus "reterritorialization"; "spaces of place" versus "space of flows." These dichotomies can be interpreted as different proposals and/or diagnoses in respect to the geographic scale and functional scope of emerging institutions of metropolitan governance. The paper aims to trace the empirical question of which direction we are heading by analyzing recent metropolitan governance reforms in six West German metropolitan areas. The findings show that there is a general trend to create soft institutions of governance on a larger scale as a reaction to global competition and continental integration. Beyond this commonality, we discover quite different institutional trajectories. The regions which are strongly embedded in the global economy tend toward a "deterritorialized" form of metropolitan governance with rather weak institutions characterized by large geographic scales and functional specialization. In contrast, the regions which are not as much embedded in the global economy have been able to create strong governance institutions on a regional level characterized by a rather small geographic scope and based on a territorial logic of functional integration and geographic congruence. [source] Host density predicts presence of cuckoo parasitism in reed warblersOIKOS, Issue 6 2007Bård G. Stokke In some hosts of avian brood parasites, several populations apparently escape parasitism, while others are parasitized. Many migratory specialist brood parasites like common cuckoos, Cuculus canorus, experience a short breeding season, and in order to maintain local parasite populations host densities should be sufficiently high to allow efficient nest search. However, no studies have investigated the possible effect of host density on presence of cuckoo parasitism among populations of a single host species. Here, we investigated possible predictors of common cuckoo parasitism in 16 populations of reed warblers, Acrocephalus scirpaceus, across Europe. In more detail, we quantified the effect of host density, number of host breeding pairs, habitat type, mean distance to nearest cuckoo vantage point, predation rate and latitude on the presence of cuckoo parasitism while controlling for geographical distance among study populations. Host density was a powerful predictor of parasitism. We also found a less pronounced effect of habitat type on occurrence of parasitism, while the other variables did not explain why cuckoos utilize some reed warbler populations and not others. This is the first study focusing on patterns of common cuckoo-host interactions within a specific host species on a large geographic scale. The results indicate that if host density is below a specific threshold, cuckoo parasitism is absent regardless of the state of other potentially confounding variables. [source] Lost in the Supermarket: The Corporate-Organic Foodscape and the Struggle for Food DemocracyANTIPODE, Issue 3 2009Josée Johnston Abstract:, The corporatization of organics has been critiqued for the concentration of ownership, as well as the ecological consequences of the long distances commodities travel between field and table. These critiques suggest a competing vision of food democracy which strives to organize the production and consumption of food at a proximate geographic scale while increasing opportunities for democratically managed cooperation between producers and consumers. This paper examines how the corporate-organic foodscape has interacted and evolved alongside competing counter movements of food democracy. Using discourse and content analysis, we examine how corporate organics incorporate messages of locally scaled food production, humble origins, and a commitment to family farms and employees, and explore some of the complexity of the corporate-organic foodscape. This paper contributes to the understanding of commodity fetishism in the corporate-organic foodscape, and speaks more generally to the need for sophisticated understandings of the complex relationship between social movement innovation and market adaptation. [source] Dispersal ability determines the genetic effects of habitat fragmentation in three species of aquatic insectAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2010Kozo Watanabe Abstract 1.The dispersal ability of species and the geographic scale of habitat fragmentation both may influence the extent of gene flow between fragments, but their interactions have rarely been tested, particularly among co-occurring species. 2.Population genetic structures of three species of aquatic insect were compared in streams fragmented by reservoirs and in unfragmented streams in north-eastern Japan, using 52, 37, and 58 RAPD markers. The three species studied included a strong disperser Cincticostella elongatula (Ephemeroptera: Ephemerellidae), an intermediate disperser Stenopsyche marmorata (Trichoptera: Stenopsychidae), and a weak disperser Hydropsyche orientalis (Trichoptera: Hydropsychidae). 3.The patterns of genetic isolation by distance (IBD) supported a priori hypotheses of dispersal ability. The strong disperser (C. elongatula) exhibited significant IBD only at the largest spatial scale studied (among drainages, r=0.50, P<0.01). The intermediate disperser (S. marmorata) showed IBD both within (r=0.22, P<0.01) and among (r=0.45, P<0.01) drainages. The weak disperser (H. orientalis) did not exhibit significant IBD at any scale. 4.Pairwise genetic differentiation (,) indicated that neither the weak disperser nor the strong disperser were genetically differentiated above and below reservoirs when compared with reference sites. This was in contrast to previous results for S. marmorata, for which subpopulations were genetically fragmented across larger (>4.1,km), but not smaller (<2.9,km) reservoirs. 5.We suggest that intermediate dispersers, i.e. those at equilibrium between migration and genetic drift within drainages, are more likely to be affected by fragmentation than either strong or weak dispersers. Intermediate dispersers could therefore be used as indicator species in studies aimed at detecting the effects of distance between habitat fragments (e.g. reservoir size) for conservation planning. Copyright © 2010 John Wiley & Sons, Ltd. [source] A land snail's view of a fragmented landscapeBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009HEIKE KAPPES Habitat fragmentation may influence the genetic structure of populations, especially of species with low mobility. So far, these effects have been mainly studied by surveying neutral markers, and much less by looking at ecologically relevant characters. Therefore, we aimed to explore eventual patterns of covariation between population structuring in neutral markers and variation in shell morphometrics in the forest-associated snail Discus rotundatus in relation to habitat fragment characteristics. To this end, we screened shell morphometric variability and sequence variation in a fragment of the mitochondrial 16S rDNA gene in D. rotundatus from the fragmented landscape of the Lower Rhine Embayment, Germany. The 16S rDNA of D. rotundatus was highly variable, with a total of 118 haplotypes (384 individuals) forming four clades and one unresolved group. There was a geographic pattern in the distribution of the clades with the river Rhine apparently separating two groups. Yet, at the geographic scale considered, there was no obvious effect of fragmentation on shell morphometrics and 16S rDNA variation because GST often was as high within, as between forests. Instead, the age of the habitat and (re-)afforestation events appeared to affect shell shape and 16S rDNA in terms of the number of clades per site. The ecologically relevant characters thus supported the presumably neutral mitochondrial DNA markers by indicating that populations of not strictly stenecious species may be (relatively) stable in fragments. However, afforestation after large clearcuts and habitat gain after the amendment of deforestation are accompanied by several, seemingly persistent peculiarities, such as altered genetic composition and shell characters (e.g. aperture size). © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 839,850. [source] Large genetic divergence of new, morphologically similar species of sterile lichens from Europe (Lepraria, Stereocaulaceae, Ascomycota): concordance of DNA sequence data with secondary metabolitesCLADISTICS, Issue 4 2008Judith Fehrer Lichenized fungi of the genus Lepraria are known for their paucity of morphological characters. Species identification is therefore largely based on secondary chemistry. We investigated different chemotypes of the morphologically highly similar L. jackii species complex by internal transcribed spacer (ITS) sequencing. In phylogenetic analyses including all available Lepraria species, samples belonging to different chemotypes of the L. jackii agg. corresponded to four highly divergent clusters. While true L. jackii was genetically uniform, the other three clades represented previously unrecognized species. They originated from different major speciation events, and two of them were not closely related to any other species. Assessment of intraspecific genetic variability revealed four different patterns with respect to geographic scale. ITS sequences proved to be the most reliable and distinctive characters for species recognition in the Lepraria jackii complex and were in accordance with chemical and ecogeographic data. Frequent occurrence of long branches, relatively few resolved relationships despite high genetic variability, and the discovery and description of a considerable part of the Lepraria species within the last 10 years suggest that the genus is probably much larger than currently known. The diversification of this asexual group in the potential absence of recombination is discussed. © The Willi Hennig Society 2008. [source] Why do mountains support so many species of birds?ECOGRAPHY, Issue 3 2008Adriana Ruggiero Although topographic complexity is often associated with high bird diversity at broad geographic scales, little is known about the relative contributions of geomorphologic heterogeneity and altitudinal climatic gradients found in mountains. We analysed the birds in the western mountains of the New World to examine the two-fold effect of topography on species richness patterns, using two grains at the intercontinental extent and within temperate and tropical latitudes. Birds were also classified as montane or lowland, based on their overall distributions in the hemisphere. We estimated range in temperature within each cell and the standard deviation in elevation (topographic roughness) based on all pixels within each cell. We used path analysis to test for the independent effects of topographic roughness and temperature range on species richness while controlling for the collinearity between topographic variables. At the intercontinental extent, actual evapotranspiration (AET) was the primary driver of species richness patterns of all species taken together and of lowland species considered separately. In contrast, within-cell temperature gradients strongly influenced the richness of montane species. Regional partitioning of the data also suggested that range in temperature either by itself or acting in combination with AET had the strongest "effect" on montane bird species richness everywhere. Topographic roughness had weaker "effects" on richness variation throughout, although its positive relationship with richness increased slightly in the tropics. We conclude that bird diversity gradients in mountains primarily reflect local climatic gradients. Widespread (lowland) species and narrow-ranged (montane) species respond similarly to changes in the environment, differing only in that the richness of lowland species correlates better with broad-scale climatic effects (AET), whereas mesoscale climatic variation accounts for richness patterns of montane species. Thus, latitudinal and altitudinal gradients in species richness can be explained through similar climatic-based processes, as has long been argued. [source] Corticolous arthropods under climatic fluctuations: compensation is more important than migrationECOGRAPHY, Issue 1 2005Andreas Prinzing Animals can cope with fluctuating climates by physiological tolerance, tracking of climatic fluctuations (migration) and compensatory redistribution among (micro)habitats (compensation). Compensation is less demanding and thus more important than migration at large geographic scales. It is not clear however which strategy is more important at the small scale of a microhabitat landscape. I investigated how six arthropod species (Collembola, Oribatei, Psocoptera, Isopoda) respond to microclimatic fluctuations at the surface of exposed tree trunks. Across a nine-month period I characterized the microclimatic zonation of 299 trunks, and focally sampled the arthropods from different microhabitat types (different cryptogam species and bark crevices) within different microclimatic zones. I found that compensatory microhabitat-use was a general phenomenon. The distribution of all species across microhabitats was influenced significantly by ambient microclimate. Also, the arthropods' microhabitat use changed throughout their ontogeny, and microhabitats were used even if they were rare. Most interestingly, the arthropods responded to microclimatic fluctuations primarily by redistribution among microhabitats and less by fluctuations of overall abundances across all microhabitats. Hence compensation was more important than migration. The animals moved for centimeters to decimeters rather than for decimeters to meters; they perceived and utilized their environment primarily at the finest, but also most complex scale. This has implications for the resilience of arthropod populations, their interactions with cryptogams and the turnover of species between macrohabitats. [source] Alliance-Driven Governance: Applying a Global Commodity Chains Approach to the U.K. Biotechnology IndustryECONOMIC GEOGRAPHY, Issue 1 2008Kean Birch Abstract As the economy has globalized, it has also regionalized, which has led to the integration of different spaces across different scales. A number of theories contend that the endogenous assets of these locations provide them with the means to compete in this globalizing economy, especially in relation to knowledge-based sectors like biotechnology. Among these theories, the cluster concept stands out. However, there is little support for the arguments that local linkages are the central contributors to innovation. Extralocal linkages have also been highlighted, suggesting that other theories that account for these linkages may prove useful in the discussion of knowledge-based sectors, in general, and biotechnology, in particular. One such theory is the concept of global commodity chains, which explicitly concerns the interconnections within and across different geographic scales. As yet it has seldom been applied to the biotechnology industry. This article uses the approach to explore the U.K. biotechnology industry. [source] Politics of Scale and the Globalization of the South Korean Automobile IndustryECONOMIC GEOGRAPHY, Issue 2 2003Bae-Gyoon Park Abstract: This article explains the liberalization and globalization of the South Korean automobile industry, with an emphasis on the multiscalar processes of globalization. In particular, it explores the processes by which the South Korean government shifted its policy for the automobile industry, from a nationalist and protectionist orientation toward liberalization in the late 1990s, which, in turn, attracted inward investments from foreign automakers and facilitated the globalization of the nation's automobile market. While exploring the roles of diverse actors and forces,operating at various geographic scales,in these processes, I placed more analytical weight on examining the ways in which contestation between national and local forces contributed to the government's liberalization policy. I argue that the globalization of the South Korean automobile industry in recent years was not only an outcome of the globalizing strategies of foreign automakers, but also was facilitated by an institutional fix by the nation-state (particularly the liberalization of policy) to a regulatory deficit, which stemmed from the national-local tension with respect to a state-led economic restructuring project. [source] The Limits to Globalization Theory: A Geographic Perspective on Global Economic Change,ECONOMIC GEOGRAPHY, Issue 3 2002Henry Wai-chung Yeung Abstract: The nature of globalization and global economic change has been a subject of immense academic research during the past two decades. The Janus face of globalization, however, continues to obfuscate our understanding of its complex processes and alleged geographic outcomes. In this article, I theorize on the indispensable role of geography in conceptualizing economic globalization. I argue that economic globalization is an inherently geographic phenomenon in relation to the transcendence and switchability of geographic scales and discursive practices as sociospatial constructions. Given its complex spatiality, economic globalization is more a phenomenon in need of explanations than a universal cause of empirically observable outcomes in the so-called globalization theory. To illustrate my theoretical claims, I analyze the complex interrelationships between globalization processes and the recent Asian economic crisis. Some implications for future globalization research in geography are offered. [source] LATITUDINAL VARIATION IN SPECIATION MECHANISMS IN FROGSEVOLUTION, Issue 2 2010Xia Hua Speciation often has a strong geographical and environmental component, but the ecological factors that potentially underlie allopatric and parapatric speciation remain understudied. Two ecological mechanisms by which speciation may occur on geographic scales are allopatric speciation through niche conservatism and parapatric or allopatric speciation through niche divergence. A previous study on salamanders found a strong latitudinal pattern in the prevalence of these mechanisms, with niche conservatism dominating in temperate regions and niche divergence dominating in the tropics, and related this pattern to Janzen's hypothesis of greater climatic zonation between different elevations in the tropics. Here, we test for latitudinal patterns in speciation in a related but more diverse group of amphibians, the anurans. Using data from up to 79 sister-species pairs, we test for latitudinal variation in elevational and climatic overlap between sister species, and evaluate the frequency of speciation via niche conservatism versus niche divergence in relation to latitude. In contrast to salamanders, we find no tendency for greater niche divergence in the tropics or for greater niche conservatism in temperate regions. Although our results support the idea of greater climatic zonation in tropical regions, they show that this climatic pattern does not lead to straightforward relationships between speciation, latitude, and niche evolution. [source] DIVERGENCE WITH GENE FLOW IN THE ROCK-DWELLING CICHLIDS OF LAKE MALAWIEVOLUTION, Issue 5 2000Patrick D. Danley Abstract Within the past two million years, more than 450 species of haplochromine cichlids have diverged from a single common ancestor in Lake Malawi. Several factors have been implicated in the diversification of this monophyletic clade, including changes in lake level and low levels of gene flow across limited geographic scales. The objectives of this study were to determine the effect of recent lake-level fluctuations on patterns of allelic diversity in the genus Metriaclima, to describe the patterns of population structure within this genus, and to identify barriers to migration. This was accomplished through an analysis of allele frequencies at four microsatellite loci. Twelve populations spanning four species within Metriaclima were surveyed. The effect of lake-level fluctuations can be seen in the reduced genetic diversity of the most recently colonized sites; however, genetic diversity is not depressed at the species level. Low levels of population structure exist among populations, yet some gene flow persists across long stretches of inhospitable habitat. No general barrier to migration was identified. The results of this study are interpreted with respect to several speciation models. Divergence via population bottlenecks is unlikely due to the large allelic diversity observed within each species. Genetic drift and microallopatric divergence are also rejected because some gene flow does occur between adjacent populations. However, the reduced levels of gene flow between populations does suggest that minor changes in the selective environment could cause the divergence of populations. [source] Seed supply for broadscale restoration: maximizing evolutionary potentialEVOLUTIONARY APPLICATIONS (ELECTRONIC), Issue 4 2008Linda M. Broadhurst Abstract Restoring degraded land to combat environmental degradation requires the collection of vast quantities of germplasm (seed). Sourcing this material raises questions related to provenance selection, seed quality and harvest sustainability. Restoration guidelines strongly recommend using local sources to maximize local adaptation and prevent outbreeding depression, but in highly modified landscapes this restricts collection to small remnants where limited, poor quality seed is available, and where harvesting impacts may be high. We review three principles guiding the sourcing of restoration germplasm: (i) the appropriateness of using ,local' seed, (ii) sample sizes and population characteristics required to capture sufficient genetic diversity to establish self-sustaining populations and (iii) the impact of over-harvesting source populations. We review these topics by examining current collection guidelines and the evidence supporting these, then we consider if the guidelines can be improved and the consequences of not doing so. We find that the emphasis on local seed sourcing will, in many cases, lead to poor restoration outcomes, particularly at broad geographic scales. We suggest that seed sourcing should concentrate less on local collection and more on capturing high quality and genetically diverse seed to maximize the adaptive potential of restoration efforts to current and future environmental change. [source] Mexican Jay social group size varies with habitat in northeastern MexicoJOURNAL OF FIELD ORNITHOLOGY, Issue 2 2006Nirmal K. Bhagabati ABSTRACT We evaluated the hypothesis that social group size in Mexican Jays (Aphelocoma ultramarina) varies with habitat structure. We counted the social group size of Mexican Jays over a range of elevations and forest types in a single mountain range in northern Mexico (Sierra El Carmen, Coahuila). Group size increased significantly with elevation, in contrast to a population of Mexican Jays in Arizona that showed no such trend in another study. Among the vegetation variables measured, those relating to size of pines and oaks were especially important in explaining variation in group size. Because acorns and pine nuts are a major part of the diet of Mexican Jays, sites with larger oaks and pines may produce larger nut crops and support larger groups of jays. Elevation did not significantly explain variance in group size after taking vegetation into account. We compared group size and habitat variation across different parts of the geographic range of Mexican Jays. Our analysis indicates that variation of social group size in Mexican Jays is influenced by habitat quality at both local and geographic scales. Detailed studies on habitat structure and demographics of this population are needed to further clarify aspects of habitat quality important to these jays, and the mechanisms by which variation in social structure is maintained. SINOPSIS Evaluamos la hipótesis en donde se indica que el tamaño de los grupos en el Azulejón Mexicano (Aphelocoma ultramarina) varía con la estructura del hábitat. Determinamos el tamaño del grupo social a través de elevaciones variadas y tipos de bosques a lo largo de una cordillera en la Sierra El Carmen, Coahuila, del norte de México. El tamaño del grupo incremento significativamente con la elevación, en contraste con una población de azulejones estudiada en Arizona. Entre las variables medidas en la vegetación, encontramos unas relacionadas al tamaño de los pinos y los robles que fueron especialmente importante en la explicación del tamaño de los grupos. Dado el caso de que las semillas y nueces son un componente principal en la dieta de las aves, los lugares con árboles de mayor tamaño pudieran producir más alimento y a su vez sostener grupos mayores de azulejones. La elevación no explicó significativamente la variación en el tamaño de los grupos, una vez incluido en el análisis la vegetación. Comparamos tamaño de grupos y la variación en hábitat a través de diferentes partes de la distribución geográfica del ave. Nuestro análisis indica que la variación de tamaño de los grupos esta influenciada por la calidad del hábitat tanto al nivel local como geográfico. Estudios detallados en la estructura del hábitat y estudios demográficos son necesarios para determinar el mecanismo a través del cual se mantiene la variación en grupos. [source] Spatial and temporal scales of adaptive divergence in marine fishes and the implications for conservationJOURNAL OF FISH BIOLOGY, Issue 2006D. O. Conover Knowledge of geographic and temporal scales of adaptive genetic variation is crucial to species conservation, yet understanding of these phenomena, particularly in marine systems, is scant. Until recently, the belief has been that because most marine species have highly dispersive or mobile life stages, local adaptation could occur only on broad geographic scales. This view is supported by comparatively low levels of genetic variation among populations as detected by neutral markers. Similarly, the time scale of adaptive divergence has also been assumed to be very long, requiring thousands of generations. Recent studies of a variety of species have challenged these beliefs. First, there is strong evidence of geographically structured local adaptation in physiological and morphological traits. Second, the proportion of quantitative trait variation at the among-population level (QST) is much higher than it is for neutral markers (FST) and these two metrics of genetic variation are poorly correlated. Third, evidence that selection is a potent evolutionary force capable of sustaining adaptive divergence on contemporary time scales is summarized. The differing spatial and temporal scales of adaptive v. neutral genetic divergence call for a new paradigm in thinking about the relationship between phenogeography (the geography of phenotypic variation) and phylogeography (the geography of lineages) in marine species. The idea that contemporary selective processes can cause fine-scale spatial and temporal divergence underscores the need for a new emphasis on Darwinian fishery science. [source] GEOGRAPHIC SCALE AND FUNCTIONAL SCOPE IN METROPOLITAN GOVERNANCE REFORM: THEORY AND EVIDENCE FROM GERMANYJOURNAL OF URBAN AFFAIRS, Issue 2 2006Joachim K. Blatter New dichotomies emerge, for example, "jumping of scale" versus "relativation of scales"; "deterritorializiaton" versus "reterritorialization"; "spaces of place" versus "space of flows." These dichotomies can be interpreted as different proposals and/or diagnoses in respect to the geographic scale and functional scope of emerging institutions of metropolitan governance. The paper aims to trace the empirical question of which direction we are heading by analyzing recent metropolitan governance reforms in six West German metropolitan areas. The findings show that there is a general trend to create soft institutions of governance on a larger scale as a reaction to global competition and continental integration. Beyond this commonality, we discover quite different institutional trajectories. The regions which are strongly embedded in the global economy tend toward a "deterritorialized" form of metropolitan governance with rather weak institutions characterized by large geographic scales and functional specialization. In contrast, the regions which are not as much embedded in the global economy have been able to create strong governance institutions on a regional level characterized by a rather small geographic scope and based on a territorial logic of functional integration and geographic congruence. [source] Do insects lose flight before they lose their wings?MOLECULAR ECOLOGY, Issue 19 2009Population genetic structure in subalpine stoneflies Abstract Wing reduction and flightlessness are common features of alpine and subalpine insects, and are typically interpreted as evolutionary adaptations to increase fecundity and promote local recruitment. Here, we assess the impact of wing reduction on dispersal in stoneflies (Plecoptera: Gripopterygidae: Zelandoperla) in southern New Zealand. Specifically, we present comparative phylogeographic analyses (COI; H3) of strong-flying Zelandoperla decorata (144 individuals, 63 localities) vs. the co-distributed but weak-flying Zelandoperla fenestrata species group (186 individuals, 81 localities). The latter group exhibits a variety of morphotypes, ranging from fully winged to completely wingless. Consistent with its capacity for strong flight-mediated dispersal, Z. decorata exhibited no substantial phylogeographic differentiation across its broad South Island range. Conversely the weak-flying fenestrata species group exhibited substantial genetic structure across both fine and broad geographic scales. Intriguingly, the variable degrees of wing development observed within the fenestrata species group had no apparent impact on levels of phylogeographic structure, which were high regardless of morphotype, suggesting that even fully winged specimens of this group do not fly. This finding implies that Zelandoperla flight loss occurs independently of wing loss, and might reflect underlying flight muscle reduction. [source] Genetic diversity of the arbuscular mycorrhizal fungus Glomus intraradices as determined by mitochondrial large subunit rRNA gene sequences is considerably higher than previously expectedNEW PHYTOLOGIST, Issue 2 2008Boris Börstler Summary ,,Glomus intraradices is a widespread arbuscular mycorrhizal fungus (AMF), which has been found in an extremely broad range of habitats, indicating a high tolerance for environmental factors and a generalist life history strategy. Despite this ecological versatility, not much is known about the genetic diversity of this fungal species across different habitats or over large geographic scales. ,,A nested polymerase chain reaction (PCR) approach for the mitochondrial rRNA large subunit gene (mtLSU), distinguished different haplotypes among cultivated isolates of G. intraradices and within mycorrhizal root samples from the field. ,,From analysis of 16 isolates of this species originating from five continents, 12 mitochondrial haplotypes were distinguished. Five additional mtLSU haplotypes were detected in field-collected mycorrhizal roots. Some introns in the mtLSU region appear to be stable over years of cultivation and are ancestral to the G. intraradices clade. ,,Genetic diversity within G. intraradices is substantially higher than previously thought, although some mtLSU haplotypes are widespread. A restriction fragment length polymorphism approach also was developed to distinguish mtLSU haplotypes without sequencing. Using this molecular tool, intraspecific genetic variation of an AMF species can be studied directly in field plants. [source] Winning back more than words?THE CANADIAN GEOGRAPHER/LE GEOGRAPHE CANADIEN, Issue 1 2005Power, discourse, quarrying on the Niagara Escarpment This paper explores the controversy and public hearing on the proposed extension of the largest limestone quarry in Canada, operated by Dufferin Aggregates at Milton, Ontario. The quarry constitutes an important source of construction material for the nearby Greater Toronto Area. However, the quarry is protected by the provincial Niagara Escarpment Planning and Development Act and located inside the UNESCO-designated Niagara Escarpment Biosphere Reserve. The proposal has therefore attracted considerable opposition from the public institution charged with its protection, the Niagara Escarpment Commission, as well as environmental groups and local residents. To make sense of the tensions, conflicts and outcome of the Dufferin case, we consult and apply several critical literatures. We see the conflict as part of a transformation of the countryside from a space of production to a space of consumption, where there is a shift in emphasis from resource extractive to scenic and ecological landscape values, and the displacement of productive classes, farmers and workers, in favour of a service class of professionals and retirees. Within this transformation, we identify a ,power geometry' of actor networks of different coalition groups that form allegiances and engage in struggles at different geographic scales. These actor networks operate within the set frames of a dominant development discourse and a popular environmentalist discourse that both include and exclude other ways of seeing and managing the escarpment. Cet article examine la controverse et l'audience publique sur l'aggrandissement projetée de la plus vaste carrière de calcaire au Canada, operée par Dufferin Aggregates à Milton, Ontario. La carrière constitue une source importante de matériaux de construction pour la région métropolitaine de Toronto. Toutefois, cette carrière est non seulement protégée par la loi du développement et de l'aménagment de l'Escarpement du Niagara, mais elle est également située dans la Réserve Biosphère désignée par l'UNESCO. Cette proposition d'aggrandissement de la carrière a donc suscité l'opposition de la Commission de l'Escarpement du Niagara, institution publique désignée pour la protection, ainsi que de certains groupes environnementaux et résidents locaux. Afin d'examiner les tensions, conflits et résultat du cas de la carrière Dufferin, nous avons consulté et appliqué plusieurs littératures critiques. Nous considérons d'abord ce conflit comme faisant partie de la transformation de la campagne d'un site de production en un site de consommation, où l'emphase passe de l'extraction d'une resource à la revalorisation aesthétique et écologique du paysage, accompagnée par le déplacement des classes productives, agriculteurs et ouvriers, en faveur de la classe de services professionnels et retraités. Émergeant de cette transformation, nous identifions une ,géométrie de pouvoir , des réseaux d'acteurs issus de différentes coalitions formant des allégeances et s'engageant dans des formes de résistances à différentes échelles géographiques. Ces réseaux d'acteurs opèrent dans les paramètres d'un discours dominant de développement et d'un discours populaire d'environnementalisme qui tout à la fois inclus et exclus d'autres façons de voir et de gérer l'escarpement. [source] Risky subjects: changing geographies of employment in the automobile industryAREA, Issue 2 2001David Butz This paper examines employment in the Canadian automobile industry in terms of Beck's (1992) Risk Society. We demonstrate that risk transcends terms of employment, to encompass injury, lay-off, and displacement. Work becomes increasingly risky with the blurring of employment relations within and among three geographic scales: the globe, the locale and the plant. We argue for an embodied account of the experience of risk which emphasizes the inscription of different temporal and spatial configurations of work on the body. [source] A new model Gondwanan taxon: systematics and biogeography of the harvestman family Pettalidae (Arachnida, Opiliones, Cyphophthalmi), with a taxonomic revision of genera from Australia and New ZealandCLADISTICS, Issue 4 2007Sarah L. Boyer The phylogeny of the temperate Gondwanan harvestman family Pettalidae is investigated by means of a new morphological matrix of 45 characters, and DNA sequence data from five markers, including two nuclear ribosomal genes (18S rRNA and 28S rRNA), one nuclear protein coding gene (histone H3), and two mitochondrial genes,one protein coding (cytochrome c oxidase subunit I) and one ribosomal (16S rRNA). Phylogenetic analyses using an array of homology schemes (dynamic and static), criteria (parsimony and maximum likelihood), and sampling strategies (optimal trees versus Bayesian phylogenetics) all agree on the monophyly of Pettalidae as well as several of its subclades, each of which is restricted to a modern landmass. While most genera as traditionally defined are monophyletic, Rakaia and Neopurcellia, distributed across Queensland (Australia) and New Zealand, are not. Instead, the species from Queensland, previously described under three genera, constitute a well-supported clade, suggesting that in this case biogeography prevails over traditional taxonomy. A taxonomic emendation of the genera from Queensland and New Zealand is presented, and the new genus Aoraki is erected to include the species of the New Zealand denticulata group. A biogeographical hypothesis of the relationships of the former temperate Gondwana landmasses (with the exception of Madagascar) is presented, although ambiguity in the deep nodes of the pettalid tree renders such inference provisional. The data suggest that neither the South African fauna, the New Zealand fauna nor the Australian fauna is monophyletic but instead monophyly is found at smaller geographic scales (e.g., Western Australia, Queensland, NE South Africa). © The Willi Hennig Society 2007. [source] | |||||||||||||||||||||||||