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America
Kinds of America Selected AbstractsIS TIGHTER FISCAL POLICY EXPANSIONARY UNDER FISCAL DOMINANCE?: HYPERCROWDING OUT IN LATIN AMERICACONTEMPORARY ECONOMIC POLICY, Issue 2 2010WILLIAM C. GRUBEN Hypercrowding out occurs when fiscally dominated governments' domestic credit demands are so intrusive to a nation's financial system that a move toward fiscal surplus lowers interest rates and increases growth. We sample nine Latin American countries to test for these relationships. The impulse-response results of vector error correction models, six nations test positive for these two connections, suggesting market concern despite recent efforts toward fiscal balance. (JEL E430, E620, O230, O540) [source] REALITIES OF HEALTH POLICY IN NORTH AMERICA: GOVERNMENT IS THE PROBLEM, NOT THE SOLUTIONECONOMIC AFFAIRS, Issue 4 2008Brett J. Skinner Healthcare systems in North America are sometimes criticised as being expensive or socially irresponsible relative to comparable systems in OECD (Organisation for Economic Co-operation and Development) countries or regions. These perceived health system failures are often mistakenly attributed to greater private sector involvement in the delivery of medical care or the provision of medical insurance in Canada and the USA. However, the exact nature and scope of state involvement in the healthcare sector in Canada and the USA is also often misunderstood and underestimated. This paper presents a fact-based context for evaluating health policy in North America. [source] BANKING SPREADS IN LATIN AMERICAECONOMIC INQUIRY, Issue 4 2009R. GASTON GELOS Intermediation spreads in Latin America are high by international standards. This paper examines the determinants of bank interest margins in that region using bank- and country-level data from 85 countries, including 14 Latin American economies. The results suggest that Latin America has higher interest rates, less efficient banks, and larger reserve requirements than other regions and that these factors have a significant impact on spreads. However, Latin American countries do not differ markedly from their peers in other aspects that are found important in determining the cost of financial intermediation, such as inflation and bank profit taxation. (JEL E43, E44, G21, O54) [source] BEARING WITNESS: TOBACCO, PUBLIC HEALTH AND HISTORY THE CIGARETTE CENTURY: THE RISE, FALL AND DEADLY PERSISTENCE OF THE PRODUCT THAT DEFINED AMERICA.ADDICTION, Issue 7 20092000., Edited by A.M. Brandt MARKETING HEALTH: SMOKING AND THE DISCOURSE OF PUBLIC HEALTH IN BRITAIN First page of article [source] ALCOHOL PROBLEMS IN NATIVE AMERICA: THE UNTOLD STORY OF THE RESISTANCE AND RECOVERY,THE TRUTH ABOUT THE LIEADDICTION, Issue 1 2007JOSEPH WESTERMEYER No abstract is available for this article. [source] EVIDENCE FOR HISTORICAL INTROGRESSION ALONG A CONTACT ZONE BETWEEN TWO SPECIES OF CHAR (PISCES: SALMONIDAE) IN NORTHWESTERN NORTH AMERICAEVOLUTION, Issue 5 2002Z. Redenbach Abstract Phylogeographic analyses can yield valuable insights into the geographic and historical contexts of contact and hybridization between taxa. Two species of char (Salmonidae), Dolly Varden (Salvelinus malma) and bull trout (S. confluentus) have largely parapatric distributions in watersheds of northwestern North America. They are, however, sympatric in several localities and hybridization and some introgression occurs across a broad area of contact. We conducted a comparative phylogenetic analysis of Dolly Varden and bull trout to gain a historical perspective of hybridization between these species and to test for footprints of historical introgression. We resolved two major Dolly Varden mitochondrial DNA (mtDNA) clades (with 1.4,2.2% sequence divergence between haplotypes) that had different geographical distributions. Clade N is distributed across most of the range of Dolly Varden, from southern British Columbia through to the Kuril Islands in Asia. Clade S had a much more limited distribution, from Washington state, at the southern limit of the Dolly Varden range, to the middle of Vancouver Island. The distribution and inferred ages of the mtDNA clades suggested that Dolly Varden survived the Wisconsinan glaciation in a previously unsuspected refuge south of the ice sheet, and that Dolly Varden and bull trout were probably in continuous contact over most of the last 100,000 years. When bull trout were included in the phylogenetic analysis, however, the mtDNA of neither species was monophyletic: Clade S Dolly Varden clustered within the bull trout mtDNA clade. This pattern was discordant with two nuclear phylogenies produced (growth hormone 2 and rRNA internal transcribed sequence 1), in which Dolly Varden and bull trout were reciprocally monophyletic. This discordance between mtDNA- and nDNA-based phylogenies indicates that historical introgression of bull trout mtDNA into Dolly Varden occurred. Percent sequence divergence within these introgressed Dolly Varden (clade S) was 0.2,0.6%, implying that the introgression occurred prior to the most recent glaciation. Our analysis and other evidence of contact between divergent lineages in northwestern North America strongly suggests that the area may be the site of previously unsuspected suture zones of aquatic biotas. [source] LATE-GLACIAL GLACIER EVENTS IN SOUTHERNMOST SOUTH AMERICA: A BLEND OF ,NORTHERN' AND 'SOUTHERN' HEMISPHERIC CLIMATIC SIGNALS?GEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 2 2005D.E. SUGDEN ABSTRACT. This paper examines new geomorphological, chronological and modelling data on glacier fluctuations in southernmost South America in latitudes 46,55°S during the last glacial,interglacial transition. Establishing leads and lags between the northern and southern hemispheres and between southern mid-latitudes and Antarctica is key to an appreciation of the mechanisms and resilience of global climate. This is particularly important in the southern hemisphere where there is a paucity of empirical data. The overall structure of the last glacial cycle in Patagonia has a northern hemisphere signal. Glaciers reached or approached their Last Glacial Maxima on two or more occasions at 25,23 ka (calendar) and there was a third less extensive advance at 17.5 ka. Deglaciation occurred in two steps at 17.5 ka and at 11.4 ka. This structure is the same as that recognized in the northern hemisphere and taking place in spite of glacier advances occurring at a time of high southern hemisphere summer insolation and deglaciation at a time of decreasing summer insolation. The implication is that at orbital time scales the,northern' signal dominates any southern hemisphere signal. During deglaciation, at a millennial scale, the glacier fluctuations mirror an antiphase 'southern' climatic signal as revealed in Antarctic ice cores. There is a glacier advance coincident with the Antarctic Cold Reversal at 15.3,12.2 ka. Furthermore, deglaciation begins in the middle of the Younger Dryas. The implication is that, during the last glacial,interglacial transition, southernmost South America was under the influence of sea surface temperatures, sea ice and southern westerlies responding to conditions in the 'southern' Antarctic domain. Such asynchrony may reflect a situation whereby, during deglaciation, the world is more sensitized to fluctuations in the oceanic thermohaline circulation, perhaps related to the bipolar seesaw, than at orbital timescales. [source] CHRONOLOGY OF THE LAST GLACIATION IN CENTRAL STRAIT OF MAGELLAN AND BAHÍA INÚTIL, SOUTHERNMOST SOUTH AMERICAGEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 2 2005R.D. McCULLOCH ABSTRACT. Glacier fluctuations in the Strait of Magellan tell of the climatic changes that affected southern latitudes at c. 53,55°S during the Last Glacial Maximum (LGM) and Late-glacial/Holocene transition. Here we present a revised chronology based on cosmogenic isotope analysis, 14C assays, amino acid racemisation and tephrochronology. We unpick the effect of bedrock-derived lignite which has affected many 14C dates in the past and synthesise new and revised dates that constrain five glacier advances (A to E). Advance A is prior to the LGM. LGM is represented by Advance B that reached and largely formed the arcuate peninsula Juan Mazia. Carbon-14and 10Be dating show it occurred after 31 250 cal yrs BP and culminated at 25 200,23 100 cal yrs BP and was then followed by the slightly less extensive advance C sometime before 22 400,20 300 cal yrs BP. This pattern of an early maximum is found elsewhere in South America and more widely. Stage D, considerably less extensive, culminated sometime before 17 700,17 600 cal yrs BP and was followed by rapid and widespread glacier retreat. Advance E, which dammed a lake, spanned 15 500,11770 cal yrs BP. This latter advance overlaps the Bølling-Allerød interstadials and the glacier retreat occurs during the peak of the Younger Dryas stadial in the northern hemisphere. However, the stage E advance coincides with the Antarctic Cold Reversal (c. 14800,12700 cal yrs BP) and may indicate that some millennial-scale climatic fluctuations in the Late-glacial period are out of phase between the northern and southern hemispheres. [source] THIS IS NOT AMERICA: EMBEDDING THE COGNITIVE-CULTURAL URBAN ECONOMYGEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 2 2010Robert C. Kloosterman ABSTRACT. The aim of this article is to broaden the epistemological basis for investigating the current shift to cognitive-cultural economies and the resurgence of cities and its socio-spatial articulation. The point of departure here is that the drivers of the structural changes are indeed more or less ubiquitous, but are played out in different national institutional and urban contexts resulting in potentially diverging cognitive-cultural economies. Four main drivers of change after 1980 are distinguished. The first is the rise of a new technological paradigm based on digital technology. The second is the thrust towards deregulation and privatization as planks of the neo-liberal political programme. The third is the intensification of all kinds of linkages between regions across the globe. The fourth driver constitutes the processes of individualization and increasing reflexivity that have fragmented consumer markets. By identifying distinct filters which might shape and mould the impact of these more general drivers on concrete urban areas, a comprehensive framework is presented that can be used to analyse and compare the trajectories of cities while linking them to a larger narrative of societal change. A central line of reasoning is that agglomeration economies , pivotal in Allen Scott's analysis of the emergence of a cognitive-cultural economy , are themselves embedded in concrete social and institutional contexts which impact on how they are played out. To make this point, we build upon Richard Whitley's business systems. Given this institutional diversity, we expect that various institutional contexts will generate different cognitive-cultural economies. [source] SHIFTING SYNANTHROPY OF THE CROW IN EASTERN NORTH AMERICAGEOGRAPHICAL REVIEW, Issue 2 2010DANIEL W. GADE abstract. The American crow (Corvus brachyrhynchos) falls into a category of wild organisms, called "synanthropes," that have developed an affinity for, or dependency on, human interventions in the landscape. The distribution and numbers of crows in North America east of the Mississippi River have been largely tied to the anthropogenic fragmentation of the forest. As ground feeders, crows need open space for foraging, but they also need trees for nesting and roosting. Conflicts between corvids and people centered on the former's damage to agriculture. Both Native American peoples and Euro-American settlers sought to thwart corvine preference for maize through a series of ingenious measures. After 1950 rural concern about corvine depredations greatly diminished. The appearance of large winter roosts in cities shifted the conflict with crows. Like humans, crows have undergone change, and their synanthropic character can be seen as fundamental to their biogeography. [source] THE PENTECOSTAL MOVEMENT AND BASIC ECCLESIAL COMMUNITIES IN LATIN AMERICA: SOCIOLOGICAL THEORIES AND THEOLOGICAL DEBATES,INTERNATIONAL REVIEW OF MISSION, Issue 361 2002MICHAEL BERGUNDER First page of article [source] ESALEN: AMERICA AND THE RELIGION OF NO RELIGION.JOURNAL FOR THE SCIENTIFIC STUDY OF RELIGION, Issue 3 2007By Jeffrey J. Kripal No abstract is available for this article. [source] AFRICA,SOUTH AMERICA: Bank of the SouthAFRICA RESEARCH BULLETIN: ECONOMIC, FINANCIAL AND TECHNICAL SERIES, Issue 9 2009Article first published online: 2 NOV 200 No abstract is available for this article. [source] The Journal of Industrial Ecology gratefully acknowledges the financial support of THE EDUCATIONAL FOUNDATION OF AMERICAJOURNAL OF INDUSTRIAL ECOLOGY, Issue 3 2008Article first published online: 25 SEP 200 [source] 2002 ANNUAL MEETING OF THE PHYCOLOGICAL SOCIETY OF AMERICAJOURNAL OF PHYCOLOGY, Issue 4 2001Article first published online: 21 DEC 200 No abstract is available for this article. [source] SYNTHESIS OF MOLECULAR RESEARCH ON BATRACHOSPERMUM HELMINTHOSUM (RHODOPHYTA) FROM STREAM REACHES IN EASTERN NORTH AMERICAJOURNAL OF PHYCOLOGY, Issue 2001Article first published online: 24 SEP 200 Vis, M. L., Hall, M. M., Machesky, N. J. & Miller, E. J. Department of Environmental and Plant Biology, Ohio University, Athens, OH 45701 USA The freshwater red alga Batrachospermum helminthosum was collected from eleven streams throughout the species range in eastern North America as follows: three stream reaches from Ohio, and one each from Michigan, Indiana, Tennessee, Louisiana, North Carolina, Connecticut, Rhode Island and Massachusetts. The molecular marker technique of inter-simple sequence repeats (ISSR) and sequence data from the plastid encoded rubisco large subunit gene (rbcL), the mitochondrial COX2-COX3 gene spacer region, and the nuclear region of ITS1-5.8S rDNA-ITS2 were employed to examine biogeographic trends in this alga. Analysis of the rbcL sequence revealed 5 genotypes with one genotype representing individuals from seven stream reaches. Data from the ISSR molecular markers gave a distinct banding pattern for each of 165 individuals examined. ISSR results showed all individuals within a reach clustered together but did not provide well-defined groupings based on stream reach. The sequence data for the COX2-COX3 gene spacer was invariant among individuals from a stream reach. The individuals from Connecticut, Rhode Island and 2 Ohio stream reaches were identical and similarly the individuals from the North Carolina and another Ohio location did not vary in sequence so that seven genotypes were recorded among the individuals from the eleven stream reaches. Analysis of the ITS1-5.8S rDNA-ITS2 region showed sequence variation not only among individuals from different streams but also among individuals from the same reach. The utility and congruency of these data sets to answer biogeographic questions will be discussed. [source] 2002 ANNUAL MEETING OF THE PHYCOLOGICAL SOCIETY OF AMERICAJOURNAL OF PHYCOLOGY, Issue 1 2001Article first published online: 21 DEC 200 [source] A SYSTEMATIC STUDY OF GIGAR-TINACEAE FROM PACIFIC NORTH AMERICA BASED ON MOLECULAR AND MORPHOLOGICAL EVIDENCEJOURNAL OF PHYCOLOGY, Issue 2000J.R. Hughey Greater than 50 species of Gigartinaceae have been described from Pacific North America, about half of which are currently recognized. Although the family is treated extensively in the taxonomic literature, many of the species are still confused and a comprehensive revision is required. We sequenced the rbcL (RuBisCO) gene and ITS (Internal Transcribed Spacer) 1, 2, and 5.8S regions from a large number of recent collections and identified a discrete of number data sets. These were analysed in comparison with the morphological evidence for each of the taxa. Uncertain of the possibility that our operational taxonomic units may not correspond to the types, we developed a protocol for isolating PCR-friendly DNA from herbarium specimens, some reaching back as far as 1670. The DNA profiles of types and historically important specimens were compared to those for recently collected silica gel-dried and formalin-fixed material and assigned correct names. Species studied ranged from Alaska to Mexico and the Gulf of California and were compared to outgroup taxa from Pacific South America and the Southern Ocean. Particular attention was paid to variations in morphology as they relate to habitat with emphasis on the presence or absence of different morphological forms among sympatric and allopatric populations. We recognize 10 species in Chondracanthus (including one new combination and one new species) and 16 species in Mazzaella (including two new combinations and two new species). Finally, we tested a phylogenetic hypothesis inferred for the Gigartinaceae from rbcL sequences for congruence with one generated from ITS sequences. [source] THE REDISCOVERY OF AMERICAN SACRED SPACESRELIGIOUS STUDIES REVIEW, Issue 4 2004Louis P. Nelson Book reviewed in this article: THE HERMENEUTICS OF SACRED ARCHITECTURE: EXPERIENCE, INTERPRETATION, COMPARISON (2 volumes) By Lindsay Jones TEMPLES OF GRACE: THE MATERIAL TRANSFORMATION OF CONNECTICUT'S CHURCHES, 1790,1840 By Gretchen Buggeln WHEN CHURCH BECAME THEATRE: THE TRANSFORMATION OF EVANGELICAL ARCHITECTURE AND WORSHIP IN THE NINETEENTH-CENTURY AMERICA By Jeanne Kilde PRAYERS IN STONE: CHRISTIAN SCIENCE ARCHITECTURE IN THE UNITED STATES, 1894,1930 By Paul Eli Ivey SHUL WITH A POOL: THE "SYNAGOGUE-CENTER" IN AMERICAN JEWISH HISTORY By David Kaufman MYTHS IN STONE: RELIGIOUS DIMENSIONS OF WASHINGTON, D.C. By Jeffrey F. Meyer UGLY AS SIN: WHY THEY CHANGED OUR CHURCHES FROM SACRED PLACES TO MEETING SPACES AND HOW WE CAN CHANGE THEM BACK AGAIN By Michael S. Rose BUILDING FROM BELIEF: ADVANCE, RETREAT, AND COMPROMISE IN THE REMAKING OF CATHOLIC CHURCH ARCHITECTURE By Michael E. DeSanctis ARCHITECTURE IN COMMUNION: IMPLEMENTING THE SECOND VATICAN COUNCIL THROUGH LITURGY AND ARCHITECTURE By Steven J. Schloeder [source] EXCHANGE RATE REGIMES AND MONETARY COOPERATION: LESSONS FROM EAST ASIA AND LATIN AMERICA,THE JAPANESE ECONOMIC REVIEW, Issue 3 2004TAKATOSHI ITO This paper analyses the mechanisms of, and draws lessons from, currency crises in Asian and Latin American countries in the 1990s and 2000s. In Asian countries fiscal deficits were insignificant in size, and were not part of a crisis trigger, while in Latin America they played a major role in the crisis story. Crisis management by international financial institutions has been evolving over the last 10 years, and private-sector involvement (PSI) has occupied centre-stage in efforts to reform the international financial architecture. Sovereign debts, a focus of PSI discussions, were neither a cause nor a propagation of the Asian crises. [source] ACADEMIC SURGERY IN NORTH AMERICAANZ JOURNAL OF SURGERY, Issue 5 2008Murray F. Brennan MD No abstract is available for this article. [source] BRIDGING THE AMERICAS: HUMBOLDTIAN LEGACIESGEOGRAPHICAL REVIEW, Issue 3 2006Anne Buttimer No abstract is available for this article. [source] CHEMICAL CHARACTERIZATION OF TIN-LEAD GLAZED POTTERY FROM THE IBERIAN PENINSULA AND THE CANARY ISLANDS: INITIAL STEPS TOWARD A BETTER UNDERSTANDING OF SPANISH COLONIAL POTTERY IN THE AMERICAS,ARCHAEOMETRY, Issue 4 2009J. G. IÑAÑEZ Majolica pottery was the most characteristic tableware produced in Europe during the Medieval and Renaissance periods. Because of the prestige and importance attributed to this ware, Spanish majolica was imported in vast quantities into the Americas during the Spanish Colonial period. A study of Spanish majolica was conducted on a set of 186 samples from the 10 primary majolica production centres on the Iberian Peninsula and 22 sherds from two early colonial archaeological sites on the Canary Islands. The samples were analysed by neutron activation analysis (NAA), and the resulting data were interpreted using an array of multivariate statistical approaches. Our results show a clear discrimination between different production centres, allowing a reliable provenance attribution of the sherds from the Canary Islands. [source] Confidentiality, privacy, and public safety: Managing information disclosure disputes between hospitals and law enforcement agenciesCONFLICT RESOLUTION QUARTERLY, Issue 2 2006R. Kyle Friesen This article explores the conflict that exists throughout North America from the intersection of privacy rights of patients and law enforcement needs for access to patients' personal records and the process by which a disclosure protocol was successfully negotiated and implemented. [source] The impact of victim-offender mediation: A cross-national perspectiveCONFLICT RESOLUTION QUARTERLY, Issue 3 2000Mark S. Umbreit The field of victim-offender mediation, now in its third decade, has grown extensively throughout North America and Europe, with programs in more than twelve hundred communities. This article reports on results from three related studies on the consequences of participating in victim-offender mediation, including programs in four of the United States (Umbreit, 1996, 1994a, 1994b; Umbreit and Coates, 1993), four provinces of Canada (Umbreit, 1999, 1995c), and two cities in England (Umbreit and Roberts, 1996). VOM is implemented differently in various places, reflecting cultural norms and mores. Given innumerable ways of doing victim-offender mediation, are there common experiences shared among participants that can inform program delivery and justice policy? The VOM model was found to be a highly transportable and flexible program in diverse settings. High levels of client satisfaction with both the process and outcome were found, and a high level of fairness was expressed. VOM continues to be a promising model, reflecting the principles of the restorative justice movement and offering a firm foundation of practice wisdom and research from which other newer forms of victim-offender dialogue, such as family group conferences, circles, and boards, can benefit (Bazemore and Umbreit, 1999). [source] Outcomes and Prognostic Factors of Systolic as Compared With Diastolic Heart Failure in Urban AmericaCONGESTIVE HEART FAILURE, Issue 1 2005Peter A. McCullough MD We sought to describe a large heart failure (HF) population with respect to systolic and diastolic abnormalities in terms of demographics, echocardiographic parameters, and survival. Using data abstracted from the Resource Utilization Among Congestive Heart Failure (REACH) study, a targeted subpopulation of 3471 patients had electrocardiographic, echocardiographic, and clinical data taken from automated sources during the first year of diagnosis. Among the HF population, 1811 (52.2%) had diastolic HF. Prevalence of diastolic HF trended with age, from 46.4% in those less than 45 years to 58.7% in those 85 years or older (p=0.001 for trend). Patients with diastolic HF had a higher mean ejection fraction (55.7% vs. 28.0%), lower left ventricular end-systolic diameter (3.11 vs. 4.74 cm), and lower left atrium: aortic outlet ratio (1.28 vs. 1.38) (p=0.001 for each comparison). Annualized age, sex, and race-adjusted mortality were 11.2% and 13.0% for those with diastolic and systolic HF, respectively (p=0.001). In a large, racially mixed, urban HF population, those with diastolic HF predominate and enjoy better-adjusted survival than counterparts with systolic HF. [source] Conservation Challenges for the Austral and Neotropical America SectionCONSERVATION BIOLOGY, Issue 4 2009GERARDO CEBALLOS América Austral y Neotropical; América Latina; desarrollo de capacidades Abstract:,The Austral and Neotropical America (ANA) section of the Society for Conservation Biology includes a vast territory with some of the largest relatively pristine ecosystems in the world. With more than 573 million people, the economic growth of the region still depends strongly on natural resource exploitation and still has high rates of environmental degradation and biodiversity loss. A survey among the ANA section membership, with more than 700 members, including most of the section's prominent ecologists and conservationists, indicates that lack of capacity building for conservation, corruption, and threats such as deforestation and illegal trade of species, are among the most urgent problems that need to be addressed to improve conservation in the region. There are, however, strong universities and ecology groups taking the lead in environmental research and conservation, a most important issue to enhance the ability of the region to solve conservation and development conflicts. Resumen:,La sección América Austral y Neotropical (AAN) de la Sociedad para la Biología de la Conservación incluye un vasto territorio con unos de los ecosistemas relativamente prístinos más extensos del mundo. Con más de 573 millones de habitantes, el crecimiento económico de la región aun depende fuertemente de la explotación de recursos naturales y aún tiene altas tasas de degradación ambiental y pérdida de biodiversidad. Un sondeo de la membresía de la sección AAN, con más de 700 miembros, incluyendo la mayoría de los ecólogos y conservacionistas más prominentes de la sección, indica que la carencia de desarrollo de capacidades para la conservación, la corrupción y amenazas como la deforestación y el comercio ilegal de especies, son algunos de los problemas que requieren ser atendidos más urgentemente para mejorar la conservación en la región. Sin embargo, hay universidades y grupos ecológicos que están tomando el liderazgo en investigación ambiental y conservación, un tema importante para mejorar la habilidad de la región para resolver conflictos de conservación y desarrollo. [source] Availability of Formal Academic Programs in Conservation Biology in Latin AmericaCONSERVATION BIOLOGY, Issue 6 2007Martín Mendez First page of article [source] One Hundred Fifty Years of Change in Forest Bird Breeding Habitat: Estimates of Species DistributionsCONSERVATION BIOLOGY, Issue 6 2005LISA A. SCHULTE aptitud del hábitat; ecología aviar; ecología de paisaje; planificación de conservación Abstract:,Evaluating bird population trends requires baseline data. In North America the earliest population data available are those from the late 1960s. Forest conditions in the northern Great Lake states (U.S.A.), however, have undergone succession since the region was originally cut over around the turn of the twentieth century, and it is expected that bird populations have undergone concomitant change. We propose pre-Euro-American settlement as an alternative baseline for assessing changes in bird populations. We evaluated the amount, quality, and distribution of breeding bird habitat during the mid-1800s and early 1990s for three forest birds: the Pine Warbler (Dendroica pinus), Blackburnian Warbler (D. fusca), and Black-throated Green Warbler (D. virens). We constructed models of bird and habitat relationships based on literature review and regional data sets of bird abundance and applied these models to widely available vegetation data. Original public-land survey records represented historical habitat conditions, and a combination of forest inventory and national land-cover data represented current conditions. We assessed model robustness by comparing current habitat distribution to actual breeding bird locations from the Wisconsin Breeding Bird Atlas. The model showed little change in the overall amount of Pine Warbler habitat, whereas both the Blackburnian Warber and the Black-throated Green Warbler have experienced substantial habitat losses. For the species we examined, habitat quality has degraded since presettlement and the spatial distribution of habitat shifted among ecoregions, with range expansion accompanying forest incursion into previously open habitats or the replacement of native forests with pine plantations. Sources of habitat loss and degradation include loss of conifers and loss of large trees. Using widely available data sources in a habitat suitability model framework, our method provides a long-term analysis of change in bird habitat and a presettlement baseline for assessing current conservation priority. Resumen:,La evaluación de tendencias de las poblaciones de aves requiere de datos de referencia. En Norte América, los primeros datos disponibles de poblaciones son del final de la década de 1960. Sin embargo, las condiciones de los bosques en los estados de los Grandes Lagos (E.U.A.) han experimentado sucesión desde que la región fue talada en los inicios del siglo veinte, y se espera que las poblaciones de aves hayan experimentado cambios concomitantes. Proponemos que se considere al período previo a la colonización euro americana como referencia alternativa para evaluar los cambios en las poblaciones de aves. Evaluamos la cantidad, calidad y distribución del hábitat para reproducción de tres especies de aves de bosque (Dendroica pinus, D. fusca y D. virens) a mediados del siglo XIX e inicios del XX. Construimos modelos de las relaciones entre las aves y el hábitat con base en la literatura y conjuntos de datos de abundancia de aves y los aplicamos a los datos de vegetación ampliamente disponibles. Los registros topográficos de tierras públicas originales representaron las condiciones históricas del hábitat, y una combinación de datos del inventario forestal y de cobertura de suelo representaron las condiciones actuales. Evaluamos la robustez del modelo mediante la comparación de la distribución de hábitat actual con sitios de reproducción de aves registrados en el Wisconsin Breeding Bird Atlas. El modelo mostró poco cambio en la cantidad total de hábitat de Dendroica pinus, mientras que tanto D. fusca como D. virens han experimentado pérdidas sustanciales de hábitat. Para las especies examinadas, la calidad del hábitat se ha degradado desde antes de la colonización y la distribución espacial del hábitat cambió entre ecoregiones, con la expansión del rango acompañando la incursión de bosques en hábitats anteriormente abiertos o el reemplazo de bosques nativos con plantaciones de pinos. Las fuentes de pérdida y degradación de hábitats incluyen la pérdida de coníferas y de árboles grandes. Mediante la utilización de fuentes de datos ampliamente disponibles en un modelo de aptitud de hábitat, nuestro método proporciona un análisis a largo plazo de los cambios en el hábitat de aves y una referencia precolonización para evaluar prioridades de conservación actuales. [source] Susceptibility of a Northern Hardwood Forest to Exotic Earthworm InvasionCONSERVATION BIOLOGY, Issue 4 2005MICHAEL J. GUNDALE Acer saccharum; Bosque Nacional Ottawa; lombrices invasoras; Sylvania Wilderness Area; uso del suelo Abstract:,Numerous exotic earthworm species are colonizing northern hardwood forests of North America, where no native earthworms exist. Upon invasion, earthworms have been shown to alter the surface soil environment and plant populations and communities. We sought to identify land-use factors in the Ottawa National Forest (ONF), Michigan (U.S.A.), that contribute to earthworm invasion in forest dominated by sugar maple (Acer saccharum Marsh.) so that the susceptibility to additional colonization could be evaluated. We sampled earthworm communities in Sylvania Wilderness Area, a unique old-growth hardwood forest, and nonwilderness sites influenced by recreational fishing, recent timber harvesting, or roads. All the nonwilderness sites contained one to five species of exotic earthworms. In contrast, only 50% of wilderness sites contained exotic earthworms, all of a single species. Nonwilderness sites also had thinner litter and duff layers, higher soil C and N content, and higher nitrogen mineralization potentials than Sylvania sites. Two central differences between Sylvania and nonwilderness sites were that all nonwilderness sites were in close contact with roads and had a history of timber harvest, whereas these factors were not present in Sylvania Wilderness Area. Using average rates of colonization, we constructed two geographic information system models to estimate the percentage of sugar maple on the ONF falling within a theoretical 100-year invasion distance of roads and of second-growth sugar maple as relative indices of susceptibility to invasion. Both models indicated high susceptibility to invasion, with 91.7% and 98.9% of sugar maple habitat falling within a theoretical 100-year invasion distance of roads or historical harvests, respectively. Resumen:,Numerosas especies de lombrices exóticas están colonizando los bosques boreales, en los que previamente no existían lombrices terrestres nativas. Por encima de la invasión, se ha demostrado que las lombrices alteran el ambiente superficial del suelo, así como a las comunidades y poblaciones de plantas. Tratamos de identificar factores de uso del suelo en el Bosque Nacional Ottawa (BNO), Michigan, E. U. A., que contribuyen a la invasión de lombrices en bosques dominados por arces (Acer saccharum Marsh.), para poder evaluar la susceptibilidad a futuras invasiones. Muestreamos comunidades de lombrices en Sylvania Wilderness Area, un bosque maduro único, y en sitios no silvestres influenciados por pesca deportiva, cosecha reciente de madera o caminos. Todas las áreas no silvestres contenían 1 - 5 especies de lombrices exóticas. En contraste, solo 50% de los sitios silvestres contenían lombrices exóticas, todas de una sola especie. Los sitios no silvestres también tenían capas de hojarasca y de mantillo más delgadas, mayor contenido de C y N del suelo y mayor potencial de mineralización del nitrógeno que los sitios en Sylvania. Dos diferencias centrales entre Sylvania y los sitios no silvestres fueron que estos estaban en contacto cercano con caminos y tenían una historia de cosecha de madera, mientras que estos factores no estuvieron presentes en Sylvania Wilderness Area. Utilizando tasas promedio de colonización, construimos dos modelos de sistemas de información geográfica para estimar el porcentaje de arces en el BNO que queda a una distancia teórica de invasión en 100 años; con caminos y arce de crecimiento secundario como índices relativos de susceptibilidad a la invasión. Ambos modelos indicaron alta susceptibilidad a la invasión, con 91.7% y 98.9% del hábitat de arce dentro de la distancia teórica de invasión en 100 años o con cosechas históricas, respectivamente. [source] | ||||||||||||||||||||||||||||||||||||||||||||||