932 resultados para Gale, George W.
Resumo:
The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon(1-3). With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses(4-9). As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world's major tropical regions. Our analysis reveals great variation in reserve `health': about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.
Resumo:
Competition theory predicts that local communities should consist of species that are more dissimilar than expected by chance. We find a strikingly different pattern in a multicontinent data set (55 presence-absence matrices from 24 locations) on the composition of mixed-species bird flocks, which are important sub-units of local bird communities the world over. By using null models and randomization tests followed by meta-analysis, we find the association strengths of species in flocks to be strongly related to similarity in body size and foraging behavior and higher for congeneric compared with noncongeneric species pairs. Given the local spatial scales of our individual analyses, differences in the habitat preferences of species are unlikely to have caused these association patterns; the patterns observed are most likely the outcome of species interactions. Extending group-living and social-information-use theory to a heterospecific context, we discuss potential behavioral mechanisms that lead to positive interactions among similar species in flocks, as well as ways in which competition costs are reduced. Our findings highlight the need to consider positive interactions along with competition when seeking to explain community assembly.
Resumo:
Wydział Nauk Politycznych i Dziennikarstwa: Zakład Stosunków Międzynarodowych
Resumo:
Desde el segundo gobierno de George Walker Bush, estudiosos de las Relaciones Internacionales, analistas políticos, periodistas y los medios de comunicación en general, manifestaron su preocupación por el lenguaje religioso que dicho presidente usaba en sus discursos, y por la forma como las posturas religiosas del gobierno Bush estaban afectando la política exterior de los Estados Unidos. Surgieron hipótesis que indicaban una fuerte influencia evangélica en la toma de decisiones del mandatario norteamericano en los temas internacionales, sobresaliendo en estas consideraciones las relaciones entre Estados Unidos e Israel. El hecho de que las ideas religiosas se mezclaran con la política y pudiesen dirigir las relaciones entre los Estados causo bastante conmoción. Especialmente en un país donde la religión y la política se creían separadas una de la otra. Una relación digna de ser analizada en la medida en que parecía estar afectando la política de Estados Unidos hacia Medio Oriente; punto clave de los temas geopolíticos más críticos de hoy en día como lo son el terrorismo, el petróleo y el llamado “choque de civilizaciones”. La cooperación entre Estados Unidos e Israel y la política exterior estadounidense hacia el Medio Oriente fueron temas prioritarios en la agenda de la administración de George W.Bush. La cuestión clave era entonces comprobar si efectivamente dichas políticas fueron una en prioridad debido a la presión de los grupos evangélicos en el gobierno republicano de Bush hijo, o por el contrario, si la política de cooperación con Israel respondía más a una política de Estado que trasciende la coyuntura del gobierno Bush.
Resumo:
Este estudio de caso, pretende analizar el uso de las herramientas de marketing político, desde las elecciones primarias hasta la elección presidencial en el 2004 en Estados Unidos, en la que George W. Bush del Partido Republicano busca la reelección frente a su rival John F. Kerry del Partido Demócrata.
Resumo:
Bound with the author's Peck's boss book. [Chicago], 1900.