Burkholderia species are ancient symbionts of legumes

Burkholderia has only recently been recognized as a potential nitrogen-fixing symbiont of legumes, but we find that the origins of symbiosis in Burkholderia are much deeper than previously suspected. We sampled 143 symbionts from 47 native species of Mimosa across 1800 km in central Brazil and found that 98% were Burkholderia . Gene sequences defined seven distinct and divergent species complexes within the genus Burkholderia . The symbiosis-related genes formed deep Burkholderia -specific clades, each specific to a species complex, implying that these genes diverged over a long period within Burkholderia without substantial horizontal gene transfer between species complexes.     

The Politics of Mediation: Local–Global Interactions in the Central Amazon of Brazil

The proliferation of a nongovernmental sector held the promise of linking local actors with national and international ones, thereby contributing to a highly participatory, Habermasian ideal in which the formerly marginalized would find greater participation and expression. Yet the role of international agents in community-based resource management projects has recently come under scrutiny. In addressing these issues in this article, I consider the roles of different interlocutors in two contrastive phases in an Amazonian community's movement to preserve its endangered fisheries. The comparative exercise demonstrates how institutional agents, by establishing a discourse that structures the criteria through which collective demands may be problematized, may inadvertently shift from mediation to domination, and from local partnering to local production.     

The New Immigration: An Interdisciplinary Reader

The New Immigration: An Interdisciplinary Reader. Marcelo M. Suarez-Orozco, Carola Suarez-Orozco, and Desiree Baolian Quin, eds. New York: Routledge, 2005. 366 pp.     

Effects of Season and Scale on Response of Elk and Mule Deer to Habitat Manipulation

Abstract: Manipulation of forest habitat via mechanical thinning or prescribed fire has become increasingly common across western North America. Nevertheless, empirical research on effects of those activities on wildlife is limited, although prescribed fire in particular often is assumed to benefit large herbivores. We evaluated effects of season and spatial scale on response of Rocky Mountain elk (Cervus elaphus) and mule deer (Odocoileus hemionus) to experimental habitat manipulation at the Starkey Experimental Forest and Range in northeastern Oregon, USA. From 2001 to 2003, 26 densely stocked stands of true fir (Abies spp.) and Douglas-fir (Pseudotsuga menziesii) were thinned and burned whereas 27 similar stands were left untreated to serve as experimental controls. We used location data for elk and mule deer collected during spring (1 Apr-14 Jun) and summer (15 Jun-31 Aug) of 1999–2006 to compare use of treated and untreated stands and to model effects of environmental covariates on use of treated stands. In spring, elk selected burned stands and avoided control stands within the study area (second-order selection; large scale). Within home ranges (third-order selection; small scale), however, elk did not exhibit selection. In addition, selection of treatment stands by elk in spring was not strongly related to environmental covariates. Conversely, in summer elk selected control stands and either avoided or used burned stands proportional to their availability at the large scale; patterns of space use within home ranges were similar to those observed in spring. Use of treatment stands by elk in summer was related to topography, proximity to roads, stand size and shape, and presence of cattle, and a model of stand use explained 50% of variation in selection ratios. Patterns of stand use by mule deer did not change following habitat manipulation, and mule deer avoided or used all stand types proportional to their availability across seasons and scales. In systems similar to Starkey, manipulating forest habitat with prescribed fire might be of greater benefit to elk than mule deer where these species are sympatric, and thus maintaining a mixture of burned and unburned (late successional) habitat might provide better long-term foraging opportunities for both species than would burning a large proportion of a landscape.