Field and remotely sensed measures of soil and vegetation carbon and nitrogen across an urbanization gradient in the Boston metropolitan area

Understanding the impact of urbanization on terrestrial biogeochemistry is critical for addressing society’s grand challenge of global environmental change. We used field observations and remotely sensed data to quantify the effects of urbanization on vegetation and soils across a 100-km urbanization gradient extending from Boston to Harvard Forest and Worcester, MA. At the field-plot scale, the normalized difference vegetation index (NDVI) was positively correlated with aboveground biomass (AGB) and foliar nitrogen (N) content and negatively correlated with impervious surface fraction. Unlike previous studies, we found no significant relationship between NDVI or impervious surface area (ISA) fraction and foliar N concentration. Patterns in foliar N appeared to be driven more strongly by changes in species composition rather than phenotypic plasticity across the urbanization gradient. For forest and non-residential development, soil nitrogen content increased with urban intensity. In contrast, residential land had consistently high soil N content across the gradient of urbanization. When field observations were scaled-up to the Boston Metropolitan Statistical Area (MSA), we found that soil and vegetation N content were negatively correlated with ISA fraction, an indicator of urban intensity. Our results demonstrated the importance of accounting for the influence of impervious surfaces when scaling field data across urban ecosystems. The combination of field data with remote sensing holds promise for disentangling the complex interactions that drive biogeochemical cycling in urbanizing landscapes. Empirical data that accurately characterize variations in urban biogeochemistry are critical to gain a mechanistic understanding of urban ecosystem function and to guide policy makers and planners in developing ecologically sensitive development strategies.     

L'émergence d'un nouveau mode de gouvernement local des réseaux en Allemagne. Une ville moyenne et son Stadtwerk face au processus de libéralisation

On the basis of a long-term study of a Stadtwerk located in a middle-sized town, questions are raised about changes in the local governance of networks in Germany. Neoliberal reforms and the budgetary crisis at the communal level are powerful factors driving change, which, for municipal authorities, reflects not a loss of power as such but a transformation of the relations it used to have with its Stadtwerk. A new type of interaction is emerging; it is much more formalized and based on standing relatively clear of politics. Municipal authorities are taking back the role of strategic and financial leadership that had been downplayed during the previous period characterized by a monopoly and communal prosperity.     

A post-apartheid paradigm? a view from the outside

The South African student movements of 2015 and 2016 have critically recalled the question: how to dismantle the thinking inherited from apartheid? More than twenty years after the fall of the racist regime, this question still haunt South African humanities. While the term “post-apartheid” might have addressed this urgency and even crystallized an intellectual ambition, it’s multiple and sometimes contradictory meanings have made it hard to establish a paradigm. The authors of this special section have sought to interrogate the use and abuse of the concept in the literature of their respective disciplines, keeping in mind that, whatever its polysemy, the term has become a reference point for the humanities worldwide, as untranslatable as it is inescapable.     

A Cause-of-Death Decomposition of Young Adult Excess Mortality

We propose a method to decompose the young adult mortality hump by cause of death. This method is based on a flexible shape decomposition of mortality rates that separates cause-of-death contributions to the hump from senescent mortality. We apply the method to U.S. males and females from 1959 to 2015. Results show divergence between time trends of hump and observed deaths, both for all-cause and cause-specific mortality. The study of the hump shape reveals age, period, and cohort effects, suggesting that it is formed by a complex combination of different forces of biological and socioeconomic nature. Male and female humps share some traits in all-cause shape and trend, but they also differ by their overall magnitude and cause-specific contributions. Notably, among males, the contributions of traffic and other accidents were progressively replaced by those of suicides, homicides, and poisonings; among females, traffic accidents remained the major contributor to the hump.