Conceptualizing multidimensional barriers: a framework for assessing constraints in realizing recreational benefits of urban green spaces

This article was supported by the German Research Foundation (DFG) and the Open Access Publication Fund of Humboldt-Universität zu Berlin.Although potential urban green space accessibility is being discussed widely, specific barriers that affect accessibility are often under-estimated. They do not equate to limited or uneven accessibility nor are they exclusively related to physical settings. Rather, the range of barriers and their complex interactions, including people’s perceptions, personal conditions, and institutional frameworks, make this topic less clear cut and difficult to put into practice for planning purposes. Given the importance of barriers when people make decisions, we present a conceptual framework to capture the cumulative and interactive effects of different barriers on realizing recreational benefits of urban green spaces. The framework classifies physical, personal, and institutional barriers and highlights their interactions based on three case studies: Stockholm, Leipzig, and Lodz. We argue that constraints to the accessibility of urban green spaces are not so much the interactions between various physical, personal, and institutional barriers, but more the significance that beneficiaries assign to them as perceived barrier effects. Studying barriers seeks to improve the knowledge about the non-use of urban green spaces and to enable us to draw conclusions about the actual accessibility of recreational benefits. Deduced from the conceptual framework, three pathways are contrasted for improving accessibility to the recreational benefits of urban green spaces: the environment, knowledge, and engagement. We argue that these pathways should not be a diffuse objective, but a sensitive and scale-dependent re-balance of individual, physical, and institutional factors for considering justice in environmental and green space planning and management. Our systematic conceptualization and classification of multidimensional barriers enables a more comprehensive understanding of individuals’ decisions in terms of accessing recreational benefits.Peer Reviewe

Scale-crossing brokers and network governance of urban ecosystem services:The case of stockholm

Urban ecosystem services are crucial for human well-being and the livability of cities. A central challenge for sustaining ecosystem services lies in addressing scale mismatches between ecological processes on one hand, and social processes of governance on the other. This article synthesizes a set of case studies from urban green areas in Stockholm, Sweden - allotment gardens, urban parks, cemeteries and protected areas - and discusses how governmental agencies and civil society groups engaged in urban green area management can be linked through social networks so as to better match spatial scales of ecosystem processes. The article develops a framework that combines ecological scales with social network structure, with the latter being taken as the patterns of interaction between actor groups. Based on this framework, the article (1) assesses current ecosystem governance, and (2) develops a theoretical understanding of how social network structure influences ecosystem governance and how certain actors can work as agents to promote beneficial network structures. The main results show that the mesoscale of what is conceptualized as city scale green networks (i.e., functionally interconnected local green areas) is not addressed by any actor in Stockholm, and that the management practices of civil society groups engaged in local ecosystem management play a crucial but neglected role in upholding ecosystem services. The article proposes an alternative network structure and discusses the role of midscale managers (for improving ecological functioning) and scale-crossing brokers (engaged in practices to connect actors across ecological scales). Dilemmas, strategies, and practices for establishing this governance system are discussed

Improving participatory resilience assessment by cross-fertilizing the Resilience Alliance and Transition Movement approaches

The concept of resilience is currently being widely promoted and applied by environmental and development organizations. However, their application of resilience often lacks theoretical backing and evaluation. This paper presents a novel cross-fertilization of two commonly used approaches for applying resilience thinking: the grassroots movement of Transition Towns and the Resilience Alliance's Resilience Assessment. We compared these approaches through a text analysis of their key handbooks and combined them in a series of participatory workshops with a local partner active in the Transition Movement. Our results demonstrate that despite sharing a number of key features, these two approaches have complementary strengths and weaknesses. Strengths of the Transition Movement include its motivating overarching narrative of the need to transform in response to global sustainability challenges, as well as practical tools promoting learning and participation. The Resilience Assessment's conceptual framework and structured process generated context-specific understanding of resilience, but provided little guidance on navigating transformation processes. Combining the Resilience Assessment's theory on complex systems with the Transition Movement's methods for learning also generated synergies in fostering complexity thinking. Based on these findings, we believe that integrating strengths from both approaches could be widely useful for practitioners seeking to apply resilience for sustainable development. Our study also highlights that methods for assessing resilience can be improved by combining insights from science and practice

Improving participatory resilience assessment by cross-fertilizing the Resilience Alliance and Transition Movement approaches

The concept of resilience is currently being widely promoted and applied by environmental and development organizations. However, their application of resilience often lacks theoretical backing and evaluation. This paper presents a novel cross-fertilization of two commonly used approaches for applying resilience thinking: the grassroots movement of Transition Towns and the Resilience Alliance's Resilience Assessment. We compared these approaches through a text analysis of their key handbooks and combined them in a series of participatory workshops with a local partner active in the Transition Movement. Our results demonstrate that despite sharing a number of key features, these two approaches have complementary strengths and weaknesses. Strengths of the Transition Movement include its motivating overarching narrative of the need to transform in response to global sustainability challenges, as well as practical tools promoting learning and participation. The Resilience Assessment's conceptual framework and structured process generated context-specific understanding of resilience, but provided little guidance on navigating transformation processes. Combining the Resilience Assessment's theory on complex systems with the Transition Movement's methods for learning also generated synergies in fostering complexity thinking. Based on these findings, we believe that integrating strengths from both approaches could be widely useful for practitioners seeking to apply resilience for sustainable development. Our study also highlights that methods for assessing resilience can be improved by combining insights from science and practice

Translocation of 40 nm diameter nanowires through the intestinal epithelium of Daphnia magna

Nanowires (NWs) have unique electrical and optical properties of value for many applications including lighting, sensing, and energy harnessing. Consumer products containing NWs increase the risk of NWs being released in the environment, especially into aquatic ecosystems through sewage systems. Daphnia magna is a common, cosmopolitan freshwater organism sensitive to toxicity tests and represents a likely entry point for nanoparticles into food webs of aquatic ecosystems. Here we have evaluated the effect of NW diameter on the gut penetrance of NWs in Daphnia magna. The animals were exposed to NWs of two diameters (40 and 80 nm) and similar length (3.6 and 3.8 μm, respectively) suspended in water. In order to locate the NWs in Daphnia, the NWs were designed to comprise one inherently fluorescent segment of gallium indium phosphide (GaInP) flanked by a gallium phosphide (GaP) segment. Daphnia mortality was assessed directly after 24 h of exposure and 7 days after exposure. Translocation of NWs across the intestinal epithelium was investigated using confocal fluorescence microscopy directly after 24 h of exposure and was observed in 89% of Daphnia exposed to 40 nm NWs and in 11% of Daphnia exposed to 80 nm NWs. A high degree of fragmentation was observed for NWs of both diameters after ingestion by the Daphnia, although 40 nm NWs were fragmented to a greater extent, which could possibly facilitate translocation across the intestinal epithelium. Our results show that the feeding behavior of animals may enhance the ability of NWs to penetrate biological barriers and that penetrance is governed by the NW diameter

Raman Signal Enhancement Dependence on the Gel Strength of Ag/Hydrogels Used as SERS Substrates

A series of hydrogel samples composed of Ag nanoparticles dispersed in carrageenan gels have been prepared and used in SERS studies. These studies demonstrate the dependence of the enhancement of the SERS signal on the strength of the Ag/polysaccharide hydrogel. 2,2'-Dithiodipyridine was used as the analyte probe. Several strategies were employed in order to vary the gel strength. These include the increase of the polysaccharide content in the gel, the addition of KCl as cross-linker, and the variation of the type of carrageenan (kappa, l, lambda) network. An increase in the gel strength originates an increase in the SERS enhancement observed. The results have been interpreted considering hot spots increase due to the formation of Ag particles nanojunctions as the biopolymer matrix tends to rearrange into stronger gels. This is the first report showing that there is a direct correlation between the gel strength of a hydrogel composite used as substrate and its analytical SERS sensitivity