Diversity in mind: Towards a differentiated understanding of migrants’ recreational practices in urban forests

This paper presents results of a study investigating the relationship between migration and recreation in urban forests in two German cities. Research in this field is growing in Europe, yet in certain countries, such as Germany, it remains underdeveloped. Until now, it has revealed ambiguities and diverging results. Furthermore, it has been the subject of criticism and calls for more differentiation between and within migrant groups, as well as for more reflection on the categorisation of “migrant” or “ethnic group”. This paper builds on these claims and aims to shed new light on forest recreation and ethnicity through a context-sensitive research approach in the tradition of symbolic interactionism. It draws upon the analysis of 42 qualitative interviews conducted with people with a Turkish, Russian-German and no migration background. The analysis leads to the construction of five narratives, each of them regrouping respondents who share a similar perspective on a specific theme. The narratives show how personal life context and its interlinkages with migration influence the individual's perspectives on and uses of urban forest. They also show how lifestyle and gender shape recreational practices independently from migration background. Beyond the focus on individual experience, collective recreational practices attributed to some groups are expressed in the narratives. This paper addresses the social aspect of leisure and discusses how forest recreation affects the social construction of groups such as migrant groups.     

Temporal variation of characteristic scales in urban landscapes: an insight into the evolving internal structures of China’s two largest cities

Urbanization has induced profound landscape changes. While the spatiotemporal patterns of urban landscapes have been extensively studied, the manner by which the internal structures of already urbanized areas change remains little understood. Characteristic scales are an important measure of landscape structure, and they represent the typical spatial extents of landscape elements in hierarchies. In this study, we quantified temporal variations of the characteristic scales in the central urban landscapes of Beijing and Shanghai over an 18?year period. Using transect data from Landsat images, characteristic scales were identified through wavelet analysis and then classified into several discrete domains using the k-means clustering method. These characteristic scale domains appeared to correspond with the typical extents of the blocks and block clusters in the study areas. Results showed that the number of the characteristic scale domains changed within a small range of 3?C5 while the mean values of the characteristic scales within the domains showed substantial temporal variation. Larger characteristic scales were more variable than smaller ones in both cities. Distinguishing relative change rates of building forms, land use and street layout of urban landscapes allowed us to interpret these differences. The street layout of urban landscapes usually reacts slowly to the force of change, acting as the skeleton of the urban landscape. As a result, block sizes can remain relatively stable and corresponding characteristic scales present inheritance features. Land use and building forms are more susceptible to changes. Block clusters with flexible extents could result in significant variation of characteristic scales.     

The changing landscape of wildfire: burn pattern trends and implications for California’s yellow pine and mixed conifer forests

Purpose

Wildfire spatial patterns drive ecological processes including vegetation succession and wildlife community dynamics. Such patterns may be changing due to fire suppression policies and climate change, making characterization of trends in post-fire mosaics important for understanding and managing fire-prone ecosystems.

Methods

For wildfires in California’s yellow pine and mixed-conifer forests, spatial pattern trends of two components of the post-fire severity matrix were assessed for 1984–2015: (1) unchanged or very low-severity and (2) high-severity, which represent remnant forest and stand-replacing fire, respectively. Trends were evaluated for metrics of total and proportional burned area, shape complexity, aggregation, and core area. Additionally, comparisons were made between management units where fire suppression is commonly practiced and those with a history of managing wildfire for ecological/resource benefits.

Results

Unchanged or very low-severity area per fire decreased proportionally through time, and became increasingly fragmented. High-severity area and core area increased on average across most of California, with the high-severity component also becoming simpler in shape in the Sierra Nevada. Compared to suppression units, managed wildfire units lack an increase in high-severity area, have less aggregated post-fire mosaics, and more high-severity spatial complexity.

Conclusions

Documented changes in severity patterns have cascading ecological effects including increased vegetation type conversion risk, habitat availability shifts, and remnant forest fragmentation. These changes likely benefit early-seral-associated species at the expense of mature closed-canopy forest-associated species. Managed wildfire appears to moderate some effects of fire suppression, and may help buy time for ecosystems and managers to respond to a changing climate.

     

Suburban habitats and their role for birds in the urban–rural habitat network: points of local invasion and extinction?

Suburban habitats in naturally forested areas present a conundrum in the urban–rural habitat network. Typically, these habitats contain less than half of the native woodland bird species that would exist at these sites if they were not developed. They also contain more total bird species than if these sites were left in a natural state. This apparent contradiction raises the question of “How do suburban habitats function in the urban–rural habitat network?” In this study, we analyze bird distributions on three rural-to-urban gradients in different ecoregions of the United States: Oxford, Ohio; Saint Paul, Minnesota; and Palo Alto, California. All three gradients exhibit similar patterns of extinction of native species followed by invasion of common species and subsequent biotic homogenization with urbanization. This patterning suggests that suburban land uses, those represented by the intermediate levels of development on the gradients, are a point of extirpation for woodland birds as well as an entry point for invasive species into urban systems. Furthermore, there are consistent patterns in the functional characteristics of the bird communities that also shift with intensifying urbanization, providing insight on the possible mechanisms of homogenization and community structure in urban ecosystems including an increase in the number of broods per year, a shift in nesting strategies, a decrease in insectivorous individuals, an increase in granivorous individuals, and a decrease in territoriality. Consequently, it appears that there are specific traits that drive the shift in community composition in response to urban and suburban land use. These results have significant implications for improving understanding of the mechanisms of suburban community ecology and conserving birds in urban habitat networks.     

Stress-resistant trees are more common in urban than rural forests: A case study of Cleveland,Ohio’s natural parks

Natural parks are comprised of preserved forested natural areas that are undergoing natural ecological processes. These areas can offer a refuge for local biodiversity and contribute substantially to ecosystem services in both rural areas with relatively low population densities, as well as high-density urban areas. Forested natural parks located in urban areas should experience more stressful environmental conditions than nearby rural areas, yet we know relatively little about how urbanization impacts tree communities within these important natural habitats. To better understand the impact of urbanization on forests, we investigated the species composition, abundance, and diversity of midstory and canopy trees as well as tree seedlings in urban and rural natural parks in and around Cleveland, Ohio. We found that both urban and rural natural parks have similar tree abundance, but midstory and canopy trees as well as tree seedling communities in the urban natural parks included higher abundances of stress-tolerant species compared to rural parks. In addition, this pattern was driven by changes in native tree species, as we observed low abundance of invasive species. More stress-resistant native species in urban areas include Quercus rubra and Prunus serotina, in contrast to rural natural parks which are dominated by Acer spp. and Fagus grandifolia. Lastly, we show that urban and rural natural parks have similar species diversity within plots, but we found higher variation in community composition among urban natural parks compared to among rural parks. Furthermore, Q. rubra and P. serotina were significantly larger in rural natural parks, indicating that both environmental stress and successional stage could drive compositional differences. Thus, we show that urbanization can have unexpected effects on plant community composition and diversity. Our study refutes the idea that these are degraded habitats, highlights the need to conserve them, and suggests that characterization of local variation in self-assembled urban tree communities will provide the most accurate picture of their management needs and potential ecosystem services.     

Efficacy of Insecticides against Lygus hesperus Knight (Hemiptera: Miridae) in the California’s Central Coast Strawberry

ABSTRACT

The western tarnished plant bug, Lygus hesperus Knight (Hemiptera: Miridae), is an important insect pest of strawberry (Fragaria ananassa Duchesne) in the Central Coast of California. Because little is known about efficacy of new insecticides, especially sulfoxaflor and flupyradifurone, against L. hesperus, two replicated insecticide experiments were conducted in 2014 and 2015 in commercial strawberry fields naturally infested with L. hesperus. The insecticides, sulfoxaflor, flupyradifurone, flonicamid, thiamethoxam fenpropathrin, essential oils (rosemary and peppermint oils), and mineral oil, were compared with untreated check. Higher and lower rates of flupyradifurone and sulfoxaflor were tested. Higher rates of sulfoxaflor and flupyradifurone were effective in suppressing L. hesperus. The industry standard, thiamethoxam + fenpropathrin, was effective in 2014 but not in the 2015 experiment. Flonicamid provided a moderate level of efficacy against L. hesperus in both years. The number of predacious bugs was significantly lower in the higher rate of flupyradifurone than in other treatments, although the number of spiders was not significantly different among treatments.     

Greening residential quarters in China: What are the roles of urban form,socioeconomic factors,and biophysical context?

Residential greenspace has great intracity variations. Its driving factors have been widely investigated in Western countries (e.g., in Europe and North America), where residential areas are mostly privately owned, but few studies have examined the determinants of residential greenspace in China, where land is owned by the government. Taking the subtropical city of Changsha, China, as an example, this study mapped the percent green cover (PGC) in residential quarters with a fine-resolution satellite image. We also investigated its driving factors measured from multisource geospatial data. The results show that (1) the PGC in the residential quarters showed great spatial variation, with an average of 36.6% (0–85.7%) and a standard deviation of 18.3%. (2) Urban form, biophysical context, and socioeconomic factors together explained 49.18% of the variation in the PGC, and they independently explained 22.87%, 11.17%, and 2.31% of the variation, respectively. (3) Residential quarter size, PGC in the surrounding buffer zone, residential quarter age, housing value, and population density significantly and positively impact the PGC, while percent building cover, floor area ratio, and distance to city center had significant negative impacts. The strongest positive and negative impacts came from PGC in the surrounding buffer zone and percent building cover, respectively. Socioeconomic factors, the dominant driving factors in Western countries, show little impact on residential PGC. These findings expand our understanding of the intracity variation in greenspace coverage and the driving factors, which sheds light on the effective planning and management of urban greenspaces in China.     

Alternative stable states in Australia’s Wet Tropics: a theoretical framework for the field data and a field-case for the theory

The vegetation of the Wet Tropics bioregion of Far North Queensland is a complex system whose components (mainly tropical rainforests and fire-prone forests and woodlands) have mostly been studied independently from each other. We suggest that many characteristics of the vegetation are consistent with those of a complex, dynamic, spatially heterogeneous system which exhibits alternative stable states. We propose these states are driven and maintained by the interaction of vegetation-specific positive feedback loops with the regions’ environmental parameters (such as topography, steep humidity gradients and seasonality) and result in the rainforest/fire-prone vegetation mosaic that characterises the area. Given the regions’ magnitude, biodiversity and complexity, we propose the Wet Tropics as an important new example and a good testing ground for alternative stable state and resilience theories in large heterogeneous natural systems. At the same time, thinking in terms of alternative stable states and resilience creates a new context for understanding the regions’ biological dynamics.     

A review of the concept ‘management’ in relation to urban landscapes and green spaces: Toward a holistic understanding

The management of urban landscapes concerns existing urban open spaces such as public parks, playgrounds and residential green spaces. It involves many different actors and organizations and its practice is of importance for the sustainable development of cities. As a research field, it needs further theoretical development and common definitions. For example, the central term ‘management’ is seldom defined in the relevant literature regarding an urban landscape context, and public participation in management processes is unusual. This paper introduces urban landscape management as an overarching concept that brings together knowledge about management of urban landscapes from fields such as urban forestry, park management and landscape planning. Based on a literature review, a common understanding of management in an urban landscape context is proposed, including organizational and strategic aspects of managerial activities. Our approach is that urban landscapes are ultimately managed to provide user benefits. Urban landscape management can be viewed as a complex process that includes a number of different actors, elements and relationships, mutually affecting each other. This view supports future studies of urban landscape management and its role in sustainable urban development.     

A landscape vulnerability framework for identifying integrated conservation and adaptation pathways to climate change: the case of Madagascar’s spiny forest

Context

Integrated conservation decision-making frameworks that help to design or adjust practices that are cognisant of environmental change and adaptation are urgently needed.

Objective

We demonstrate how a landscape vulnerability framework combining sensitivity, adaptive capacity, and exposure to climate change framed along two main axes of concern can help to identify potential strategies for conservation and adaptation decision-making, using a landscape in Madagascar’s spiny forest as a case-study.

Methods

To apply such a vulnerability landscape assessment, we inferred the sensitivity of habitats using temporal and spatial botanical data-sets, including the use of fossil pollen data and vegetation surveys. For understanding adaptive capacity, we analysed existing spatial maps (reflecting anthropogenic stressors) showing the degree of habitat connectivity, matrix quality and protected area coverage for the different habitats in the landscape. Lastly, for understanding exposures, we used climate change predictions in Madagascar, together with a digital elevation model.

Results

The fossil pollen data showed how sensitive arid-adapted species were to past climate changes, especially the conditions between 1000 and 500 cal yr BP. The spatial analysis then helped locate habitats on the two-dimensional axes of concern integrating sensitivity, adaptive capacity and climate change exposure. By identifying resistant, resilient, susceptible, and sensitive habitats to climate change in the landscape under study, we identify very different approaches to integrate conservation and adaptation strategies in contrasting habitats.

Conclusion

This framework, illustrated through a case study, provides easy guidance for identifying potential integrated conservation and adaptation strategies, taking into account aspects of climate vulnerability and conservation capacity.

     

A review of the outcomes from contracting out urban green space maintenance: What we know,don’t know and should know

Private delivery, i.e. contracting out, of maintenance services in urban parks and green spaces has since the 1980s been spurred by neoliberal reform promises of improved performance. This article contributes to discussions of whether contracting out park and green space maintenance services is a well-performing alternative by evaluating what is known – and not known – about the outcomes in a narrative review of thirteen studies bridging experiences from four decades and three country contexts. It is found that the balance of reported economic and managerial outcomes mostly are on the positive side while the balance of reported outcomes related to service quality and staff are found to be on the negative side. Findings indicate that reforms have partly delivered on their promises. However, the reviewed studies are found to be dominated by evaluations based on governing values inherent in neoliberal management reforms rather than alternative management paradigms, rely on older data from a limited number of country contexts, and lack an accumulated understanding of explanation of outcomes. Finally, the reviewed studies pay little or no attention to the details of the development of different contracting and organizational models within contemporary urban green space management. Future research can expand further on what is known by addressing these key caveats.     

Impact of urban park’s tree,grass and waterbody on microclimate in hot summer days: A case study of Olympic Park in Beijing,China

Urban heat island (UHI) often cause negative impact and has been linked to heart stroke rate, morality, human comfort, energy consumption and air pollution. Fortunately, urban green spaces have been considered as an effective element to mitigate UHI through their cooling effect. However, further empirical research is necessary in order to efficiently guide the design and planning of urban green space. We observed the impacts of urban park's tree, grass and waterbody on microclimate inside the Olympic park of Beijing during summer days. The results indicated that, on average, the park was 0.48–1.12 °C cooler during the day, as well as increased air humidity 2.39–3.74% and reduced human comfort index 1.02–2.43 to generate more comfortable thermal environment. Urban park's cluster trees with short ground vegetation generated higher cooling effect than single trees, grass and waterbodies; proper irrigation regime enhanced the cooling effect of grasses, even the irrigated grass have similar cooling effect with small waterbody on sunny, windless summer days. Therefore, we advise to increase undergrowth coverage and grass irrigation management in order to take advantage of cooling effect of urban parks.