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- Andersson, Erik, 1978-
(författare)
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Managing the Urban Greens : Maintaining ecological functions in human dominated landscapes
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- At the core of this thesis lie two realisations: First, like other ecosystems, those in urban landscapes provide humans with a number of ecosystem services, some recognized while others are not. Second, in cities just as in other intensively used social-ecological systems, management is of central importance. This thesis focuses on how we may manage green areas in cities in an ecologically sustainable way, and enjoy functioning ecosystems close to where most people live. The thesis has four specific objectives: 1) analyse methods for describing the urban landscape, 2) analyze methods for managing urban landscapes rather than single patches of urban green areas, 3) explore the effects of management on diversity patterns and its implications for ecological functions, and 4) investigate the motivations behind the use of different management practices.My results show that changes in urbanization were most distinct at a small scale and that the presence of different bird species depended mostly on access to habitat. They also show that groups of small habitat patches can maintain many of the values of larger patches as long as they are sufficiently close for the organism to move between them, and that matrix heterogeneity must be accounted for. To identify such connected patches and assess their ecological importance I have developed two modelling approaches, one to select suitable model organisms and one to analyse spatial configuration. Further, management is shown to create ecological differences even in areas that are superficially similar, and the roots to these differences are ascribed to the knowledge, institutions and sense of place among different groups of managers. Finally, I try to combine these objectives and sketch out how the organisation of management could be changed to overcome scale mismatches and rigidity. There is potential, both for protection and for management, at all scale levels and this potential should be tapped and nurtured to improve our ability to cope with changes.
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| 3. |
- Andersson, Erik, et al.
(författare)
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Patterns and scale relations among urbanization measures in Stockholm, Sweden
- 2009
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Ingår i: Landscape Ecology. - : Springer Science and Business Media LLC. - 0921-2973 .- 1572-9761. ; 24, s. 1331-1339
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Tidskriftsartikel (refereegranskat)abstract
- In this study we measure urbanization based on a diverse set of 21 variables ranging from landscape indices to demographic factors such as income and land ownership using data from Stockholm, Sweden. The primary aims were to test how the variables behaved in relation to each other and if these patterns were consistent across scales. The variables were mostly identified from the literature and limited to the kind of data that was readily accessible. We used GIS to sample the variables and then principal component analyses to search for patterns among them, repeating the sampling and analysis at four different scales (250 × 250, 750 × 750, 1,250 × 1,250 and 1,750 × 1,750, all in meters). At the smallest scale most variables seemed to be roughly structured along two axes, one with landscape indices and one mainly with demographic factors but also impervious surface and coniferous forest. The other land-cover types did not align very well with these two axes. When increasing the scale this pattern was not as obvious, instead the variables separated into several smaller bundles of highly correlated variables. Some pairs or bundles of variables were correlated on all scales and thus interchangeable while other associations changed with scale. This is important to keep in mind when one chooses measures of urbanization, especially if the measures are indices based on several variables. Comparing our results with the findings from other cities, we argue that universal gradients will be difficult to find since city shape and size, as well as available information, differ greatly. We also believe that a multivariate gradient is needed if you wish not only to compare cities but also ask questions about how urbanization influences the ecological character in different parts of a city.
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| 4. |
- Barthel, Stephan, 1968-
(författare)
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Recalling Urban Nature : Linking City People to Ecosystem Services
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Societal development is dependent on the generation of ecosystem services (ES) to sustain it; however, many ES are degrading. This thesis investigates how social-ecological features behind practices of actor groups shape the generation of ES. The empirical basis is case studies in the urban landscape of Stockholm, Sweden, and the methodological approach is interdisciplinary. Paper I shows that the urban landscape owes it current flow of ES to co-evolutionary processes and that governance with the aim of sustaining ES must take into account historical property rights and the involvement of a diversity of actor groups, as well as ecological processes of the larger landscape. Paper II studies allotment gardens, cemeteries and city parks in relation to the generation of pollination, seed dispersal and pest regulation. Differences in social features behind practice are reflected primary as higher abundance of pollinators in the informally managed allotment gardens and as differences in the compositions of seed dispersers and insectivores’ birds. Thus, voluntary and often ignored actor groups, motivated by sense-of-place, support the generation of some ES here. Paper III shows how practice, linked to ES generation, is retained and stored among allotment gardeners, and modified and transmitted through time, by means of social-ecological memory (SE-memory). SE-memory is an emergent property of a dual process of participation and reification and it facilitates monitoring of local change and links practice, often in habits, to place specific processes that underlie provisioning ES. Paper IV explores how spatial scale mismatches between ecological process and processes of management can be bridged by a spatially explicit and flexible social network structure of governance. Urban ES are a product of human driven co-evolution, consequently sustaining ES in urban landscapes is not about conservation without people, but shaped by and dependent on management practice by people. Practice that links to generation of ES are facilitated by SE-memory of local actors that holds long term management rights. Consequently, local communities of ecosystem practice, which contribute to the production of ES should explicitly be taken into account in urban green governance.
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| 5. |
- Bodin, Örjan, et al.
(författare)
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The value of small size: loss of forest patches and ecological thresholds in southern Madagascar
- 2006
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Ingår i: Ecological Applications. - : the Ecological Society of America. - 1051-0761 .- 1939-5582. ; 16:2, s. 440-451
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Tidskriftsartikel (refereegranskat)abstract
- Many services generated by forest ecosystems provide essential support for human well-being. However, the vulnerability of these services to environmental change such as forest fragmentation are still poorly understood. We present spatial modeling of the generation of ecosystem services in a human-dominated landscape where forest habitat patches, protected by local taboos, are located in a matrix of cultivated land in southern Madagascar. Two ecosystem services dependent on the forest habitats were addressed: (1) crop pollination services by wild and semidomesticated bees (Apoidea), essential for local crop production of, for example, beans, and (2) seed dispersal services based on the presence of ring-tailed lemurs (Lemur catta). We studied the vulnerability of these ecosystem services to a plausible scenario of successive destruction of the smallest habitat patches. Our results indicate that, in spite of the fragmented nature of the landscape, the fraction of the landscape presently covered by both crop pollination and seed dispersal services is surprisingly high. It seems that the taboo system, though indirectly and unintentionally, contributes to upholding the generation of these services by protecting the forest patches. Both services are, however, predicted to be very vulnerable to the successive removal of small patches. For crop pollination, the rate of decrease in cover was significant even when only the smallest habitat patches were removed. The capacity for seed dispersal across the landscape displayed several thresholds with habitat patch removal. Our results suggest that, in order to maintain capacity for seed dispersal across the landscape and crop pollination cover in southern Androy, the geographical location of the remaining forest patches is more crucial than their size. We argue that in heavily fragmented production landscapes, small forest patches should increasingly be viewed as essential for maintaining ecosystem services, such as agricultural production, and also should be considered in the ongoing process of tripling the area of protected habitats in Madagascar.
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| 6. |
- Borgström, Sara, 1977-, et al.
(författare)
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Scale mismatches in management of urban landscapes
- 2006
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Ingår i: Ecology & Society. - : RESILIENCE ALLIANCE. - 1708-3087. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- Urban landscapes constitute the future environment for most of the world’s human population.An increased understanding of the urbanization process and of the effects of urbanization at multiple scalesis, therefore, key to ensuring human well-being. In many conventional natural resource managementregimes, incomplete knowledge of ecosystem dynamics and institutional constraints often leads toinstitutional management frameworks that do not match the scale of ecological patterns and processes. Inthis paper, we argue that scale mismatches are particularly pronounced in urban landscapes. Urban greenspaces provide numerous important ecosystem services to urban citizens, and the management of theseurban green spaces, including recognition of scales, is crucial to the well-being of the citizens. From aqualitative study of the current management practices in five urban green spaces within the GreaterStockholm Metropolitan Area, Sweden, we found that 1) several spatial, temporal, and functional scalesare recognized, but the cross-scale interactions are often neglected, and 2) spatial and temporal meso-scalesare seldom given priority. One potential effect of the neglect of ecological cross-scale interactions in thesehighly fragmented landscapes is a gradual reduction in the capacity of the ecosystems to provide ecosystemservices. Two important strategies for overcoming urban scale mismatches are suggested: 1) developmentof an integrative view of the whole urban social–ecological landscape, and 2) creation of adaptivegovernance systems to support practical management.
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| 9. |
- Elmqvist, Thomas, et al.
(författare)
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Urban Systems
- 2008
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Ingår i: Encyclopedia of ecology. - : Elsevier, Oxford. ; , s. 3665-3672
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Bokkapitel (refereegranskat)
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| 10. |
- Ernstson, Henrik, 1972-
(författare)
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In Rhizomia : Actors, Networks and Resilience in Urban Landscapes
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- With accelerating urbanization it is crucial to understand how urban ecosystems play a part in generating ecosystem services for urban dwellers, such as clean water, spaces for recreation, stress relief and improved air quality. An equally important question relate to who gets to enjoy these benefits, i.e. the distribution of ecosystem services, and how issues of power and equity influence the management of ecosystems. Through case studies from the urban landscape of Stockholm, this doctoral thesis engages with these perspectives through combining ecological theory with social theory, including social network analysis, actor-network theory and social movement theory. Strategies for how to improve urban ecosystem management are presented along with frameworks for how to analyze issues of power and equity in relation to natural resource management.Paper I shows that ecosystem management can be studied through analyzing the structure of social networks, i.e. the patterns of relations between agencies, stake-holders and user groups. Paper II and Paper III analyze, based on a network survey of 62 civil society organizations and in-depth interviews, a transformational process of how an urban local movement managed to protect a large urban green area from exploitation (The Stockholm National Urban Park). Paper IV discusses, based on several case studies from Stockholm, a conducive network structure for linking managers and user groups (e.g. allotment gardens, cemetery managers, and urban planners) across spatial ecological scales so as to improve urban green area management. Paper V presents a framework to analyze the social-ecological dynamics behind the generation and distribution of ecosystem services in urban landscapes.The thesis points towards the notion of "a social production of ecosystem services" and argues for deeper engagement with urban political ecology and critical geography to inform governance and collective action in relation to urban ecosystems.
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