Maria Ignatieva

Planning and design of ecological networks in urban areas

Urban ecological networks are defined differently in ecology, urban planning and landscape ecology, but they all have linearity and linkage in common. Early urban representations evolved from the constraints of deep ecological structure in the landscape to built elements that must work around natural linear obstacles—rivers, coastlines, dunes, cliffs, hills and valley swamps. Village commons were linked by roads. The Industrial Revolution led to accelerating urban growth, where the role of open space focussed on public health and transport. The Renaissance, Baroque and Picturesque movements accentuated networks in wooded parks, boulevards and sweeping riverine vistas. These provided a new aesthetic and sense of grandeur in the urban centres of European empires and later their colonies. Grafted onto this visual connectivity has been an awakened ecological understanding of spatial dynamics. The emergent notion of ecological corridor functionality provided support for green linear features, although initially this was based on untested theory. The idea of organisms moving along green highways seemed logical, but only recently has unequivocal empirical evidence emerged that demonstrates this functionality. Nevertheless, the main role of corridors may be to provide habitat rather than to act as connectors of nodal habitats. Most organisms can utilise stepping stones, and these may accommodate desired meta-populations while deterring pest movement. Swale drains and treatment wetlands provide riparian services and serve as biodiversity corridors. However, to most people the obvious function is visual—providing green fingers through what would otherwise be urban grey. The health benefits of these are have been demonstrated to be psychological as much as biophysical.

Patterns and Trends in Urban Biodiversity and Landscape Design

Urbanization destroys or modifies native habitats and creates new ones with its infrastructure. Because of these changes, urban landscapes favor non-native and native species that are generalists. Nevertheless, cities reveal a great variety of habitats and species, and, especially in temperate cities, the diversity of vascular plants and birds can be higher than in the surrounding landscapes. The actual occurrence of a species, however, depends on habitat availability and quality, the spatial arrangements of habitats, species pools, a species’ adaptability and natural history, and site history. In addition, cities are particularly human-made ecological systems. Top-down and bottom-up activities of planners, land managers, and citizens create the urban biodiversity in general and in detail. Plants and animals in cities are the everyday life contact with nature of the most humans on our earth. The intrinsic interplay of social and ecological systems with a city often forms unique biotic assemblages inherent to that city. To support native biodiversity, landscape architects, conservation biologists, and other groups are linking landscape design with ecosystem structure and function to create and restore habitats and reintroduce native species in cities.

Biodiverse green infrastructure for the 21st century: from “green desert” of lawns to biophilic cities

Abstract Modern urban green infrastructures are following globalisation trends and contribute to homogenization at all levels of green areas from the master plan to the finest scale. We discuss the place and role of three principal urban living spaces, the “skeleton” of green infrastructures: lawns, green walls and green roofs. This “trio” of modern GI elements provide significant ecosystem services, it contributes to biodiversity and social values; and have environmental and economic impact. The main goal of our approach to sustainable GI is to introduce a new landscape architecture style – biodiversinesque – as an alternative to the existing global homogenised picturesque-gardenesque. This new approach will combine the best achievements of innovative and alternative landscape design solutions (biodiverse lawns, pictorial meadows, walls and green roofs) and implement them on three major scales: city, intermediate neighborhood and the small biotope level.

The challenges of planning and designing urban green networks in Scandinavian and Chinese cities

During the 20th century, a variety of concepts were developed aimed to provide frameworks for green space planning and design in urban areas. Both China and Scandinavia represent important experience in green space planning and management. However, none of the current concepts is generated based on the explicit combination of both a Western and Eastern context. In this paper, based on the analysis of various green space planning concepts and their development, a novel ‘hybrid’ approach is introduced. This ‘Green Network’ concept focuses on green and blue connectivity in urban areas and comprises the network of green spaces and the surface water system within and around settlements. The concept offers a platform for integrating best practices from Scandinavian and Chinese open space planning and can provide a guiding tool for sustainable urban development.

A socio-ecological perspective of urban green networks: the Stockholm case

Landscape fragmentation threatens habitats, biodiversity and other ecosystem services. In tackling this threat, the dynamic processes of social-ecological systems should be recognised and understood. Although network analysis based on graph theory has been recognised as an efficient way of spatially understanding landscape or habitat connectivity, only few studies have offered specific approaches or suggestions for integrating detailed social-ecological values into geographical distributions. As a contribution to bridging this gap, this paper introduces a social-ecological network model for the issue of landscape or habitat fragmentation applied to the case of Stockholm, Sweden. Graph theory was used in combination with sociotope and biotope maps for simple visualisation of network situations in two-dimensional maps. The European crested tit (Lophophanes cristatus), European common toad (Bufo bufo) and human beings were selected as indicator species, based on a landscape ecology analysis in Stockholm Municipality in 2009. Slope, land use and human disturbance maps were assessed in order to decide cost values of travelling from node to node. Lease-cost-path accumulation was used to create ideal reference maps of green networks. Three separate maps were then developed for suggesting efficient routes for three indicators in city scale that mainly connect from the Royal National City Park to the other parts of the city. The model in Hjorthagen neighbourhood to highlight two practical paths that link this fragmented community to its neighbouring park areas. Findings make it possible to address two scales of network improvement strategies, namely first for the city-scale green network that connects geographical habitats (nodes) and the regional green wedges of the city, and the second that of neighbourhood links between habitats in detailed layers of green networks. Strategic improvement potentials are presented based on ideal reference maps of green networks correspondingly.