No 4 (2016)

Urbanization is a global land-use change tendency, responsible for substantial environmental changes. At the same time urban ecosystems are vulnerable to global changes, and their adaptation is necessary to maintain sustainable functionality and important ecosystem services. Sustainable urban development demands for integration of innovative green technologies and natural-based solutions in urban management, which is only possible through a collaboration of scientists, landscape designers, civil engineers and policy-makers.

To understand the soil ecology of the forest ecosystem, the dynamics of soil-ecological indicators in the soil-plant system were studied through physical, chemical and biological parameters at various sites of the Forest Experimental Station of the Russian State Agrarian University of Moscow Agricultural Academy; a unique forest ecosystem known for its heavy metal pollution and unregulated recreation. The results showed that soil compaction had the strongest ability to increase risk of heavy metal mobility. Recreational activity caused a 2-3-fold increase in the density of the soil, resulting in poor aeration and significant heavy metal contamination, affecting the stability and functioning of the green spaces. Moreover, the proximity of the urban environment had a negative effect on the state of the stand. The maximum heavy metal migration capacity determined by biological uptake was found in the root systems of 70-80-year-old oak tree stands and the minimum, in the roots of pine and birch phytocoenosis. The systems’ normal functions were hindered due to reduction in microbial activity.

It is necessary to reconsider the role of natural areas and landscape approaches to improve the quality of urban environment for a sustainable development of modern cities. The development of city’s green infrastructure, what is integrated in “landscape urbanism” term, implies the restoration of environment natural components by expansion of urban boundaries or searching for reserved areas of “abandoned” landscape in a city structure [10]. Creating a new development strategy of natural environment territories, in terms of post-industrial reality and progressive urbanization is the part of city's spatial development that must be adapted and supplied carefully. It is necessary to search for new development models of urban space, where the landscape typology and nature features are the means of environment identity [13]. The rapid degradation of natural areas, as a result of “densification” of a city and building development in the largest cities of Russia, primary Moscow, was observed from the beggining of 90-ies of the 20th century. It has led to the disappearance of natural areas, what influenced an environmental stress strengthening in different parts of an urban space, especially in its center, and strong recreational pressure on park areas, that are the most popular within a city. For changing this situation and creating a new scenario for parks development in the center of Moscow, it is necessary to form new urban objects, both in the center and in the middle and peripheral parts of the city. Scenario of sustainable urban development at different urban levels includes innovative ideas for life harmonization, associated with the concept of “living” cities, sustainable urbanization, preservation of historical heritage and new building technologies [5].

The article reveals the importance of urban greening as a part of sustainable urban development concept. We examinethe ecological, social, cultural, spatial benefits of urban greening promotionas well as the possible constrains to urban space vegetating. It is shown that the assessment of tree benefits can be important for implementation of sustainable urban development. In turn,appropriate urban greening assessment is also important. The article provides existing urban greening assessment methods and their implementation in real-life practices.

Contamination with heavy metals is among key anthropogenic pressures, experienced by urban lawns. It results in depletion of their environmental quality and functions. Implementation of fertilizers, containing silicon, is a promising approach to increase urban lawns’ sustainability to heavy metals’ pollution. Based on the field experiment, an influence of cadmium contamination on the chemical features and biomass quality of modeled urban green lawn ecosystems was studied. We demonstrated an increase of cadmium consumption by biomass on the second year of observations as the result of diatomite implementation together with mineral fertilizers. Both total sugar and disaccharides’ content in biomass was 15-20% higher for the contaminated plots where diatomite was implemented together with mineral fertilizers, compared to the uncontaminated control. This evidences a positive effect of the implemented reclaiming on stress tolerance of the green lawns.

Soil respiration (Rs) is an important terrestrial CO2 efflux and receives significant attention at different scale levels. However, the sampling density is limited and global Rs databases are biased towards natural ecosystems. Urbanization is among the most important current land-use trends and its role will likely grow in the future. Urban soils store considerable amount of carbon and are very heterogeneous and dynamic, which affects Rs. Our understanding of the Rs spatial variability is limited, especially for the regions with heterogeneous bioclimatic conditions and high urbanization level. The methodological constraints of direct Rs measurements in the field limit the number of observations. As an alternative approach to approximate the spatial variability of Rs, we used basal respiration (BR) as an indirect measurement. We implemented digital soil mapping technique to map BR as a proxy of Rs in a heterogeneous and urbanized Moscow Region. Topsoil and subsoils BR maps were developed for the region and spatial variability per land-use and soil type was analyzed. BR averaged for the urban areas was lower than in forests and meadows, however, urban areas became the hotspots of BR’s spatial variability in the region. Considerable contribution of subsoil layers to the total BR was also found with the maximal 30% contribution in urban soils. Although the absolute levels of respiration remained uncertain, the spatial patterns of BR are likely to correspond well with Rs patterns, determined by soil type, land use and allocation of urban areas.