SCUOLA DI DOTTORATO UNIVERSITA’ DEGLI STUDI MILANO-BICOCCA Department of Earth and Environmental Sciences PhD program in Chemical, Geological and Environmental Sciences Cycle XXIX Curriculum in Environmental Science MULTIPLE ECOSYSTEM SERVICES PROVIDED BY URBAN FORESTS IN THE URBAN AREA OF MILAN Candidate: Claudia Canedoli Registration number: 787838 Tutor: Emilio Padoa-Schioppa Co-tutor: Roberto Comolli Coordinator: Frezzotti Maria Luce ACADEMIC YEAR 2015 / 2016 The future is not somewhere we are going, it is something we are making. Richard Hobbs, 1997 This PhD Thesis has been reviewed by: Riccardo SANTOLINI, Università degli Studi di Urbino Carlo Bo Janez PIRNAT, University of Ljubljana TABLE OF CONTENTS pg. ABSTRACT 4 GENERAL INTRODUCTION 6 The Millennium Ecosystem Assessment 6 Ecosystem services 9 Ecosystem services and urban areas 11 Valuation of urban ecosystem services 13 Project aims and framework 15 Chapter I - Landscape fragmentation and urban sprawl in the urban region of Milan 18 Abstract 19 1. Introduction 19 1.1 Measuring landscape fragmentation and urban sprawl 22 2. Materials and methods 23 2.1 Defining the urban region of Milan 23 2.2 Landscape fragmentation 28 2.3 Urban sprawl 31 3. Results and Discussion 33 3.1 Extension of the urban region of Milan 33 3.2 The current status of landscape fragmentation in the UR of Milan 36 3.3 Spatio-temporal patterns of urban sprawl 38 4. Conclusions 41 References 43 Appendix of Chapter I 46 Chapter II – Urban parks as habitat providers for biodiversity: a multi-scale analysis in the 50 urban area of Milan Abstract 51 1. Introduction 51 2. Materials and methods 54 2.1 Study area 54 2.2 Bird surveys 55 2.3 Environmental features 56 3. Data analysis 56 3.1 Detectability and abundance of birds 56 3.2 Relationships between species richness and abundance at landscape scale 57 3.3 Relationships between species occurrence and abundance at site scale 58 4. Results 59 1 4.1 Birds surveys 59 4.2 Relationships between species richness and abundance at landscape scale 61 4.3 Relationships between species occurrence and abundance at site scale 63 5. Discussion 66 6. Conclusions 70 References 71 Chapter III - Diversity and hydrocarbon-degrading potential of epiphytic microbial 75 communities on Platanus x acerifolia leaves in an urban area Abstract 76 1. Introduction 76 2. Materials and methods 79 2.1 Sampling 79 2.2 DNA extraction 80 2.3 Illumina sequencing 80 2.4 Sequence analysis 81 3. Results and Discussion 82 3.1 Phylogenetic diversity 82 3.2 Diversity of alkB phylotypes 87 4. Conclusions 92 References 92 Appendix of Chapter III 99 Chapter IV – Urban soils properties and organic carbon stock in the urban area of Milan 103 Abstract 104 1. Introduction 104 1.1 Carbon sequestration by soil 104 1.2 Urban soils 106 1.3 Estimate Carbon stock for urban soils 107 2. Study area 109 3. Materials and methods 109 3.1 Soil sampling 109 3.2 Soil chemical analysis 113 3.3 Environmental variables 113 3.4 Statistical analysis 114 4 Results 115 4.1 Urban soils properties 115 4.2 Carbon stock in urban soils 119 5. Discussion 124 5.1 Urban soils properties 124 5.2 Carbon stock in the urban soils of Milan 125 5.3 Enhancing the accuracy of C stock estimates and constrains posed by urban areas 127 6. Conclusions 130 References 131 2 Chapter V – Public participatory mapping of cultural ecosystem services: match or mismatch 136 between citizen perception and park management in the Parco Nord of Milan Abstract 137 1. Introduction 137 2. Materials and Methods 139 2.1 Study area 139 2.2 Participatory mapping of CES 141 2.3 Map of park management 143 2.4 Data analysis 144 3. Results and Discussion 149 3.1 Cultural ecosystem services perceived by parks dwellers 149 3.2 Comparison of maps of CES 156 3.3 Consideration about this methodological approach: opportunities and needs 158 4. Conclusions 160 References 161 Appendix of Chapter IV 165 GENERAL CONCLUSIONS 169 REFERENCES 177 SUPPLEMENTARY MATERIALS 182 Urban forests and biodiversity 183 The soundscape methodology for bird monitoring in urban parks 184 PAPERS AND CONFERENCE PROCEEDINGS 186 AKNOWLEDGMENTS 188 3 _________________________________________________________________________ Abstract ABSTRACT Cities, just as any other social-ecological system, depend on ecosystems and their components to sustain long- term conditions for life. The provision of ecosystem services (ES) varies spatially across landscapes, determined by diverse human social, political and ecological interactions and it involves the analysis of the environment in an interdisciplinary perspective based on the integration of ecological and socio-economic dimensions. A growing empirical base confirms that urbanization profoundly affects how we connect with and use natural resources but how these impacts play out, in particular with reference to ecosystem functioning and biodiversity, is not yet well understood. Quantification of ES can be difficult in areas containing complex land-cover mosaics, and that often represent novel ecosystems in terms of their composition. However, it has been extensively demonstrated that urban areas may be important source of ES. Because of their importance, a deeper knowledge about ES provisioning in urban areas is strongly advocated. In this context, particular importance is emphasized for urban parks and new forest plantings in urban, peri-urban or urbanized contexts. This study represented a multi-disciplinary research that focused on the analysis of multiple ecosystem services in the urban area of Milan (Italy) with particular regard to those provided in urban parks and forests. Five specific studies had been developed in order to analyse different ecosystem services related to biodiversity, pollution mitigation, organic carbon storage by soils, and cultural services. The first study proposed a methodology to spatially define the extent of the urban region (UR) of Milan. Milan UR area was morphologically characterized by a northern band of natural and semi-natural lands which was separated from the southern agricultural lands by a semi-continuous urban ‘belt’. In this region, the expansion of the urban tissue was analysed by quantifying the current degree of landscape fragmentation and characterizing historical trends (in the past 50-years) of urban sprawl in the UR. The fragmentation was computed with a metric that produced a map of the spatial distribution of fragmentation, as well as quantitative data on the level of fragmentation present in different planning areas relevant to planners. Results revealed that the UR of Milan suffers of high degree of landscape fragmentation throughout the area, with the major fragmented territories in the north of the city Milan (Monza and Varese). Urban sprawl showed an increasing trend in the last 50 years, reaching alarming values to date. Overall, Milan UR showed a chaotic proliferation of dispersed buildings and under-utilized infrastructure that lead to increase in energy requirements and resources depletion. A balance in urban compaction and maintenance of green spaces is a major challenge for urban planners. In the second study the role of urban forests in providing suitable habitats for biodiversity was analysed. In order to detect how environmental features of the urban area of Milan affected biodiversity, landscape features, site features and vegetation structure were analysed with a multi-scale analysis. For twenty-eight birds species 4 _________________________________________________________________________ Abstract was described the different response (presence) to specific environmental features. The study showed how the biodiversity patterns found can be explained by considering the effects of environmental features acting at different scales and that urban green areas can therefore be actively managed by foresters and city planners to preserve the biological diversity that they harbour. The third study deal with the the regulative role of vegetation in urban areas in contribute to reduce air pollution levels and offset greenhouse gas emissions. This study represents a preliminary work that aimed at analyse the hydrocarbon-degrading potential of epiphytic microbial communities on Platanus x acerifolia, trees common used in an urban area. Further investigations are needed in order to quantify the actual contribution of bacteria in air pollutant removal per unit of leaf weight or leaf area under different environmental conditions, and at the evaluation of the efficiency of different plant-bacteria systems in air quality improvement. The fourth study deal with the estimation of organic carbon (OC) storage by urban soils of parks, forests and other typology of urban land covers. As urban soils are normally excluded from traditional OC stock estimation because of the misleading assumption that they do not store C, this study aims to investigate urban soils characteristics and compare C stock of different type of urban land cover and use. Mean OC stock found for the urban soils of Milan was comparable to values found in the Lombardy region by previous studies. OC stock was found higher for parks compared to other areas, but no significant differentiation was found in order to define a typical C stock for each land cover or use type. Results highlight how the complex heterogeneity of urban soils together with the uncertainty of their origins, their history and management may summarize the reasons of the limitation in our capacity to model their characteristics. The fifth study analysed cultural ecosystem services (CES) perceived by citizen in one of the larger park of the study area (Parco Nord). The study aimed to present a methodology to integrate CES mapping with decision support in land use planning. Public participatory GIS techniques (PPGIS) were used to map people perception of cultural benefits. A comparison analysis with cultural benefits perceived by people and those intended to be provided by park management was performed. Results showed places in the park that had bundles of different values, and other places with clusters of the same value type.