Strategic Assessment of Vegetation Cover Connectivity in the Tehran Metropolis: Identifying Priority Management Zones

Structural fragmentation in urban green space networks contributes to reduced ecological sustainability, disrupted ecosystem service performance, and weakened environmental resilience in metropolitan areas. This study aims to spatially evaluate the structural connectivity of Tehran’s green space network and identify priority intervention zones at both neighborhood and district levels. To achieve this, an up-to-date vegetation cover map was produced using Sentinel-2 satellite imagery with a 10-meter spatial resolution, applying object-based image classification. Three key landscape metrics—Percentage of Landscape (PLAND), Proximity Index (PROX), and Landscape Shape Index (LSI)—were subsequently calculated using FRAGSTATS software and visualized in ArcGIS. For enhanced comparability, the metrics were normalized and integrated into a weighted composite index. This fine-scale analytical framework enabled the ranking of structural connectivity across urban zones and the identification of ecological discontinuities.The results indicate that the northern parts of Tehran exhibit the highest levels of ecological sustainability and spatial continuity, whereas the central, eastern, and portions of the western zones suffer from severe fragmentation and disconnection. These findings can inform decision-making in targeted green space management, the design of spatially explicit interventions, green infrastructure regeneration, urban environmental policy formulation, and the optimal allocation of ecological resources and investments. The proposed framework—characterized by high interpretability, mappability, and transferability—serves as a practical tool for advancing environmental justice and promoting sustainable green infrastructure planning in rapidly expanding metropolitan contexts.
 
Extended Abstract
1-Introduction
The rapid pace of urbanization in the metropolises of developing countries—particularly Tehran—has led to significant consequences for the city’s spatial structure and environmental quality. Among the most pressing challenges is the decline in spatial connectivity within urban green space networks, which undermines the ecological sustainability of the urban environment. Beyond their aesthetic value, green spaces deliver a range of ecosystem services, including air pollution mitigation, temperature regulation, groundwater recharge, and enhanced quality of life for residents. However, the realization of these benefits depends largely on the degree to which urban green patches are spatially integrated and interconnected. Within this context, structural connectivity in landscape configuration is recognized as a foundational element in urban ecological analysis. Spatial connectivity among green networks facilitates energy flows, the movement of biological species, and equitable access to green areas for urban residents. Despite some initiatives in Tehran—such as the establishment of a greenbelt and the acquisition of garden lands—a comprehensive and scientifically grounded approach to evaluating and managing green space connectivity remains largely absent. This study therefore aims to rigorously assess the structure and spatial connectivity of vegetation cover across Tehran’s metropolitan area and to identify priority intervention zones at both neighborhood and district levels. What distinguishes this research from previous studies is its emphasis on fine-scale, place-based analysis, systematically extended to broader spatial scales.
 
2-Materials and Methods
To achieve the study’s objectives, a quantitative and analytical approach was employed, integrating remote sensing data, spatial analysis, and principles of landscape ecology. In the initial phase, an up-to-date vegetation cover map of Tehran was generated using Sentinel-2 satellite imagery with a spatial resolution of 10 meters. Image classification was performed using an object-based method combined with the Normalized Difference Vegetation Index (NDVI), resulting in an overall classification accuracy of 89% and a Kappa coefficient of 0.84. Subsequently, three key landscape metrics were calculated: Percentage of Landscape (PLAND), Proximity Index (PROX), and Landscape Shape Index (LSI). These metrics respectively quantify the extent of green cover, the spatial adjacency and cohesion of green patches, and their geometric complexity. The indices were computed using a circular moving window with a 500-meter radius, selected to reflect both Tehran’s heterogeneous urban structure and the human perception of walkable urban scales. The analysis utilized Ecognition Developer, ArcGIS, FRAGSTATS, and Expert Choice software. To integrate the three metrics, a normalization procedure was applied, and relative weights were assigned through pairwise comparison. This process yielded a composite Green Space Connectivity Index ranging from 0 to 1, representing the degree of connectivity for each spatial unit. The resulting index formed the basis for final analyses at both neighborhood and district levels across Tehran.
 
3- Results and Discussion
The results derived from the calculation and analysis of landscape metrics at both regional and local scales offer a clear depiction of the connectivity status of Tehran’s green space network. The findings indicate that the northern districts—particularly Districts 1, 3, 2, 4, and 5—exhibit the highest levels of structural connectivity. These areas benefit from extensive green cover, close spatial proximity among patches, and more regular geometries, all of which contribute to enhanced ecological sustainability.
In contrast, Districts 10, 9, 8, 21, and 12 were identified as having the lowest connectivity index values. In these districts, green patches tend to be fragmented, spatially isolated, and characterized by irregular, jagged shapes. Such spatial configurations diminish the provision of ecosystem services, exacerbate urban heat island effects, and undermine environmental justice. Neighborhood-level analysis yielded comparable results. Neighborhoods such as Baharan, Darband, Niavaran, and Darakeh demonstrated favorable levels of connectivity, whereas Northern Afsarieh, Karun, Salsabil, and Imam Khomeini neighborhoods recorded the lowest values. These spatial disparities highlight that the distribution of green spaces in Tehran is not only inequitable but also lacks the spatial coherence required to support long-term ecological resilience.
 
4- Conclusion
The findings of this study underscore the urgent need to reassess Tehran’s urban green space management strategies. The multidimensional analysis of green space network connectivity reveals that the central, eastern, and southern sectors of the city require immediate intervention to regenerate their green infrastructure. Recommended actions include linking fragmented green patches, establishing green corridors, improving local access to green spaces, and converting underutilized land into vegetated areas. The integrated connectivity index not only facilitates the prioritization of zones for targeted interventions but also provides a robust framework for optimal resource allocation, participatory planning, and the advancement of environmental justice at both neighborhood and district levels. Furthermore, this model is adaptable to other megacities in Iran and globally that face similar challenges, provided that input data and contextual conditions are appropriately localized. Ultimately, the sustainability of urban green spaces hinges on data-driven decision-making and the formulation of spatially targeted policies aimed at mitigating spatial discontinuities within the urban landscape.