|Ph.D Student||Toger Marina|
|Subject||Urban Open Spaces: Network Morphology, Dynamics and|
Influence on Wildlife Foraging in Haifa
|Department||Department of Architecture and Town Planning||Supervisors||Professor Daniel Czamanski|
|Professor Itzhak Benenson|
|Full Thesis text|
There is ample empirical evidence that native flora and fauna inhabit open spaces within cities. Some overabundant species of urban wildlife present a challenge to other species, ecosystem services, and people. By tracing the movement of wildlife in the urban environment, I investigate the morphology of the Network of Urban Open Spaces (NUOS) as an infrastructure for wild animals - specifically wild boars. As a case study, I focus on Haifa, Israel, whose complex NUOS has changed considerably due to urban expansion. Using a high-resolution spatially explicit agent-based model, I study how the wild fauna interacts with the city environment.
This study departs from an understanding of urban open spaces as increasingly subject to planning efforts to mitigate their further decay - sometimes fuelling controversial public discourse. Recognizing the crude spatial resolution and conceptual mode of evaluation characterizing extant research on the environmental impact of urbanization-induced shrinking of the NUOS, it defines a need for a more systematic appraisal of the amount, morphology and dynamics of urban open spaces. Developing a multi-scale model of the spatial configuration of the urban open spaces and its impact on wildlife, I trace the evolution and morphology of Haifa NUOS. The study investigates changes in fragmentation, clustering and connectivity over time using a graph-theoretic approach that reveals species-specific connectivity patterns of the NUOS. It exposes the connectivity among the open space patches of the urban landscape with its highly heterogeneous permeability at a fine scale critical for the wildlife (formalized as multiple least-cost-paths), while retaining the context of larger scales defining the urban environment.
The analysis reveals an increasing fragmentation and elimination of open spaces in Haifa over the past 60 years. However, a deeper view reveals that Haifa’s landscape preserves a network of open patches interconnected by corridors: The city remains porous for percolation of large and medium-sized wild mammals into and throughout the city. Using an agent-based model of wild boars penetration into the city, the study explains the ever-growing presence of wild boars despite the shrinkage in NUOS. Applying optimal foraging theory, the model uses high-resolution GIS data on Haifa landscape and cover. The model points to a complex network of open spaces that provides a good fit to empirical observations, and elucidates how the city remains porous and attractive to wildlife: The multi-scale view reveals a “road network” that makes food throughout the city accessible at a relatively low search cost.
Discussing common policies for controlling the penetration and movement of wild boars in urban residential neighborhoods, I apply the model to evaluate likely implications. I emphasize the importance of urban morphology, landscape heterogeneity and the distribution of food sources for the development of urban wildlife - a nexus that becomes visible only through by augmenting traditional models with a fine-grained analysis, which also considers microstructures such as backyards and grassed areas. The network of the open spaces shapes the city’s porosity for specific animal species and their ability to exploit the urban habitat. In this way, the city remains part of nature.