8. Remote Sensing and Spatial Modelling of the Urban Environment

With the beginning “urban millennium” (UNESA 2007), our interest in the societal, economic, and ecological functioning of urban systems is rapidly increasing (Pickett et al. 2001). Half of the world’s population inhabits cities, with an increasing share of megacity dwellers or people living in mega-urban regions (Kraas 2007). Urban agglomerations steer processes from the local to the global level and urban ecological science needs to develop a deeper understanding of how matter and energy flows driven by urban ecosystems function across scales (Grimm et al. 2008; Kaye et al. 2006). While a city’s physical footprint is limited, the ecological footprint of our increasingly urbanized world is rapidly expanding. Urban agglomerations are estimated to extend on an ecological footprint of up to 200–300 times their actual physical size (Folke et al. 1997). The sustainable provision of urban ecosystem services and maintaining urban biodiversity is hence closely connected to mitigating effects of imbalanced rapid urbanization (McGranahan and Satterthwaite 2003). Accordingly, urban ecology is becoming more prominent and will determine how sustainable future cities will develop from an environmental perspective. There is an urgent need for in-depth process understanding and a more profound knowledge of land use decisions that drive the urban structure and thereby heavily impact the urban environment and the provision of ecosystem services. Actually, urban regions offer the most intense interaction of humans with ecosystems and thereby a wealth of opportunities to gain a deeper understanding of related land use processes and impacts on urban ecosystem services. However, urban ecology is intrinsically complex; it exhibits many different research facets and an overarching theory is still to be developed. A methodologically sound basis is mandatory to lay the foundation of such theoretical frameworks and to provide input for model-based research to test hypotheses in urban ecology and land use change (LUC) impacts on urban ecosystem services (Alberti 2005; Pickett et al. 2008).