As key locations for impacts and benefits associated with biodiversity, urban areas are a critical frontier for improved stewardship. While cities across California have long been global leaders in managing threatened and endangered species, Los Angeles recently embarked on a more comprehensive approach to biodiversity when the Los Angeles City Council passed the May 10, 2017 Biodiversity Motion (Motion 25A, Council File No. 15-0499). The motion directed the development of a customized biodiversity index focused on conservation and access to biodiversity, among other products. The motion was in line with the City’s official goal of no-net-biodiversity loss by 2035. Together, this goal and motion suggest that biodiversity in LA shall not only be protected, but that its benefits will also be maximized to support urban resiliency and livability. This doctoral dissertation is organized into three chapters describing key analysis tools and results associated with the LASAN Biodiversity Team’s process of implementing the Biodiversity Motion.
As a first step, the LASAN team convened a transdisciplinary group of scholars, practitioners, and City staff to measure an established index, the Singapore Index on Cities’ Biodiversity, to provide a baseline measurement of biodiversity and a starting point for creating a the customized Index (LA City Index). Chapter 1 presents the initial Singapore Index measurement process and proposes indicators, preliminary measurement methods, and a long-term LA City Index measurement strategy. The LA City Index includes indicators that account for three core themes of urban biodiversity: conservation of native biodiversity, equitability and social aspects of biodiversity, and governance and management activities. The LA City Index is tailored specifically to the Los Angeles context and to monitor progress toward the 2035 no-net-loss target. It is intended to be institutionalized within municipal environmental management practices and a central tool in implementing a future LA Biodiversity Policy.
The results presented in Chapter 1 drove the decision to map ecological subregions, or “ecotopes”, for Los Angeles (Chapter 2). A key point of consensus early in the initial process was that, at over 300,000 acres (121,000 hectares) of extremely diverse ecological conditions, the future LA City Index needed to better account for the distribution and variation of biodiversity across the City, versus the cumulative City-wide assessment provided for the Singapore Index. Ecotopes combine landform, microclimate, and biotic characteristics, key building blocks of biodiversity, to differentiate subregional-scale spatial units for measuring and reporting the LA City Index results. They are also envisioned as future management units to address biodiversity and related urban ecosystem stewardship of ecosystem services, pollution, and ecological hazards. Chapter 2 presents the theoretical basis and methods for selecting and partitioning 27 subregional ecotopes associated with the City of Los Angeles.
The final chapter, Chapter 3, presents measurement methods, results, and stewardship implications associated with two key indicators of the LA City Index: habitat quality and connectivity of landscapes and open space. The research integrates high-resolution land cover and vegetation datasets, and connectivity modeling tools, to estimate and map habitat quality across the City and surrounding areas at a 10-foot (3-meter) spatial resolution. Connectivity of habitat areas is then modeled using Omniscape at a 30-foot resolution for the Elysian Valley sub-area as a proof of concept for the broader City. The result is a quantitative, spatial, “wall-to-wall” valuation of urban landcover as habitat for native biodiversity to live and move, ranging from the most natural to the most urban locations. This spatially explicit measure of connectivity provides an important tool toward quantifying biodiversity change in the City. Results suggest implications for both habitat conservation and equitable access to urban nature, two key objectives of the Biodiversity Motion and 2035 no-net-loss biodiversity target. It also provides an important dataset for incorporating biodiversity stewardship considerations into urban and landscape design and planning.
These tools are intended to become institutionalized within the City of Los Angeles’s urban biodiversity stewardship activities and serve as a model for Cities worldwide. Their process of development demonstrates a model of the “ecology for cities” paradigm by engaging a transdisciplinary group of experts to inform products that are responsive to both stewardship needs and trends in research. Such actionable, place-based science is central to shaping the physical ecology of cities while expanding opportunities for new directions in research. These products are, therefore, also well aligned with the Environmental Science & Engineering (ESE) dissertation goal of producing “scholarly and original work applied towards solving a significant environmental problem [that]...typically address policy as well as technical dimensions…”.
Change in cities is often rapid, and the potential to shape urban biodiversity is immense. Along with ecosystem services, ecological hazards, and pollution, biodiversity is integral to comprehensive urban ecosystem stewardship. Cities are just beginning to formally address urban ecology comprehensively, and rapid expansion of stewardship is necessary to accommodate urgent climate-driven changes to urban ecosystems. Cities’ ability to provide urban forest cooling benefits, accommodate changing flood regimes, or maintain equitable access and conservation of biodiversity within fragmented urban landscapes are a few examples of the importance of urban ecology and biodiversity stewardship toward urban resiliency. The scientific community must also rapidly respond to support stewardship decision making, and transdisciplinary models like the one demonstrate a path toward actionable scientific research. Effective urban ecosystem stewardship will not only succeed in achieving resilience and sustainability in the face of the climate crisis but will leverage ecology and biodiversity to support the next generation of urban enrichment.