Understanding Ecosystem Services Along Urban Streams Using Citizen Science, Social Media Data, and Expert Input

About 75% of the streams and rivers in Southern California are biologically degraded. Widespread development and flood control have created an urban river condition known for geomorphic simplification, reduced societal value of stream systems, and ecological simplification. The global degradation of streams has resulted in a freshwater biodiversity crisis that, by many measures, eclipses terrestrial biodiversity loss. However, while responsible for many pressures to ecosystems, cities can enhance aspects of ecosystem health and aid in reducing biodiversity loss. Cities can also host the ecosystem services, however degraded, that enhance community cohesion, resilience, and well-being. A growing urban river revitalization movement in the region, in various states of implementation, offers an opportunity to critically examine the opportunities and challenges that are presented by our local urban rivers. In this dissertation, I identify cultural ecosystem services (CES) along the Los Angeles River using FlickR data and examine the relationship between CES and site attributes using Maxent, a presence-only species distribution model. I find that I am able to identify 5 typologies of CES using FlickR text and photos, that two reaches of the Los Angeles River, a completely channelized and a semi-natural, soft-bottom reach of the River, host the highest CES intensity, and that relative suitability of CES occurrence is related to the presence of historical bridges, access, and median flow. Then, using a more traditional application of Maxent, I examine avian species habitat relationships at the catchment scale for species found along urban and semi-natural streams in Southern California. I find that I am not able to identify predictors of habitat suitability for generalist species at the catchment scale, in part due to contradicting model evaluation metrics, and describe limitations with the use of citizen science data, catchment scale analysis, model valuation, and the application of Maxent to highly urban settings. Finally, following statewide investments in green infrastructure projects that enhance water quality and water capture and recognizing the opportunity to support urban biodiversity in distributed multi-benefit projects, I make use of the Delphi method and the expertise of biodiversity experts to identify habitat goals for green infrastructure projects and associated metrics. I describe the Delphi process and the difficulty in reaching consensus due to disagreement in the feasibility and likelihood of success for several goals and objectives. I describe a preliminary framework to capture the habitat value of green infrastructure projects and compare it to established biodiversity frameworks