Library

SFEI collaborated with the International Union for the Conservation of Nature (IUCN) and the International Olympic Committee (IOC) to create a guide to incorporating nature into urban sports, from the development of Olympic cities to the design and management of the many sport fields throughout the urban landscape. We applied the Urban Biodiversity Framework developed in Making Nature’s City to the world of sports, with case studies drawn from international sport federations, Olympic cities, and individual sport teams and venues around the world. The guide is part of IUCN’s ongoing collaboration with IOC to develop best practices around biodiversity for the sporting industry.

Download the report

This study investigates the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW), representing managed and natural settings. Using an array of ecological and geomorphic field analyses, we discuss site characteristics favorable to SAW health and regeneration, make recommendations for restoration and management, and identify next steps. Findings from this study will contribute to the acquisition, restoration, and improved management of SAW as part of the Santa Clara Valley Habitat Plan (VHP).

With rising sea levels and the increased likelihood of extreme weather events, it is important for regional agencies and local municipalities in the San Francisco Bay Area to have a clear understanding of the status, composition, condition, and elevation of our current Bay shore, including both natural features and built infrastructure.

The purpose of this Bay shore inventory is to create a comprehensive and consistent picture of today’s Bay shore features to inform regional planning. This dataset includes both structures engineered expressly for flood risk management (such as accredited levees) and features that affect flooding at the shore but are not designed or maintained for this purpose (such as berms, road embankments, and marshes). This mapping covers as much of the ‘real world’ influence on flooding and flood routing as possible, including the large number of non-accredited structures.
This information is needed to:

1. identify areas vulnerable to flooding.
2. identify adaptation constraints due to present Bay shore alignments; and
3. suggest opportunities where beaches, wetlands, and floodplains can be maintained or restored and integrated into flood risk management strategies.

The primary focus of the project is therefore to inform regional planners and managers of Bay shore characteristics and vulnerabilities. The mapping presented here is neither to inform FEMA flood designation nor is it a replacement for site-specific analysis and design.

The mapping consists of two main elements:

1. Mapping of Bay shore features (levees, berms, roads, railroads, embankments, etc.) which could affect flooding and flood routing.
2. Attributing Bay shore features with additional information including elevations, armoring, ownership (when known), among others.

SFEI delineated and characterized the Bay shore inland to 3 meters (10ft) above mean higher high water (MHHW) to accommodate observed extreme water levels and the commonly used range of future sea level rise (SLR) scenarios. Elevated Bay shore features were mapped and classified as engineered levees, berms, embankments, transportation structures, wetlands, natural shoreline, channel openings, or water control structures. Mapped features were also attributed with elevation (vertical accuracy of <5cm reported in 30 meter (100ft) segments from LiDAR derived digital elevation models (DEMs), FEMA accreditation status, fortification (e.g., riprap, buttressing), frontage (e.g., whether a feature was fronted by a wetland or beach), ownership, and entity responsible for maintenance. Water control structures, ownership, and maintenance attributes were captured where data was available (not complete for entire dataset). The dataset was extensively reviewed and corrected by city, county, and natural resource agency staff in each county around the Bay. This report provides further description of the Bay shore inventory and methods used for developing the dataset. The result is a publicly accessible GIS spatial database.

Major Findings
Over the past 150 years, lower San Francisquito Creek and the adjacent baylands have been modified for the sake of land reclamation and flood control. This study focused on developing an understanding of the magnitude of habitat change since the mid-19th century through comparisons of key historical and contemporary landscape-scale habitat features, as well as several key landscape metrics that relate to ecological functions and landscape resilience. The major findings from the analyses conducted for this study are as follows:
• Historically, the San Francisquito Creek Baylands included a mosaic of habitat types, including an extensive tidal marsh plain with salt pannes and an expansive tidal channel network, a broad bay flat, and a relatively wide contiguous low-gradient tidal-terrestrial transition zone.
• Since the late 19th century, a combination of land reclamation and the inland migration of the shoreline has resulted in a 55% decrease in tidal marsh area, a 67% decrease in total tidal channel length, a 40% reduction in channel flat area, a 20% increase in bay flat area, and a 95% decrease in tidal-terrestrial transition zone length.
• Land reclamation has also resulted in the creation of new features that did not exist in the area historically including tidal lagoons, non-tidal open water features, and non-tidal wetlands.
 

Recommendations
The findings from this study provide insight into the drivers for and magnitude of habitat change within the San Francisquito Creek Baylands, and can therefore help inform climate-resilient approaches for regaining some of the lost landscape features and ecological functions. Specific management recommendations developed from the study findings are as follows:
• The dramatic decrease in tidal marsh area and associated tidal channel length since the mid-1800s make tidal marsh restoration a high priority. To make restored areas sustainable over the long-term, restoration should include reestablishing regular tidal inundation as well as reestablishing a connection with San Francisquito Creek and the delivery of freshwater and fine sediment. Restoration efforts should focus on large contiguous areas with minimal infrastructure and should ideally be done sometime over the next decade to ensure the restored areas will have a chance of surviving the sharp increase in the rate of sea level rise that is predicted to occur around 2030 (Goals Update 2015).
• Similarly, the dramatic decrease in the tidal-terrestrial transition zone makes it a high priority for any restoration vision for this area. The transition zone provides distinct ecological services and marsh migration space, and is in need of restoration throughout the South Bay. Since most of the upland land along the historical tidal-terrestrial transition zone is currently developed, near-term restoration efforts should focus on creating transition zone habitats on the bayside of flood risk management levees (Goals Update 2015).
• The landscape metrics used in this study (tidal habitat area, tidal channel length, and tidal-terrestrial interface length) can be used to help design resilient landscape restoration and adaptation strategies around the mouth of San Francisquito Creek. Specifically, the metrics can be used to assess the long-term ecological benefit associated with various processes-based restoration approaches (i.e., approaches that create habitat features and establish physical processes required for habitat resilience). Additional useful landscape metrics are being developed as part of the Resilient Silicon Valley project (see Robinson et al. 2015).

EXECUTIVE SUMMARY
As sea level rise accelerates, our shores will be increasingly vulnerable to erosion. Particular concern centers around the potential loss of San Francisco Bay’s much-valued tidal marshes, which provide natural flood protection to our shorelines, habitat for native wildlife, and many other ecosystem services. Addressing this concern, this study is the first systematic analysis of the rates of marsh retreat and expansion over time for San Pablo Bay, located in the northern part of San Francisco Bay.

Key findings:
• Over the past two decades, more of the marshes in San Pablo Bay have expanded (35% by length) than retreated (6%).
• Some areas have been expanding for over 150 years.
• Some marsh edges that appear to be retreating are in fact expanding rapidly at rates of up to 8 m/yr.
• Marsh edge change may be a useful indicator of resilience, identifying favorable sites for marsh persistence.
• These data can provide a foundation for understanding drivers of marsh edge expansion and retreat such as wind direction, wave energy, watershed sediment supply, and mudflat shape.
• This understanding of system dynamics will help inform management decisions about marsh restoration and protection.
• This study provides a baseline and method for tracking marsh edge response to current and future conditions, particularly anticipated changes in sea level, wave energy, and sediment supply.

Recommended next steps:
• This pilot study for San Pablo Bay marshes should be extended to other marshes in San Francisco Bay.
• These initial marsh expansion and retreat findings should be further analyzed and interpreted to improve our understanding of system drivers and identify management responses.
• A program for repeated assessment should be developed to identify and track changes in shoreline position, a leading indicator of the likelihood marsh survival.

The Sacramento-San Joaquin Delta has been transformed from the largest wetland system on the Pacific Coast of the United States to highly productive farmland and other uses embodying California’s water struggles. The Delta comprises the upper extent of the San Francisco Estuary and connects two-thirds of California via the watersheds that feed into it. It is central to the larger California landscape and associated ecosystems, which will continue to experience substantial modification in the future due to climate change and continued land and water use changes. Yet this vital ecological and economic link for California and the world has
been altered to the extent that it is no longer able to support needed ecological functions. Approximately 3% of the Delta’s historical tidal wetland extent remains wetland today; the Delta is now crisscrossed with agricultural ditches replacing the over 1,000 miles of branching tidal channels.

Imagining a healthy Delta ecosystem in the future and taking bold, concrete steps toward that future requires an understanding and vision of what a healthy ecosystem looks like. For a place as extensive, unique, and modified as the Delta, valuable knowledge can be acquired through the study of the past, investigating the Delta as it existed just prior to the substantial human modifications of the last 160 years. Though the Delta is irrevocably altered, this does not mean that the past is irrelevant. Underlying geologic and hydrologic processes still influence the landscape, and native species still ply the waters, soar through the air, and move across the land. Significant opportunities are available to strategically reconnect landscape components in ways that support ecosystem resilience to both present and future stressors.

For centuries humans have reduced and transformed Mediterranean-climate oak woodland and savanna ecosystems, making it difficult to establish credible baselines for ecosystem structure and composition that can guide ecological restoration efforts. We combined historical data sources, with particular attention to mid-1800s General Land Office witness tree records and maps and twentieth century air photos, to reconstruct 150 years of decline in extent and stand density of Valley oak (Quercus lobata Neé) woodlands and savannas in the Santa Clara Valley of central coastal California. Nineteenth century Valley oak woodlands here were far more extensive and densely stocked than early twentieth century air photos would suggest, although reconstructed basal areas (7.5 m2/ha) and densities (48.9 trees/ha) were not outside the modern range reported for this ecosystem type. Tree densities and size distribution varied across the landscape in relation to soil and topography, and trees in open savannas were systematically larger than those in denser woodlands. For the largest woodland stand, we estimated a 99% decline in population from the mid-1800s to the 1930s. Although most of the study area is now intensely developed, Valley oaks could be reintroduced in urban and residential areas as well as in surrounding rangelands at densities comparable to the native oak woodlands and savannas, thereby restoring aspects of ecologically and culturally significant ecosystems, including wildlife habitat and genetic connectivity within the landscape.