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Whipple, A.; Grantham, T.; Desanker, G.; Hunt, L.; Merrill, A.; Hackenjos, B.; Askevold, R. A. 2019. Chinook Salmon Habitat Quantification Tool: User Guide (Version 1.0). Prepared for American Rivers. Funded by the Natural Resources Conservation Service Conservation Innovation Grant (#69-3A75-17-40), Water Foundation and Environmental Defense Fund. A report of SFEI-ASC’s Resilient Landscapes Program. SFEI Contribution No. 953. San Francisco Estuary Institute: Richmond, CA.

The Salmon Habitat Quantification Tool provides systematic, transparent, and consistent accounting of the spatial extent, temporal variability, and quality of salmon habitat on the landscape. It is part of the multi-species assessment of the Central Valley Habitat Exchange (CVHE, www.cvhe.org). The suitability criteria applied in the tool were established by Stillwater Sciences and the Technical Advisory Committee (TAC), and the Chinook salmon HQT habitat evaluation and User Guide development was led by American Rivers and the San Francisco Estuary Institute. The approach uses commonly-applied concepts for evaluating suitable habitat based on modeling, with methods adapted from the hydrospatial analysis approach developed by Alison Whipple (2018).

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Whipple, A.; Robinson, A.; Safran, S. M. 2022. ELEVATION AND OPPORTUNITY IN THE DELTA: Restoring the right thing in the right place. SFEI Contribution No. 1082. San Francisco Estuary Institute: Richmond, Ca.

 

A future Sacramento-San Joaquin Delta and Suisun Marsh (“Delta” herein) that supports healthy ecosystems and native species, while also meeting flood risk reduction, water supply, water quality, carbon sequestration, economic, and cultural objectives, requires that appropriate restoration and management actions be taken in the right place at the right time. Geographic setting affects the potential opportunities available—not all actions are suitable everywhere. Physical factors determining what types of activities are appropriate now and in the future include a site’s elevation, degree of tidal and fluvial influence, salinity, soil type, and local effects of climate change, which all vary spatially across the Delta. While there has been considerable progress over the last several decades, continued acceleration of the pace and scale of enhancement actions appropriate to landscape position is needed. Understanding the physical template is necessary for developing strategies that move beyond opportunistic restoration, support resilience over time, and have the potential to connect and magnify benefits across the larger landscape.

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Whipple, A.; Grossinger, R. M.; Davis, F. W. 2010. Shifting Baselines in a California Oak Savanna: Nineteenth Century Data to Inform Restoration Scenarios. Restoration Ecology 19 (101), 88-101 . SFEI Contribution No. 593.

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.

Whipple, A.; Grossinger, R. M.; Rankin, D.; Stanford, B.; Askevold, R. A. 2012. Sacramento-San Joaquin Delta Historical Ecology Investigation: Exploring Pattern and Process. SFEI Contribution No. 672. SFEI: Richmond.

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.

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Whipple, A.; Grenier, L.; Safran, S. M.; Zeleke, D.; Wells, E.; Deverel, S.; Olds, M.; Cole, S.; Rodríguez-Flores, J.; Guzman, A.; et al. 2022. RESILIENT STATEN ISLAND: Landscape Scenario Analysis Pilot Application. SFEI Contribution No. 1083. San Francisco Estuary Institute: Richmond, Ca.

A central motivating question for the Sacramento-San Joaquin Delta science and management community is what should be done, where and when, to support future Delta landscapes that are ecologically and economically viable and resilient to change. Actions must be taken that have the greatest potential for achieving multiple benefits. This is especially important given the urgency to rapidly transition Delta landscapes to address biodiversity loss, erosion of ecosystem resilience, flood risk, water supply reliability, and cultural and economic sustainability. Landscape-scale planning is needed to examine how individual actions add up to meaningful change. Such planning involves figuring out how different areas can provide different functions at different times and helps show how choices made now can help shift trajectories toward desired outcomes. Too often, land use and management decisions are made based on a limited set of objectives or at the site scale, resulting in missed opportunities. Actions (or inaction) should not foreclose on critical opportunities. Moving forward, there is great need to more effectively compare possible future scenarios across a range of ecological and economic factors. This scenario analysis for Staten Island — a large Delta island managed for multiple uses and facing challenges similar to elsewhere in the Delta — provides an approach to help address this need.

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