Synthesis of data and studies relating to Delta Smelt biology in the San Francisco Estuary, emphasizing water year 2017

Interagency Ecological Program (IEP) | November 1st, 2021

In the San Francisco Estuary (SFE), the effects of freshwater flow on the aquatic ecosystem have been studied extensively over the years and remains a contentious managem

In the San Francisco Estuary (SFE), the effects of freshwater flow on the aquatic ecosystem have been studied extensively over the years and remains a contentious management issue. It is especially contentious with regards to the Delta Smelt (Hypomesus transpacificus), a species endemic to the SFE that has been listed as threatened under the Federal Endangered Species Act and endangered by the State of California. Early studies of Delta Smelt distribution within the SFE suggested that Delta Smelt habitat is determined largely by freshwater flow; however, the exact mechanisms and processes producing such benefits remained unclear. In the summer of 2017, the Flow Alteration Management, Analysis, and Synthesis Team (FLOAT-MAST) was established to analyze, synthesize, and summarize the data collected from the various flow-related monitoring and special studies occurring in 2017(see Table Intro 4). This report will focus on the 2017 summer-fall status of Delta Smelt and its habitat following a record wet year. There has been a long-term decline in the abundance of Delta Smelt associated with a decline in other pelagic fishes. Investigators concluded that the decline has likely been caused by the interactive effects of several causes, including changes in both physical and biotic habitats, many of which are tied to amount and timing of freshwater flow. For this report, we formulated a number of basic predictions about the likely effects of high flows in 2017 on Delta Smelt and their habitat (Table 3). We use a qualitative weight of evidence approach to evaluate whether these predictions were supported by available data. Data sources included a variety of long-term monitoring surveys conducted by Interagency Ecological Program (IEP) agencies, as well as model outputs. Delta Smelt population, health, and life history metrics rarely responded as predicted. Water temperature appears to have a stronger effect on Delta Smelt growth rate and some metrics of life history diversity than outflow or X2 position. Other life history diversity attributes varied but did not appear to be driven by outflow or temperature. Health status was difficult to interpret. Low prevalence of lesions and improved nutritional condition during the drought was contradicted by declining overall population levels. Because of the sparse catches of Delta Smelt in the post-POD years, we consider the data insufficient to reach firm conclusions about the predictions concerning range and distribution of Delta Smelt, especially in the fall. The prediction of high survival was not supported. The 2017 Delta Smelt year class began with poor recruitment in spring of 2017 and below average survival for spring to summer and summer to fall. Thus, low production and low survival led to low abundance of all life stages. During the fall to winter period survival improved, yet the resulting adults were low in number. Foraging success of the fish captured, as measured by stomach fullness, was high for juveniles and adults in 2017 relative to recent years associated with the higher densities of common zooplankton prey that occurred in 2017.

Technical Report on the Scientific Basis for Alternative San Joaquin River Flow and Southern Delta Salinity Objectives

California State Water Resources Control Board (SWRCB) | February 15th, 2012

The State Water Resources Control Board (State Water Board) is in the process of reviewing the San Joaquin River (SJR) flow objectives for the protection of fish and wild

The State Water Resources Control Board (State Water Board) is in the process of reviewing the San Joaquin River (SJR) flow objectives for the protection of fish and wildlife beneficial uses, water quality objectives for the protection of southern delta agricultural beneficial uses, and the program of implementation for those objectives contained in the 2006 Water Quality Control Plan for the San Francisco Bay/Sacramento-San Joaquin Delta Estuary (2006 Bay- Delta Plan). Figure 1.1 displays the project area corresponding to SJR flow objectives and program of implementation and Figure 1.2 displays the project area for the southern Delta water quality objectives and program of implementation. The information and analytical tools described in this report (referred to hereafter as Draft Technical Report or Technical Report) are intended to provide the State Water Board with the scientific information and tools needed to consider potential changes to these objectives and their associated program of implementation. In this quasi-legislative process, State Water Board staff will propose amendments to the SJR flow objectives for the protection of fish and wildlife beneficial uses, southern Delta water quality objectives for the protection of agricultural beneficial uses, and the program of implementation contained in the 2006 Bay-Delta Plan. Also, the environmental impacts of these amendments will be evaluated in a Substitute Environmental Document (SED) in compliance with the California Environmental Quality Act. Any changes to water rights consistent with the revised program of implementation will be considered in a subsequent adjudicative proceeding.

The Delta as Changing Landscapes

University of California, Davis (UC Davis) | July 1st, 2016

What happens at one place in a landscape influences and is influenced by what happens in other places. Consequently, management and restoration that focus on individual p

What happens at one place in a landscape influences and is influenced by what happens in other places. Consequently, management and restoration that focus on individual places may fail to recognize and incorporate interactions across entire landscapes. The science of landscape ecology, which emphasizes the interplay of landscape structure, function, and change at multiple scales, offers a perspective that can integrate the spatial relationships of ecological processes and the functional interconnections of land and water in the Delta. Although the Delta is one of the most studied estuaries in the world, applications of landscape science have been limited. We describe why it is important to incorporate landscape science into management and restoration, emphasizing how Delta landscapes have changed over the past centuries. The land–water linkages of the past have been broken, waterways have been over-connected, and hard boundaries have replaced the gradual and dynamic transitions among landscape patches. The contemporary landscape also has new, novel assemblages of species and stressors that were not there in the past. This historical perspective indicates how knowledge of past landscape functions can contribute to the restoration and management of contemporary landscapes. We illustrate these points with case studies of inundation dynamics and riparian woodlands, and use a third example to describe a landscape approach to restoration. We propose that science that encompasses the multiple, interacting components of functional landscapes in the Delta will foster resilient and enduring restoration and management outcomes that benefit both people and wildlife. We suggest several ways of moving landscape science to the forefront of management and restoration in the Delta.

The effects of aquatic area abundance, buffer, and hydrology on depressional wetland condition based on CRAM

San Francisco Estuary Institute (SFEI) | April 1st, 2016

The potential of collaborative solutions to improve management of California (United States) wildlands

Restoration Ecology, Society for Ecological Restoration (SER) | November 13th, 2024

The Pulse of the Bay: The 25th Anniversary of the RMP

San Francisco Estuary Institute (SFEI) | July 1st, 2017

San Francisco Bay is the defining feature of our region and a world-class ecosystem. The Bay Area is also known world-wide as a cradle of innovation, excellence, and succ

San Francisco Bay is the defining feature of our region and a world-class ecosystem. The Bay Area is also known world-wide as a cradle of innovation, excellence, and success, especially in the technology sector. Less well known is the fact that over the past 25 years the Bay Area has been a world leader in water quality monitoring, supporting a pioneering program for the Bay that demonstrates how regional collaboration can provide the science needed to protect and improve water quality in a treasured ecosystem. The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) was established in 1993 and, with sustained local funding and continuous improvement, is going stronger than ever a quarter century later.

The Regional Monitoring Program for Water Quality in San Francisco Bay, California, USA: Science in support of managing water quality

Regional Studies in Marine Science (Elsevier) | October 22nd, 2015

The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) is a novel partnership between regulatory agencies and the regulated community to provide the

The Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) is a novel partnership between regulatory agencies and the regulated community to provide the scientific foundation to manage water quality in the largest Pacific estuary in the Americas. The RMP monitors water quality, sediment quality and bioaccumulation of priority pollutants in fish, bivalves and birds. To improve monitoring measurements or the interpretation of data, the RMP also regularly funds special studies. The success of the RMP stems from collaborative governance, clear objectives, and long-term institutional and monetary commitments. Over the past 22 years, high quality data and special studies from the RMP have guided dozens of important decisions about Bay water quality management. Moreover, the governing structure and the collaborative nature of the RMP have created an environment that allowed it to stay relevant as new issues emerged. With diverse participation, a foundation in scientific principles and a continual commitment to adaptation, the RMP is a model water qualitymonitoring program. This paper describes the characteristics of the RMP that have allowed it to grow and adapt over two decades and some of the ways in which it has influenced water quality management decisions for this important ecosystem.

The Science Charade in Species Conservation

Supreme Court Economic Review | September 2nd, 2017

The Endangered Species Act (ESA) is among the nation’s most important and powerful environmental laws. It is also a source of great conflict and controversy.  The list

The Endangered Species Act (ESA) is among the nation’s most important and powerful environmental laws. It is also a source of great conflict and controversy.  The listing of individual species, the designation of critical habitat and the implementation of conservation measures often prompt fierce legal and political battles. In these conflicts, activists on all sides claim that “sound science” supports their respective positions, and scoff at the “junk science” relied upon by the other side. The U.S. Fish & Wildlife Service fails to rely upon the best science, critics claim.  If it did, they charge, it would adopt policies more to their liking.  The debate over the use of science under the ESA is part of the “science charade” that clouds substantive policy debate about species conservation.3 What typically divides competing interest groups is not a devotion to science, but sharply divergent policy preferences dressed up in scientific garb. The political debate over the use of science under the ESA tends to obscure the dividing line between science and policy and undermines the development of more effective and equitable conservation strategies. Further, efforts to reform the ESA by mandating additional scientific procedures or increasing judicial scrutiny of the use of science by federal agencies will do little to address the ESA’s underlying problems or make species conservation efforts more effective.  Scientific research is necessary to inform species conservation decisions. But species conservation is not – and cannot be – a wholly scientific exercise. Judgments about what constitutes a distinct species or how to evaluate incomplete scientific data necessarily draw upon normative premises. More significantly, policy decisions about what sorts of conservation measures should be adopted are not scientific at all. Whether habitat loss will reduce the likelihood that a given species or population will survive in the wild may be a scientific question, but what measures should be adopted to conserve such habitat, and at what cost, is a normative policy judgment. Science can – indeed, must – inform such inquiries, but science cannot tell us what to do. Engaging in the “science charade,” either by pretending that ESA implementation may be guided by scientific judgment alone or by claiming that reforms of how science is used is unlikely to improve species conservation. To the contrary, efforts to constrain or control the use of science in ESA listing decisions or enhance judicial review of agency scientific determinations will undermine the quality and reliability of ESA science and lead to less effective conservation policy.  Whatever ails the ESA, a failure to incorporate adequate science is not the cause of the disease. As this Article explains, efforts to augment the amount or type of science used in ESA decision-making, whether through additional procedural mandates or altered standards of judicial review, will not address the conflicts that afflict species conservation policy. In some cases, such measures could further undermine the ESA’s ability to conserve species.  Part I of the Article gives a brief overview of the ESA, its operation, and the scientific requirements written into the Act. Part II describes the “science charade,” through which policymakers and others pretend that policy judgments are purely scientific questions, and the legal and political incentives that ensure this artifice persists. Part III details how the ESA’s structure generates political pressure on the use of science and encourages the science charade in species conservation. Part IV explains why various “sound science” reforms will not address these problems, and Part V outlines alternative policy reforms. 

The Seasonal Cycle of Surface Soil Moisture

American Meteorological Society (AMS) | June 29th, 2022

The seasonal cycle contributes substantially to soil moisture temporal variability in many parts of the world, with important implications for seasonal forecasting releva

The seasonal cycle contributes substantially to soil moisture temporal variability in many parts of the world, with important implications for seasonal forecasting relevant to agriculture and the health of humans and ecosystems. There is considerable spatial variability in the seasonal cycle of soil moisture, yet a lack of global observations has hindered the development of parsimonious theories explaining that variability. Here, we use 6 years of global satellite observations to describe and explain the seasonal cycle of surface soil moisture globally. An unsupervised clustering algorithm is used to identify five distinct seasonal cycle regimes. Each seasonal cycle regime typically arises in both hemispheres, on multiple continents, and across substantially different local climates. To explain this spatial variability, we then show that the observed seasonal cycle regimes are reproduced very well by a simple but physically based water balance model, which only uses precipitation and downwelling surface shortwave radiation as inputs, and includes no free parameters. Surprisingly, no information on vegetation or land cover is required. To our knowledge, this is the first characterization of the seasonal cycle of surface soil moisture based on global observations.

Toward a Preemptive Ecology for Rapid, Global, and Increasingly Irreversible Environmental Change: A Discussion Paper with Implications for Research and Management in the Sacramento-San Joaquin Delta

Delta Stewardship Council (Delta Council) | November 15th, 2019

People have extensively modified the Sacramento-San Joaquin Delta since the 1850s. Rapid change is not new, but the nature of rapid change that is beginning to be experie

People have extensively modified the Sacramento-San Joaquin Delta since the 1850s. Rapid change is not new, but the nature of rapid change that is beginning to be experienced has new qualities. The Delta Independent Science Board, working in conjunction with the Delta Science Program and the Delta Plan Interagency Implementation Committee, is assessing the adequacy of environmental and ecological research in the Delta, how well that research is addressing emerging challenges, and how it might be improved. This paper is a part of that process. Each member of the Delta Independent Science Board has contributed to this document, but there is not a consensus among the members around the full content of this paper. This paper is written to inform and stimulate discussion around controversial yet important issues.