The evolution of dam induced river fragmentation in the United States

Nature Portfolio (Springer Nature) | June 28th, 2023

The global threat of drying lands: Regional and global aridity trends and future projections

United Nations Convention to Combat Desertification | December 9th, 2024

Most of the world’s land—more than three-quarters—has become permanently dryer in recent decades. A combined global area equal to half the size of Australia has tra

Most of the world’s land—more than three-quarters—has become permanently dryer in recent decades. A combined global area equal to half the size of Australia has transformed from humid lands to drylands with less rain for crops, pastures, nature and people. These stark statistics are among the many grim revelations from new analyses revealed in this groundbreaking report. For the first time, scientists within UNCCD Science-Policy Interface have clearly documented current and future drying trends and impacts that reveal a global, existential peril previously shrouded by a fog of scientific uncertainty. Its name is aridity—the climatic and enduring condition of too little life-supporting moisture—and its effects threaten the lives and livelihoods of billions across almost every region of the globe.

The Green Visions Plan for 21st Century Southern California: 21. Hydrology and Water Quality Modeling of the Calleguas Creek Watershed

University of Southern California (USC) | November 2nd, 2009

The hydrology and water quality simulation presented in this report is a part of the Green Visions Plan for 21st Century Southern California project. The primary

The hydrology and water quality simulation presented in this report is a part of the Green Visions Plan for 21st Century Southern California project. The primary focus of the Calleguas Creek Watershed water quality modeling is to determine the pollutant concentration and loads entering the stream network and to what degree surface waters are subject to water quality impairments.

The Influence of Zooplankton Availability on Delta Smelt Condition and Foraging Across Habitat Contexts

Publisher not available | December 19th, 2025

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dep

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dependent effects can help optimize and target management efforts. In this analysis, we investigate how environmental and food-web conditions interactively affect condition and foraging of Delta Smelt (Hypomesus transpacificus), an endangered fish endemic to the San Francisco Estuary (the estuary). Food limitation, in terms of pelagic zooplankton availability, is considered a main factor that contributes to the decline in Delta Smelt abundance. Our overarching objective was to examine whether the effect of zooplankton on Delta Smelt depended on habitat context. Specifically, we hypothesized that zooplankton would less positively effect Delta Smelt condition—as measured by hepatosomatic index (HSI)—and foraging success in areas with nearby tidal wetlands, because these adjacent habitats may provide access to prey items from the epibenthos and fringing vegetation. In contrast, in regions with limited proximity to wetlands, we hypothesized that Delta Smelt would rely more on pelagic prey, which would manifest as a more positive effect of zooplankton on body condition and foraging success for Delta Smelt. Using models that accounted for habitat in multiple ways, we found little evidence that zooplankton and habitat interactively influenced Delta Smelt condition or gut fullness. Rather, the influence of zooplankton on HSI and gut fullness was generally positive across habitat contexts. Given the well-documented food limitation in the estuary, promoting the availability of pelagic zooplankton is a rational, albeit complex, management aim. Furthermore, our results suggest that efforts to increase zooplankton would broadly benefit Delta Smelt across a wide range of habitat contexts.

The Instream Flow Incremental Methodology: A Primer for IFIM

U.S. Department of the Interior (DOI) | March 1st, 1995

This booklet is a primer on the Instream Flow Incremental Methodology (IFIM). Our objective for this primer is to give you a short but comprehensive introduction to the b

This booklet is a primer on the Instream Flow Incremental Methodology (IFIM). Our objective for this primer is to give you a short but comprehensive introduction to the background, philosophical and ecological underpinnings, individual components, and steps in applying IFIM. As a primer, we have tried to keep it simple. Scientific names and other technical details have been avoided, but the primer includes relevant definitions (with key words or phrases indicated in italics for their first use), summaries of the literature where you may wish to turn for further reading, and explanations to increase your understanding of what IFIM is all about and how it works. The primer should reinforce your growing knowledge and provide the necessary stepping stones into more advanced, certified training in IFIM methods. This primer is divided into five more or less independent sections. The first section reviews the history of instream flow problems in the United States. Reading this section should provide you with an understanding ofwhy IFIM emerged to solve certain complex water management problems and hint at future directions. The second section discusses the choice of instream flow methods and, more importantly, provides a framework for deciding whether IFIM is appropriate for the kind of problems you might be facing. The third section reviews the ecological underpinnings of IFIM from a historical perspective. This section is meant to show you the degree to which IFIM components, or models, represent the essence of the biological systems that we are attempting to understand. It is more detailed than the other sections and meant specifically to be of interest to biologists and ecologists. Section four delves into the broader philosophical, problem-solving approach embodied in IFIM.  This perspective is important because the 'facts' alone rarely dictate good decisions; it is how we employ those facts to resolve instream flow problems in an interdisciplinary decision making arena that is important. The fifth section outlines the logical steps in applying IFIM and the information flow that holds them together. Here you will learn how to navigate through the IFIM process from tentative problem identification to problem resolution.

The Natural Flow Regime

Oxford University Press (OUP) | December 1st, 1997

Humans have long been fascinated by the dynamism of free-flowing waters. Yet we have expended great effort to tame rivers for transportation, water supply, flood con

Humans have long been fascinated by the dynamism of free-flowing waters. Yet we have expended great effort to tame rivers for transportation, water supply, flood control, agriculture, and power generation. It is now recognized that harnessing of streams and rivers comes at great cost: Many rivers no longer support socially valued native species or sustain healthy ecosystems that provide important goods and services.

The NOAA NCEI marine microplastics database

Nature Portfolio (Springer Nature) | October 20th, 2023

Microplastics (<5 mm) pollution is a growing problem affecting coastal communities, marine ecosystems, aquatic life, and human health. The widespread occurrence of m

Microplastics (<5 mm) pollution is a growing problem affecting coastal communities, marine ecosystems, aquatic life, and human health. The widespread occurrence of marine microplastics, and the need to curb its threats, require expansive, and continuous monitoring. While microplastic research has increased in recent years and generated significant volumes of data, there is a lack of a robust, open access, and long-term aggregation of this data. The National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI) now provides a global open access to marine microplastics data on an easily discoverable and accessible GIS web map and data portal. The objective of this data portal is to develop a repository where microplastics data are aggregated, archived, and served in a user friendly, consistent, and reliable manner. This work contributes to NCEI’s efforts towards data standardization, integration, harmonization, and interoperability among national and international collaborators for monitoring global marine microplastics. This paper describes the NOAA NCEI global marine microplastics database, its creation, quality control procedures, and future directions.

The Pacific Decadal Oscillation modulated marine heatwaves in the Northeast Pacific during past decades

Nature Portfolio (Springer Nature) | June 19th, 2023

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

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

The Public Trust Doctrine and California Water Law: National Audubon Society v. Department of Water and Power

University of California College of the Law, San Francisco (UC Law SF) | June 15th, 1982

Conflicting demands on dwindling surface water supplies in California have led to frequent challenges of state decisions to grant diversions of water that impair or destr

Conflicting demands on dwindling surface water supplies in California have led to frequent challenges of state decisions to grant diversions of water that impair or destroy ecological, recreational, or other instream uses of surface waters. This Comment examines the fundamental problems of surface water allocation in California and addresses the possibility of incorporating the public trust doctrine into the current water law system. The Comment then evaluates a recent attempt to apply the public trust doctrine in National Audubon Society v. Department of Water and Power. The Comment concludes by offering an alternative means to public trust protection of California's surface waters.