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. 

Toward a Resilient Global Society: Air, Sea Level, Earthquakes, and Weather

American Geophysical Union (AGU) | April 30th, 2019

Society's progress along the four corners of prepare, adsorb, respond and adapt resilience square is uneven, in spite of our understanding of the foundational science and

Society's progress along the four corners of prepare, adsorb, respond and adapt resilience square is uneven, in spite of our understanding of the foundational science and a growing sense that urgent action is needed. The resilience vignettes describe the meaning and impact of current and near‐term change in four major domains: human health impacts from air pollution, coastal inundation from sea‐level rise, damaging earthquakes in populated areas, and impacts from extreme precipitation. Given our understanding of the scientific principles, societal action, from preparation to adaption, will be critical in minimizing the negative impacts of today's changes. The unprecedented rates of change in today's Earth system argue for urgent action in support of a resilient global society.

Toward Natural Infrastructure to Manage Shoreline Change in California

California Natural Resources Agency (CNRA) | August 27th, 2018

Flooding and erosion caused by rising sea levels and powerful storms threaten property throughout coastal California. To protect against these climate-change related thr

Flooding and erosion caused by rising sea levels and powerful storms threaten property throughout coastal California. To protect against these climate-change related threats, landowners will certainly take action, and the default industry standard response has been to try to “hold the line” against the encroaching sea by constructing seawalls, dikes, levees and other forms of coastal armoring. While armoring may in some cases provide acceptable short-term protection, armoring also tends to accelerate shoreline erosion, exacerbating hazards to people and leading to the eventual loss of critical wildlife habitat and public beaches. Natural Shoreline Infrastructure can be as effective as armoring, while having the added benefits of preserving coastal habitat and public access. Recognizing this, California agencies have mandated that decision-makers prioritize its use in planning and investment decisions. Yet, planners have encountered many stumbling blocks as they have tried to incorporate these approaches into coastal resilience plans. Major obstacles include: a lack of a common definition and shared terminology; lack of expertise; lack of precedent; and the absence of siting guidance and technical design standards. Here, we set out to enable planners to adopt Natural Shoreline Infrastructure by filling in the missing information. With the input of dozens of coastal managers who served on our Technical Advisory Committee, we developed a definition and collected a list of case studies where Natural Shoreline Infrastructure has already been successfully deployed in California. Drawing from these and other projects, we collected into one place the first detailed technical guidance for implementation, including siting criteria and design thresholds. These criteria inform decisions about where and when to use six types of Natural Shoreline Infrastructure (e.g. sand dunes, seagrass beds). Using Monterey Bay and Ventura County projects as examples, we demonstrate how to use the technical guidance in tandem with spatial data to match a particular shoreline environment with appropriate Natural Shoreline Infrastructure options, creating “blueprints” for action. The information in this report is intended to facilitate the use of Natural Shoreline Infrastructure along California’s coast, improving the resilience of communities and habitats in the face of climate change.

Towards the Protection, Restoration, and Enhancement of the Delta Ecosystem: A Synthesis. Appendix A: Summary of Existing Habitat and Species-Specific Plans, Strategies, and Management Approaches

Delta Stewardship Council (Delta Council) | March 15th, 2018

Tree height explains mortality risk during an intense drought

Nature Portfolio (Springer Nature) | September 26th, 2019

Forest mortality is accelerating due to climate change and the largest trees may be at the greatest risk, threatening critical ecological, economic, and social be

Forest mortality is accelerating due to climate change and the largest trees may be at the greatest risk, threatening critical ecological, economic, and social benefits. Here, we combine high-resolution airborne LiDAR and optical data to track tree-level mortality rates for ~2 million trees in California over 8 years, showing that tree height is the strongest predictor of mortality during extreme drought. Large trees die at twice the rate of small trees and environmental gradients of temperature, water, and competition control the intensity of the height-mortality relationship. These findings suggest that future persistent drought may cause widespread mortality of the largest trees on Earth.

Trend analysis of ground-water levels and spring discharge in the Yucca Mountain region, Nevada and California, 1960–2000

U.S. Geological Survey (USGS) | July 1st, 2002

Trends in Fish and Invertebrate Populations of Suisun Marsh January 2017 - December 2017

University of California, Davis (UC Davis) | January 31st, 2019

Suisun Marsh, at the geographic center of the northern San Francisco Estuary, is important habitat for native and non-native fishes. The University of California, Davis,

Suisun Marsh, at the geographic center of the northern San Francisco Estuary, is important habitat for native and non-native fishes. The University of California, Davis, Suisun Marsh Fish Study, in partnership with the California Department of Water Resources (DWR), has systematically monitored the marsh's fish populations since January 1980. The study’s main purpose has been to determine environmental and anthropogenic factors affecting fish distribution and abundance. 

Trends in nitrogen, phosphorus, and sediment concentrations and loads in streams draining to Lake Tahoe, California, Nevada, USA

Science of the Total Environment (Elsevier) | August 19th, 2020

Lake Tahoe, a large freshwater lake of the eastern Sierra Nevada in California and Nevada, has 63 tributaries that are sources of nutrients and sediment to the lake. The

Lake Tahoe, a large freshwater lake of the eastern Sierra Nevada in California and Nevada, has 63 tributaries that are sources of nutrients and sediment to the lake. The Tahoe watershed is relatively small, and the surface area of the lake occupies about 38% of the watershed area (1313 km2). Only about 6% of the watershed is urbanized or residential land, and as part of a plan to maintain water clarity, wastewater is exported out of the basin. The lake's clarity has been diminishing due to algae and fine sediment, prompting development of management plans. Much of the annual discharge and nutrient load to the lake results from snowmelt in the spring and summer months. To understand the relative importance of land use, climate, forest management, and other factors affecting trends in nutrient stream concentrations and loads, a Weighted Regression on Time Discharge and Season (WRTDS) model simulated these trends over a time frame of >25 years (mid-1970s to 2017). All studied locations generally show nitrate concentration and load trending down. Ammonium concentration and load initially trended down then increased continuously after 2005. Some locations show initially decreasing orthophosphate trends, followed by small significant increases in concentration and loads starting around 2000 to 2005. Total Kjeldahl nitrogen, total phosphorus and suspended sediment mostly trended downward. Overall, the trends in various forms of nitrogen were observed at most sites irrespective of the degree of development and indicate a change in ecological conditions is affecting the nitrogen cycle throughout the watershed, most likely attributable to forest aggradation and fire suppression. Ratios of bioavailable nitrogen in the form of nitrate and ammonium to orthophosphate have also trended downward during the period of record suggesting a shift of these streams from phosphorus limited to nitrogen limited.

Tulare Lake Basin Hydrology and Hydrography: A Summary of the Movement of Water and Aquatic Species

U.S. Environmental Protection Agency (EPA) | April 12th, 2007

This report provides a summary of the historic and current hydrology of the Tulare Lake Basin (Basin) and describes past, present and potentiai future movement of water o

This report provides a summary of the historic and current hydrology of the Tulare Lake Basin (Basin) and describes past, present and potentiai future movement of water out of the Basin, and potential movement of bioiogical organisms and toxicants within and outside of the Basin. This study was initiated at the request of the U.S. Environmental Protection Agency (USEPA).

Two and a half decades of United States wildfire burn zone disaster data, 2000-2025

Nature Portfolio (Springer Nature) | December 17th, 2025

Growing wildfire frequency and urban development expanding into fire-prone areas have heightened wildfire risk for wildland-urban interface (WUI) communities. When burn z

Growing wildfire frequency and urban development expanding into fire-prone areas have heightened wildfire risk for wildland-urban interface (WUI) communities. When burn zones come near or cross into communities, the heat, flames, and smoke can harm human health—directly or via psychosocial stressors—to the point of becoming a disaster. We harmonized six wildfire datasets to create the first U.S.-wide spatial dataset of wildfire burn zone disasters. Our criteria for a wildfire burn zone disaster were wildfires that burned near a community (≥96 people per km2 or met WUI criterion) and resulted in ≥1 civilian fatality, ≥1 destroyed structure, or received federal disaster declaration. We identified 6,212 U.S. wildfire burn zone disasters between 2000–2025. The annual number of these disasters ranged between 61 in 2001 and 570 in 2011 (median = 217), with an increasing trend over the study period. California had the highest number of wildfire burn zone disasters (n = 878, 14.1%). These data may inform demographic, economic, and population health research, as well as policymaking and resource allocation.