Almost half of the world’s human population lives in coastal areas, and associated coastal development has significantly degraded or destroyed many coastal ecosystems. Burgeoning human populations and rising sea levels only further constrain the availability of habitat that coastal species depend on.

California’s 1,100 mile coast has more than 200 threatened, endangered or rare species living in coastal habitats. There are hundreds of coastal estuaries that provide critical rearing habitat for marine species, and are also important for recreation, water filtration, and carbon sequestration.

Only 10 percent of California’s historic coastal wetlands remain. Without intervention, we are at risk of losing 40 percent of our remaining coastal wetlands to sea level rise over the coming decades. Conservancy scientists are working to reverse these trends. 

Freshwater Systems

California is one of the most hydrologically altered landscapes in the world. As water becomes…>>

Groundwater

In a normal year, groundwater accounts for 40 percent of California’s water supply. That…>>

Surface Flows

Californians have fundamentally altered many of the state’s rivers and streams with dams,…>>

Terrestrial Systems

In California, a day’s drive can take a visitor from record-setting desert heat to glaciated…>>

Wildlands

Nearly half of California is protected in some land status that prevents most kinds of intensive…>>

Harvested Landscapes

A third of California is privately-owned forestland, woodland or grassland. From redwood forests on…>>

Cultivated Landscapes

California is the leading agricultural state in the country and it’s agriculture generates…>>

Urban Areas and Infrastructure

With California’s population on track to reach 50 million people, the demand for energy,…>>

Fisheries

Wild capture fisheries supply food and jobs for hundreds of millions of people across the globe. Yet…>>

Coastal Conservation

Almost half of the world’s human population lives in coastal areas, and associated coastal…>>

Science in Action

Terrestrial | Planning | Technology | Economics

Wildfire and Communities

How can land protection and restoration help protect communities from wildfire?

Terrestrial | Marine | Economics | Science

TNC and FEMA

How do we increase climate resilience in ways that work for people and nature?

2022 | Marine | Technology | Science | Publications & Reports

Lost Fishing Gear is a Key Contributor to Ocean Plastic Pollution

Brandon Kuczenski, Camila Vargas Poulsen, Eric L. Gilman, Michael Musyl, Roland Geyer, Jono Wilson

More than 4.5 million fishing vessels ply ocean waters each year, setting countless nets, traps, hooks and lines. Much of this fishing gear is made of plastic components and a significant fraction of…

2022 | Marine | Technology | Science | Publications & Reports

Use of Simple Indicators to Improve Fisheries Management

William J. Harford, Ricardo Amoroso, Richard J. Bell, Matias Caillaux, Jason Marc Cope, Dawn Dougherty, Natalie Anne Dowling, Frank Hurd, Serena Lomonico, Josh Nowlis, Dan Ovando, Ana M. Parma, Jeremy D. Prince, Jono R. Wilson

Overfishing threatens the health of ocean ecosystems. Effective fisheries management is key to minimizing ocean impacts and improving outcomes for millions of fishing dependent people throughout the…

2022 | Freshwater | Science | Publications & Reports

Hydraulic Properties of the Riffle Crest and Applications for Stream Ecosystem Management

Gabriel Rossi, Darren Mierau, Jennifer Carah

A simple stream depth measurement at the deepest part of a riffle crest in a river or stream provides an easy-to-measure and inexpensive metric for ecological researech, environmental flow management,…

2022 | Freshwater | Technology | Science | Publications & Reports

Modeling Functional Flows in California’s Rivers

Theodore E. Grantham, Daren M. Carlisle, Jeanette Howard, Belize Lane, Robert Lusardi, Alyssa Obester, Samuel Sandoval-Solis, Bronwen Stanford, Eric D. Stein, Kristine T. Taniguchi-Quan, Sarah M. Yarnell, Julie K. H. Zimmerman

Protecting water in rivers is made more challenging by the lack of quantitative estimates of the amount of water required to protect river ecosystems. The authors developed a model and made…

2022 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Transforming Palmyra Atoll to native-tree dominance will increase net carbon storage and reduce dissolved organic carbon reef runoff

Kate Longley-Wood, Mary Engels , Kevin D. Lafferty, John P. McLaughlin, Alex Wegmann

Native forests on tropical islands have been displaced by non-native species, leading to calls for their transformation. Simultaneously, there is increasing recognition that tropical forests can help…

2022 | Freshwater | Science | Publications & Reports

Functional Flows in Groundwater-Influenced Streams: Application of the California Environmental Flows Framework to Determine Ecological Flow Needs

Sarah M. Yarnell, Ann Willis, Alyssa Obester, Ryan A. Peek, Robert A. Lusardi, Julie Zimmerman, Theodore E. Grantham, Eric D. Stein

Very few rivers have protections to protect flow for species and ecosystems, in part because of the complexity and resources required to develop ecological flow criteria - the amount of water needed…

2022 | Terrestrial | Science | Publications & Reports

Oren Pollak Memorial Research Fund - 2022 RFP

Brynn Pewtherer

The Oren Pollak Memorial Research Fund was established in 2000 in memory of Dr. Oren Pollak, a leading grassland ecologist and restoration pioneer, as well as an ardent champion and mentor for…

2022 | Freshwater | Terrestrial | Marine | Science | Publications & Reports

Conservation Science Catalyst Fund - 2021 Annual Report

Brynn Pewtherer, Scott Morrison

The Nature Conservancy deploys science to help overcome major challenges facing people and nature. In today’s fast-paced world, turning threats to nature into opportunities for conservation…

2021 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Sacramento River: balancing ecological and social restoration goals to restore riparian habitat along a lowland floodplain river, California, USA

Case study by: K.D. Holl, G.H. Golet

Advancing conservation requires understanding the constraints imposed on natural systems by human societies. This understanding typically comes from engagement with local stakeholders, as opposed…

2021 | Freshwater | Terrestrial | Science | Publications & Reports

Integrating citizen science data with expert surveys increases accuracy and spatial extent of species distribution models.

O.J. Robinson, V. Ruiz-Gutierrez, M.D. Reynolds, G.H. Golet, M. Strimas-Mackey and D. Fink

Information on species’ habitat associations and distributions, across wide spatial and temporal scales, is fundamental for guiding conservation. Yet these data are often in short supply. In…

2021 | Terrestrial | Planning | Science | Publications & Reports

Enhancing Habitat Value for Shorebirds in Rice Agriculture

Case study by: Khara Strum (Audubon California), Kristin Sesser (Point Blue Conservation Science), Greg Golet (TNC)

This case study communicates lessons learned by TNC and partners from years of research and monitoring of habitat enhancement projects in Sacramento Valley rice agriculture. It is a contribution to…

2021 | Terrestrial | Marine | Planning | Technology | Science | Publications & Reports

Jack and Laura Dangermond Preserve Invasive Plant Species Action Plan

Moses Katkowski, H. Scott Butterfield, John Knapp, Kelly Easterday, Laura Riege, Mark Reynolds

This 5-year action plan describes the vision for invasive plant species mapping, monitoring and treatment at the Jack and Laura Dangermond Preserve in Sourthern California. The plan is adaptive and…

2021 | Terrestrial | Science | Publications & Reports

Assessing the reliability of raptor pellets in recording local small mammal diversity

Maria C Viteri, Mary Allison Stegner, Elizabeth A. Hadly

Biodiversity monitoring is a core part of conservation practice, however all sampling methods include biases. In particular, small mammal live-trapping, the field standard, produces highly skewed…

2021 | Freshwater | Science | Publications & Reports

The California Environmental Flows Framework: Meeting the Challenges of Developing a Large-Scale Environmental Flows Program

Eric D. Stein, Julie Zimmerman, Sarah M. Yarnell, Bronwen Stanford, Belize Lane, Kristine T. Taniguchi-Quan, Alyssa Obester, Theodore E. Grantham, Robert A. Lusardi, Samuel Sandoval-Solis

The first step to protecting rivers is figuring out how much water they need to protect species and ecological functions - known as ecological flow criteria. Scientists have struggled to develop flow…

2021 | Freshwater | Terrestrial | Planning | Technology | Science | Publications & Reports

Planting Stormwater Solutions: A methodology for siting nature-based solutions for pollution capture, habitat enhancement, and multiple health benefits

Kelsey Jessup, Sophie S. Parker, John M. Randall, Brian S. Cohen, Rowan Roderick-Jones, Shona Ganguly, Jill Sourial

This paper presents results from Planting Stormwater Solutions, part of TNC’s Urban Conservation work in Los Angeles. The authors develop a methodology to prioritize siting of vegetated…

2021 | Marine | Science | Publications & Reports

Disease-driven mass mortality event leads to widespread extirpation and variable recovery potential of a marine predator across the eastern Pacific

S. L. Hamilton, V. R. Saccomanno, W. N. Heady, A. L. Gehman, S. I. Lonhart, R. Beas-Luna, F. T. Francis, L. Lee, L. Rogers-Bennett, A. K. Salomon and S. A. Gravem

The sunflower sea star (Pycnopodia helianthoides) is an important mesopredator in kelp forest ecosystems that was devastated by the outbreak of sea star wasting disease (SSWD). This study quantifies…

2021 | Terrestrial | Planning | Science | Publications & Reports

Framework for Resilience: Tahoe-Central Sierra Initiative

P. Manley, K. Wilson, N. Povak

The Framework for Resilience offers a shared vision for resilience that recognizes the interdependent nature of social and ecological values. These values are described by ten pillars that represent…

2021 | Terrestrial | Planning | Publications & Reports

Assessment of Current Landscape Conditions: Tahoe-Central Sierra Initiative

Kristen N. Wilson, Patricia N. Manley

Climate change, high-severity wildfire, and drought threaten the resilience of forests and communities in the Sierra Nevada. The Tahoe–Central Sierra Initiative (TCSI) is a partnership of state…

2021 | Freshwater | Terrestrial | Science | Publications & Reports

Biological responses to stream nutrients: A Synthesis of Science From Experimental Forests and Ranges

Kristen Wilson, Dale W. Johnson, Douglas F. Ryan, ed.

Authored by TNC staff and colleague, Chapter 8 of this report synthesizes environmental monitoring and studies performed at Sagehen Experimental Forest that are relevant to water quality regulatory…

2021 | Freshwater | Terrestrial | Marine | Planning | Publications & Reports

Coastal Adaptation Vision for Naval Base Ventura County Point Mugu: Technical Report

Environmental Science Associates (ESA) for The Nature Conservancy and Naval Base Ventura County