There are many and increasing threats to biodiversity. To protect the plants and animals that share our world, we need to understand what they need to survive – and ideally, thrive – in a warming, more crowded world. And we need to better understand how meeting those needs can align with other societal values.

To do that, our scientists conduct ecological research to elucidate conservation problems, test hypotheses and solutions, and monitor results. We collaborate with the scientific community to inform and review our work, and share our findings with scientists and conservation practitioners around the world.

Science in Action

Terrestrial | Marine | Economics | Science

TNC and FEMA

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

Freshwater | Terrestrial | Science

Rewilding the San Joaquin Valley

40 years of science sets the course for the largest recovery of species in U.S. history

2024 | Terrestrial | Planning | Science | Publications & Reports

Quantitative methods for integrating climate adaptation strategies into spatial decision support models

Nicholas A. Povak, Patricia N. Manley, Kristen N. Wilson

This study presents a methodology to integrate spatial assessments of current and future forest conditions to understand the potential to achieve desired conditions under climate change with ongoing disturbances. The output is a strategic (where to go) and tactical (what to do) map to improve…


2024 | Terrestrial | Science | Publications & Reports

Oren Pollak Memorial Research Fund - 2024 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 grassland ecology students. As The Nature Conservancy’s lead ecologist in California in the…


2023 | | Planning | Science | Publications & Reports

Quantifying the smoke-related public health trade-offs of forest management

Claire L. Schollaert, Jihoon Jung, Joseph Wilkins, Ernesto Alvarado, Jill Baumgartner, Julien Brun, Tania Busch Isaksen, Jamie M. Lydersen, Miriam E. Marlier, Julian D. Marshall, Yuta J. Masuda, Charles Maxwell, Christopher W. Tessum, Kristen N. Wilson, Nicholas H. Wolff, June T. Spector

By modeling six scenarios of forest management, wildfire, and health impacts from smoke from 1981-2020, we found that moderate amounts of prescribed fire can decrease harmful particulate matter exposure and reduce asthma related hospitalizations and emergency department visits. This case study from the Tahoe Central…


2023 | Terrestrial | Planning | Science | Publications & Reports

Contrasting management paradigms for pronghorn in the arid Southwest and their northern range: a review

William T. Bean, H. Scott Butterfield, Craig Fiehler, David Hacker, Jeanette K. Howard, Russell Namitz, Brandon Swanson, Thomas J. Batter

TNC launched a Water for Wildlife project motivated by understanding the importance of standing free water across the season for wildlife in general, but most importantly for those species sensitive to water availability during times of the year when water is typically limiting in California,…


2023 | Terrestrial | Science | Publications & Reports

Mojave Desert land-use change: revisiting conservation values after a decade of growth and development

Michael J. Clifford, Sophie S. Parker, Brian S. Cohen, Elaine York, Joel Tuhy

This paper provides an assessment of changes in the conservation value of lands in the Mojave Desert of Nevada and Utah resulting from renewable energy and other development between 2010 and 2018. The authors use conservation value as determined by the Mojave Desert Ecoregional…


2023 | Terrestrial | Planning | Science | Publications & Reports

Interstate 15 Wildlife Crossing Design Considerations for Focal Wildlife Species. Santa Ana-Palomar Mountains Linkage Southern California

Trish Smith, Cheryl Brehme, Jill Carpenter, Nancy Frost, Megan Jennings, Barbara Kus, Scott Quinnell, Spring Strahm, T. Winston Vickers

The Nature Conservancy and the California Department of Transportation are planning 3 wildlife crossing infrastructure projects along a 3-mile stretch of Interstate 15 (I-15) in the Santa Ana-Palomar Mountains Linkage in southern California. While wildlife crossings are becoming more common, optimal designs that meet the…


2023 | Freshwater | Terrestrial | Science | Publications & Reports

Statistical evaluation of the similarity of characteristics in springs of the California Desert, United States

Adam H. Love, Andy Zdon, Naomi S. Fraga, Brian Cohen, Maura Palacios Mejia, Rachel Maxwell, Sophie Parker

This paper presents results from the Mojave Desert Springs research project. The authors present a comprehensive statistical analysis of similarities between California desert springs. An observed lack of correlation between the springs’ hydrologic and ecological parameters suggests that each spring represents a somewhat unique…


2023 | Terrestrial | Science | Publications & Reports

Supporting the “virtuous cycle” in urban ecosystems: how research can inform plans, policies, and projects that impact urban resilience

Michele Romolini, Sophie S. Parker, Gregory B. Pauly, Eric M. Wood

This editorial introduces a group of 11 articles published as part of an organized research topic in the Urban Greening section of the journal Frontiers in Sustainable Cities. In contrast with the abundance of literature that describes the negative impacts of humans and anthropogenic change,…


2023 | Marine | Economics | Science | Publications & Reports

Static management presents a simple solution to a dynamic fishery and conservation challenge

Christopher M. Free, Lyall F. Bellquist, Karin A. Forney, Jenn Humberstone, Kate Kauer, Qui Lee, Owen R. Liu, Jameal F. Samhouri, Jono R. Wilson, Darcy Bradley

Dynamic ocean management frameworks can be a useful approach to fisheries management under climate change. In the oceans, marine heatwaves are increasingly common symptoms of climate change that can impact ecosystems, economies, and communities. The recent 2014-2016 marine heatwave in the NE Pacific resulted in…


2023 | Freshwater | Science | Publications & Reports

A decision‐support framework for dam removal planning and its application in northern California

Suman Jumani, Lucy Andrews, Theodore E. Grantham, S. Kyle McKay, Jeffrey Duda, Jeanette Howard

California has a dam problem. Since the start of the 20th century, the state has built thousands of dams on its rivers and streams. Now, more than 75% of the largest dams are greater than 50 years old. This means that a significant proportion of…


2023 | Terrestrial | Planning | Science | Publications & Reports

Exploring interacting effects of forest restoration on wildfire risk, hydropower, and environmental flows

Benjamin P. Bryant, Tessa Maurer, Phillip C. Saksa, John D. Herman, Kristen N. Wilson, Edward Smith

The authors of this study analyzed how wildfires and forest restoration, specifically thinning and prescribed fire being implemented in the French Meadows Project in the central Sierra Nevada, could impact streamflow, hydropower generation, and ecological flows for a threatened frog (Foothill yellow legged frogs). By…


2023 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

A resilient and connected network of sites to sustain biodiversity under a changing climate

Mark G. Anderson, Melissa Clark, Arlene P. Olivero, and D. Richard Cameron

In response to biodiversity loss, scientists have called for the protection of well-connected systems of protected areas covering 30 to 50% of the planet. However, as climate change drives shifts in species, conservation plans based on current biodiversity patterns will become less effective. The authors…


2023 | Marine | Science | Publications & Reports

Characterizing state-managed and unmanaged fisheries in coastal marine states and territories of the United States

Michael C. Melnychuk, Charmane E. Ashbrook, Richard J. Bell, Lyall Bellquist, Kate Kauer, Jono R. Wilson, Ray Hilborn, Jay Odell

America’s fisheries provide nearly two million jobs and contribute $117 billion to the national GDP. Although state and territory fisheries account for 40% of the commercial value of U.S. marine fisheries overall, there has not been a nationwide synthesis of the performance of state/territory fisheries…


2023 | Marine | Technology | Science | Publications & Reports

The CALFISH database: A century of California's non-confidential fisheries landings and participation data

Christopher M. Free, Camila Vargas Poulsen, Lyall F. Bellquist, Sophia N. Wassermann, Kiva L. Oken

Commercial and recreational fisheries in California influence a long and dynamic history of coastal economies, cultural heritage, and marine ecosystem health. Fisheries-dependent data sources are critical for monitoring these trends over time, but even public data sources are often difficult to access. This slows down…


2023 | Marine | Science | Publications & Reports

Use of management strategy evaluation to understand the value of citizen science in managing an iconic California recreational fishery

Lyall Bellquist, William J. Harford, Frank Hurd, Alexis Jackson, Jeremy D. Prince, Jan Freiwald, Anna Neumann, Jack Likins, Jono Wilson

Conventional fisheries management relies largely on professional sources of scientific data collection, typically from academic or government institutions. Development of community-led data sources (i.e., citizen/community science) has been slow, partially due to data quality concerns. Accelerating stressors to marine ecosystems and the dynamic nature of…


2023 | Marine | Science | Publications & Reports

Post-release survival and prolonged sublethal effects of capture and barotrauma on deep-dwelling rockfishes (genus Sebastes): implications for fish management and conservation

Nicholas C. Wegner, Elan J. Portner, Drew T. Nguyen, Lyall Bellquist, Andrew P. Nosal, Alena L. Pribyl, Kevin L. Stierhoff, Paul Fischer, Ken Franke, Russell D. Vetter, Philip A. Hastings, Brice X. Semmens, and John R. Hyde

Historical overfishing led to depletion of several groundfish species on the US west coast. Two of these species, Cowcod and Bocaccio, heavily influenced the expansion of groundfish regulations to rebuild multiple stocks. However, the effects of fishing-induced barotrauma, and the effectiveness of descending devices as…


2023 | Marine | Economics | Science | Publications & Reports

Impact of the 2014–2016 marine heatwave on US and Canada West Coast fisheries: Surprises and lessons from key case studies

Christopher M. Free, Sean C. Anderson, Elizabeth A. Hellmers, Barbara A. Muhling, Michael O. Navarro, Kate Richerson, Lauren A. Rogers, William H. Satterthwaite, Andrew R. Thompson, Jenn M. Burt, Steven D. Gaines, Kristin N. Marshall, J. Wilson White, Lyall F. Bellquist

As symptoms of climate change, extreme environmental events (e.g., marine heatwaves) now represent the greatest global threat to the oceans, causing profound ecosystem and socioeconomic impacts. The recent marine heatwave on the North America west coast was the largest ever recorded, but the extent of…


2023 | Marine | Planning | Science | Publications & Reports

U.S. exempted fishing permits: Role, value, and lessons learned for adaptive fisheries management

Lindsay Bonito, Lyall Bellquist, Alexis M. Jackson, Kate Kauer, Mary G. Gleason, Jono Wilson, Stuart Sandin

Experimentation supports adaptive and climate-ready fisheries management in numerous contexts. Exempted Fishing Permits (EFPs) enable fisheries participants, scientists, and managers to collaboratively test new fishing regulations and/or gear types that might advance fishery sustainability, although no evaluation of federal EFP performance had ever been conducted.…


2023 | Marine | Economics | Science | Publications & Reports

Characterization of a developing recreational deep-drop fishery for swordfish off southern California

Scott A. Aalbers, Michael Wang, Lyall Bellquist, Kate Kauer, Alexis Jackson, Chugey A. Sepulveda

An emerging recreational fishery for swordfish has recently developed in California, outpacing existing fisheries monitoring programs, which prevents accurate estimation of swordfish catch and effort as well as any potential bycatch. The study documents a sharp increase in swordfish catch relative to previous decades, and…