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

Freshwater | Terrestrial | Marine | Science

Research for Impact

How do we design scientific research to have impact in the world?

Freshwater | Science

Restoring California’s Largest River

How can we restore large rivers and floodplains to benefit nature and people?

2020 | Freshwater | Terrestrial | Science | Publications & Reports

A meta-analysis contrasting active versus passive restoration practices in dryland agricultural ecosystems

M. Florencia Miguel, H. Scott Butterfield, Christopher J. Lortie

This meta-analysis provides a global synthesis of the which restoration practices – active vs. passive – are most successful at restoring plants, animals, and other ecosystem functions to dryland agricultural (grazing and farmlands) ecosystems, including the San Joaquin Valley of California where The Nature Conservancy…


2020 | Freshwater | Terrestrial | Technology | Science | Publications & Reports

The utility of environmental DNA from sediment and water samples for recovery of observed plant and animal species from four Mojave Desert springs

Maura Palacios Mejia, Emily Curd, Kiumars Edalati, Mark A. Renshaw, Roy Dunn, Daniel Potter, Naomi Fraga, Jenna Moore, Justin Saiz, Robert Wayne, Sophie S. Parker

This paper presents results from the Mojave Desert Springs research project. The authors used an environmental DNA (eDNA) technique to assess biodiversity at four naturally occurring springs. They compared the effectiveness of detecting DNA in water and sediment with conventional field survey and…


2020 | Freshwater | Terrestrial | Technology | Science | Maps & Webmaps

Planting Stormwater Solutions

Brian Cohen, Kelsey Jessup, Sophie Parker, John Randall, Jill Sourial

Cities across Southern California are investing in new infrastructure to address the challenges of stormwater management. We promote the use of nature-based solutions to ensure projects both treat stormwater and yield multiple additional benefits. TNC’s spatial analyses, summarized in this poster, help prioritize where to site…


2020 | Freshwater | Science | Publications & Reports

Groundwater Thresholds for Ecosystems: A Guide for Practitioners

Melissa M. Rohde, Laurel Saito, Ryan Smith

In addition to benefiting humans, groundwater is a critical water supply to many ecosystems, providing a buffer during dry periods and critical habitat for rare and endemic species. Increasing groundwater use to meet human water demands can outcompete these ecosystem water needs, causing irreversible damage to…


2020 | Freshwater | Terrestrial | Planning | Science | Publications & Reports

Shaping land use change and ecosystem restoration in a water-stressed agricultural landscape to achieve multiple benefits

Benjamin P. Bryant, T R. Kelsey, Adrian L. Vogl, Stacey A. Wolny, Duncan J. MacEwan, Paul C. Selmants, Tanushree Biswas, H S. Butterfield

Irrigated agriculture has grown rapidly over the last 50 years, helping food production keep pace with population growth, but also leading to significant habitat and biodiversity loss globally. Now, in some regions, land degradation and overtaxed water resources mean historical production levels may need to…


2020 | Freshwater | Science | Publications & Reports

Evaluating and Protecting Environmental Water Assets: A Guide for Land Conservation Practitioners

Author: Chris Alford, Editors and Reviewers: Amy Campbell, Monty Schmitt, Sara Press, Wendy Eliot, Bob Neale

Evaluating and Protecting Environmental Water Assets: A Guide for Land Conservation Practitioners, a publication by TNC and the Sonoma Land Trust (SLT), provides provides easy to understand guidance, resources, and tools that California land trusts, open space districts, resource conservation districts, and others can…


2020 | Freshwater | Science | Publications & Reports

Characterizing benthic macroinvertebrate and algal biological condition gradient models for California wadeable Streams, USA

Michael J. Paul, Ben Jessup, Larry R. Brown, James L. Carter, Marco Cantonatie, Donald F. Charles, Jeroen Gerritsena, David B. Herbst, Rosalina Stancheva, Jeanette Howard, Bill Isham, Rex Lowe, Raphael D. Mazor, Patina K. Mendez, Peter R. Ode, Alison O'Dowd, John Olson, Yangdong Pan, Andrew C. Rehn, Sarah Spaulding, Martha Sutula, Susanna Theroux

Water resource agencies assess stream water quality by determining the bugs and algae present to develop biotic indices. Yet translating these technical measures into meaningful language is difficult. This study finds that by placing technical numerical measures/indices into categories of condition allows resource manages to…


2020 | Terrestrial | Planning | Science | Publications & Reports

Santa Ana Mountains to eastern Peninsular Range Conservation Connectivity Infrastructure Planning Project for Interstate 15 and Closely Associated Roadways

Dr. Winston Vickers, Karen C. Drayer, Trish Smith, Brian Cohen

Highways across the greater San Diego region in southern California are major barriers and causes of mortality for mountain lions and are contributing to the species’ genetic restriction and threat of extirpation. Due to their large territories, mountain lions must regularly cross highways in this…


2020 | Freshwater | Terrestrial | Technology | Science | Publications & Reports

Mojave Desert Springs: setting an ecological baseline

Sophie S. Parker

This article appears in the Desert Report, a news publication of the Sierra Club California/Nevada Desert Committee. The article introduces the Mojave Springs Research Project, led by The Nature Conservancy, that involves a research collaboration with UCLA, the California Botanic Garden, and Partner Engineering and…


2020 | Terrestrial | Technology | Science | Data

Low-impact land use pathways to deep decarbonization of electricity

Grace C. Wu, Emily Leslie, Douglas Allen, Oluwafemi Sawyerr, D. Richard Cameron, Erica Brand, Brian Cohen, Marcela Ochoa, Arne Olson

California has ambitious climate and energy policies that call for the development of significant amounts of new zero-carbon energy by midcentury. The Power of Place study looks at multiple pathways to meet California's clean energy demand in alignment with decarbonization goals while limiting the impacts…


2020 | Terrestrial | Planning | Science | Publications & Reports

Roadmap to Restoration

Rodd Kelsey, Scott Butterfield, Abigail Hart, Ruthie Redmond, Hope Bigda-Peyton

This Policy Brief summarizes the results of a study on the potential for strategic habitat restoration in the San Joaquin Valley of California as an important part of reducing overall water demand to achieve groundwater sustainability under the Sustainable Groundwater Management Act (SGMA). It also provides policy…


2020 | Marine | Science | Publications & Reports

Effective fisheries management instrumental in improving fish stock status

Ray Hilborn, Ricardo Oscar Amoroso, Christopher M. Anderson, Julia K. Baum, Trevor A. Branch, Christopher Costello, Carryn L. de Moor, Abdelmalek Faraj, Daniel Hively, Olaf P. Jensen, Hiroyuki Kurota, L. Richard Little, Pamela Mace, Tim McClanahan, Michael C. Melnychuk, Cóilín Minto, Giacomo Chato Osio, Ana M. Parma, Maite Pons, Susana Segurado, Cody S. Szuwalski, Jono Wilson, Yimin Ye

Does fisheries management work at improving the status of fish stocks? The answer is a resounding, yes. This article compiles estimates of the status of global fish stocks, comprising roughly half of the world’s fish catch. Findings suggest that on average, fish stocks are increasing…


2020 | Terrestrial | Planning | Technology | Science | Publications & Reports

Jack and Laura Dangermond Preserve Rangeland Management Plan

Butterfield, H.S., M. Katkowski, J. Cota, O. Sage, C. Sage, K. Easterday, D. Zeleke, L. Riege, S. Gennet, K. Lin, B. Leahy, M. Bell, M. Reynolds

Cattle grazing is the dominant land management tool TNC has to manage biodiversity and reduce the threat of catastrophic wildfire at the TNC's Jack and Laura Dangermond Preserve. This Rangeland Management Plan, intended to guide rangeland management through 2025, details the adaptive management approach TNC…


2020 | Terrestrial | Science | Publications & Reports

Habitat selection by spotted owls after a megafire reflects their adaptation to historical frequent-fire regimes

Gavin M. Jones, H. Anu Kramer, Sheila A. Whitmore, William J. Berigan, Douglas J. Tempel, Connor M. Wood, Brendan K. Hobart, Tedward Erker, Fidelis A. Atuo, Nicole F. Pietrunti, Rodd Kelsey, R. J. Gutierrez, M. Zachariah Peery

This study examined spotted owl habitat selection after the King Fire in California using satellite tracking of 26 different owls . The authors found that whether severe fire was "good" or "bad" for owls depended on patch size and configuration: owls selected smaller but avoided…


2020 | Freshwater | Terrestrial | Marine | Planning | Technology | Science | Publications & Reports

Jack and Laura Dangermond Preserve Integrated Resources Management Plan

Butterfield, H.S., M. Reynolds , M.G. Gleason, M. Merrifield, B.S. Cohen, W.N. Heady, D. Cameron, T. Rick, E. Inlander, M. Katkowski, L. Riege, J. Knapp, S. Gennet, G. Gorga, K. Lin, K. Easterday, B. Leahy, M. Bell

This Plan frames the biological and cultural significance and provides the short- and long-term goals, objectives, and priority actions for the Jack and Laura Dangermond Preserve.


2020 | Terrestrial | Science | Publications & Reports

Effects of Field and Landscape Scale Habitat on Insect and Bird Damage to Sunflowers

Sara M. Kross, Breanna L. Martinico, Ryan P. Bourbour, Jason M. Townsend, Chris McColl, T. Rodd Kelsey

Agriculture-dominated landscapes harbor significantly diminished biodiversity. Woody vegetation along field margins can provide farmers with ecosystem services and benefit biodiversity. However, when crops are damaged by the biodiversity harbored in such vegetation, farmers are reluctant to incorporate field margin habitat onto their land and may…


2020 | Marine | Science | Publications & Reports

Unusual occurrences of fishes in the Southern California Current System during the warm water period of 2014–2018

H.J. Walker Jr., Philip A. Hastings, John R. Hyde, Robert N. Lea, Owyn E. Snodgrass, Lyall F. Bellquist

In response to anomalously warm sea-surface temperatures, poleward shifts in the geographic range of hundreds of marine organisms worldwide have been documented. This paper reports on the unusual occurrences of 36 fish species recorded from the Southern California Current System (SCCS) during the period of…


2020 | Terrestrial | Technology | Science | Publications & Reports

Shrub and vegetation cover predict resource selection use by an endangered species of desert lizard

Christopher J. Lortie, Jenna Braun, Michael Westphal, Taylor Noble, Mario Zuliani, Emmeleia Nix, Nargol Ghazian, Malory Owen, H. Scott Butterfield

This paper evaluates how endangered species with highly restricted habitat needs and increasingly small population sizes (using blunt-nosed leopard lizard as our example), select and use available habitat. The paper paired a novel experimental – telemetry and remotely-sensed data – and analytical – resource selection…