The Bridge Collaborative operates under the direction of our four founding Secretariat members who guide decision-making and the implementation of our work.

KATHARINE KREIS, Secretariat Member

Katharine Kreis is the Director of Strategic Initiatives and Lead for Nutrition Innovation at PATH. Her work is predominantly focused on identifying new tools, technologies and methodologies to help better track, predict, target and address malnutrition. Prior to joining PATH, Katharine held senior positions at the Global Alliance For Improved Nutrition and the Bill & Melinda Gates Foundation. She also served as a US Foreign Service officer with the US Agency for International Development, where she managed a development portfolio aimed at improving health outcomes. Katharine has served on a number of advisory councils, including the Micronutrient Forum and the World Economic Forum’s Global Agenda Council on Nutrition.

LYDIA OLANDER, Ph.D., Secretariat Member

Lydia Olander directs the Ecosystem Services Program and is an adjunct associate professor at the Nicholas Institute for Environmental Policy Solutions at Duke University. She leads the National Ecosystem Services Partnership which has worked with the US government to incorporate ecosystem services into federal decision making. She also works on environmental markets and mitigation, including forestry and agricultural-based climate mitigation; wetland, stream and endangered species mitigation; and water quality trading.
Nicholas Institute >

CLAUDIA RINGLER, Ph.D., Secretariat Member

Claudia Ringler is the Deputy Division Director of the Environment and Production Technology Division at the International Food Policy Research Institute (IFPRI), a member of CGIAR, a global research partnership for a food-secure future. She currently leads IFPRI’s Natural Resource Management group, co-leads the Institute’s water research program and is also a flagship co-lead for the CGIAR Research Program on Water, Land and Ecosystems. She chairs the Food, Energy, Environment and Water Nexus network, and is or has been a member at various international assessments as well as policy panels. Claudia is a recognized thought leader on water for food and natural resource management with a focus on the Global South.

HEATHER TALLIS, Ph.D., Secretariat Chair

Heather Tallis is Global Managing Director and Lead Scientist for Strategy Innovation at The Nature Conservancy, the world’s largest environmental organization. She is a recognized scientific leader in bringing human well-being considerations into conservation, making connections to education, health, poverty alleviation, water management, agriculture, security, infrastructure development and national accounts. Heather directs the iTeam, an effort to bring innovation and integration to conservation. Previously, Heather served the Conservancy as Chief Scientist and was Senior Research Scientist at Stanford University for the Natural Capital Project.

Advisory Council

Our work is guided by the advice and feedback of our Advisory Council—a diverse group of senior leaders from across sectors who share our commitment to collaborative problem solving.


Myanmar Director, PATH


Executive Director, Lean Impact
Lean Impact >


President, EcoHealth Alliance
EcoHealth Alliance >


Distinguished Fellow, The Energy and Resources Institute (TERI)


Director General, International Food Policy Research Institute (IFPRI)


Senior Nutrition and Food Systems Officer in the Nutrition and Food Systems Division, UN Food and Agriculture Organization


Chief, Environmental Safeguards Unit (ESG), Inter-American Development Bank


Chief Executive Officer, FHI 360
FHI 360 >


CEO, Panorama
Panorama >


Vice President, Global Health Programs, PATH


Former CEO, Partners In Health



Interim Chief Executive Officer, The Nature Conservancy



Director, African Women in Agricultural Research and Development (AWARD)



William and Eva Price Senior Fellow, Stanford Woods Institute for the Environment

Stanford University >


Director of Engagement, Natural History Museum, London.

Natural History Museum >


Senior Advisor, Office of the Director, Peace Corps
Council member in a personal capacity


Director, Nicholas Institute for Environmental Policy Solutions, Duke University
Nicholas Institute >


Senior Associate, Tetra Tech
Tetra Tech >


Chief Scientist and Senior VP, World Wildlife Fund


CEO, The Gold Standard Foundation


Together with the Secretariat and our network of members, our program staff make the Bridge Collaborative possible.

JOSH GOLDSTEIN, Ph.D., Bridge Collaborative Director, The Nature Conservancy

As the Director of the Bridge Collaborative, Josh works with the Secretariat and staff to engage leaders, practitioners and researchers across the health, development and environment communities to create shared evidence and drive toward lasting outcomes for people and the world we share. Based at The Nature Conservancy, Josh has worked for over 15 years on projects around the world to mainstream incorporation of nature’s benefits to people in policy, planning and business contexts. Prior to joining the Conservancy, Josh was an assistant professor at Colorado State University. He received his Ph.D. in Environment and Resources from Stanford University in 2007.

CHRISTINE JACOBS, Bridge Collaborative Design Lead, The Nature Conservancy

As the Design Lead, Christine brings human-centered design and innovation methodologies to the Bridge Collaborative team—which means she’s always looking for opportunities to learn from and co-create with our members and partners (and will try to sneak a game into just about any meeting). A systems-thinker by nature, and a Systems Engineer by training, Christine comes to The Nature Conservancy from SecondMuse, where she designed and implemented programs to foster innovative solutions and unconventional collaboration around challenges such as sustainable palm oil and circular economy manufacturing for clients such as USAID, NASA and Nike.

BARBARA MERZ, Bridge Collaborative Policy Lead, The Nature Conservancy

As the Policy Lead for the Bridge Collaborative, Barbara coordinates with our Advisory Council and other leaders to advance policies and strategies to expand impact across the health, development and environment sectors. Barbara was the lead author for the Collaborative’s Call to Action report published in October 2017. At The Nature Conservancy, Barbara is the Global Campaign Director. Previously, she served as a strategic advisor for philanthropic and social impact organizations including The Dusseldorp Forum, The Cape York Group, CanTeen, LeapFrog Investments and The Centre for Social Impact. She has also previously served as the Director of the Philanthropy Program at Harvard University’s Global Equity Initiative. She holds a J.D. from Stanford University, an M.S. from Victoria University and a B.A. in public policy from Princeton University.

JAMIE WENTZ, Bridge Collaborative Project Coordinator, The Nature Conservancy

Jamie Wentz is the Project Coordinator for the Bridge Collaborative and Executive Assistant to Heather Tallis, the Global Managing Director and Lead Scientist for Strategy Innovation at The Nature Conservancy and Bridge Collaborative Secretariat Chair. Jamie joined The Nature Conservancy’s Texas Chapter in 2014 as the Executive Assistant to the State Director. Prior to joining the Conservancy, Jamie worked as an Executive Assistant in the Geology Department at the University of Texas. Jamie holds a B.F.A. in studio art from the University of Texas at Austin.


Stephanie Zobrist is a Program Associate with the Nutrition Innovation team at PATH, based in Seattle, Washington. Her current work focuses on maternal and child nutrition in low- and middle-income countries. Prior to joining PATH, Stephanie worked as a Research Assistant with the Faculty of Health Sciences at Simon Fraser University. Her background in global health also includes past work with Management Sciences for Health and the Aga Khan Development Network. Stephanie holds a Master’s of Public Health from Simon Fraser University.

RYAN CALDER, Ph.D., Postdoctoral Fellow, Duke University

Ryan’s research quantifies environmental and human health impacts of civil infrastructure and policy interventions. He holds a doctorate in environmental health from the Harvard T.H. Chan School of Public Health, as well as master and bachelor degrees in civil engineering from Concordia University, Canada. He has worked as an analyst for Quebec’s environment ministry, as an engineer in environmental consulting and as a research fellow at the Harvard John A. Paulson School of Engineering and Applied Sciences. His expertise centers on integrated modeling of fate and transport of waterborne contaminants, and the resulting human exposures and health outcomes. Ryan is more broadly interested in environmental policy and management of emerging risks.

SARA MASON, Policy Associate, Duke University

Sara Mason works as a policy associate at the Nicholas Institute for Environmental Policy Solutions at Duke University. She received her Master of Environmental Management degree from Duke, focusing in ecosystem science and conservation. Sara is part of the Ecosystem Services Program at the Nicholas Institute, and she works as one of the coordinators for the National Ecosystem Services Partnership. Her work currently focuses on ways to integrate ecosystem services into decision-making and on the interdisciplinary nature of biodiversity conservation. Prior to joining the Nicholas Institute, Sara worked in ecological field research and endangered animal rehabilitation.


Elizabeth Bryan is a Senior Scientist at IFPRI where she conducts policy-relevant research on sustainable agricultural production, natural resource management, small-scale irrigation, climate change and gender. Her current work focuses on trade-offs and synergies across the intersection of climate-smart agriculture, nutrition, gender and the environment, and she has published widely on these topics. Prior to joining IFPRI, Elizabeth worked at the World Bank’s Poverty Reduction Group and the Latin American Program of the Woodrow Wilson International Center for Scholars. Elizabeth holds an M.A. in International Development from American University.