USA NPN National Phenology Network

Taking the Pulse of Our Planet

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National Coordinating Staff pictured at a Winter, 2017 retreat in Tucson, Arizona.


The USA-NPN's National Coordinating Office (NCO) guides the development of the Network, facilitates communication between scientists, land managers, policy-makers, and the public who are interested in assessing the effects of global change on natural ecological systems. Staff members are employees of The University of Arizona.

Theresa Crimmins

Theresa Crimmins 
(520) 621-8523
Short CV 
Follow me on Twitter @TheresaCrimmins

Dr. Theresa Crimmins is the Director for the USA National Phenology Network and has been a part of the organization since 2007. Hailing from Ohio and Michigan, she received a B.S. and M.A at Western Michigan University and a Ph.D. from the University of Arizona. In her role with the Network, Theresa supports an amazing team of individuals and works enthusiastically to support the growth and use of phenology data and resources curated by the USA-NPN, involvement in Nature’s Notebook, and a broader appreciation of phenology among scientists and non-scientists alike.

Theresa also maintains an active research career and has published over 60 peer-reviewed articles and book chapters in journals including Geophysical Research Letters, Global Change Biology, PLoS ONE, and Journal of Ecology. Her writing has also appeared in Scientific American and the Arizona Daily Star, and she has appeared in the PBS productions SciGirls and American Spring Live as well as on NPR and The Weather Channel. She currently serves on the editorial board for Ecosphere. In 2018, Theresa received the Alumni Achievement Award from the Department of Geography as well as the Globally-Engaged Pillar Award from the College of Arts and Sciences at Western Michigan University.

LoriAnne BarnettLorianne Barnett
Pronouns: She/Her/Hers
Education Coordinator
(520) 621-1803
Find me on LinkedIn

LoriAnne's Resume-Short CV
Follow me on Twitter @loriannebarnett

LoriAnne Barnett is the USA-National Phenology Network’s Education Coordinator. She develops Nature’s Notebook curriculum for formal and non-formal settings and teaches program planning and volunteer management. She has taught both youth and adults the importance of place and connection to the natural world and serves as an advocate underrepresented audiences in science and education.

LoriAnne holds a B.A. in Environmental Studies from Shippensburg University of Pennsylvania and a M.A. in Environmental Science and Environmental Education from Prescott College in Arizona.  She serves as President of the Arizona Association for Environmental Education and Executive Director of the Arizona Master Naturalist Association

Ellen DennyEllen Denny
Monitoring Design & Data Coordinator
Full CV

Ellen Denny coordinates the development of the USA-NPN protocols for the collection of standardized ground-based plant and animal phenology observations across the nation.  She also serves as a scientific data manager for the National Phenology Database, and as a global liason, helping to advise developing national phenology networks around the world, and working towards global integration of phenology data.
Ellen has a B.S. in Aquatic Biology from Brown University, and an M.F.S. (Forest Science) from the Yale School of Forestry & Environmental Studies. Her professional interests began in marine invertebrate ecology, shifted to ecological restoration, and eventually landed in terrestrial ecosystem ecology. She spent a decade working as a field ecologist and data manager in the forests of New England before coming to the USA-NPN in 2008. Ellen still lives in Kittery, Maine, and participates remotely in the Tucson-based National Coordinating Office.

Kathy GerstKathy Gerst
Research Scientist
Data Product Coordinator
(520) 621-1740
Full CV

Dr. Kathy Gerst is an ecologist conducting phenology research and developing data products with the USA-NPN since 2011. In her current role, she brings together stakeholders, researchers, and agencies to ensure science is useful for the health and resiliency of people and the environment.  She coordinates the delivery of data and tools to meet the needs of scientists and managers across diverse applications, including invasive species and land surface phenology. Previously, she was a liaison with the California Phenology Project facilitating the implementation of plant phenology monitoring in California National Parks.  

Kathy received a B.S. in Ecology, Behavior and Evolution from UCLA in 2001. She completed her PhD in Ecology and Evolutionary Biology in 2011 at the University of Arizona where she carried out research on the evolutionary ecology, reproductive biology, and physiology of desert annual plants. Broadly, she is interested in understanding how species, communities, and populations respond to a variable and changing environment.

Lee MarshLee Marsh
IT Coordinator
Applications Programmer
(520) 621-1636

Lee Marsh manages the development of IT tools and infrastructure, including the database, web site, mobile apps and physical hardware that all make the NPN run. He also helps develop, enhance and maintain the USA-NPN's PHP, Java and AngularJS web applications. He also plays a key role in data integration efforts.

Lee graduated from the University of Illinois, Springfield, with a B.S. in computer science, and spent several years working in the private industry before coming to the NPN. His interests include computer gaming, creative writing and weight lifting.

Stuart MarshStuart Marsh Photo
Planning and Administration
(520) 621-8574

Dr. Stuart Marsh received the B.S. degree (1973) in Geology from George Washington University, Washington, DC, and the M.S. (1975) and Ph.D. (1979) degrees in Applied Earth Sciences from Stanford University. Professor Marsh joined the faculty at the University of Arizona in 1988. Prior to coming to the UA he held positions in industry and the federal government. He served as Director of the School of Natural Resources and the Environment from 2012 to until July 2018 and he served as Chair of the Arid Lands Resource Sciences Interdisciplinary Ph.D. Program from 2002 through 2012. He has also served on the Graduate Interdisciplinary Programs Advisory Committee (GIDPAC) from 2007 through 2010, as Director of the Arizona Remote Sensing Center from 2004 through 2011. He was a recipient of a J. William Fulbright Senior Scholar Award, multiple awards from the American Society of Photogrammetry and Remote Sensing, NASA, and the USDA. His research focuses on the integration and analysis of multitemporal airborne and satellite remote sensing data with GIS technologies to map and monitor environmental change. He has worked on mapping land-cover change in environmentally sensitive areas of Africa, the Middle East, Mexico, and the U.S. This work helped to create new techniques to map land-cover change at global scales, develop rule-based and geostatistical models of vegetation distribution under varying climatic regimes, and evaluate the environmental impacts of land-cover change within arid environments and urban riparian and rural/urban fringe habitats.

Erin Posthumus

Erin Posthumus
Outreach Coordinator and US Fish & Wildlife Service Liaison
(520) 621-1670
Short CV

Erin Posthumus leads USA-NPN's outreach and engagement efforts with Nature's Notebook observers and USA-NPN partners. She is also the USA-NPN's liaison to the US Fish & Wildlife Service and is working with National Wildlife Refuges across the country to implement phenology monitoring to meet their resource management goals.

Erin received her B.A. in Environmental Biology from the University of Colorado at Boulder, then worked on a variety of field biology projects around the US and abroad. She first came to the USA-NPN as a Peace Corps Fellow in 2010, during her graduate program at the University of Arizona's School of Natural Resources and the Environment. In 2013 she was awarded a Master of Science for her research on wildlife species diversity at endangered red squirrel middens. 

Alyssa RosemartinAlyssa Rosemartin 
Partner & Application Specialist
Short CV

Alyssa Rosemartin supports partnerships with resource management agencies and researchers to advance the USA National Phenology Network's mission to improve scientific understand and decision-making. She also contributes to in-house data product development, including quality control.

Alyssa has fourteen years of experience working in the field of natural resources, in IT, research, education and project management.  Alyssa received a B.A. in Spanish and environmental science in 2000 from Smith College and an M.S. in wildlife conservation and management from the University of Arizona's School of Natural Resources and the Environment in 2008. Her thesis explores the relationship between food availability and reproductive investment in terns, as well as breeding bird use of wetlands in the northern Gulf of California. 

Sara SchafferSara Schaffer
Pronouns: She/Her/Hers
Participant Services Specialist
(520) 621-1631

Sara Schaffer works for the USA-NPN as a Participant Services Specialist. She has experience with graphic design, photography and publishing. She creates, formats and edits several of the documents produced by the NPN. She is also the primary contact for many situations within the USA-NPN, chances are if you've used our contact form, you've gotten a response from Sara. Sara also provides support by completing various tasks related to daily operations and procedures.

Sara is a born and raised Tucsonan, and received her B.S. in Microbiology from the University of Arizona in May 2010. In her free time, she enjoys the company of her dog, cycling, yoga, acro yoga, traveling, fire dancing and canyoneering.  Sara teaches indoor cycling, weightlifting and yoga for a few local gyms, and is a circus arts performer.

Jeff SwitzerJeff Switzer
Systems Analyst
(520) 621-1636

Jeff Switzer will be using his programming skills to enhance and debug all aspects of the USA-NPN's IT infrastructure. His duties range from solving problems with the mobile apps to creating features for the website to optimizing the database. He assists the USA-NPN team in making processes and functionalities more efficient and more adept to handling observer’s needs.  

Jeff graduated from the University of Wyoming with B.S. degrees in computer science and mathematics. As a graduate student, he researched resource-bounded dimension and joined a startup where he developed an electronic medical records system. He then spent two years teaching in Africa before joining the NPN team. When he's not coding you can find him camping, mountain biking, making music, and drinking tea.

Kevin WongKevin Wong Photo
Application Systems Analyst/Developer
(520) 621-1636

As an Application Systems Analyst/Developer, Kevin Wong helps maintain and enhance the USA-NPN's software infrastructure and generate reports for science team members.

Kevin earned a B.S. in Physics and Pure Math from UC Riverside, and an M.S. in physics from the Ohio State University studying low-temperature condensed matter physics. He later transferred to the Cognitive Psychology PhD program where he did statistical analysis and modeling on fMRI brain data. Next, he worked at an ecommerce startup as a software engineer creating and maintaining ETL pipelines for ads. Kevin's interests include scalable machine learning, cooking, video games, and exploring new ideas.


Maxine CruzMaxine Cruz
NASA Space Grant Intern

Maxine Cruz is an undergraduate at the University of Arizona majoring in Biosystems Engineering while pursuing a minor in Mechanical Engineering. She is currently working with Dr. Kathy Gerst and Dr. Katy Prudic as a NASA Space Grant intern to develop scientific outreach materials to communicate about the diversity and seasonality of insect pollinators in Tucson, Arizona using the USA NPN database, eButterfly, and iNaturalist.

When classes are beyond the horizon, Maxine enjoys playing tennis, painting, and going hiking. She also has a passion for insects and loves to collect and mount them. Maxine is a member of the Mycocats and CEASA clubs on campus as well.

Sydney FillerSydney Fuller
NASA Space Grant Intern

Sydney Fuller is an undergraduate student at the University of Arizona double-majoring in mathematics and economics. She began working with the NPN as a 2019-2020 UA/NASA Space Grant Research Fellow. Sydney is currently working with Kathy Gerst to research methods to predict pollen release using NPN's data. Sydney transferred from the University of Vermont in 2019. Before beginning college, Sydney worked on several organic farms throughout the country. Outside of class, Sydney is active in the British Parliamentary competitive debate community and is part of the Arabic Flagship Program at UA.

Jessica GilesJessica Giles
Graduate Research Associate

Jessica Giles is presently enrolled in the Master of Public Health in Epidemiology and Biostatistics Program at the University of Arizona. In addition, she holds a Bachelor of Science in Nursing from Indiana State University. She brings to her role medical experience in both private healthcare settings and as a medic with the U.S Army. Her greatest strengths lie in research development and the critical analysis of data to bring clarity to complex issues. As a Registered Nurse, she has worked in a team environment where she developed strong skills for communication, planning, project development, and leadership. She is proud to direct these skills toward her work on the Powell Center Mosquito Phenology Project. Outside of work and study, Jessica enjoys outdoor activities and volunteering. 

Dionna Hatch Dionna Hatch Photo
Community Outreach Associate
(520) 621-1803

Dionna Hatch is originally from Michigan, but left in 2002 and has since lived in Guatemala, Ohio, Pennsylvania, India, Sri Lanka, Kenya, and Nigeria before settling with her family of six in Tucson, Arizona in 2014. She served as an Agroforestry and Income Generation Peace Corps Volunteer in Guatemala from 2002 to 2004. In Guatemala, she worked with two women's groups on projects like aloe shampoo, flower nurseries, cooking and baking classes, and wood-burning stoves. 

Dionna is also pursuing her Masters in Landscape Architecture as the logical combination of a Bachelors of Science in Environmental Science and Management (Michigan State University; 2000) and a Masters in Public Health (Wright State University; 2008). Her academic interests include utilizing green spaces to fight climate change, improve human health, and provide a soothing aesthetic in a busy world. Dionna will be helping to develop some curriculum materials for local schools, assisting with the development of a new school garden project, and checking in with our partners at Manzo Elementary School's Ecology Lab as they use Nature's Notebook.

Hayley LimesHayley Limes
NASA Space Grant Intern

Hayley Limes is an undergraduate student at the University of Arizona majoring in Environmental Science with an emphasis on physical and chemical dynamics. Originally from Colorado, Hayley is interested in ecology and how climate change is affecting the natural world. Before working with the USA-NPN Hayley was a part of the Bio/Diversity internship program, where she made and taught lessons focused on pollinators and environmental science. This year she will be working with Erin Posthumus and the Nectar Connectors using Nature’s Notebook phenology data to understand how climate change is affecting pollinators and their food sources. 

In her free time Hayley loves singing, crocheting, making pottery, and hiking with her dogs.

Sehdia MansaraySehdia Mansaray
Community Outreach Associate
(520) 621-1803

Sehdia Mansaray recently moved to Tucson from North Carolina to pursue a Masters in Development Practice at the University of Arizona. Before moving to Tucson, she was an agroforestry volunteer in Senegal with the Peace Corps. It was a move directed by her majors in Environmental Science and Anthropology. In Senegal she worked on live fencing and fruit tree propagation projects and served on volunteer committees like the Diversity & Inclusion Committee. As part of the NPN, she'll be working on a needs assessment project to understand the engagement and connection of community members with the environment. The project will also look at levels of inclusivity and equity within programming.

In her free time, she enjoys dancing, playing guitar, writing, and binge watching mystery shows.

Reilly RodriguezReillyRodriguez.jpg
Student Administrative Associate
(520) 621-8571

Reilly Rodriguez is an undergraduate student at the University of Arizona, double majoring in Law and History, specifically interested in environmental law. She works on the administrative side of the National Phenology Network, assisting with the travel and expenditure processes of USA NPN.

Reilly is a part of the university’s marching band, the Pride of Arizona, as a member of the Color Guard. Off-campus, Reilly is involved in a variety of projects, such as the Tucson Fringe Theater Festival as the executive assistant to the board. In addition, she is a black belt in kung-fu and is in the process of becoming an instructor.

Elizabeth WashburnLiz Washburn
Graduate Research Associate

Elizabeth (Liz) Washburn is currently a graduate student at University of Arizona in the Mel & Enid Zuckerman College of Public Health. Her concentration is in Applied Epidemiology and she is working towards a career that bridges the fields of conservation biology and public health. Liz is working with USA-NPN is examining the association of allergenic tree species and the exacerbation of asthma in the Northeast Region.

Liz received her B.S. in Biology from University of Washington in 2015 and currently works at the Taft School, which is an independent boarding school in Watertown, CT, teaching chemistry, biology, and infectious disease to 10-12th grade students. Prior to teaching, she worked for the Nature Conservancy as a land steward. Outside of work and school, Liz enjoys being active outdoors with her black lab named Finley, skiing, and cooking.