40. Theresa Crimmins on the Power of Plant Phenology

THERESA CRIMMINS BIO

Theresa Crimmins is an internationally recognized phenology researcher, director of the USA National Phenology Network, and associate professor in the School of Natural Resources and the Environment at the University of Arizona. In her role with the Network, Theresa supports an amazing team 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 has published over 70 peer-reviewed articles and book chapters in journals including Nature, Geophysical Research Letters, Global Change Biology, and Journal of Ecology. Her writing has appeared in Scientific American, The Hill, and the Old Farmer’s Almanac, and Nautilus Magazine. She shared her thoughts about the importance of observing phenology in a TEDx talk in October 2024 and her book Phenology was published through MIT Press in early 2025.

You can learn more about Theresa by visiting the USA National Phenology Network website.

SHOW NOTES

  • How an early interest in plant biology and hands-on classes in college sparked Theresa’s passion for plants

  • The pivotal role of a professor in shaping her botanical interests

  • Transitioning from biology to geography to learn GIS and mapping technologies

  • Returning to ecology for her Ph.D. to escape computer work and engage with the outdoors again

  • Studying Lehmann lovegrass (Eragrostis lehmanniana) and modeling its potential spread under future climate scenarios

  • Leading the USA National Phenology Network and coordinating a national-scale citizen science program

  • Defining phenology as the study of seasonal biological events and their links to environmental conditions

  • Why phenology is a valuable tool for understanding species’ responses to climate change

  • The power of phenological cues like “oak leaves the size of squirrel ears” and their ecological basis

  • Dr. Dan Herms using bloom times of indicator plants like spirea and lilac to predict insect activity like pine needle scale and developing the Ohio State Phenology Calendar

  • Encouraging gardeners to observe and document bloom sequences as a gardening tool

  • Nature’s Notebook as a citizen science platform for tracking phenology across the country

  • Benefits of contributing observations to formal databases for research and conservation

  • How to develop a personal phenological calendar by tracking repeated seasonal patterns

  • Growing degree days as a method for quantifying heat accumulation and predicting biological events

  • Accumulated Growing Degree Day models

  • The value of even simple observations written in journals or calendars

  • How Nature’s Notebook provides standardized protocols and mobile or paper options for data entry

  • Explanation of phenophases as distinct life cycle events like leaf-out, flowering, and fruit drop

  • Observing multiple phenophases on a plant at the same time and how to identify them

  • The depth and utility of the Phenophase Primer (and Botany Primer) as a visual guide to nuanced plant development

  • How detailed observation fosters wonder and reduces plant blindness

  • The delight and insight Theresa found in observing her saguaro cactus begin to bud for the first time

  • The emotional and restorative impact of observing Patty’s memorial Palo Verde tree

  • How phenology cultivates gratitude, mindfulness, and a stronger relationship with nature

  • Creating a weekly habit of phenological observation as a calming personal practice

  • Developing regional bloom calendars as cultural records of seasonal events

  • How long-distance migrants triggered by sun angle may arrive too late for peak caterpillar abundance

  • The importance of citizen science in documenting shifts and informing conservation strategies

  • Writing the book to make phenology more accessible and to shift everyday attention to seasonal life

  • The challenge of maintaining the network and transitioning from federal to foundation support

  • Clarifying the difference between phenology and phrenology, a common misconception

  • Native moon calendars and Japanese microseasons as inspirations for localized phenological tracking

  • Documented mismatches between bird migration and insect emergence due to differing climate cues

  • Observing ocotillos flowering without leafing out in response to drought, challenging common assumptions

  • Examples of stress-induced flowering and how plants may behave unpredictably under extreme conditions

  • Advocating for surprising others with botanical facts to spark curiosity and connection

  • Using plant-based activities, like dissecting fruits with kids or adults, to nurture appreciation for plants

  • Resources on the USA-NPN website including Nature’s Notebook, training modules, and local programs

  • The potential for community-building through shared phenology observation projects

  • Theresa’s favorite recent read: The Comfort of Crows by Margaret Renkl

  • How routine observation sharpens awareness, deepens ecological literacy, and creates personal meaning

  • You can learn more about Theresa by visiting the USA National Phenology Network website.