1. Introduction to Phenology
USA-NPN NCO
September 2016

2. What is phenology?
Recurring plant and animal life cycle stages and their timing and relationships with weather and climate
Phenology refers to recurring plant and animal life cycle stages, such as leafing and flowering, maturation of agricultural plants, emergence of insects, and migration of birds. It is the study of these seasonal changes, especially their timing and relationships with weather and climate.
Photos: Brian F Powell

3. Why phenology? Phenology is nature’s calendar Photos: Brian F Powell
Phenology affects nearly all aspects of the environment, including the abundance and diversity of organisms, their interactions with one another, their functions in food webs, and seasonal behavior, as well as global-scale cycles of water, carbon, and other chemical elements.
Photos: Brian F Powell

4. Why phenology? Photos: Brian F Powell, Erin E Posthumus
Phenology is a key component of life on earth.  Many birds time their nesting so that eggs hatch when insects are available to feed nestlings.  In turn, insect emergence is often synchronized with leaf-out in their host plants. For many people, allergy season starts when particular flowers bloom—earlier flowering means earlier allergies.  Farmers and gardeners need to know when to plant to avoid frosts, and they need to know the schedule of plant and insect development to decide when to apply fertilizers and pesticides.

5. Why phenology? nadiah.org/phenology.html
Changes in phenological events like flowering and bird migrations are among the most sensitive biological responses to climate change. Across the world, many spring events are occurring earlier—and fall events are happening later—than they did in the past. However, not all species and regions are changing at the same rate, leading to mismatches. How plants and animals respond to climate can help us predict whether their populations will grow or shrink – making phenology a “leading indicator” of climate change impacts.
nadiah.org/phenology.html

6. Observable life cycle events or PHENOPHASES
How do we observe phenology?
Observable life cycle events or PHENOPHASES
Activity
Reproduction
Development
ANIMAL
For all plants and animals, each of the life cycle events we can observe are called phenophases. At the most basic level they are : What is the animal doing, its reproduction and development? And for plants, the Leaves, Flowers, and Fruits of the life cycle.
Leaves
Flowers
Fruits
PLANT

7. Who observes phenology?
 Photos: Brian F Powell, Thoreau image from the National Portrait Gallery, Washington, Nina Leopold Bradley photo from Journal Sentinel files
Many people observe phenology without even knowing it. Gardeners who notice when plants bloom, or managers studying when animals visit natural areas are tracking phenology. Students who study life cycles of plants and animals are studying phenology. If you have noticed changes in the natural world around you, then you have observed phenology too!

8. Join us! Photos: Brian F Powell
There is still so much to learn about phenology. You can help advance the field by:
Collecting data for Nature’s Notebook in your yard, a nearby park or as part of a field study.
Organizing a phenology effort locally for data collection, research and/or education.
Participating in one of our Research Communities or attending a phenology-related meeting.
We invite you to join us!
Photos: Brian F Powell

9. Contact nco@usanpn.org
Questions?
Contact
USA-NPN NCO
September 2016