“The study of how the biological world times natural events is called phenology. Scientists now understand that plants and animals take their cues from their local climate. Climate (long-term weather patterns) is impacted by non-biological factors--temperature, precipitation, and available sunlight. Species use the predictable yearly changes in the climate to determine when they start natural events such as breeding or flowering.
|Snow Geese at HNWR, by Keith Crabtree|
Visitors want to know, “When will the geese be here?’ “When can I see the Painted Bunting?” and so on. We have all been watching the monarch migration this month. Soon we may see some fall color in the leaves of deciduous trees.
|Painted Bunting, by Phil McGuire|
The three main non-biological factors listed by the National Wildlife Federation as playing a part in the timing of natural events are sunlight, temperature, and precipitation.
NWF adds that birds in the Northern Hemisphere are believed to depend on day length for when to begin their spring migration to nesting grounds. Another example given is that of frogs, which depend on temperature and precipitation to determine when to begin breeding, while plants depend on all three factors for bloom time.
|Milkweed at HNWR, by Carrie Chambers|
“Phenology is an important subject to study, because it helps us understand the health of species and ecosystems. Animals and plants do not live in bubbles--every species has an impact on those in its food chain and community. The timing of one species' phenological events can be very important to the survival of another species.”
|Monarch Caterpillar at HNWR, by Brenda K. Loveless|
So as you watch for signs of autumn, remember you are awaiting a phenological event!