At-Home STEM Activities: It's All About Timing

As we get ready for the start of summer, you might be thinking about how this June compares with last June or a June from years in the past- maybe it feels warmer or colder, greener or full of more colors, wetter or drier. Maybe the baby robins in a nest near your house are getting ready to fly or the beans in your garden have just barely sprouted, and you’re wondering if that is happening earlier or later than last year. If you are thinking about wildlife and plants, then you are thinking about phenology- the study of events in plant and animal life cycles and how they change with the seasons and years.  

Are these flowers blooming earlier or later?

Given concerns about global climate change, phenology is a very important way of understanding how the timing of natural events is changing from year to year and decade to decade as conditions change. Researchers who study phenology look at everything from the date of last snowfall to the hatching of frog eggs in a particular year and then compare those dates with dates from the past and look for patterns.  

You can find the patterns in changing climates, too, if you look through the data. For example, on Lake Winnipesaukee in New Hampshire, the date of ‘ice out’ (the earliest that enough ice has melted in spring for a ship to travel between Alton Bay, Center Harbor, Meredith, Wolfeboro, and Weirs Beach)- this date has been recorded every year since 1887. If you take some graph paper and chart the date from each year since 1887 (ice out date on the y-axis, year on the x-axis, find the data at https://www.winnipesaukee.com/index.php?pageid=iceout), you will see a trend. While there is a lot of variation in the data as you look from year to year, the latest ice out dates were in the 1800s and the earliest ice out dates have been since 2000- warmer overall global temperatures mean the ice disappears earlier.  

Mean ice out dates on Lake Winnipesaukee have gotten earlier over the last 135+ years- I added the trend line in black to illustrate the general change.

You can also help collect the data tracking these changes. Researchers want to get as much information on phenological changes as possible, and that’s where you come in- pick a plant or plants that you see on a regular basis, maybe in your backyard or on your way to work or school, and start paying attention to how the appearance changes over time: when do the leaves first appear? How about flowers? When do the leaves fall off? Or pick a bird species you only see in summer, like a Great Blue Heron- when is the first time you see it each year? You can add your data to those collected by other people and help fill in the gaps for researchers- The USA National Phenology Network collects and organizes data like these through Nature’s Notebook- they will provide tracking sheet templates, teach you how to classify what you observe, and help analyze the data for trends.  They need citizen scientists like you to collect as much data as possible for their analyses.

Why is this important? Partly researchers are trying to understand how plant and animal species are responding to global climate change- by looking at when certain events are happening, and if that represents a shift in schedule, they can determine if and how much these species are adjusting their life cycles. If one species of forest shrub, for example, is still leafing out at the same time each year but another is leafing out earlier, that second species may be so well established by the time the first has leaves that the second can monopolize the sunlight and outcompete the other. And there is also concern about phenological mismatch- when two species that interact are no longer in sync. If migratory birds that depend on insects to feed their young start migration to their breeding grounds based on amount of daylight but the insects hatch based on daily temperatures, the insects might all hatch before the birds arrive and there won’t be enough food for chicks. By understanding which environmental cues different species are responding to, they can predict levels of climate change stress for those species.