Phenology: telling time by nature’s clock, with cary institute

Margaret Roach

It's all connected outdoors, and the science of phenology can help us understand exactly how. Called "nature's clock," or "nature's calendar," phenology is the study of recurring life-cycle stages among plants and animals, and of their timing and relationships with weather and climate. So not just "the peepers peeped today" (like the one not peeping, above, on a leaf in my garden), but the whole intricate picture outside at a given time.

By putting it all together, scientists can gain a better understanding of an entire ecosystem's intimate interactions–providing a critical view into the effects of a changing climate. But they need our help, gardeners–and learning to be more objective, keener observers can open a whole world of smaller "aha's" up to each of us, too.

I got a lesson in phenology from Victoria Kelly, Environmental Monitoring Program Manager at the Cary Institute of Ecosystem Studies in Millbrook, New York, not far from my garden or from Robin Hood Radio, the NPR affiliate where my show is created each week. Environmental Monitoring is a longterm program at Cary, begun in the 1980s and designed specifically to monitor climate—and the air, precipitation and water chemistry.

Now Cary is adding biological monitoring to the effort, by establishing a "phenology trail" on the grounds of the not-for-profit environmental research organization, whose team of scientists look at the ways different phenomena interact, and the effect on nature. The trail is part of a nationwide network of collaborations with the USA National Phenology Network.

Around the country, citizen-science volunteers are being recruited to join in making observations. Not just scientists, who cannot possibly record all the needed data themselves, but also educators and students, nonprofits and NGOs and Native American tribes and clubs and others—amateur and professional naturalists alike—will observe and record what happens when. The 2015 nationwide goal: 1.5 million phenological observation records.

Whether you officially help or not, phenology is fascinating–and already Cary scientists have some predictions to make about creatures as welcome as the peepers, or disliked as black-legged ticks. Vicky was the guest on the March 9, 2015 edition of my radio show and podcast.


Q. Can you give some examples of the kinds of interactions that you focus on, Vicky, and why you look for what you look for?

A. It’s pretty simple: We’re looking at things like when do the trees leaf out, when do the flowers come out? We’ll be asking people who volunteer to actually note the dates these things are observed, because as the climate changes, we expect that some of these occurrences will shift with these changes—and that can wreak havoc.

Some of your gardener listeners might remember times when the apples and other fruit trees blossomed and then a hard frost happened, for instance. They blossomed because the temperature warmed up, forcing the blossoms open, but then the freeze came. The same kind of thing can happen to trees and other plants in nature, so we wonder if the climate as it changes is going to result in more of this happening. We really need to monitor this—actually take data on a yearly basis to predict it and understand it.

Q. We might note that a particular tree—whether native or a specimen in a garden—like, for instance, the shadbush or serviceberry (Amelanchier), which blooms at the forest edges early in the season. So you’d note that, and then you’d also note what else was happening?

A. We’ll be using the framework of the National Phenology Network, and they have forms, which ask questions of the observers: Do you see leaves? Do you see breaking buds? Are they flower buds? Do you see seeds?

We’ll be monitoring all kinds of phenophases of these plants—the switch from one phase to another. In addition, we’ll be asking observers to note if they see insects, and animals—specific kinds of insects and animals:  different kinds of butterflies, frogs, newts, turtles, birds. That’s going to give us an idea of when those phenophases happen with the plants, and whether they co-occur with the arrival or presence of different animals that may use those plants .

Q. As a host plant, or to gather pollen or nectar from, for instance.

So this is different from degree days, isn’t it?

A. Degree days is a measure of temperature; a measure of cumulative temperature. It’s an index that can be used to predict when a phenophase might occur, or an insect might emerge. But it’s essentially just a measure of temperature.

Q. So at a certain number of degree days, that may precipitate one of these phenophases.

A. Correct. Usually what happens is that you calculate degree days, and at a specific number, a leaf might emerge, or an insect might appear. We expect that the date at which that number happens is going to shift with climate change.

Q. I read a 2013 research paper at the Cary Institute website on when the peepers peep each year, written by a colleague of yours, Gary Lovett. Over the 15 years of record, the DFC or date of first calling was never the same.

A. That paper showed that the peepers’ date of first calling got earlier and earlier of that 15 year period. He’s able to estimate when the peepers will peep, based on that degree day number.

Q. So there can be a sort of forecasting…

A. Right, you can predict the date.

Q. In the 15 years of data, there were dates of first calling as varied as about a month, from 9 March to as late as 4 April in different years studied.

A. These organisms, like the peepers, have evolved to become active during a specific period of time. Usually the triggers for becoming active are based on daylength, not temperature, but sometimes temperature can force things. What we’re concerned about is that with climate change, we’ll see—like we have with the peepers—early activity, but then a late frost can really do some damage.

So again: We’re embarking on this program to really collect the data to know if this is happening, and to what extent.

Q. Some gardening friends say—and this is where these more folksy versions of phenology come in, or maybe what you could call conventional wisdoms—they say such things as “prune roses when the forsythia blooms,” and “look for Eastern tent caterpillars at crabapple bud break” if you want to get rid of them. As far as the peppers go: “Plant peas when the peppers peep” is another one. Are they on to anything, and can such correlations and inferences be made?

A. They do make some sense sometimes biologically, and we can glean a lot of information from those folk wisdoms of the ages. But what we’re really looking for at this point are some numbers to back up those folk tales. The way to do that is to go out and collect the data—to note the dates that things occur.

Those folk tales are based on what has occurred over the ages, but things have changed. They may have worked in the past—but we’re not sure they’ll continue to work.

Q. Tell us about some of the other projects at Cary, like the one studying peepers.

A. There are a lot of them. There is work that Rick Ostfeld [above, making observations], who’s a disease ecologist at Cary, has recently published about activity level of ticks. We used to call May “Lyme Disease Awareness Month,” and he is suggesting that we shift that to April, because of the change in activity level. So there are all kinds of applications for this kind of work.

We’ve been studying all kinds of systems, but this will be the first time that we’re setting  out to collect data in an organized way about the phenology of plants in a specific place here at Cary. This study of phenology is a new and developing research area, and it’s turning out to be a promising development for ecology.

Q. And the new project this year at Cary that you’re recruiting helpers for the phenology trail?  What’s the goal there?

A. The program that I have just set up is the Fern Glen Phenology Trail. There are about 20 marked plants in our beautiful, enchanting Fern Glen here at the Institute.

It’s a small parcel of land with little trails and boardwalks and a deck that overlooks the creek. We’re asking citizen-science volunteers to visit those marked plants and to answer questions about what they observe.

They’ll collect data—their observations—about whether they see leaves, flowers, fruit, and how many of each. We’ll be able to tell when leaves first emerged, or the flowers finished. We hope to be able to collect these data over a long period of time—decades—so we can evaluate the effects of climate change and other factors on the organisms that we share this planet with.

Q. You already know the plant palette and the animals of this area of the Institute, so besides ferns, what else is in the Fern Glen?

A. It was a garden at one time, and is still maintained sort of as a rough garden. A lot of native plants have been planted there–bluebead [Clintonia borealis], hepaticas, trilliums, jewelweed, among others. We’ve selected a group of plants to study that are representative of a range of types of plants and of a range of timing in emergence, flowering, fruiting.

So, for example, we’ve marked red maples, witch-hazels and spicebush—as well as the forbs. [Above, left to right, spicebush and hepatica blooms at Cary.]

Q. Spicebush is one of my favorite woody plants, and I think it’s underappreciated by gardeners. Wonderful—and important, too, because it blooms so, so early, providing the first insects with sustenance. [Blooms in Margaret’s garden, below.]

A. It’s a very interesting plant, and you’re right: It’s one of the first bloomers. There is a long period of time to observe spicebush. It blooms very early, it develops leaves, and it sets fruit in late October into November—a really interesting plant.

Q. Lindera benzoin. And since so many listeners are gardeners, I want to add that it’s also a beautiful large shrub that can grow at the woodland edge, with a great architecture: multistemmed and low-breaking. And the yellow fall color is exceptional. I rarely get to see the fruit for long—the local critters seem to know, “Margaret’s got spicebush fruit. Let’s go get it.”

A. The red fruit is beautiful, and spicebush is easy to grow—plus a swallowtail butterfly requires the spicebush for reproduction. We have lots of it in the Fern Glen, and will be observing its phenophases over a long period of time, hopefully.

Q. So to reiterate for those listening elsewhere, this Fern Glen Phenology Trail is just one undertaking—which happens to be near me—in a nationwide effort by the National Phenology Network. Their Nature’s Notebook national online program of recording data has set a goal to collect 1.5 million observation records in 2015. Schools, for example, or other groups can start a program, or join an existing program.

A. We’re part of the national program, and we’re also part of a regional program. The Environmental Monitoring & Management Alliance is a group of about eight sites along the Hudson River, from the New York Botanical Garden to the Huyck Preserve—including the Mohonk Preserve, and Vassar College Preserve and others.  And there is also the New York Phenology Project—all parts of this bigger endeavor by the national network.

There are phenology trails all over the country.

[Individuals anywhere can register to join an existing project, or even get set up to observe in their own backyards at the national Nature’s Notebook online program.]

Q. It’s so interesting: If the observations many of us may have thought of as folksy gardening wisdom are made in a more objective manner, with more of a scientist’s eye, they can really make such a difference in a much more pressing issue at hand, such as a changing climate.

A. We can get so much more with the help of citizen scientists than we can on our own.

Cary Institute of Ecosystem Studies | Millbrook, New York 12545 | Tel (845) 677-5343

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