Signs of the Season Can Provide Important Climate Change Data

By Rebecca Zeiber, originally published by NH Sea Grant

Citizen scientists in southeastern N.H. are documenting small-scale impacts of climate change in their backyards and neighborhoods. Equipped with pencils and data sheets or simply an app on their mobile device, these volunteers will meticulously record the dates of seemingly innocuous events: What date the tree buds open up, when chipmunks begin scurrying through the yard, and when blackbirds begin nesting in nearby marshes.

The volunteers, led by NH Sea Grant/UNH Cooperative Extension coastal ecosystems specialist Alyson Eberhardt, are currently receiving training in phenology – seasonal changes – of plants and animals.

“Phenology is nature’s calendar,” Eberhardt explained. “It’s the timing of plant and animal life cycle events: Migration, reproduction, senescence. If you have seasonal allergies, you’re probably already aware of the timing of plants releasing their pollen.”

Alyson Eberhardt discusses plant identification with volunteers as part of their phenology training

The collection of phenology data is nothing new – Henry David Thoreau’s essay “Walden,” written in his cabin in 19th century Massachusetts, describes the flora and fauna of each season around the nearby ponds. Likewise, Aldo Leopold famously documented flowering times of species in Wisconsin in the mid-20th century. However, it was previously believed these natural events were static, occurring at the same time every year. Not so, Eberhardt says, at least not anymore.

Phenology’s link to temperature and precipitation means that climate change has implications for plant and animal populations, including alterations in their diet or geographic distribution, genetic shifts and possible extinction or the introduction of new species.

The training for this Granite State phenology effort is an extension of the Signs of the Seasons program initiated in 2010 by Maine Sea Grant. N.H. Audubon Society is also collecting phenology data, so there is potential for future collaboration, Eberhardt said.

These efforts are the start of long-term datasets to detect trends, adding to the information already collected throughout the U.S. as part of the National Phenology Network (NPN). The NPN prescribes certain protocols that allow for consistent data recording across the country. Volunteers at a recent phenology meeting hosted by Eberhardt were given a list of common indicator species from the NPN, such as monarchs, dandelions, robins and red maples, along with more locally relevant species including the common loon, American eel, sugar maples and rockweed – a common algae that grows in N.H. coastal waterways. Rockweed is of particular interest because scientists can evaluate its growth like the rings of a tree to determine years of good or bad growth. Evaluating its growth relative to weather conditions allows this species to serve as an excellent indicator for climate change impacts, Eberhardt explained.

Volunteers – or citizen scientists, as Eberhardt calls them – will collect data every two weeks, although peak phonological times in spring and fall may encourage more frequent observations. They will then enter their data into the NPN database available online. Although data collection based on the national list is encouraged, Eberhardt is interested in developing data collection protocols for species that may not be on the NPN list, such as marsh grasses, phytoplankton and nuisance insects like black flies, ticks and mosquitoes.

“For me, a side benefit from collecting this data has been an increased connection to my backyard,” Eberhardt said. “I’m now keenly aware of what’s going on, I feel a new connection to it and that’s very fulfilling. I go out in the morning in my pajamas with my cup of coffee and my data sheets, just observing what’s around me.”

There are researchers who may benefit from the data as well: Dave Burdick, UNH research associate professor of marine ecology and restoration, is working closely with volunteers to monitor invasive phragmites populations, a reed that grows in salt marshes and crowds out the native marsh species. Martha Carlson, UNH Forest Watch coordinator, is interested in how climate change is impacting sugar maples. Any information collected by the citizen scientists on sugar maples or the eastern white pine may help inform her research, Eberhardt said.

“What’s the local story for climate change in N.H.? That’s what we really want to find out,” she added.

For more information or to volunteer, please contact Alyson Eberhardt at 603.862.6709 or

PREP is part of the U.S. Environmental Protection Agency’s National Estuary Program, a joint program between local, state and federal agencies established under the Clean Water Act with the goal of protecting and enhancing nationally significant estuarine resources. PREP is supported in part by an EPA matching grant and is housed within the School of Marine Science and Ocean Engineering at the University of New Hampshire.