HBO series highlights our climate change research

Posted by Richard Primack

A new HBO series called Saving My Tomorrow features kids telling their stories about the need to protect the environment. Children are shown leading protest, at rallies, speaking from the heart, and singing powerful songs, all in defense of the environment. The need to address the dangers of climate change is a central theme.

One of the featured examples is how the observations on flowering times made by Henry David Thoreau can be used to demonstrate the effects of climate change. Of course, this is based on the research carried out by our group. The program likens the observations of Thoreau to a postcard from the past enabling us to see our impacts on the environment. With an audience of millions, this HBO program has given our research even broader exposure, especially to children and parents.

See our research featured at the beginning of this video:

Autumn migration of North American landbirds

Posted by Libby Ellwood

As you've recently been reading on this blog, autumn is the neglected season of phenology research. Recognizing this issue, a few members of the Primack lab family (Richard, Amanda and Libby) and our good friend and colleague at the Manomet Center for Conservation Science, Trevor Lloyd-Evans, wondered if and how the timing of autumn bird migration was changing in Massachusetts. We were curious how the longer growing season, delayed leaf senescence in trees, and increased availability of insect food sources that can accompany warmer weather would impact birds' migration to southern wintering grounds.

Gray catbird in the hands of a volunteer bander at Manomet Center for Conservation Science

To explore this, we used data of 37 bird species from the Manomet bird banding program between August and November from 1969-2012. We found that 14 species have migration dates correlated with temperature: 13 are migrating later with warmer temperature and one, the gray catbird, migrates earlier with warmer temperature, as you can see in the figure below.

The relationship between mean stopover dates and changes in stopover date with August + September temperature for species demonstrating significant changes in stopover with temperature. The x-axis represents the mean stopover date of the species over all years, and the y-axis represents the slope of stopover date and temperature, days °C–1. Species abbreviations are standardized codes: BHVI (Blue-headed Vireo), REVI (Red-eyed Vireo), BRCR (Brown Creeper), RCKI (Ruby-crowned Kinglet), SWTH (Swainson’s Thrush), HETH (Hermit Thrush), AMRO (American Robin), GRCA (Gray Catbird), COYE (Common Yellowthroat), AMRE (American Redstart), BLPW (Blackpoll Warbler), MYWA (Myrtle Warbler), WTSP (White-throated Sparrow), and SCJU (Slate-colored Junco).



All in all, autumn bird migrations are quite variable and species are responding in different ways to a changing climate.  Further, it appears that some bird species may respond differently to autumn environmental cues than plants and insects, which has implications for the success of individual species and the ecosystem as a whole. Read more about this study here.

Autumn, the Neglected Season in Climate Change Research

Posted by Amanda Gallinat

Most of the research on how climate change affects phenology has focused on spring. Unfortunately, this has left the autumn season comparatively neglected in climate change research! This neglect is likely because autumn events including leaf senescence, fruit ripening, insect diapause, and autumn bird migration, are often less sudden and visually apparent than their spring counterparts, and autumn events are driven by more complex environmental factors.

Our recent review, published in Trends in Ecology and Evolution, aims to bring autumn into the spotlight by digesting the existing research on the effects of climate change on autumn phenomena and by providing recommendations for the future of autumn research.

In this review, we identify five key topics that are ripe for research in the field of autumn phenology: 1) The drivers of autumn phenology, 2) The methods used to study autumn phenology, 3) The influence of autumn on carbon storage, 4) Invasive species, pests, and pathogens in autumn, and 5) Interspecies interactions.

Through our exploration of these topics, we find that changes in autumn phenology alter the reproductive capacity of individuals, exacerbate invasions, allow pathogen amplification and higher disease transmission rates, reshuffle natural enemy-prey dynamics, shift the ecological dynamics among interacting species, and affect the net productivity of ecosystems.

Figure 1. The expected effects of climate change on the timing of leaf senescence, fruit ripening, insect diapause, and bird migration in the temperate ecosystems of Eastern North America, based on the published literature. Gray broken lines indicate the direction in which an event will shift; darker stippling indicates a response that is common, while lighter stippling indicates a response that is comparatively rare.

By identifying the challenges of monitoring autumn events compared to spring, we provide recommendations to address common pitfalls in autumnal research. We also identify groups that are likely to be especially vulnerable to species invasions and ecological mismatch as autumn climate continues to change. As these findings shape the emerging research here in the Primack Lab, we hope that other researchers will also find this synthesis beneficial for their future work on autumn phenology and climate change.

See the full article HERE.

Climate Change:What It Means for Newton and How We Can Help

Posted by Caitlin McDonough MacKenzie

“When I began studying climate change in 2002, the effects here in eastern Massachusetts were much less obvious than they are now.” — Richard Primack

The winter issue of the Newton Conservators Newsletter opens with a cover story about the effects of climate change and sea level rise on the Boston area. Dr. Primack wrote this popular article for his Newton neighbors — outlining the basics of climate change, its local effects, and its potential future impacts. Primack serves as an advisor for the Newton Conservators, an advisory group that has been working on environmental and land protection issues since 1961. Primack's article notes Boston’s luck during Hurricane Sandy in October 2012 — we narrowly missed Sandy’s 13-foot storm surge — and considers a future of rising sea levels in a city built on former mudflats and tidal marshes. The sea walls and dams currently protecting Boston from storm surges were designed to withstand 20^th century hurricanes, and are not equipped to hold against sea levels expected to rise 1-3 feet by 2100. Primack encourages readers to take action, write to political leaders, and participate in the citizen science projects that help researchers to understand the ecological effects of climate change here in Massachusetts.

This map shows the impact of 7.5 feet of flooding above mean high tide on the Boston Harbor coastline. The areas shown in color are vulnerable to flooding under these circumstances. -The Boston Harbor Association

Monitoring Fruit Phenology at the Arnold Arboretum and Beyond

Posted by Amanda Gallinat

"This crop grows wild all over the country—wholesome, bountiful, and free, a real ambrosia."

-Henry David Thoreau, Wild Fruits

In addition to observing flowering and leafing out times of wild plants in Concord, Thoreau also took an active interest in fruit phenology. Fleshy fruits that ripen in late-summer and autumn provide food for animals like migratory songbirds, which in turn disperse the seeds of the fruits they eat. Despite the importance of fruits, surprisingly little is known about how much variation exists in the fruiting phenology of different species, how native and invasive species differ in their fruiting phenology, or how fruit ripening times are responding to climate change.

An American Robin (Turdus migratorius) consumes the fruits of a non-native crab apple tree at the Arnold Arboretum in Boston, MA

This autumn, the Primack Lab began a new endeavor: to track the fruiting times of over 250 species at the Arnold Arboretum in Boston, MA. Every ten days, members of our lab ventured into the arboretum with the goal of documenting the first and last fruiting dates of species across the vast collections of fleshy-fruited plants. We will use the data gathered this season and in future seasons to assess the variation in fruiting phenology among an exceptionally broad group of species, and we hope to compare our observations to those recorded at other arboreta across the world. 

Amanda Gallinat collects information on fruiting times in the Viburnum collection of the Arnold Arboretum 

Our monitoring at the Arnold Arboretum is complemented by our observations of native and invasive fruiting species at Manomet Center for Conservation Sciences in Plymouth, MA. There we are investigating seasonal changes in fruit availability for migratory songbirds, differences in the seasonal profiles of native and invasive fruits, and how songbird diets (which are primarily composed of fruits in autumn) have changed over the past 25 years. 

Fleshy fruits of American Pokeweed (Phytolacca americana) at different stages of ripeness at Manomet in Plymouth, MA

Primack Lab featured on French TV!

Posted by Richard Primack and Amanda Gallinat

This autumn, a crew from the Film Concept Associes of France came to Massachusetts to shoot an episode of the program Nature's Keepers for French TV. The program's director, Cecile Favier, interviewed us on the connection of our research to conservation issues in Massachusetts. She was particularly interested in how we have used the historical observations of Henry David Thoreau to measure the effects of climate change on plant and animal communities in Concord, MA.

We had a great experience sharing our work with the French crew, and we will post a link to the program when it is available in 2015! 

At Great Meadow National Wildlife Refuge in Concord, Richard explains (with great emotion!) how Thoreau's phenology records can be used to demonstrate the impact of climate change on the flowering times and abundance of wildflower species.

At Manomet Center for Conservation Science, Amanda describes her investigation into fruiting times, and how migratory bird species may be altering their diets in response to climate change and species invasions. 

Leaf out times using herbarium specimens

Posted by Richard B. Primack

Scientists are interested in knowing how a warming climate will affect the leafing out times of trees, and if leafing out times are earlier now than in the past due to a warming climate. If trees are leafing out earlier now, that could extend the growing season, and forests could be absorbing more carbon dioxide and producing more wood. However, until recently there was no good way to determine when tree species leafed out in the past.

Figure 1.Two specimens of Populus grandidentata accessed online from the G.S. Torrey Herbarium at the University of Connecticut (EEB, 2004). Young leaves and flowers are visible on the left specimen (collected 10 May 1936), but only mature leaves on the right specimen (collected 8 June 1932).

We have found that herbarium specimens of most New England tree species can be used to determine past leaf out times. These herbarium specimens are flattened dried twigs, often collected when the plants are in full flower. These specimens each have labels that show the date and location of collection. About 15% of the specimens also have young, unfolding leaves on them, and so can be used to determine past leaf out dates.

Figure 2. Leaf-out dates are significantly correlated with annual variation in April temperatures, with early leaf-out in warmer years (slope = -2.70; P < 0.01). (Figure 4 in Am. J. Bot article)

Using over 1500 New England herbarium specimens with young leaves, we were able to determine that trees in New England leaf out earlier in warm years than cold years, that trees are leafing out earlier now than in the past, and that trees leaf out earlier in warmer more southern locations in New England than in more northern and colder locations. This method promises to be useful to climate change biologists and ecosystem ecologists when applied to other areas and over larger regions.

Figure 3. Mean leaf-out dates for each town. (A) Towns with at least two data points. Major geographical features are labeled. Towns with only one or no data points are shown in white. (B) Towns with at least five data points; towns that are notably early or late are labeled by name. Towns with four or fewer data points are shown in white. (Figure 5 in Am. J. Bot. article)

To see the full article, published in American Journal of Botany, click here.