Climate Change Research

Climate change and phenology: Most of our current research follows from our interest in the effects of climate change on phenology, or seasonal biological events. Richard Primack’s book, Walden Warming, presents our work in Concord to a popular audience.

Some of our most recent work has recognized autumn as the neglected season in climate change and phenology research. We are actively engaged in research on the effects of climate change on autumn events including bird migration, fruit ripening, and leaf senescence.

Recent papers have also explored shifts in the phenology of leafing out and butterfly activity. We have looked at the drivers of leaf-out across years and locations at several international botanical gardens, and have conducted experiments on the drivers of leaf-out using a novel method of clipped twigs as proxies for wild plants.


Record-breaking heat in the Springs of 2012 and 2010 were tied to record-breaking early flowering times in New England, a phenomenon we described and modeled in PLOS ONE. Our data for that paper can be found here (WI) and here (MA).

We have investigated the effects of temperature on runners in the Boston marathon (photo above by Noah Reid). You can also read about this research in Live Science.


We found phenological changes in plants and birds in the US and the UK, and demonstrate the importance of incorporating phylogeny in this study.

An overview of much of the phenological research that we have done in Concord can be found in this BioScience article. Articles on specific aspects of this research are described below.


Flowering times in Concord, Massachusetts: How have flowering times changed over the past 150 years, a time of rapid climate change? We are attempting to answer that question by examining the botanical record of Concord. We are looking for clues as to why some species' flowering times have changed dramatically as a result of climate change, while other species do not seem to have been affected. The results of this study are showing how communities may shift in response to climate change. Read more about these articles in Ecology and Proceedings of the National Academy of Sciences. Click here for a follow-up of the latter article.


We specifically address the differences in phenological response between native and non-native plant species in Concord in this PLoS ONE article.


These are the data on which the Concord studies are based. We encourage others to make use of these data. We request that you acknowledge the source of the data, and cite our papers where appropriate. We also request that you inform us of any use of the data. Please note that these data are based on four years of our fieldwork on flowering times, and six years of our field work on species abundance; we recognize that further work might discover new populations of species that we were not able to find. We encourage people to find such new populations of species that we were not able to locate.


Changing flora of Concord: Several generations of botanists have documented the presence and absence of plant species in Concord. We have examined this exceptional botanical record to identify species that have become rare or locally extinct and those that have become common over the past 150 years. We are also considering how intensity of sampling and changing population size effects first flowering dates.

New sources of long-term phenological data: Long-term data documenting how species have responded to climate change are relatively rare. We are attempting to identify novel sources of long-term phenological data to be used in climate change research. We are also testing these new sources of data to find the strengths and limitations of each source.


Herbarium specimens are one source of phenological data that we have used to address changing flowering times in Boston. Another source is photographs.


Click here to read our review article about phenological research in botanical gardens. Botanical gardens are playing an increasingly important role in climate change research, and their collections can be used to track warming.

We have also looked at changes in phenology in other parts of the world including the UK and East Asia. Japan and South Korea have a long tradition of recording plant and animal phenologies. We investigated flowering times of cherry trees at Mt. Takao, Japan as well as the phenologies of a variety of organisms throughout both countries.