Selby Vaughn
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A bumblebee pollinates a sundrop flower. |
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The group collected and examined various bees to learn identification techniques. |
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A group photo taken in the Primacks' garden. |
In Professor Richard Primack's Lab at Boston University, we study the effects of climate change on the timing of seasonal biological events and species diversity. By teaming up with Henry David Thoreau and other local naturalists, we investigate how climate change is affecting plants, insects and birds right here in the Boston area.
Selby Vaughn
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A bumblebee pollinates a sundrop flower. |
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The group collected and examined various bees to learn identification techniques. |
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A group photo taken in the Primacks' garden. |
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Normal leaves of a chestnut tree sapling |
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Chestnut leaves several days after crushing to simulate the effects of a late frost |
Richard Primack
“There is absolutely no common sense; it is common nonsense.” Henry David Thoreau in Reform Papers.
For several decades, Tom Ogren, a horticulturist from California, has claimed that the worsening problems of allergy across the USA are due to government officials planting only male trees in cities. In his view, “botanical sexism” has led to city trees producing an excessive amount of pollen with disastrous consequences for people suffering from allergies.
As pointed out in a recent article in the Boston Globe, his theory is actually almost entirely wrong.
First of all, many common city trees, such as lindens, Norway maples, oaks, birches, and flowering pears, do not have separate male and female plants.
Oak trees are commonly planted as street trees, but do not have separate male and female plants. |
Second, for species with separate male and female trees, such as some maples, ashes, junipers, and sassafras, government officials don’t just plant male trees as he claims.
Thirdly, many common street trees, such as cherry trees, flowering pears, and crabapples, are insect pollinated, and don’t contribute to allergy problems.
Flowering pear trees are insect pollinated, and don’t contribute to allergy problems. |
Finally, Ogren claims that planting more female trees would reduce pollen in the air because the female flowers would capture the pollen from the air. This is not tree, as the stigmas of the female flowers of wind-pollinated trees, such as oaks, probably only capture less than one in a million of the pollen grains released into the air.
So while Ogren’s ideas are dramatic and lurid, they lack common sense.
Richard B. Primack
Larger issues of the time that engaged Thoreau, such as the fight against slavery in the United States and Darwin’s theory of evolution, are important themes in the book. The book also connects Thoreau’s observations to the current concern for global climate change, summarizing the research work of our lab group on changing flowering times in Concord.
The book is visually beautiful with colorful illustrations of plants and animals that make the book especially welcoming.
Figure 3. Drawing of a great horned owl.
This is a wonderful book for introducing children to phenology and nature study, and their connection to climate change and larger social issues.
Richard B. Primack
Figure 1. Chlorophyll content and Photosynthetically Active Radiation (PAR) did not change in a lake at Niwot Ridge during the 2020 pandemic. |
Figure 2. The Enhanced vegetation index (EVI) increased in Georgia coastal marshes during the 2020 pandemic. |
Figure 3. Fisheries practices and animal populations are striking different at contrasting LTER sites, obscuring the effects of the pandemic. |
“It is folly to attempt to educate children within a city. The first step must be to remove them out of it.” Henry David Thoreau in his Journal.
On April 2, Professor Richard Primack presented a keynote address at the National Science Teachers Association annual meeting in Houston, Texas. His talk, Walden Warming: Climate Change Comes to Thoreau’s Concord, provided an overview of the research that he and his students have been doing over the past 20 years with support from the National Science Foundation.
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Richard Primack at the conference along with David Foord and Lisa Janeway from the Brandwein Institute. |
As he describes, “I spoke about how a warming climate is causing the plants of Concord, MA, to flower and leaf out earlier now than in the time of Henry David Thoreau in the 1850s. I tailored my talk to emphasize projects that science teachers could use to help their students investigate the biological effects of climate change, such as the use of twig experiments.”
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Boston University undergrads Selby Vaughn (left) and Taylor Reagan evaluating twig experiments in the Primack lab. |
Because of the pandemic, this was the first time in three years that the NSTA conference had been held in person. While the conference normally has around 10,000 attendees, this year there were just 4,000 people. Primack’s talk was sponsored by the Brandwein Institute, an environmental foundation.
Richard B. Primack
“Let us spend one day as deliberately as Nature, and not be thrown off the tracks by every nutshell and mosquito’s wing that falls on the rails.” Henry David Thoreau in Walden.
Lots of new phenology data is becoming available from digitized herbarium specimens, citizen science programs, and photographs uploaded to the iNaturalist app. But how do these data sets compare in terms of detecting the effects of temperature and climate change on flowering times?
A new study compares three separate phenology datasets from Denmark: i) herbarium specimen data spanning 145 years, ii) one year of flowering data collected from a citizen science program, and, iii) data derived from a year of photographs uploaded to iNaturalist. Each dataset includes flowering dates of three common plant species: Allium ursinum (ramsons), Aesculus hippocastanum (horse chestnut), and Sambucus nigra (black elderberry).
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Photo: Ransoms, horse chestnut, and black elderberry. |
The iNaturalist dataset provided the most extensive geographic coverage across Denmark and the largest sample size, and recorded peak flowering in a way comparable to herbarium specimens. The directed citizen science dataset recorded much earlier flowering dates because the program objective was to report first flowering, and so was less comparable to the other two data sets.
Herbarium data demonstrated the strongest effect of spring temperature on flowering in Denmark, possibly because it included year-to-year variation in temperature, while the other datasets only included one year of spatial variation in temperature across Denmark. Combining herbarium data with iNaturalist data provides an even more effective method for detecting climatic effects on phenology. Phenology observations from citizen science programs and iNaturalist will increase in value for climate change research once additional years are available.
This article is published as:
Iwanycki Ahlstrand N, Primack RB, Tøttrup AP. 2022. A comparison of herbarium and citizen science phenology datasets for detecting response of flowering time to climate change in Denmark. International Journal of Biometeorology https://doi.org/10.1007/s00484-022-02238-w