Thursday, April 3, 2014

The Primack Lab in Popular Science!

The Primack Lab's work on climate change and spring phenology in Concord, MA was recently featured on the website Popular Science! 

In this feature, five figures show how plants, insects, and birds respond to warming spring temperatures. See some of the figures below, and then check out the rest at Popular Science:

"The New Spring, Brought To You By Climate Change, In Five Charts"


Libby Ellwood and others show that flowering times are more sensitive to spring temperatures than songbird arrival times. 


From Caroline Polgar and others, insects, plants, and birds in Concord shift earlier in response to a single degree Fahrenheit, but their temporal shifts differ in magnitude.


From Libby Ellwood and others, the Primack Lab shows how flowering dates have changed in Concord, MA since 1850, and present three possible scenarios for flowering under future climate change. 

Check out the full feature HERE!

Monday, February 17, 2014

Walden Warming: Climate change comes to Thoreau's woods

Posted by Richard B. Primack 




In his meticulous notes on the natural history of Concord, Massachusetts, Henry David Thoreau records the first open flowers of highbush blueberry on May 11, 1853. If he were to look for the first blueberry flowers in Concord today, mid-May would be too late. In the 160 years since Thoreau’s writings, warming temperatures have pushed blueberry flowering three weeks earlier, and in 2012, following a winter and spring of record-breaking warmth, blueberries began flowering on April 1—six weeks earlier than in Thoreau’s time.  

For the past 12 years, my students, colleagues and I have been investigating the effects of climate change on the plants, birds, and insects of Walden Pond and the surrounding area of Concord. By combining Thoreau’s observations from 160 years ago with modern observations, we have used Concord as a living laboratory to study the impacts of a warming world. In a new book due out in early March, I describe this scientific adventure. And in the final chapter, I try to imagine how Thoreau would react to the modern challenge of climate change, and what his advice would be for dealing with this crisis.

Find more information on the book here.

Thursday, January 30, 2014

Species Extinction is a Great Moral Wrong


Posted by Phil Cafaro (Colorado State University) and Richard Primack

(Phil Cafaro of Colorado State University, guest blogger)

“Our village life would stagnate if it were not for the unexplored forests and meadows which surround it. We need the tonic of wilderness, to wade sometimes in marshes where the bitterns and the meadow-hen lurks.. and the mink crawls with its belly close to the ground... We need to witness our won limits transgressed, and some life pasturing freely where we never wander. We can never get enough of Nature.” -Thoreau, Walden

Natural species are the primary expressions of organic nature’s order, creativity and diversity. They represent thousands of millions of years of evolution and achievement. They show incredible functional, organizational and behavioral complexity. Every species, like every person, is unique, with its own history and destiny. When people take so many resources or degrade so much habitat that another species is driven extinct we have taken or damaged too much, and brought a valuable and meaningful story to an untimely end.”

So we assert in a new editorial in Biological Conservation: "Species extinction is a great moral wrong". We wrote this short essay in response to recent suggestions by Peter Kareiva, the chief scientist at the Nature Conservancy, and his colleagues that extinguishing species is morally acceptable as long as these losses do not rebound and harm people themselves.

We argue that this view is selfish and unjust, and should be rejected. Human beings already control more than our fair share of Earth’s resources. If increased human numbers or economic demands threaten to extinguish other species then we need to limit our numbers and economic demands. Rather than embrace the Anthropocene Epoch, a new term used to indicate the current and increasing influence of humans on the global environment and its associated extinctions, conservation biologists should work to preserve a diverse, wild and flourishing natural world.

Sunday, January 12, 2014

Walden trees and shrubs leaf out earlier now than in Thoreau's time

Posted by Richard Primack, Amanda Gallinat and Caroline Polgar

"One attraction in coming to the woods to live was that I should have the leisure and opportunity to see the spring come in." -Thoreau, Walden

From 1852 to 1860 Henry David Thoreau recorded the leaf out times of common trees and shrubs around Walden Pond and elsewhere in Concord. For the past 5 years, we have recorded the leafing out dates of 43 of the same species in Concord. We have found that these woody plants, including red maple and blueberries, are now leafing out 18 days earlier than in Thoreau’s time. Earlier leafing out times can be added to the list of spring phenomena in Concord and elsewhere affected by the warming temperatures associated with climate change, including flowering dates, butterfly flight times, and bird arrivals. 

New leaves of Black Oak (Quercus velutina) in Concord, MA

We also carried out lab experiments to test the responsiveness of 50 tree and shrub species in Concord to warming temperatures in the late winter and early spring associated with predicted climate change. For the past two winters, we collected leafless dormant twigs from each species, and placed them in cups of water in our lab.  Over the following weeks, we observed how quickly each species produced their leaves in these unseasonably warm lab conditions. 

 We clipped and rinsed twigs weekly before returning them to the light banks in the lab

We evaluated twigs weekly for budburst or new leaves

We found that invasive non-native shrubs, such as Japanese barberry and multiflora rose, are able to leaf out within a few days once they are exposed to warm temperatures even in the middle of winter, whereas native shrubs and trees need to go through a longer winter chilling period before they can leaf out -- and even then their response is slow. These experiments, building on Thoreau’s observations, show that as spring weather continues to warm, the invasive shrubs will gain a further competitive advantage.

 One month after twigs were collected in January, most exotic shrubs had leafed out, about half of the native shrubs, and very few of the native trees had leafed out.

We describe these observations in greater detail in an article just published in the scientific journal New Phytologist.

 Most of our 2013 twig clipping team, hard at work in the lab!





Saturday, December 28, 2013

Using handheld chlorophyll meters to monitor leaf senescence

Posted by Amanda Gallinat, Laura Garrison, and Richard Primack

"The Artist is he who detects and applies the law from observation of the works of Genius, whether of man or Nature. The Artisan is he who merely applies the rules which others have detected." -Thoreau

The timing of leaf senescence is of increasing interest to climate change biologists, as leaf senescence marks the end of the growing season and the onset of winter dormancy. Most biologists monitor leaf senescence with somewhat subjective measures of leaf color change and drop. In the Primack Lab, we use a combination of leaf color change and drop to assess the date on which at least 50% of the leaves on an individual are no longer photosynthetically active. Last autumn, we became interested in empirically testing our methods of observation for gauging leaf senescence dates at the Arnold Arboretum.


The subjective color categorization of Viburnum carlesii leaves, with the atLEAF (left) and SPAD-502 (right).

Predominantly used in agriculture, handheld chlorophyll meters are one way to empirically measure relative chlorophyll content and, by proxy, photosynthetic activity. The most widely used chlorophyll meter on the market, the Minolta SPAD-502 costs about $2600.00. In constrast, the atLEAF is a relatively new chlorophyll meter which can be purchased for one tenth of the cost. Last autumn, the Primack Lab from Boston University and Laura Garrison from Brown University teamed up to compare the performance of the SPAD-502, the atLEAF, and our own subjective color categorization on leaves at various stages of senescence from the Viburnum and maple collections at the Arnold Arboretum.

We found that the relative chlorophyll readings from the SPAD-502 and atLEAF meters were highly correlated both to one another and to chlorophyll content determined with spectrophotometry. We also found that the relative chlorophyll values from each meter supported our subjective color categorization, with the exception of red leaves which were often difficult to predict.


There is a very strong correlation between atLEAF and SPAD-502 chlorophyll readings for Viburnum carlesii leaves. The point colors reflect the color of the leaf measured: green, reddish green, red, and reddish yellow. R2=0.98.

As monitoring of autumn leaf senescence increases, we believe subjective observations of leaf color change and drop will remain valuable. The inexpensive atLEAF meter offers an opportunity for scientists to empirically gauge chlorophyll content in cases where subjective observations fail, such as in the case of red leaves.


Sunday, December 15, 2013

Locally adapted conservation biology textbooks can help biodiversity


Posted by Richard Primack

Books are the treasured wealth of the world and the fit inheritance of generations and nations.
-Thoreau, Walden

In too many developing nations, students struggle to read English-language textbooks that typically don’t even include examples from their region.

"A Primer of Conservation Biology" Chinese edition

For 18 years, I have been inviting scientists to be co-authors of foreign-language editions of my textbooks “Essentials of Conservation Biology” and “A Primer of Conservation Biology.”   My co-authors translate the English text into their own language and insert local examples and photos to make it more relevant to their students, as described in a recent article in BioScienceFor example, the Indonesian edition features tropical deforestation and orangutan conservation. 

So far, 29  translations have appeared in 18 languages with a dozen more in production and four being planned. Some editions cover countries or regions with large populations, such as China, South Asia, the Arabic-speaking world, and Latin America, while others cover less populous countries, such as Estonia, Nepal, Greece, and Mongolia. Many of these have been widely adapted for teaching university courses.

An unexpected benefit of these translated textbooks is that I have incorporated some of the best country-specific case studies back into the English-language versions, enriching their global perspective.

"A Primer of Conservation Biology" Greek edition


This textbook approach would be worth extending to related disciplines, including ecology, environmental science, wildlife biology, forestry, and agriculture, and even perhaps geography, medicine, and economics.

Saturday, November 30, 2013

The statistics of bird arrivals

Posted by Libby Ellwood


 "'But,' says one, 'you do not mean that the students should go to work with their hands instead of their heads?' I do not mean that exactly, but I mean something which he might think a good deal like that ... 
How could youths better learn to live than by at once trying the experiment of living? 
Methinks this would exercise their minds as much as mathematics." 
-Henry David Thoreau, Walden


(Photo of a magnolia warbler by Richard Primack)

Last spring Richard Primack and I visited our friend and colleague Trevor Lloyd-Evans at Manomet Center for Conservation Sciences. For over 40 years researchers and volunteers have been banding birds at Manomet and have compiled an impressive dataset of migration dates at this beautiful coastal location. These unique records provide many details of the migration including first and mean arrival dates of particular species, population size, and morphological information such as mass and wing length. Members of the Primack lab have found these data incredibly useful for answering questions of how bird migrations have changed over time and in relation to warming temperatures (Miller-Rushing et al. 2008).

At Manomet we met up with the creative team of Chedd-Angier Production Company, a group working with the Annenberg Foundation to develop educational videos that explore statistical concepts through real-life examples. They thought our research on bird arrivals at Manomet would be a good fit for the "Normal Curves" segment. When the number of captured birds of a given species is graphed over the course of a migration season a "normal curve" is created and this is an important tool for understanding migration patterns and changes.

After a morning of banding, we spoke with them about how the analyses we do can answer questions about changes in bird migrations and populations, and how this is important for conservation efforts.

You can watch the full video here:
Against All Odds: Normal Curves


(Photo of Trevor and a common grackle by Patrick Roberts)

Miller-Rushing, A. J., T. L. Lloyd-Evans, R. B. Primack, and P. Satzinger. 2008. Bird migration times, climate change, and declining population sizes. Global Change Biology 14: 1–14.