Sugar Poisons Leaves?

By Richard B. Primack

“In my experience I have found nothing so truly impoverishing as what is called wealth.” 

- Henry David Thoreau in his Journal. 

An innovative recent article in Science proposes that earlier leaf senescence of trees in autumn is promoted by summer condition of high light and warm temperature that favor high levels of photosynthesis.   According to this hypothesis, rapidly photosynthesizing leaves will accumulate sugar in their leaves and deplete nitrogen reserves,  promoting early leaf senescence. This early leaf senescence caused by high levels of summer photosynthesis will tend to cancel the later autumn leaf senescence caused by warmer autumn conditions associated with climate change.  

During sunny dry conditions in Boston, black birch leaves undergo leaf senescence in August. 

This study raises several key questions.  Is their “poison sugar hypothesis” a widely applicable result, or just another additional factor that contributes to variation in leaf senescence?  How can we be sure that their result is really due to high photosynthetic rate and not just due to the well-known effects of  summer drought stress? And finally, do their results apply to other species and other places?  

When their wetland habitats dry out during a drought, the leaves of coast pepperbush wilt and undergo early senescence.  

 

Here is a copy of their article from Science.

Christine Rollinson wrote a Perspective about this topic for Science.

Ula Chrobak reported on the story for Popular Science.

Flood of concerns about Newton's Cheesecake Brook

By Richard B. Primack
 

“A storm is a new, and in some respects more active, life in nature.”

- Henry David Thoreau in his Journal.

 
After a heavy June thunderstorm, Cheesecake Brook on the northern edge of Newton flooded and nearly poured over its banks into the surrounding streets and neighborhoods. With a changing climate, such intense storm events will only get more frequent and flooding danger will get worse. 

Cheesecake Brook flooded during the June 28, 2020 thunderstorm.  
Photos courtesy of CRWA.

 
 
More than a century ago the brook was confined within a narrow stone-lined channel. This straight channel carries sand and other suspended debris directly into the Charles River, along with dissolved phosphorus and nitrogen from lawns and roads, harming water quality.
 

People sampling for aquatic invertebrates in Cheesecake Brook.

 
To address these problems, the Charles River Watershed Association (CRWA) is developing a plan for restoring the sloping banks and natural winding pattern of the brook to increase water retention capacity, reduce flooding, and allow nutrient absorption. The plan includes bioretention basins to trap sand and other debris from streets and outfalls. Large rocks placed in the brook will reduce water velocity and erosion and provide habitat for migratory fish and insect larvae.
 
This is just the first step in a long process of planning, design and fundraising before the project begins and the brook is restored.
 
This is a shorter version of an article that appeared in the Newton Tab.

Black gum trees bring scarlet to autumn

By Richard B. Primack

 

“How much of beauty – of color, as well as form – on which our eyes daily rests goes unperceived by us!”  - Henry David Thoreau in his Journal.

 

The leaves of black gum trees turn brilliant scarlet in late autumn, giving the trees a fiery appearance. At other times of the year, black gums, also known as tupelo trees, are hard to spot in their wetland habitats.   Wild black gum trees are actually surprisingly common at many wetland locations around Boston, especially along the Charles River.

 

A wild tree in the Webster Woods in Newton with red leaves in October.

 

Without their scarlet autumn leaves, black gum trees are recognized by their horizontal branches,  giving trees a distinctive pagoda-like appearance, their tooth-less leaves which are often wider toward the tip than at the base, and their light-gray flaky bark.  Birds also feast on their small black fruits for a few weeks in late September. 

 

Scarlet leaves of black gum up close.

 

Newton resident Nyssa Patten was named for the black gum tree, which has the scientific name Nyssa sylvatica.  When she was borne, her parents planted a black gum tree in their yard, and each year they take her photograph next to the tree.  

Nyssa Patten examines scarlet-colored black gum leaves at the Newton Center playground.

This posting was adapted from an article in the Newton Tab.

Wine making changes with the times

By Richard B. Primack 

“As some heads cannot carry much wine, so it would seem that I cannot bear so much society.”

- Henry David Thoreau in his correspondence. 

In addition to apples and pumpkins, autumn is the time when grapes ripen and people make wine. In Newton, the practice of wine making is changing from the old ways in Italy. 

Mario Battista makes wine every year, but not from the grapes on his own prolific vines. Each year, he buys boxes of Zinfandel grapes and uses these to make about 180 bottles of wine. What does he do with all this wine? Mario says, “I used to have a glass of red wine every night, but my doctor told me to cut back, so I give most of it to my friends.” 

So, if he buys grapes, why all of these grape vines in his yard? Mario explains, “Before I used to grow white seedless grapes to eat, but now I grow vines mostly for shade, and let the birds eat the grapes.” 

Mario Battista and his son Franco sitting in the shade of their grape vine.

John Nicolazzo, another Newton winemaker, bought Cabernet grape juice from California this year instead of grapes, which makes the whole process easier. John says, “I drink some of the wine, but most of it I give away.” 

John Nicolazzo shows his bottles of wine. 

Figs in Newton

Mario and John’s gardens also have 6 to 10 foot tall fig trees growing in pots. Figs are of special interest to Newton, as the famous Fig Newton cookie is named for the city. In past autumns, Newton fig growers would bend over each tree and it bury in a trench for the winter. But now Mario and John cart the potted figs into the garage at the end of the season. It is not the same as the old way, but it works. 

John with his grandson in front of his fig trees. 

This is a shortened version of an article that appeared in the Newton Tab.

The Anthropause: How is it impacting wildlife?

By Richard B. Primack

“I have been sick for so long that I have almost forgotten what it is to be well.”  -Henry David Thoreau in his correspondence. 

In a recent article in CNN World, journalist Caitlin Hu poses the question, “Can nature heal itself? What the pandemic has shown us.”

In many places during the time of the pandemic lockdown, wildlife have become more active and widespread due to reduced human activity. However, at other locations, poaching levels have increased due to reduced enforcement and the need for rural people to find sources of income.  A major concern is also what will happen to national parks and the ecotourism industry now that revenues have declined precipitously.  

The pandemic lockdown offers an unprecedented opportunity to determine how reduced human activity affects conservation efforts. In particular, this will help us evaluate the effectiveness of conservation management and might suggest new management strategies once the pandemic is over.   

How will the pandemic affect the abundance and management of wildlife, such as this brown bear?
(Photo by Robert F. Tobler, Source Wikimedia Commons, license CC-BY-SA 4.0)

Springs are hotspots of biodiversity, but vulnerable to climate change

By Tara K. Miller

 

Springs are important ecosystems to support biodiversity. They are fed by groundwater and maintain more stable temperature and water conditions throughout the year than the surrounding landscape. These factors support a wide variety of plant species. However, springs are isolated – aquatic islands in a terrestrial landscape – which makes it harder for plants to disperse and move to find more suitable conditions as the climate changes.

As climate change progresses, the Subarctic mainland of Norway is expected to experience increased temperatures and precipitation, thus changing the suitability of spring habitats for different plant species.

A spring in Kvannfjellet in Balsfjord county, Norway.
Photo credit: Jutta Kapfer.

We expect that the species composition of plant communities in springs will change due to climate change. In order to measure the extent of the effects of climate change on these communities and to predict future risk, it is important to study which species are currently present in springs, and which conditions support the presence of different species. We recorded which species were present at 49 spring sites in northern Norway. We also recorded the conditions at the springs, including water quality conditions (water temperature, pH, and the pace of the water flowing from the spring), climatic conditions (air temperature and precipitation), and the spatial location of the spring (altitude and geographical coordinates).

A spring in Bentsjordskaret in Tromsø county, Norway, with Tara recording species data.
Photo credit: Jutta Kapfer.

We found that both climatic and water quality conditions were important for determining which species were present in which springs, indicating that as these conditions change with climate change, species may be forced to move to new springs with suitable conditions, or their numbers may decline.

Altitude was also important in determining where species were present. Therefore, altitude may be a limiting factor for plant species in adapting to climate change. For example, if a species is already located at the highest-altitude spring location or if there are no suitable spring sites located at nearby higher altitudes, it may be unable to disperse and migrate to a new, suitable habitat.

Identifying moss species requires a close look under the microscope

Our research gives us a new understanding of the conditions that are important for supporting the presence of different species in Subarctic springs.

Read the full paper here: PDF

Pandemic and then drought impact the woods

By Richard B. Primack

“Let a slight snow come and cover the earth, and the tracks of men will show how little the woods and fields are frequented.”  - Henry David Thoreau in his Journal.

The COVID-19 pandemic began in March.  Soon large numbers of people thronged to the Webster/Hammond Woods for some exercise and fresh air during the lockdown. While it was good that people were using the Woods, the hikers and mountain bikers widened existing trails and made many new trails. The Newton city government reacted by putting up signs stating that using bicycles and making new trails were not allowed.  By July, fewer people were coming into the Woods and human impacts were reduced. City officials are considering closing off the new trails later in autumn. 

A new trail formed in the Woods by hikers and bikers.

The city put signs to discourage biking in the Woods.

This summer also marked one of the most severe droughts in Boston’s history.  Streams and springs in the Woods ran dry. Black birch leaves turned yellow and began to fall in August, especially on the ridges. Leaves of coast pepperbush and sassafras were drooping with thirst. The soil was dry and cracked and mushrooms of all types were almost completely absent.  The forest was quiet as the drought was too severe to support an active community of birds and insects. Such extremes of weather are one of the predicted outcomes of climate change.

Sassafras leaves drooping due to drought stress.

Early yellowing of black birch leaves due to the drought.

For more details, see:

Newton Tab:

https://newton.wickedlocal.com/news/20200514/popularity-of-newtons-parks-during-pandemic

Boston Globe:

https://www.bostonglobe.com/2020/09/25/metro/with-record-temperatures-little-rain-severe-drought-has-gripped-much-new-england/

Monitoring noise pollution in cities and protected areas with smartphones

 By Lucy Zipf, Richard B. Primack and Matt Rothendler

 "Only in saner moments do men hear the crickets. It is a balm to the philosopher.”  -Henry David Thoreau in his Journal.

Noise is a pervasive form of pollution in urban areas that impacts the health and well-being of humans and wildlife. It is often difficult and expensive to monitor and map noise pollution, which limits the availability of noise data and excludes community members from engaging in monitoring efforts.

In a paper just published in PLOS ONE, we describe and demonstrate a low-cost noise monitoring method using smartphones that both engages and educates community members and produces detailed noise maps of urban landscapes and protected areas. The method was demonstrated using bio-blitz style, single-day citizen science events and also as a university-level environmental science field exercise.

The noise monitoring app on a smartphone.

Participants in a monitoring event receive maps showing where they need to record sound.

The maps provide a nuanced understanding of noise distribution through city streets and protected areas, highlighting key sources of noise, such as roadways. Our maps of the Fenway neighborhood of Boston, MA, document that cheering crowds at a Fenway Park baseball game create noise levels as high as 80 decibels, which is about as loud as a lawn mower, whereas a nearby park is much quieter.

A map of the Fenway area of Boston, which includes Fenway Park.

A pdf of the article may be obtained by clicking this link: Zipf L, Primack RB, Rothendler M (2020) Citizen scientists and university students monitor noise pollution in cities and protected areas with smartphones. PLoS ONE 15(9): e0236785. https://doi.org/10.1371/journal.pone.0236785

Macroscale patterns of flowering and fruiting phenology in China

By Richard B. Primack

“If you have built castles in the air, your work need not be lost; that is where they should be. Now put the foundation under them.” - Henry David Thoreau in Walden.

Patterns of phenology are increasingly examined at larger geographic scales with on-line databases and digitized herbarium specimens. In a recent paper in the Journal of Biogeography, Chinese colleagues and I examined the timing of flowering and fruiting of over 16,000 plant species from China using over 1,300,000 records.

Spiranthes sinensis, the Chinese ladies tresses, is a herbaceous orchid species 
that grows in China. (photos courtesy of Du Yanjun)

We found that across the geographic range of China, plant species flowered earlier and fruited later at lower latitudes and lower elevations. In comparison with herbaceous plants, woody plants flowered earlier, showed stronger geographic trends, and needed a longer time for fruit development.  Variation in flowering was most strongly affected by mean annual temperature in woody plants and by temperature seasonality in herbaceous plants.

Antiaris toxicaria, the arrow poison tree, grows in Chinese forests.

These results suggest that woody plants and herbaceous plants will respond differently to climate change, though this needs to be confirmed by investigating individual species and specific locations in greater detail.

This study is noteworthy for the enormous number of species, observations, and geographical scale included.

A Flora of Home

By Tara K. Miller

After coming home during the COVID-19 pandemic, I decided to create a flora of the forest around my childhood home. A flora is a documentation of all the plant species in a location or region. 

Armed with 5-10 field identification books for trees, shrubs, herbs, and ferns, I spent hours wandering the forest, continually noticing new things in the woods where I grew up.

I picked out the tiny spring ephemerals, like spring beauties and trout lilies, that flourish before the trees leaf out.

Me and my field assistant with the spring beauties in early May

I waded through knee-high ferns, which I learned included wood ferns, lady ferns, and sensitive ferns.

I discovered that our forest boasts a few stray box elders and elms in an area dominated by maples, ash, and black cherry.

Black cherry trees are distinguishable by their “burnt-potato-chip-bark,” as my college ecology professor phrased it.

I ate wild strawberries, fought with invasive garlic mustard, and watched the eastern phoebes learn to fly.

Garlic mustard also makes a lovely pesto sauce

It’s never too late to gain a new appreciation of an old place.

Giant hibiscus flowers along the Charles

By Richard B. Primack

“How much of beauty - of color, as well as form – on which our eyes daily rest goes unperceived by us!”  -Henry David Thoreau in his Journal.

Thousands of rose mallow plants with huge flowers the size of dessert plates flower in early August on the banks of the Charles River in Newton, Needham, Waltham, and Dedham. The plants are typically 3 to 7 feet tall, and dozens of stems can grow in a clump.

Rose mallow plants emerging from the Charles River

Rose mallow flowers are usually pink, but some plants produce flowers that are darker pink, others lighter pink, and some are white. Many flowers have red markings at the base of the petals, forming a striking bull’s eye, and flowers can vary from 3 to 7 inches across.

White and pink flowers produced on neighboring plants.

Along the Charles River, about one in three plants produces flowers with a red center, and one in ten has white flowers, usually with a red center. Plants with entirely white flowers can be found but are rare.

A rare white-flowered plant.

Rose mallows are probably increasing in abundance along the Charles, as they colonize areas from which invasive purple loosestrife plants have been removed and places where beavers have cleared away woody riverside thickets.

Different plants produce flowers of different color and size.

August is a great time to be out on the river and see our spectacular native rose mallow plants growing in the wild. It is a world-class wildflower display right here in Boston.

An article about rose mallows along the Charles recently appeared in the Boston Globe.

Papaya trees growing in Newton

By Richard B. Primack

“Our circumstances answer to our expectations and the demand of our natures.”

-Thoreau in A Week on the Concord and Merrimack Rivers 

We know that climate change is already affecting what plants we can grow in the Boston area. In our Newton garden, we now have many fig trees, some of which survive outside through the winter with only minimal protection. And some day, we may be able to grow camellias and crepe myrtles in Boston. Crepe myrtles are already being sold in local garden stores in expectation of warmer years.

Crepe myrtle plants for sale in a Wayland garden store. 

However, this year we are extremely surprised to find dozens of papaya seedlings sprouting on their own in our vegetable garden. One fast-growing seedling is already 2 feet tall and is showing the distinctive deeply-lobed leaves of the species.

Papaya seedling growing in our garden. 

Papaya trees are strictly tropical, so what are papaya seedlings doing in our Newton garden? Even with our current warming climate, New England winters still have plenty of freezing temperatures and ice. The answer seems to be that last fall we added the skins and seeds of some papayas to our compost pile, and then mixed the compost into the garden soil. The round, black papaya seeds must have been deep enough in the ground to avoid freezing and may have even been warmed by the decaying compost. Now that the ground has been heated to tropical temperatures by the July sun, the seeds finally germinated.

These young saplings will certainly not be able to survive outside through next winter. Newton is not yet ready for papaya farms.

Audubon and The Wildlife Society highlight our research on bird-fruit interactions!

By Amanda S. Gallinat and Richard B. Primack

“Do not think that the fruits of New England are mean and insignificant, while those of some foreign land are noble and memorable… Better for us is the wild strawberry than the pineapple.” 

-Henry David Thoreau in his Journal

With climate change, many birds migrate later while the fruits they eat ripen earlier. The spread of late-fruiting invasive plants means birds are more likely to encounter abundant invasive fruits during migration. To see what birds eat in autumn, we identified seeds from fecal samples of birds caught at Manomet, a bird banding station. As we report in Biological Conservation (here), birds prefer native fruits even when they are in short supply compared to invasive fruits.

Recently, this research, co-authored with Trevor Lloyd-Evans, was featured by both Audubon (here) and The Wildlife Society (here)! Both articles highlight birds’ strong preferences for native fruits and the conservation importance of planting and maintaining late-fruiting native plants.

Audubon reaches a wide audience of ornithologists, birders, and nature enthusiasts, while The Wildlife Society’s audience includes students, researchers, and practitioners of conservation and wildlife biology. We are delighted for our research to reach these new audiences!

Protecting scientific diversity

By Richard B. Primack

“There are a thousand hacking at the branches of evil to one who is striking at the root.” 

-Henry David Thoreau in Walden

In a recent paper in Nature Ecology and Evolution, we argue that the scientific leadership needs to include diversity, equity, and inclusion as an important focus in all COVID-19-related recovery efforts. Decades of efforts to build an inclusive scientific community have raised awareness of the need to promote diversity in academic workplaces, but this goal is far from being achieved and is put at risk by the pandemic. 

Communities historically underrepresented in the fields of conservation, ecology, and environmental sciences, including minorities of all genders, women, researchers from the Global South, and people with disabilities, are especially vulnerable during these times. We also need to actively support the retention and diversity of early-career scientists during and after COVID-19.

Fig. 1 | We highlight key actions in the workplace, community, and policy arena that academic leadership can carry out to protect and improve diversity, equity, and inclusion (DEI) in the scientific workplace during and after the current pandemic crisis.  Credit: Rejane Santos-Silva @rejsantossilva

Ecological mismatches of wildflower and trees: Mercer Award presentation

By Richard B. Primack

As described on our April 21 post, Caitlin McDonough MacKenzie and I received the George Mercer Award from the Ecological Society of America for excellence in a recent research paper lead by a young scientist. Because the meeting is being held on-line this year, the team was asked to contribute a video for the ESA presentation.  Our video is available on youtube! 

We shared the award with three co-authors for the paper, entitled “Phenological mismatch with trees reduces wildflower carbon budgets,”  which appeared in the scientific journal Ecology Letters.

Sketches of the five co-authors as they appeared in the video.  

By Bonnie McGill. https://bonniem.weebly.com