Botanical Gardens are Ripe for Research

Posted by Tara K. Miller

“Flowers were made to be seen not overlooked.”

-Henry David Thoreau in his Journal, June 15, 1852

In late November, Richard Primack and I attended a meeting of botanical gardens at the German Centre for Integrative Biodiversity Research in Leipzig to discuss establishing an international network to monitor wildflower phenology.

Meeting participants came together from Austria, Canada, China, Germany, Norway, Scotland, and the United States.

Phenology is the timing of biological events, like flowering and fruiting.  These events are important for the survival and reproduction of wildflowers, as well as for other species that interact with wildflowers, including insects and birds. This field has taken on added significance due to the effects of climate change.

 Insects visit a Campanula species

Participants shared their experiences with phenological research and citizen science.  As a network, we plan to monitor a shared list of species that we can then compare across botanical gardens in different countries and climates.

Curator Martin Freiberg leads a tour of the Leipzig Botanical Garden

Fleshy fruit phenology at botanical gardens around the world

Posted by Amanda Gallinat

“I find a fine tupelo near Sam Barrett's now all turned scarlet. I find that it has borne much fruit -small oval bluish berries, those I see - and a very little not ripe is still left.” 

-Thoreau in his Journal, Sept 30, 1854 

Over the past several years, we have worked with an international group of researchers to record and analyze fleshy fruit ripening times at five botanical gardens located in the United States, Germany, and China. Our findings were recently published in the American Journal of Botany, in an article entitled Patterns and predictors of fleshy fruit phenology at five international botanical gardens.

Amanda Gallinat monitoring fruit phenology at the Arnold Arboretum 

We found striking variation in fruiting times among species, with ripe fruits available from May until March of the following year, and fruiting durations ranging from under 1 week to over 150 days! We also found that early stages are more consistent than late stages (likely due to variable fruit removal by wildlife) and early stages are highly consistent with one another.

Winterberry (Ilex verticillata) fruits persisted into the winter at several gardens; here they are pictured at the U.S. National Arboretum in Washington, D.C.; photo by Alan Whittemore

We also found a fairly consistent order in which species fruit across years and gardens and that fruiting times are phylogenetically conserved; that is, related species tend to fruit at similar times. This suggests that plants have evolved particular strategies for when they fruit and interact with wildlife.

Ripe silverberry (Eleagnus lanceolata) fruits at the Arnold Arboretum 

Interactions between fruits and wildlife also recently appeared in the Boston Globe! An article entitled Autumn’s Other Colors are for the Birds featured the Primack Lab’s research and commentary on bird-fruit interactions in Massachusetts.

A robin eating crabapple fruits at the Arnold Arboretum in Boston, MA; photo by Sam Roberts

Rye, NY gives insight into Boston’s future

Posted by Richard B. Primack

“The best time to plant a tree was twenty years ago. The next best time is now.”  

Chinese proverb.

Last September I visited Rye, NY, a coastal town just north of New York City.  The visit provided insight into the future ecology of eastern Massachusetts, as common species in coastal New York will extend their range northward and become more abundant in Massachusetts as the climate warms.  

Native sweet gum trees (Liquidambar styraciflua) are common in the Rye forests, and seedlings are abundant in nearby open fields; soon this species will disperse to Boston. Should we help sweet gum along by planting their seeds in places where our native Massachusetts trees are dying?

Non-native grasses and the invasive Japanese wineberry bush (Rubus phoenicolasius) grow on the damp forest floor, and in coming years, will spread northward into eastern Massachusetts and northern New England. 

The human dimensions of climate change are seen in the Rye Meeting House; during Hurricane Sandy, the harbor was flooded and seawater was over three feet deep in the building. 

One pleasant treat was dozens of monarch butterflies feeding on the white flowers of the native salt marsh groundsel bush (Baccharis halimifolia), another species likely to spread northward in coming decades.