Polly Hill Arboretum Hosts Botany Expert Peter Raven


If development continues at its current pace, our planet will stand to lose roughly two-thirds of its species by the end of the century, according to renowned botanist Peter H. Raven.

Such a widespread loss would be the largest mass extinction since the end of the Cretaceous Period, some 65 million years ago. But unlike the previous five mass extinction events - which are understood to have been sparked by ice ages, asteroids or volcanic events - this sixth extinction, as Mr. Raven calls it, will be almost purely manmade.

The forecast is understandably troubling to Mr. Raven, a worldwide expert on biodiversity and leading proponent of plant conservation.

"From either a moral or religious perspective, do we have the right to drive to extinction such a large proportion of what as far as we know are the only other living beings in the universe?" Mr. Raven asked during a telephone interview from California this week. "Or do we have a responsibility to take care of them?"

They are the types of questions Mr. Raven will try to answer during his lecture on the Vineyard next week, set for Wednesday at 7:30 p.m. in the Agricultural Hall in West Tisbury.

But in the talk, titled How Many Plants will Survive the 21st Century?, he will also discuss ways we can conserve biodiversity and help stem the loss of plant species - both by identifying and protecting rare plants in their native habitat, as well as cultivating them for educational purposes and possible use in the future.

It is exactly the type of work that lecture host Polly Hill Arboretum is doing here on the Island.

Mr. Raven said this will be his first trip to the Vineyard, and that he is excited to visit the arboretum founded and named after Mary Louisa (Polly) Hill, whom he worked with years ago at another arboretum near Boston. Highly regarded among professional horticulturists, Mrs. Hill almost a half-century ago founded the North Tisbury arboretum on a historic sheep farm where, without a greenhouse, she developed nearly 100 horticultural varieties and tended over 2,000 species.

The arboretum is equally excited to host Mr. Raven, whose accomplishments are far more lengthy than can be listed in a single newspaper article.

Polly Hill executive director Timothy Boland this week described Mr. Raven as "a powerhouse of an individual," and characterized his message as a clarion call for public action.

"He is one of the most brilliant scientists in the world in terms of plant taxonomy and study of the diversity of life on earth, and has published several of the most ground-breaking papers that still have relevance today," Mr. Boland said. "He is also not afraid to put out there all of the statistics that show we are losing our natural areas at a drastic rate. But even though his message can put fear into you, he is also hopeful that people can make a difference, that we can use scientific methodologies to develop real world solutions."

A 2001 recipient of the National Medal of Science, the top science award in the country, Mr. Raven, 70, has also been named by Time Magazine as a hero for the planet. He was born in China and raised in San Francisco, where at the age of 15 he discovered a subspecies of manzanita trees that had not been seen for half a century and was later named after him.

Mr. Raven has spent the last 35 years as both a botany professor at Washington University in St. Louis and the director of the Missouri Botanical Garden, a world-class center for research, education, and horticulture display. Under his leadership, the botanical garden also does work overseas in areas like Madagascar and the Amazon rainforest, setting up partnerships between scientists and local communities to teach them the value of native plants.

The Missouri Botanical Garden is also the national headquarters for the center for plant conservation - a network of more than 30 institutions across the country that are inventorying imperiled plants in their areas and cultivating them within botanical gardens for possible reintroduction later on.

The Polly Hill Arboretum is doing that work here on the Vineyard, monitoring rare plant populations - such as the state-listed Nantucket shadbush, exquisitely beautiful blazing star, and a series of elusive orchids - and restoring plant communities by growing them by seed.

Mr. Boland said the arboretum has also started working with other Vineyard conservation groups to identify rare plants both in protected and unprotected areas. They will then contribute their findings to the Island Plan, currently under way at the Martha's Vineyard Commission, to prioritize the protection of certain areas - like the globally rare sandplain habitat above the great ponds - that are of particular importance to our biodiversity.

While selective gathering, climate change, and invasives species all pose threats to rare plants and overall biodiversity, according to Mr. Raven, the leading cause of species extinction is habitat destruction.

The conservation aspect of his talk next week will be a fitting tribute, as it comes during the annual David H. Smith memorial lecture. A West Tisbury summer resident, distinguished doctor, scientist and conservationist, Dr. Smith was the driving force behind the preservation of the arboretum roughly 10 years ago. He was also involved in other conservation efforts on the Island, including the Moshup Trail project that has saved over 50 acres of land in Aquinnah, including some globally rare coastal heathland habitat.

Mr. Boland said one of the most amazing things that Mr. Raven has been able to accomplish in his many years of plant conservation work, is getting people to understand and appreciate the importance of the plants around them.

"When you're involved with this field, the greatest message you can promote is how plants are absolutely essential to the health of our planet," Mr. Boland said. "And Mr. Raven is a guy that gets people invigorated and excited about preserving plants."

Mr. Raven this week listed off some of the many vital roles that plants play in our world, such as improving the quality of our air and water and providing the source, either directly or indirectly, of all our food and most of our medicine.

"As we try to find sustainability for the future, plants will play an enormous role in that," he said.

He also noted that we as humans have only charted a small fraction of the earth's biodiversity - perhaps 1.6 million of the 10 million different species in existence - and that we still know very little about the rarest plant species, and what role they play in nature.

"What we are losing, we don't even know," Mr. Raven said, "and perhaps never will."

He quoted the late Aldo Leopold, one of the fathers of the American environmental movement, in suggesting that we might find an important use for these rare plants in the future: "The first rule of intelligent tinkering is to save all the cogs and wheels."

But Mr. Raven mentioned one aspect of plant conservation that is not to be overlooked.

"All of this ignores the joy we get from looking at them," he said. "Or the pleasure we get just from knowing they are there."