David Gregg worries that not enough
is being done to protect rare plants in Rhode Island.
“There are a lot of plant species
that we’re monitoring out of existence,” said Gregg, the executive director of
the Rhode Island Natural History Survey. “We check them every year, and there
are often fewer of them each year. The best-case scenario is that they stay the
same, but many populations are getting smaller and smaller.”
He believes that conservationists
must be bolder during the climate change crisis if native wild plants are going
to survive in the coming decades. Rather than simply monitoring
the status of
rare plants in Rhode Island, he is advocating for the use of more active strategies
to boost plant populations.
Salt marsh pink (Hope Leeson) |
“There’s been a big debate among
biologists about how active we should be in trying to save rare species,” Gregg
said. “Are we going to end up gardening nature? Aren’t we bound to make faulty
decisions? If we get involved in active management of rare species, aren’t we
doomed to screw it up?”
With little left to lose in some
cases, he has chosen to partner with the Rhode Island Department of
Environmental Management and the Native Plant Trust (formerly the New England
Wild Flower Society) on an effort to propagate select species of rare plants
and transplant them into the wild to augment existing wild populations and
establish new populations.
The Rhode Island At-risk Plant
Propagation Project is an outgrowth of the Rhody Native program, which was
established a decade ago to help commercial plant growers propagate native
plants for retail sale. At its peak, the program was growing 50 different
species, but eventually just one species became dominant, a salt marsh grass
used in marsh restoration projects.
“Rhody Native became a commodity
growing project, and that’s not our business,” Gregg said. “Our strength is in
rare species – learning to propagate them and experimenting with them.”
The Propagation Project began last
year with the selection of four plants to propagate to test the concept -- salt
marsh pink, wild indigo, wild lupine, and several varieties of native milkweed.
The lupine and indigo were selected in part because they are the food plant for
a rare butterfly, the frosted elfin. Just two populations of salt marsh pink
are left in Rhode Island, and they are at risk from sea level rise.
“Our populations of marsh pink have
very few plants, and we’re worried about inbreeding,” Gregg said. “The idea is
to take plants from a Connecticut restoration site, cross pollinate them with
plants from Rhode Island to reduce inbreeding, and then return some to
Connecticut and use the others to reinforce the Rhode Island populations.”
The big challenge with this kind of
project is learning how to propagate the plants in a greenhouse setting.
“These aren’t domesticated plants
we’re working with,” said Hope Leeson, a botanist for the Natural History
Survey who led the Rhody Native program. “We have to imitate the environmental
conditions the plants are adapted to – the temperature, humidity, soil, water
and other factors.”
Salt marsh pink is a particularly
challenging example. It’s an annual species that produces a large quantity of
seeds in a good year, but the seeds are extremely small – Leeson describes them
as “dust-like” – and they don’t tolerate drying, so they cannot be stored over
the winter.
“We collected seeds in October and
had to sow them immediately,” she said. “In the wild, they grow in a band of
vegetation along the top of a salt marsh, where it’s a moist sandy soil mixed
with peat. Periodically it floods as the tide comes in and then drains. I’ve
got to come up with a soil mixture that’s like the natural conditions to make
the plant happy.”
Wild indigo, on the other hand, is
very drought tolerant and doesn’t grow well in moist or humid conditions. Its
seeds – like those of wild lupine – must be scarified before they will
germinate.
“A lot of species in the pea family
have a hard seed coat that keeps them from taking in water until conditions are
right for germinating,” Leeson explained. “In the wild, lupine grows in sandy,
gravely soil, so the seeds are likely to get abraded by the sand over the
winter, allowing it to take in water to trigger the process of coming out of dormancy.”
To get lupine and indigo seeds to
germinate, Leeson must first scratch them with sandpaper to simulate the
natural scarification process.
Leeson and volunteers from the Rhode Island Wild Plant Society are raising many of the target plants in greenhouses
at the University of Rhode Island’s East Farm and at a private site in
Portsmouth.
Gregg said the project is being
undertaken on a shoestring budget to demonstrate it’s potential. “We hope
someone will realize that we have this unique capacity to do research
propagation of rare plants, and maybe that will help us find some funders to
support the project,” he said.This article first appeared on EcoRI.org on May 21, 2020.