Nature Conservancy restores sandplain grasslands

Planting native little bluestem is just one step toward increasing biodiversity and restoring a rare natural ecosystem.


The sandplain grasslands of Martha’s Vineyard are a rare and imperiled ecosystem that exist almost exclusively on islands in Massachusetts, and some of the most outstanding examples of these unique systems are right here in Katama.

When the massive glaciers that formed our Island reached the endpoint of their advance, they deposited debris collected over thousands of miles of slow crawl in a heap that is known today as the terminal moraine.

The sandplain grasslands of Katama — which look more like Western desert prairie than any habitat you might expect to see here — are a result of this massive dumping.

Through certain naturally occurring processes such as salt spray washing in from large storms, wildfires, and the ocean cooling effect, certain non-native species are dissuaded from moving in.

But those processes go only so far, and at a certain point, humans have to step in to help the native species remain, and keep non-native species from taking root.

For decades, the Nature Conservancy has been maintaining existing sandplain grasslands, and working to restore those that may have lost ground.

Nature Conservancy’s stewardship manager for the Cape and Islands, Mike Whittemore, invited The Times to head out to Bamford Preserve, where the conservancy is working on restoring a large swath of sandplain grasslands to its original level of biodiversity (and beauty).

“Although these systems contain native vegetation, and although they have processes very close to the ocean that maintain them naturally, these systems will always require humans to manage them,” Whittemore said.

Management practices like controlled burns and mowing are some ways humans have maintained the biodiversity of sandplain grasslands over the years.

Originally slated to be a housing development, the Bamford Preserve field was an agricultural grassland filled with non-native cool-season grasses. The Nature Conservancy took the land into conservation, and they have been caring for it ever since. 

The first step to ensuring Bamford Preserve eventually becomes a flourishing natural landscape with the rare native species the sandplain grasslands are known for, Whittemore said, is for the Nature Conservancy to plant native grasses, called little bluestem.

The Nature Conservancy harvests the little bluestem seed in October from other areas on-Island using special equipment, then they process all the seed and prepare it for sowing.

This year, they harvested about 100 pounds of little bluestem, and recently reached an important milestone of planting the final plot of native grasses at Bamford.

Before planting the grasses and figuring out what other native species would be best for the area, the Nature Conservancy partnered with Marine Biological Laboratories to run experiments that would determine the best land management practices going forward.

“Through those experiments, [the lab] told us that tilling once or twice really helps outcompete the non-native cool-season grasses, and helps sort of initiate the process for the warm-season native little bluestem grass, which is the foundation of sandplain grasslands,” Whittemore said.

The Nature Conservancy also enlisted the help of native plant expert Carlos Montoya, of Native Plant Associates, to help with preparing the individual plots for planting, and then sowing the seed.

Montoya explained that the little bluestem seed is chaffy, or fluffy, so it will fly away in the wind very easily if it isn’t properly prepped.

Montoya tows a specially designed drop seeder machine behind a tractor. Inside the seed box, a mechanical picker plucks the seed from the chaff, and deposits the seed through two rotating metal barrels.

The first barrel, called a cultipacker, packs the soil down and creates a lane for the seed to drop into. After the seed is dropped into the ground, a second cultipacker presses the seed into the ground so it doesn’t blow away.

“You have to compress the soil so you know you have a firm seedbed, so when the seed drops it falls right through the two cultipackers. Then the second one presses the seed in, and it will leave small imprint marks — that’s how you know it’s doing the job,” Montoya said.

The next step is to harvest native wildflowers, and plant them in the sprawling grassland so as to attract pollinators and other native fauna to the area as well. “Before you can plant the native wildflower species, you have to plant the native grasses,” Whittemore explained. “We have a whole list of wildflower species we are looking at planting. Everything from your common sandplain grassland species to more rare species.”

The Nature Conservancy will work with Polly Hill Aroboretum’s MV Wildtype program in this effort. The program seeks to provide a source for native plant species to people on the Island by collecting seed from principal habitats.

“[The arboretum] is actually going to grow us 1,000 butterfly weed plants, which are those really bright and showy orange flowers that you see covered in monarch butterflies,” Whittemore said.

Since the 1980s, the town of Edgartown has owned the large area of sandplain grasslands at the Katama Airfield, and the Nature Conservancy has been working with the town to maintain the rare and delicate ecosystem.

Now, Whittemore and the folks at the Nature Conservancy are looking at turning Bamford Preserve into another exemplary specimen of sandplain grasslands that can be studied and used as reference for scientists and conservation experts.

“This is a very important habitat, and on top of that, Martha’s Vineyard is one of the real strongholds of that system. So [the Nature Conservancy] is very focused on not just restoring this system here, but also maintaining systems so that they continue to flourish and be biodiverse. This is a research project and a restoration project that really started from the ground up,” Whittemore said.

As more and more research is conducted in the area, that information will be disseminated regionally so other folks can use the land management model created and implemented by the Nature Conservancy. 

If the Nature Conservancy and associated organizations hadn’t chosen to conserve the land and eventually work to restore it, Whittemore said, it’s possible the entire habitat could have undergone ecological succession and evolved into a forest or shrubland.

“A lot of the grassland flora that has existed in that area over the years would go away,” Whittemore said. “After it’s entirely gone, it’s very difficult to restore.”

The only way that the Nature Conservancy has been able to maintain and work to restore grasslands like this, according to Whittemore, is through long-term partnerships with other organizations and entities that share the conservancy’s goals.

It will take a few years for the grasses to fully take over, and for native fauna to start moving back in. In the meantime, Whittemore said, the Nature Conservancy will begin planting native sandplain grassland wildflowers, all harvested right here on Martha’s Vineyard.

“That’s important to protect the genetics of local Island populations,” Whittemore explained. “In the next two to three years, we expect this area to come alive into a vibrant grassland that benefits native pollinators, grassland birds, and rare species.”