"Growing Native" to Restore Nantucket's Natural Areas

Right now, the NCF Science & Stewardship greenhouse is bursting at the seams with 20 species of native plant seedlings that will be planted in trail-side restoration and pasture improvement projects later in the season. Each year, NCF Science staff members collect seed from properties around the island where there are well established populations. We try to grow a wide variety of different grass and wildflower species to boost biodiversity at restored sites. Planting a number of different species mimics the natural variety of healthy native grassland communities and creates more habitat for wildlife at all levels of the food chain.

We’re careful to collect only a small percentage of seed from any particular site. We collect common native species, but also collect more unusual ones, such as big bluestem (Andropogon gerardii). This large grass, with its distinctive “turkey claw” flowers, is common in Midwestern prairies, but it’s a Nantucket native, too. Since it needs moister, richer soil and shelter from wind and salt spray, it’s limited in where it can grow on our island, 27 miles out to sea.  Back at the NCF office, seeds are cleaned and stored in the refrigerator over the winter. Careful cleaning reduces debris and removes insects. To clean some species we use a simple setup with an adjustable blower, using aerodynamics and gravity to sort out the healthy seeds from the junk: empty seeds, pod fragments, and dead insects blow out the end of the tube while heavier “good” seeds slide back down and collect in a tub.

Storing seeds in the refrigerator keeps them alive longer and helps to prime them for germination when they are sown in the spring. Some seeds can be saved for a number of years and remain highly viable (meaning that a large percentage will still germinate successfully) while others need to be planted the next spring or they will never germinate. Each year is different in terms of which species’ seeds we are able to collect: weather conditions, insect infestations, pollination, and our management activities (such as brush-cutting and fire) all play a role in determining which species will produce ample seed. Did you know that fire can stimulate some species to produce a bumper crop of seeds? Fire may also reduce seed-eating insects by killing their eggs or overwintering adults. After a 2010 spring prescribed burn at the Head of the Plains, there was an amazing bloom of goat’s rue (Tephrosia virginiana), a showy native plant in the pea or legume family (the Fabaceae). That year we were able to collect a large paper bag of seed pods, amounting to thousands of seeds, but we haven’t been able to collect since.

 

Another species that responds with a bumper crop of seeds after fire is yellow wild indigo (Baptisia tinctoria). This plant produces large globes of foliage, and flowers vigorously after it has been burned. The fire seems to reduce the numbers of snout weevils (which are insects with a long proboscis that resemble Gonzo from the Muppet Show). These snout weevils hide inside the seed pods and eat a very high proportion of the seeds–except after a fire, or in a year when snout weevil populations are low for other reasons. Other seed collectors have had similar problems with this seed predator–check out this link to the University of Wisconsin-Milwaukee Field Station “Bug of the Week” blog posting made by Environmental Educator Kate Redmond. Writing as the “Bug Lady”, she shares photos and information about snout weevils that they encountered on a different species of Baptisia. They really do look like Gonzo, don’t they??? So, you may be wondering where you can see all these seedlings in their new habitat. Check out the ongoing trail-side restoration at Sanford Farm, where the trail surfaces have recently been improved near the northern end of this popular NCF property.

Over years of use, runners, bikers and walkers created a number of side-trails to avoid areas of soft sand. After we tested planting methods, trail hardening took place last year. Making the trail surface more durable will encourage visitors to stay on track and protect sensitive wetlands and trail-side vegetation. At Sanford Farm, this includes globally rare Sandplain Grassland and Coastal Heathland plant communities. A side benefit: the new hard-packed surface also makes Sanford Farm more accessible to families with strollers or people using wheel chairs. When first planted, the seedlings need to be protected from foot traffic with temporary fencing along the trail edges. Once the plants are well established, the fencing and signs will be removed, but it’s essential that fences remain in place for a time. Otherwise foot traffic and curious dogs will destroy our hard work.

What can you do to help? Stay on the main trails, and keep dogs from frolicking in fenced areas. And please understand that we need to use trucks to haul water weekly for the first month or so after each planting. We drive carefully and allow plenty of room for passing visitors and pets–and sometimes give a drink to the more thirsty dogs on a hot day! After a couple years, you can see that the plants have really acclimated to their new home. Check out the pictures above and below, which show plants laid out for planting, and the same site a couple years later.

Another way you can help is to add native plants to your own Nantucket garden. By doing so, you can enjoy these native wildflowers and grasses at home. Backyard gardens that contain diverse native species provide vital habitat for insects and birds, many of which are threatened by development and fragmentation. Your yard could be a bridge between natural areas or create a welcome stopping or feeding place for wildlife. Check out this article in the New York Times that reviews a great book on this topic, Doug Tallamy’s Bringing Nature Home. This book lays out a compelling argument for integrating native plants into your garden to benefit wildlife. Since many insects are adapted to need only on native plants, a small change in your yard can boost the food chain from the bottom up.