Effort Seeks to Revive Sandplain Flora
By MIKE SECCOMBE
Ever since cultivation began on the Vineyard, farmers have tried to enrich the nutrient-poor soils of the Island's sandplain grassland. Now scientists are beginning a five-year experiment on the Island trying to achieve the exact opposite.
At a cost of some $700,000, The Nature Conservancy and Marine Biological Laboratory will try various ways of de-enriching the soil on 70 acres of sandplain at Katama, with an eye toward reestablishing the grassland ecosystem which formerly existed there.
The project was formally kicked off last Friday, at a dedication ceremony for the Bamford Preserve at Herring Creek Farm, named for Roger Bamford, an Island summer resident who was instrumental in acquiring the land six years ago and who is substantially funding the research.
But preparatory work has been under way for several months already, with 180 small plots laid out for testing various ways of removing nutrients from the soil.
The land abuts the Katama air park and another large block of state-owned grassland, making it the largest contiguous area of such grassland in the northeastern United States.
Sandplain soils, explained Matt Pelikan, Islands program director for The Nature Conservancy, are very short on nutrients. The native vegetation is therefore highly adapted to live without much nitrogen, calcium and other elements.
"Because of those adaptations, they don't really benefit when more of those nutrients are present. But other plants do, so they are at a competitive disadvantage compared with things like agricultural weeds and grasses," Mr. Pelikan said.
"So in order to restore native vegetation we need to get the soil chemistry back to its former state," he added.
The purpose of the research is to find the easiest and most cost-effective way to do that, and researchers plan to try several different methods and combinations of methods.
"Among the things we will try will be growing a heavy feeding crop like corn, which takes up a lot of nitrogen, and then just chopping off and removing it," Mr. Pelikan said. He continued:
"We'll try mixing in carbon in the form of sawdust or wood chips. When you increase the amount of carbon, the microbial activity changes in the soil in way which results in less nitrogen being available for plants. It's a way to manipulate the microbiology.
"We'll even try something as crude and straightforward as removing about a foot of topsoil and exposing soil which is less enriched.
"We'll try about six or seven methods, and monitor them intensively, seeing what seems the best way to do it.
"There will be multiple replicated treatments spread across the area. Hopefully there will be enough of an experiment here to generate really statistical results."
The aim is to refine techniques which could be used in similar areas of previously farmed sandplains from Long Island to Cape Cod, to develop, as Mr. Pelikan described it, "something new for the land restoration tool box."
Initially the nonnative species would be reduced by simply tilling the soil, but it was hoped that once the site returned to its natural state and periodic burning continued, the native species, which are highly adapted to poor soils, fire and high levels of salt, would enjoy a competitive advantage.
The Katama air park sandplain grassland, which was protected about 20 years ago, is considered one of the best examples of coastal sandplain grasslands in the northeastern United States and was named one of the 40 last great places on earth in a conservation initiative by The Nature Conservancy.
"It is an exceptional ecological resource with many rare plants and many associated rare insects. And just across the road is some state-owned land which is also really good sand plain habitat. So we're filling in and expanding these two existing sites, hopefully making a much larger ecological whole of roughly 300 acres," Mr. Pelikan said.
Rare and endangered plant species which scientists hope will benefit from the restoration include New England blazing star, sandplain flax and Nantucket shadbush. Along with them come various associated insects and it is hoped some vertebrate species including grasshopper sparrows and short-eared owls.
Mr. Pelikan stressed that nearby land still under agricultural use also is important to the ecological big picture.
"We don't believe in restoring agricultural soil just willy nilly," he said. "Agriculture plays not only important social and economic roles, but also important ecological ones. Ag land is really important foraging area for a lot of kinds of wildlife.
"We think this will serve as a good example of how varying kinds of land use - conservation of different kinds, private ownership and management can add up to a very productive matrix which protects rare things while also allowing other activities to go on."