Celebrate Earth Day – help plant beachgrass

Fri, 04/15/2022 - 8:15am
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It’s time to plant beach grass! The last time the island marshaled a beachgrass planting brigade it was 2019. Because of Covid restrictions, gathering for grass planting was curtailed in 2020 and 2021. Weather-wise we are at the end of the beachgrass planting season, and we are all systems go.
On March 26, 11 students from Salve Regina University volunteered their Saturday to plant 1,700 culms (beach grass “plugs”) to fill in the bald
and thin spots of the dunes between the walk-over steps on Corn Neck Road.
On Thursday, April 21 at 4 p.m. is your chance to help this noble effort. An additional 2,300 culms are ready to go in the sand to help stabilize part of our dunes. The Town of New Shoreham has provided the funds for the culms, as well as a mix of 15 beach plum and Rosa rugosa (small native
and naturalized dune-loving shrubs.) All of these plant species are critical to the formation of land-protecting dunes.
How do beachgrass, beach plum and Rosa rugosa work to build a dune?
As a geologic feature and system, sand dunes are truly amazing. They build up as wind- blown sand particles hit an object, thus losing forward movement, and fall onto an ever-growing pile of sand. Grains of sand at slower speeds fall in front or around the stationary object. Sand grains moving at faster speeds will lose velocity when hitting an object but may continue a little further before falling to the ground behind the solid object.
In this process, sand dunes are always moving – some say “migrating” – inland and broadening and becoming the island’s rampart. Generally speaking, the wider the dune system the better. Objects that detain wind-blown sand particles include stones, fencing and plants.

Sand dune systems at their most efficacious are not only wide, they are also tall and contain some sort of inner armature to help anchor and reinforce the structure. Nature of course, has evolved the perfect plant for this task: American beachgrass (Ammophila breviligulata). Beachgrass’ genus name Ammophila, means sand-loving.

American beachgrass is ideally suited to the dune environment. The plant needs little water and is tolerant of salt and sand. At its most vigorous, a dune of beachgrass is a mass of plants interlocked below the sand by an extensive rhizomatous root system, where new plants sprout and grow upwards from these horizontal-reaching rhizomes. More critical is the fact that when stems of beachgrass intercept wind-blown sand particles, they pile up and cover over the plants, the stems become rhizomes and send up new shoots of beachgrass. In this way sand dunes grow in height and are anchored by an ever-growing mesh of both vertical and horizontal rhizome/root systems.

American beachgrass, once established throughout a sand dune system, can withstand salt, sand, wind, low nutrient and fresh water conditions; but beachgrass cannot withstand compaction of its root system by foot or vehicle traffic. And, as we have seen in recent years, low and narrow dune systems will succumb to the terrific forces of storm waves and high winds, especially when combined with high tides and the incremental rising of the world’s sea levels.
In 2012, Super Storm Sandy destroyed the dune system at the southern-most end of Corn Neck Road, and the repairs to the dunes there have been too little and unsatisfactory. Alas, the truth is that although the gash and wound in the island’s “skin” (first line of defense) was quick and decisive, the healing and rebuilding is a slow and incremental process, which has been hindered by subsequent easterly storms. Ten years is not enough time to re-fortify the dune system to its pre-2012 strength; especially as the island is increasingly impacted by climate change impacts such as sea level rise and more frequent and ferocious storms. This vulnerable dune system should receive yearly administrations of augmenting vegetation and emphatic protection from foot damage. The town – along with island-based NGOs and volunteers – has done a lot to nurse the dunes: think funding beachgrass, building walk-overs, placing supplemental sand, installing barrier and symbolic fencing. But, protecting the dunes is not a one-and-done endeavor. And, the two-year lapse of beachgrass planting has set us back a step. However the dune is better and stronger than it was post-Super Storm Sandy.

As meager an offering as is this year’s planting of 4,000 culms of American Beachgrass in the face of much larger need, it is an important next step. Rebuilding the internal structure of the dune must continue with as many culms (stems) of beachgrass as can be mustered. Remember, as a sand
dune builds one grain at a time, so too the reestablishment of beachgrass is incremental: without beachgrass the dune is only a wispy pile of sand.