Shy and reclusive, this reluctant mascot for sea level rise is not a species someone would likely happen upon by accident.  The Saltmarsh Sparrow spends their days a hop, skip, and a very long jump out from the shore and the concrete towers that dot the coastline.   This grassland sparrow lives by the tide, deep in the secluded interiors of the salt marshes that the towers overlook. 

Our good friend Alan’s gorgeous peek-a-boo birdie pictures say it all.  The Saltmarsh Sparrow, would rather not be found.

Formerly known as the Sharp-tailed Saltmarsh Sparrow, and before that, the Sharp-tailed Finch, this species only inhabits salt marshes along the East Coast, and a small region of the Gulf Coast of the United States.  Partners in Flight estimates that the breeding population has declined by 9% per year for more than a decade.  

The range of the Saltmarsh Sparrow is very limited, breeding only from Maine south to Virginia. They winter in a narrow arc along the coast from Cape Hatteras south through Georgia, skipping over the inland sections of Northern Florida, to an isolated pocket in Florida's Forgotten Coast. 

Life in a changing world

The sparrow is, of course, completely indifferent as to the causes of climate change.  It does, however, live with its feet in the marsh, and is therefore feeling the effects of sea level rise with its more frequently occurring coastal storms.  

Hidden in the grasses, mom handles all the housekeeping.  Her open cup nests are just a few inches above the surface of the high marsh.   The preferred nesting sites seem to be just below the elevation that the Black Needle Rush grows, in areas where the Salt Meadow Hay is lush enough to form cowlicks consisting of a mixture of senescent and live stems.  

Their nesting sites are well below the elevation of the highest of high tides, and, as everyone knows, tide waits for neither man nor bird.  In the best of times, brooding is a race against a 2-3 week tide window when the high tides do not reach the height of the nest.  As each day slips by, the tides inch higher and higher.  It is during this critical window, if an offshore low pressure front passes through the Gulf of Maine, causing even a minor storm surge of 6-8 inches, that the nest could be lost.

There are a number of factors at play here.  It is thought that the primary factors for the increase in flooding may be the slowing of the Gulf Stream Current , combined with, a minor storm surge caused by a passing low pressure front.  The combination of these factors can create a high tide that floods over the surface of the marsh during the neap tide cycle, which is when the sparrows are breeding.   

From July 4th to August 15th, folks who are caught out on the marsh during the middle of the day, need to be prepared to defend themselves.  

What the enemy lacks in stature, he makes up for with an anticoagulant saliva laced punch that feels like your skin just burst open.  The hotter it gets, the faster they fly, and the larger the piece of flesh they try to take from you.  

No matter how hard you try to swat them, they just shrug it off.  Only a swat with a swipe will get the job done.

For more information on Greenheads, we suggest clicking on the button below and reading Annie Graves wonderfully humorous article published by Yankee Magazine on July 15, 2013.   

What are Salt Marshes?

Contrary to Hollywood’s portrayal, salt marshes are not places to be afraid of.  No monsters waiting to take you away, no quicksand, just acres of grass peppered with the early life stages of between 75-95% of all commercially harvested fish and shellfish.

Their expansive kelly green plains are divided by meandering creeks that carved out shares in a willy-nilly fashion.  When the tide is in, the moist, cool air is invigorating with an indescribable fragrance like fresh salted herbs.   As the tide recedes, the air takes on the curious scent of sweet grass and matches. 

Salt marshes are floodplains that fill and empty twice in about 25 hours, 24 hours and 50 minutes to be exact.  In this region, the highs and lows of both of the day’s tides are different than the preceding and the following.  Over the course of a month, the tides of each week string together into a series of tides that either trend up toward flood or fall back to neap.  The month-long transition from neap to flood and back again is gradual, tide by tide, ticking away the inches in one direction or the other. 

In undisturbed marshes, if you can find such a thing, the landscape has been sculpted by the push and pull of the tides.  Fine sediments carried in by the tide filter into the grassy surfaces to form rolling plains with soft edges.  Straight, hard edges of any kind, water, grass, or the lack thereof, are relics left behind by the nearly forgotten practice of harvesting salt hay.

A Long History of Impacts

Salt marshes have always been improved and then harvested.  As far back as we can look, indigenous people would improve the marsh with elaborate fish weirs. Like Boston’s Boylston Street Fishwiers that dates back 5,200 years.

The greatest improvers were those that brought the Old World improvement methods with them.  From the moment the colonists set foot in the New World, all the way up until cars replaced horses, farmers all across New England intensively improved and then harvested the salt marsh.  Digging drainage ditches to control the grasses that grew.  Pounding tree-sized stakes into the marsh to dry and store the hay on. Building berms to limit the tide’s ability to flood the marsh.  Then finally, larger berms to block off the tide entirely to grow sweetwater crops.  Then, for all intents and purposes, it just stopped, leaving behind three centuries of scars that had been etched into the landscape. 

But, that’s not the last the marsh has seen of improvements. In an attempt to control the salt marsh mosquito and the devastating arboviruses it can spread, the Works Progress Administration (WPA) maintained and expanded upon many of the agricultural ditching in the late 1930s.  Some of these areas are still maintained today.

Hand in hand with our past, our coastal communities, and of course, the Saltmarsh Sparrow, face a new future, because it is the scars left behind by all these improvements that are now proving to be a considerable hindrance for the salt marshes to adapt to sea level rise.  

Why are Salt Marshes Valuable?

In New England, salt marshes are more than just homes for a small population of handsome sparrows, they are major socioeconomic drivers for the entire local seafood industry.  They are our protection against the storm, absorbing both wave energy on our open shores, and the floodwaters that would pour through our neighborhoods without them.  On the good days, salt marshes filter pollution and pesticides from our nearshore waters while providing a home for local wildlife and the untold recreational opportunities that are intrinsic to a good life.  A timeless remnant that has persisted in a coastal landscape that grew up around it. Salt marshes provide a multitude of ecosystem services simply because they exist.

But at this time, that future is uncertain.  Salt marshes as we know them in New England only exist in a very narrow fringe between Mean Sea Level (MSL) up to the upland edge.  During past periods of fluctuating sea levels, salt marshes migrated horizontally up into the upland as this narrow zone changed position in the landscape.  

In New England, and many other parts of the world, our 21st century shorelines are not willing or able to accommodate the salt marsh as it transitions up into our coastal shores.   Armored shorelines, concrete retaining walls, parking lots, upscale properties and property owners willing to fight tooth and nail will all be trying to hold them back. 

For all practical purposes, in New England and throughout much of the world, if we want to keep our salt marshes, and the seafood industry, storm damage protection, and our quality of life that depends on them into the future, there is no place to go but up.

Are We Going Up?

Salt marsh restoration projects in Southern New Hampshire that date back into the early 1990’s indicate that Smooth Cordgrass, the biggest of the big three salt marsh grasses in our region, does have the ability to grow a peat foundation at many times the rate of sea level rise.  So in theory, Smooth Cordgrass could dominate the marsh platform and grow the surface of the marsh vertically at the same rate as the sea is projected to rise.  However, there are a few obstacles, including the scars left behind by our forefathers, which will need to be addressed to ensure that as our potential future.

In spongy salt marsh soils, as much as 80 percent of the soil volume can be organic matter, comprised of lignin and other plant parts in the process of being decomposed.  The agricultural ditches in the surface of the salt marsh allow oxygen to enter the soil column and accelerate the rate of the decomposition of the organic matter in the soil.  In salt marshes where the agricultural and mosquito control ditching persist, the upper portions of the soil column can actually be decomposing at a faster rate than the plants and sediments can build new soil.  This process is one of many factors that can lead to a lowering of the surface of the salt marsh, known as salt marsh subsidence.