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The Sound School Inter-District Marine Education Program Newsletter – IMEP #18, Part I
Habitat Information for Fishers and Fishery Area Managers
Understanding Science Through History

Phragmites Invades Coastal Habitats 1940s
Can We Reverse Phragmites Habitats
While Creating Blue Crab Reproductive Capacity?
November 1, 2013 – A Research ISSP/Capstone Research Question
Submitted to the Habitat Restoration Working Group
October 30, 20131

[This proposal to cease chemical control and instead investigate removal and habitat substitution of Phragmites growths does not reflect the EPA/DEEP habitat restoration work group view nor has consensus been reached upon discontinuing estuarine herbicide treatments. It is the viewpoint of Tim Visel HWG Committee Member]

EPA DEEP Long Island Sound Study Habitat Committee
Tim Visel, The Sound School
Habitat Working Group Committee Member

Foreword

The introduction of Phragmites (non native species) into New England can be traced to the 1930s. The most recent introduction occurred over a two decade period now associated with the massive Connecticut turnpike post war construction project. It was perhaps planted with other grasses in the 1940s and 1950s as in other states (New Jersey – Michigan) along steep road and rail crossing to do what it does best, bind and hold loose terrestrial soil. Other possible vectors include planting for mosquito control or to enhance duck hunting. Coastal erosion control applications include upland dredge spoil stabilization. When I was investigating this Phragmites invasion decades ago I was following up on reports that it was perhaps related to soil erosion control and some of the first Soil Erosion Service (SES) practices. In 1985; the Connecticut Department of Transportation admitted it had used it along with many other grasses during Interstate Route 95 construction (phone call conversation) but then later denied using any soil erosion practices. When requesting additional CT DOT written information, I was informed that all those records had been long thrown away, so we may never know the direct seed source or what amounts were used.

From oral accounts in central coastal areas Branford area for example, (see part II) the plant made its presence known soon after Route 95 construction. The presence of these growths near or adjacent to grades/slopes decade latter raises many questions as to the source of previous seed stock. Traveling today along sections of Route 95 and Route 91 you can still see isolated stands of Phragmites decades later usually by causeways. Most often these surviving stands are in or near steep grades, areas subject to soil movement during road construction.

This strain of Phragmites inhabit mostly coastal marshes I believe to be that of Chinese origin imported into the US during a period of great species exploration. At first, “foreign” plants were “introduced” into the US for food or commercial value including ornamental uses. Later certain plant species were evaluated as part of low moisture or “dry farming” attributes after a mini dust bowl hit Midwestern farmers 1883-1889. A 1914 issue of the Farmer’s Cyclopedia- abstracts from USDA Publications and Work of Regional Experiment Stations (1912) [Farmers Cyclopedia – Volume VIII Farming Methods, soils fertilizers irrigation, rotation. Garden City, New York Doubleday, Page and Company 1914.]has on page 239 a section on Dry farming and mentions the use of non native plants suitable for dry farming techniques in low soil moisture conditions.

The grain sorghums, including milos, durra, kaffir or kaoliang, or milo maize, and are of recent introduction and have become important only within the last twenty years” and when these crops were first introduced, they were tried in various part of the US.

By 1918 (USDA 1918 Yearbook of Agriculture) examples of some field trials of non-native plants already had unintended results. One article on page 88 (1918) was titled, “Bluffs on which barberries have escaped and been running wild,” gives an impression that all had not gone well. Other grasses under review included reed canary grass, Bermuda (or Devils) grass, Johnson grass and others for special conditions. The 1948 USDA yearbook of Agriculture was devoted to grasses and mentions Sudan grass was suited for “dry conditions” and lovegrass was a “cover to be used on eroding sites.”

The association of Route 95 and non-native Phragmites does support the concept of organized planting especially on steep grades by bridges. This is supported by the rapid spread along coastal areas. In 1932, Setoria faberi Chinese foxtail or giant bristle grass was first detected in millet seed from China. By 1947 it had spread from New York to North Carolina and from Missouri to Nebraska. Millet seed from China was contaminated with other seeds (USDA Yearbook of Agriculture 1948) Route 95 was completed in 1964 and Phragmites noticed on Barn Island after duck hunting improvements were completed (in the 1940s). The first mention of Phragmites growths in Connecticut are often connected to both mosquito control and tidal restrictions (Hill and Shearin 1970). The Soil Erosion Service (later to become part of the Soil Conservation Service) had various experimental plant trials under review for cover planting, both short term and long term. For open earth areas fast growth, soil holding ability and density would all be positive factors for the prevention of soil movement making Phragmites a good choice to hold quickly disturbed soils. In fact the name Phragmites itself describes some of its abilities, it is a derivative of the Greek work “phrag” or fence. But what made it a soil conservation friend would turn to a foe along the coast as its primary vector was now water, as it was an aquatic plant. The climate in New England turned warmer (1972) as the NAO turned positive – warmer winters is now suspected in increasing the viability of seed and supported its rapid spread into coastal salt marshes.

According to the National Science Academy (1976) aquatic weeds are among the most pernicious weeds on earth and never should be introduced to non native areas. By 1976 that warning was about three decades too late for Connecticut. The introduction to the United States is now suspected to be a century ago around the time of Chinese plant trials. 2 [By 1908 non native Chinese plants were first brought to the USDA Washington greenhouse complex and seed stock purified and evaluated before being sent to regional experiment stations for field trials – testing. Phragmites is thought now to exhibit soil holding characteristics deemed useful in the 1930s, and was utilized as a soil erosion control plant cover after this time.]

Introduction

Phragmites (plant species) has many other uses besides erosion control - mulch and nitrogen uptake for instance and out west it is even used to dewater sewage sludge. Phragmites has been used worldwide for many other uses, including bedding, paper, housing (thatch roofs and side walls) animal feed and fuel. Phragmites has been attributed to the first chipboard (now termed orientated strand) panels as a plywood building material substitute. The tough fiber has longed been utilized as a primary source building material in Asia and eastern Europe. In the 1950s and 1960s as timber became source in eastern Europe Phragmites became a key (with chemical applications) ingredient for building materials – and perhaps the first compressed fiberboard sound proofing material. Ceiling tiles have many of these construction characteristics today.3 [Making Aquatic Weeds Useful National Academy of Sciences, Washington DC 1976, page 98. NAS-NRC Commission – Board on Science and Technology for International Development (BOSTID]

Phragmites is an aggressive successional plant times capable of creating and maintaining habitats that can for long periods especially in terms of warmth, and in high organic matter deposition rates, dominate all other previous habitat types. It has shown to accumulate organic matter and by doing so raise marsh elevations (similar to shoal building capacity of eelgrass Zostera marina) at least that of sea level rise. In areas of high organic loading (terrestrial leaves being a large component) Phragmites has shown its ability to trap leaves, dead stems, grasses, etc to form a fresh water sponge habitat over higher salinity salt water marshes habitat below. It forms a monoculture that is so dense it does have the ability to suspend traditional habitat succession. It resists all types of traditional control methods (isolation – cutting, mowing, burning and chemical treatments). In fact burning and cutting seems only to stimulate denser root systems later post treatment. Chemical treatments have raised concerns about the chelating (binding) of heavy metals in acidic peat below marsh surfaces.

One of the ways it has been held in check is by salinity. Perimeter trenches in salt marshes can stop spreading Phragmites roots when a high salinity “barrier moat” is usually beyond the 20 inch runner root depths and the direct applications of rock salt over two years is also highly effective (T. Visel, personal observation, Madison, East Lyme). Although chemical treatment (herbicide) has been moderately effective it is not a long term solution in many areas that have restricted or cut off tidal exchange. That is where Phragmites it seems has created its densest monocultures and greatest fire hazards. Although it is useful habitat for some bird species and small mammals that occurs mostly in the transition zones – the edges. It has over time collected enough organic matter to transform salt marsh habitats into freshwater ones (by vegetation type). Restoring tidal flow will increase salinities and slow its spread but only in areas of low organic deposition as it enjoys habitat wise that high organic debris and transition elevation areas adjacent to land. That is why it is often forms a ring salt marsh habitat type that collects terrestrial leaves and tends to “move” out from this area “invading” even the most saline Spartina marshes. It has negatively impacted estuarine fish habitats by filling them with organic matter.

Salt marshes that have been cut off from energy, i.e. no longer is flushed regularly of terrestrial organic matter or those with tidal restrictions with reduced salinity profiles report the most habitat change. They frequently contain the densest stands of Phragmites. Lowering water tables (tidal influenced) only seems to increase its coverage while holding saline waters longer (pounding) appears to arrest or even reverse coverage. The impact of removing all Phragmites peat and dredging it into a full tidal area if deep enough would end the monoculture but create sub tidal “new” habitats. (Many western US control methods mention cutting 4 to 8 inches below grade). These new habitats may act as salt ponds or dredged tidal basins that retain 30% or more of high tide volumes (they don’t dry out). In creating these new salt ponds we may increase habitat types between open shores and fresh water drainages. It is these near shore sub tidal habitats that contain nursery functions critical to many recreational and commercial fin and shellfish species.

Why Salt Ponds?

One of the habitat conditions reported by blue crabbers since 2007 has been the first catches of adult crabs often occur in lower rivers that have been dredged. Dredged basins are now thought to provide a key overwintering habitat similar to salt ponds. The second observation has been the density of star crabs, those post Megalops crabs first noticeable in seine nets especially in the Fairfield area from 2007 to 2011 are in salt ponds with long tidal retention times. Perry Mill Pond, Fairfield has been thought to contain the highest density of post Megalops blue crab stages ever seen in Connecticut.

In 2010 during a July Habitat Restoration meeting I mentioned the possibility of creating additional blue crab habitat by dredging out dense stands of Phragmites and cleaning some existing dredge cuts adjacent to coastal Route one. This was an attempt to create new habitats for crabs and increase access for blue crabbers. This proposal was pre Irene and Sandy so later the concept of increasing flood water hydraulic capacity – these new “salt ponds” could act to reduce hydraulic stress on headlands by providing “safety values” to absorb tidal surges in times of coastal storms came later. This concept did not reach a consensus at this meeting (July 2010) for discussion before the Long Island Sound Habitat Restoration Committee.

Environmental History

Connecticut has lost many of its salt ponds a century ago when poorly flushed coves (many also with manmade tidal restrictions) were identified as mosquito breeding areas that facilitated malaria outbreaks (1890 to 1915). Under health department orders (both state and local) they were frequently filled in including the salt pond to the north and west of The Sound School (see Climate Change and Public Opinion EPA DEEP LISS 2008). That former tidal basin behind a magnificent cut granite breakwater is now two baseball fields today. By 1910 most western Connecticut communities had established local committees to raise money to fill in tidal wetlands (as did New Haven) in an effort to stem the spread of Malaria. A huge debate occurred between those who still salt hayed on the marshes (Milford and to the East) and represented a valuable agricultural product then and those who championed public health – eliminating them altogether (habitat) as a source of Mosquito vectored disease.

A compromise occurred with the concept of ditching marshes – draining and lowering marsh water tables in an effort to reduce mosquito breeding habitat yet allowing the marsh to remain intact and in theory produce salt hay. This compromise was introduced and exercised by the New Haven Agricultural Experiment Station for many decades. It should be noted that on some Cape Cod marshes that salt haying is still practiced today and observers have noticed a strengthened Spartina meadow which has resisted intrusion by Phragmites. It is thought that the removal of thatch has prevented the buildup of partially reduced organic matter, or “sponge” that is so frequently found over previous salt marsh services (personal observations). Phragmites cannot withstand prolonged heavy grazing (Duke 1983) and constant mowing (and thatch removal) may reduce populations long enough for Spartina patens to return. The constant application of energy does strengthen land monoculture of grasses (mowing) so these marshes with salt hay operations could in fact be beneficial to Spartina meadow monocultures.

It is also recognized that over harvesting of salt hay can lead to the lowering of marsh levels especially in times of high heat. During the last century during an extremely hot period 1880-1920 researchers noticed increased organic respiration of sulfur reducing bacteria and marsh levels declined or in some cases collapsed leaving salt ponds (Nichols 1920). Later the federal program Works Public Administration (WPA) continued ditching programs of marshes under the direction of local or community health departments. Many of these WPA ditches remain noticeable today but the 1980s policies towards cleaning them changed, they filled in often with abundant terrestrial organic matter (leaves) and lost tidal function. Unfortunately the increase of leaves, (a renewed forest canopy) a regional leaf burning ban, warmer temperatures and increased rainfall (positive NAO Pattern) all helped the spread of Phragmites. Absent the deep perimeter ditch common to many salt marshes when regular cleaning stopped they filled in with leaves and Phragmites just “marched” across them. The Fence Creek salt marsh below Route 1 in Madison is a good example of this habitat history. Once the perimeter ditch was allowed to fill in, Phragmites quickly breached this divide and spread out to the creek edge itself. If you look south passing over Route 1 in Madison you can see this Fence Creek transition continuing but looking north the change is almost now complete. Phragmites in time with the accumulation of tree leaves will hold organic matter and bury the original marsh surface in low salinity areas that is its case history of its habitat succession. It also because its lower estuary position has helped blocked the movement of leaves ruining many shallow gradient low energy alewife runs.

Habitat Modification is Often Unsuccessful

Phragmites as determined by the National Academy of Science in 1976 is one of the most persistent aquatic weeds known on earth, it is virtually impossible to eradicate except by digging up its entire root system and increasing salinities. But that is only part of the solution with leaves and organic matter in place and seeds remaining from nearby populations in most coastal water courses (constant supply of viable seed) it is impossible to remove unless the very substrate in which its grows is also removed. This method is not unlike pond and lake associations with chemical treatments or mechanical cutting of aquatic weeds – it may first provide some temporary or limited “relief” but depending upon environmental conditions the problem (weeds) will soon reappear. The solution in this case is to reverse habitat succession completely – by dredging or dam breaches and then removing built up bottom lake or pond compost. Dredging lakes and ponds has “reversed” such habitat succession for centuries.

Removing organic compost from them (lakes and ponds) from this dredging process has restored previous habitat values to sand and gravel glacial deposits in many communities. It is a much longer lasting solution but again the organic matter inputs again over time will eventually fill in the water course. Dredging in the marine environment often has the same result. Dredging in Thames River England for the Port of London for example uncovered various artifacts that provide clues over time the rate of habitat (burial) succession over time.4 [Dredging of Harbors and Rivers – A work of the Descriptive and Technical Reference, Combining Hydrograph Dredging Hydraulics and Seamanship by E. C. Shankland, E.R.S.E. River Superintendent Port of London Glasgow, Brown Son & Ferguson, Limited Nautical Publishers 52 to 58 Darnley Street 1931 – 244 pages]

In this example the Port of London England desired to handle larger ocean vessels and dredged a channel 50 miles long into the Thames River estuary starting this project in 1909 and completed 43 miles by 1931. As dredging proceeded it uncovered artifacts long buried in organic debris including spears and bronze shields discarded by Ancient Britons and Romans dropped it was thought during naval battles in the lower Thames. A bronze statue head of Roman Emperor Hadrian (117-138 AD) tusks and teeth and bones of Woolly Mammoths, ancient wood wrecks of ships and the shells of ancient marine mollusks (Nautilus regalis). The dredging project for the Port of London was completed in 1936-37. The evidence of artifacts details river existence and transit use of the river basin for thousands of years. No doubt over time organic materials washed in and it became the thousands of acres of shallow tidal flats that grew with the discharges from land. What the dredging report printed in 1931 described is no doubt a quick habitat history dating back to much colder times – Woolly Mammoth is a now extinct species attributed to climate change. While certainly not what current scientific studies would expect, the bronze statute head of Hadrian did present a reasonable “age specific marker” that could approximate certain centuries. A similar account is found in New England’s history that describes geologic processes on our coast Harold Casner gives us a view of a turn of the century dredging project in Maine with relic oyster shells. Eventually however, dredged areas naturally tend to “fill in” again over time. Habitat modification often needs periodic energy inputs. This is a long term habitat modification process.

In consideration of geologic time our coast salt marshes here perform many of the same organic matter binding functions over long periods of time. Creeks and inlets within them have enormous habitat value for numerous salt and brackish, fin and shellfish species. The salt marsh itself forms a dense monoculture of Spartina patent out on their surface that has wide extremes in habitat conditions from subzero in the winter to a heat sink in the summer. Only a few plant species can exist in this harsh salt water “rugged” environment, but once Phragmites appears it can transition the marsh by creating a sponge of organic debris from oak and maple leaves that hold less dense fresh water from rainfall over it, as the peat accumulates so does its ability to hold fresh water. Only cutting the peat away or dredging appears to be the only lasting treatments.

In areas of mowing or chemical treatments leaf litter which quickly accumulates and new seeds from other areas drift in and the Phragmites growths reemerge. When the fresh water lens is large enough the transition this organic layer can and does support cedar trees. These are frequently called the lost salt marshes of eastern CT – a series of 31 former salt marsh habitats that were completely cut off from any tidal exchange by railroad beds. Quite simply small tidal areas, not suitable for navigation or local boating interests were just filled in. Areas behind this rail bed quickly became fresh water swamps or bogs. Phragmites appears to be denser on the northern side of most rail and road crossings in eastern Connecticut.

In some brackish environments Phragmites can live in high salinity areas with shortened or tidal restricted flows. It can withstand tidal salinity fluctuations and the burning plant tissue destroying impact of salt. These stands appear to do well even though growing in brackish water due to their tough wood like stems and usually have a brown burned bottom and a very green top. Such stands are clearly visible in the upper reaches of the Menunketesuck River in Westbrook. They are long and tall and have spread far beyond the marsh “bank.” Westbrook marshes have been crossed several times by coastal road and the Amtrak™ rail bed. A 1987 study in the East River between Madison and Guilford detected a noticeable delay in surface salinity between the areas south of the railroad crossing to the same distance above it (Bradford, Burham Connecticut College Report for the Madison Shellfish Commission 1987). A reduced salinity profile and a much longer “tidal time” caused by restrictions has allowed Phragmites to completely dominate the upper reaches of restricted flows in salt marsh meadows.

I think most recent studies of Connecticut’s marine ecology will reference the loss of salt marshes but every channel, creek and yes even those WPA mosquito ditches within them held fish and shellfish larval stages for numerous recreational and commercial fisheries. They are usually “warmer” and hold larval forms for larger times. Tidal areas such as those described above also allow juvenile stages to grow away from larger predator species, in areas of food and they provide what is called “nursery functions” that are critical for many species life cycle habitats. When Connecticut had its last severe mosquito linked disease outbreaks (Malaria) 1898-1918 many valuable creeks inlets, salt ponds were drained or filled in the west and the coastal rail crossings filling in the east. I estimate that Connecticut lost about 30 to 50% of its functioning salt mash acreage and 70% to 80% of its functioning sub tidal habitats within them. In other words we lost a large segment of functioning sub tidal habitats for dozens of estuarine dependent species (See Climate Change and Public Opinion EPA DEEP LISS 2008).With the Phragmites “invasion” sub tidal habitats have seen a new loss of function.

At a 2010 Long Island Sound meeting I proposed substantial changes to habitat mitigation, restoration and creation regulatory policy. They would have introduced the concepts of habitat creation, mitigation and restoration policies and connected them to specific habitat types (sites) and species. That discussion was tabled as it introduced creating habitats that promoted some species over another – habitat trading (mitigation) for instance. In this case Phragmites for sub tidal habitats for fin and shellfish, crustaceans (blue crabs) and wading birds. While I waited for a Bridgeport ferry recently I watched several egrets consume small crabs one at a time for an hour. I couldn’t help but think more species fin and shellfish species would benefit from these new salt ponds but that was termed habitat creation not restoration. In terms of regulatory policy it was only restoration if Phragmites abatement was attempted (no matter how fruitless perhaps long term) with native plant seed sources to recreate the original marsh surface.

A New Approach to This Habitat Invasion

Habitat creation such as artificial reef building for fish (even it seems oil rig bases have some fish habitat value), shell placement for moderately acidic marine soils and the building of sub tidal ”breakwaters” shoreline protection have been controversial. The proposal to exchange Phragmites for salt pond habitat refuge areas will be just as so. The proposal to begin to consider test salt ponds was linked to Blue Crab habitat of refuge – areas in which blue crabs could over winter. The first test sites I suggest could be Phragmites growths.

However, the State of Connecticut has done habitat creation before, willingly or by accident. The Osprey nest platform projects of the past three decades have been very successful – telephone poles with the familiar cross plank platform, sometimes equipped with raccoon tops, metal rings to prevent egg thefts. They (the platforms) in coastal marshes have been one of the greatest habitat creation success stories. The breakwater water programs of the 1890s buried existing habitats with granite boulders creating new (artificial) reefs and bird rests. The reef habitat aspect includes habitats for various fish and shellfish species that alone could fill volumes.

In 2010 the agenda discussion at the Habitat Restoration Meeting was tabled by a hand vote – so controversial then it couldn’t be discussed. We know that Phragmites is a negative habitat type in the coastal zone and replacing it is I feel a topic worthy of discussion. Certainly as much as herbicide control which asks many questions about a long term solution to invasive Phragmites which now has been here a half century.
A Capstone research question may ask, “Are we winning the Phragmites habitat war?”

Tim Visel can be reached at: tim.visel@new-haven.k12.ct.us and he welcomes any comments or reports.

Program reports are available upon request. For more information about New Haven Environmental Monitoring Initiative for IMEP reports, please contact Susan Weber, The Sound School Adult Education and Outreach Program Coordinator, at susan.weber@nhboe.net

For information about The Sound School website, publications, and / or alumni contacts, please contact Taylor Samuels at taylor.samuels@new-haven.k12.ct.us
The Sound School is a Regional High School Agriculture Science and Technology Center enrolling students from 23 participating Connecticut communities.