25 November, 2015

Controlling Phragmites with Salinity

*This research was recently published in the journal Wetland Science and Practice. The full article is available here: PhragmitesGreenhouseWSP
Among invasive, non-native wetland plants in North America, Common reed (Phragmites australis); commonly just called Phragmites is king; forming dense monocultures and crowding out native plants. A variety of this species is native to North America, but the non-native variety has been invading and choking out native vegetation in wetlands all across the country. Nantucket is no exception with large stands of Phragmites seen at Hummock Pond, Long Pond, the Creeks and various smaller wetlands around the island.
Medouie Creek, dominated by the non-native grass Phragmites australis
Medouie Creek, dominated by the non-native grass Phragmites australis
Once Phragmites becomes established, it can be very difficult to eradicate, particularly without more impacts to the wetland. Direct, judicious application of herbicide to cut stems can be effective and reduces the amount of herbicide used and minimizes impacts to other native plants but it is also very time and labor intensive. Plants can be dug up and removed although this causes severe destruction of the wetland soil. Phragmites is typically a freshwater plant and some studies and projects have shown a dramatic impact just by applying salt water to the plants. Phragmites can be very variable in its response to increased salinity with some plants seeming to survive ate moderate salinity levels and some dying back immediately upon exposure.
In 2008, NCF initiated a large-scale salt marsh restoration project at our Medouie Creek property  with the goal to reestablish salt marsh hydrology to a wetland that had been historically diked by a road (Figure 1). Previous blog posts have talked about what this restoration looked like and it's impacts on native species, including the spotted turtle. One key driver in planning this restoration project was to reduce a large population of Phragmites (~ 3.9 acres) that had invaded the diked, freshwater dominated area of the marsh (Figure 1).
Medouie Overview 2014
Figure 1: Aerial photo overview of the Medouie Creek restoration project showing the location of the Phragmites population before restoration and six years post restoration.
Restoring salt water to Medouie increased salinity in the soil and dramatically decreased the density and health of the Phragmites population over the past seven years. Even though the Phragmites has been diminished, it still covers a large area at Medouie (~2.9 acres) so we decided to conduct an experiment to determine at what level of salinity Phragmites stems specifically growing at Medouie are most impacted. Understanding the response of these local Phragmites plants to different salinity levels in a controlled environment provides us with better understanding of target salinity levels that need to be achieved at Medouie Creek to effectively control and/or drastically impact Phragmites.
Phragmites plants from Medouie were grown in pots at the NCF greenhouse and exposed to one of five different salinity levels (0, 10, 20, 30, or 40 ppt salinity - ocean water is typically between 30-32 ppt). The treatments were continued for two growing season and NCF staff monitored plant height, stem diameter, leaf number and leaf health over that time.
Phragmites at Greenhouse
Phragmites stems at the NCF greenhouse after 2 years of salinity treatments. Differences in height and flowering between the salt treatments are visually dramatic
Increased levels of salinity dramatically impacted both the size and health of Phragmites stems with a significant reduction in stem height and leaf number, particularly at salinity levels of 30 ppt and higher. The impacts of high levels of salinity were even more dramatic the second year of growth indicating that salinity effects on Phragmites growth are cumulative over time. Plants exposed to water with a salinity of 30 ppt or higher were much shorter and less robust than the other plants as can be very obviously seen in the above photo.
In the field, at Medouie Creek, salinity levels have been observed between 15-32 ppt (compared to 0-5 ppt before restoration); comparable to the experimental salinity levels that we saw negatively impacting the Phragmites. Currently these salinity levels are variable across the marsh and not consistent. Seven  years after opening a culvert under the dike road to increase salt water flow, the observed salinity levels are likely at their maximum and the chance of decreasing the Phragmites population even more is slim. Without additional dramatic increases in soil salinity, further impacts to the current Phragmites population are unlikely.
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Photo taken in Medouie Creek among the Phragmites stems before restoration took place.
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Photo taken from the exact same spot in Medouie in 2013, five years after restoration. The height and density of the Phragmites stems is dramatic but there is still more work needed to control this invasive.
Salinity  alone is not likely to be an effective control strategy unless the entire Phragmites population can be consistently exposed to adequate, increased salinity levels. At sites like Medouie Creek where the Phragmites population extends across a natural gradient of soil salinity levels, there will likely always remain a portion of the marsh favorable to Phragmites. Therefore, further management at Medouie Creek to control the Phragmites population could include opening up additional tidal access creeks to increase salinity throughout the marsh as well as targeted herbicide treatments to decrease and eliminate Phragmites located at sites exposed to lower, more tolerable salinity levels.
The Nantucket Conservation Foundation is a private, non-profit land trust that depends on contributions from our members to support our science projects, conservation property acquisitions, and land management efforts. If you are not already a member, please join us! www.nantucketconservation.org
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Restoring Illegally Created Trails on Foundation Properties

Working for the Nantucket Conservation Foundation's Science and Stewardship Department, we spend a large portion of our time maintaining and restoring Foundation properties as favorable habitats for rare plants and animals through prescribed fire, sheep grazing and mowing to name a few techniques. Nantucket is home to very unique sandplain grassland habitats and supports the highest percentage of rare species in Massachusetts.
Northern Blazing Star (Liatris novae-angliae, Asteraceae) one of the rare plants seen at Tupancy Links
Northern Blazing Star (Liatris novae-angliae, Asteraceae) one of the rare plants seen at Tupancy Links
A great benefit of Foundation property is that, even though all of our properties are privately owned, we are able to make them available for public use in ways that are in harmony with our mission to protect and restore the unique habitats and plants and animals on this island. Nantucketers have a strong appreciation and respect for the natural beauty that makes Nantucket so special.
Open sandplain grasslands at Tupancy Links
Open sandplain grasslands at Tupancy Links
Occasionally and unfortunately though, we have to care for neglect on our properties caused by visitors.  Usually this is on a small scale: removing trash and landscaping waste piles from the Head of the Plains or cleaning up pallet piles from the Middle Moors before they can be used for bonfires.
And occasionally we find very blatant misuse of NCF properties that requires very time intensive work to restore.
This summer, in early July, a new trail appeared overnight at our Tupancy Links property in an area that never before had a trail.  The new trail was a very consistent width of dead plants (apparently killed overnight) indicating that someone likely illegally used herbicide to create this path.  This new trail, approximately 1/2 a mile long!, was in a previously and very purposefully undisturbed area of the property and, unfortunately, the time intensive restoration of this site is now up to NCF staff.
Danielle raking up illegally herbicided, dead plants before reseeding at Tupancy - the illegally created trail is visible stretching behind Danielle in the distance.  This is only a small portion of the disturbance.
Danielle raking up illegally herbicided, dead plants before reseeding at Tupancy - the illegally created trail is visible stretching behind Danielle in the distance.  This is only a small portion of the disturbance.
Why do we care? Tupancy is already very heavily used by dog walkers and the public, what does one more trail hurt?
There are a few major reasons, the first being that this is private property and alterations, particularly using herbicide, is illegal. Unregulated herbicide use can be harmful, not only to native species like the Northern Harrier but also particularly in areas where dogs and children have open access. The second is that, our Foundation staff puts a lot of careful work into deciding how our properties can best be used so that the public can enjoy them while also protecting natural habitats and plants and animals that we are responsible for. Tupancy is very intensively used in some places so we have purposely not put trails in other areas to avoid disturbing rare plants and maintain areas of continuous open space. Imagine what this island would look like if everyone decided to create trails wherever they wished. NCF staff puts a lot of time into carefully considering the location of trails and property access and blatant disregard for our hard work is pretty upsetting!
Kelly and Danielle fencing a newly restored and seeded trail at Tupancy to keep foot traffic off of it.
Kelly and Danielle fencing a newly restored and seeded trail at Tupancy to keep foot traffic off of it.
How will we restore this impacted area?  Kelly, Danielle, Karen and Jen (Science and Stewardship Staff) spent time this fall collecting seeds from the native grass, little bluestem (Schizachyrium scoparium). We then raked up all of the dead plant material in a section of the new trail, disturbed the soil a little bit to promote germination and laid down a thick cover of little bluestem seeds. We fenced off the areas we seeded to prevent anyone from walking on this area while the seed germinates. Little bluestem grass establishes and grows quickly when planted in either the fall or spring.  We also fenced off an area of the herbicided trail and did not seed it which will allow us to see what might happen to this trail on its own without seeding.  Because herbicide was used so extensively here, we are not sure if native plants will be able to easily re-establish.
Reseeded area, fenced for the winter. We will monitor grass growth next year and hope this trail is able to re-establish.
Reseeded area, fenced for the winter. We will monitor grass growth next year and hope this trail is able to re-establish.
We will keep monitoring this trail and working on more restoration and seeding in the spring.  The size of this disturbance means it might take us quite a while to successfully restore this site.
NCF has been able to protect and maintain large areas of Nantucket but we can't be everywhere at once, so we need your help! Please, if you see activities on any of our properties that seem unusual or not in keeping with our mission to protect Nantucket's natural spaces, contact the Foundation office (508) 228-2884!!
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The Nantucket Conservation Foundation is a private, non-profit land trust that depends on contributions from our members to support our science projects, conservation property acquisitions, and land management efforts. If you are not already a member, please join us! www.nantucketconservation.org
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Carnivorous, Insect Eating Plants - Right here on Nantucket

Plants are remarkable at adapting to their environments and finding a way to survive in a seemingly impossible place.  Carnivory in plants, the ability to consume insects and other organisms for necessary nutrients is one of those incredible adaptation.  Carnivorous plants can seem exotic but you might be surprised to find we have some of these plants right here on Nantucket.
Carnivorous plants are one of the more unique adaptations seen in the plant kingdom. These plants are typically found living in places where, for a variety of reasons, they have a hard time getting the nutrients they need for healthy growth - which is a ready supply of nitrogen and phosphorus.
There are a variety of nutrient-poor kinds of habitats and here on Nantucket, we find carnivorous plants living in some of our more isolated wetlands.  These wetlands are called bog or poor fen wetlands and are characterized by their hydrology, where their water comes from, which in turn controls which nutrients are present and available for plants. Bog  wetlands typically only get their water from precipitation with very rarely any groundwater. This is important because groundwater will often contain nutrients it has picked up by moving through soil but precipitation typically has very little nutrients in it, the water is mostly sterile. Additionally, the soil in bog wetlands is actually purely organic and made up of a moss called Sphagnum in various stages of decomposition.  This decaying Sphagnum moss creates soil called peat and it doesn't have nutrients that are available to other plants.
Cross section of a raised bog, like Donut Bog. Precipitation comes into the wetland and a clay layer at the bottom of the kettle hole holds in the water and prevents groundwater from entering.
Cross section of a raised bog, like Donut Bog. Precipitation comes into the wetland and a clay layer at the bottom of the kettle hole holds in the water and prevents groundwater from entering, reducing nutrients and creating the perfect environment for carnivorous plants.
This means that plants growing in bog wetlands need to be adapted to lower amounts of nutrients.  We actually have quite a few of these wetlands hidden around the island, remnants of the glaciers that once moved over Nantucket.  The most well known and easy to find bog on Nantucket is Donut Pond in the Middle Moors.  It's easy to find but not easy to access though as it is surrounded by a deep moat of water.  In the center of the Pond, a bog wetland thrives!
So what is our cast of carnivorous plants on Nantucket?  The largest and showiest is the Northern Purple Pitcher Plant (Sarracenia purpurea).
One large Northern Purple Pitcher Plant
One large Northern Purple Pitcher Plant made up of many leaves shaped as pitchers.
The leaves of the pitcher plant are modified so they formed closed pitchers.  Each pitcher has a lid with a nice smooth surface, containing nectary glands which attract insects to the plant.  When insects stop to taste the nectar treat, they slip and tumble down into the pitcher.  The inside of the pitcher is covered with small downward pointing hairs so insects are unable to easily crawl back out and instead they slip down to the bottom of the pitcher which is filled with water and a whole suite of microorganisms whose job is to breakdown and digest the insect meal.  Once the insects are digested, nitrogen and phosphorus can be absorbed right into the pitcher wall and used by the plant.
Individual pitcher leaf
Individual pitcher leaf with an ant periously close to become lunch. The pitcher is rooted right into the Sphagnum moss.
The pitcher plant is long lived, usually up to 25-30 years and each year they produce 2-3 pitchers over the course of the growing season. Once a single pitcher has had 4-5 meals, it doesn't work as efficiently and the plant produces more.  Interestingly, the plant still needs to photosynthesize to produce energy for plant growth and will adapt it's leaves depending on nutrient and sun availability.  When pitcher plants are shaded out - they grow smaller pitchers with larger pure green leaf area to capture more sun rays.  When the plant is out in the open, the pitchers get larger and redder to maximize insect capture.  This is one of the more fascinating and widespread pitcher plants, growing from northern Canada all the way down to the Gulf Coast.
The lovely pitcher plant flower. Each plant produce 1-2 flowers each growing season and they are pollinated by common bees.
The lovely pitcher plant flower. Each plant produce 1-2 flowers each growing season and they are pollinated by common bees.
The second most common carnivorous plant on Nantucket is the sundews (Drosera ssp) and we have a few different species here.  These diminutive plants grow next to and around the pitcher plants but they can often be much harder to find.
The linear leaved sundew with long, skinny nectar gland covered leaves.
The linear leaved sundew with long, skinny nectar gland covered leaves.
The spatulate sundew leaf covered in sparkling and sticky nectar glands
The spatulate sundew leaf covered in sparkling and sticky nectar glands
Sundews produce carnivorous leaves covered in tasty smelling, but very sticky nectar glands.  When an insect, such as an ant, wanders across these leaves they get instantly stuck.  The leaf is then triggered to roll up around the insect and the plant begins secreting digestive enzymes.  Like with the pitcher plant, nutrients from the digested insects get absorbed right through the leaf and are used to help plant growth.  The sundew produces lovely delicate little flowers, often white or pink during the spring, making these small plants a little easier to find.
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The final carnivorous plant we find here on Nantucket is the bladderwort (Utricularia ssp.) and this is the most difficult to find and unique carnivorous plant we have.  Bladderwort plants are impossible to find unless they are flowering which usually happens for just a few weeks in the spring.  Bladderworts send up short delicate stalks with a few small yellow flowers and this is the only aboveground structure the plant has, most of this plant is living entirely below the soil surface.
A single stalk with a few delicate flowers is the only visible part of the bladderwort plant.
A single stalk with a few delicate flowers is the only visible part of the bladderwort plant.
The carnivorous parts of the bladderwort are located entirely belowground and consist of small (~0.5-1cm) sized bladders located all along the plant roots.
bladderwort-or-utricularia
These little bladders have a small valve opening covered in sensitive hairs.  When microorganisms swim too close to the hairs, the value opens and sucks in the microorganism.  Once it's trapped inside the bladder begins digestion allowing nutrients to get absorbed into the plant.
Check out this amazing and informative YouTube video showing these microscopic bladders in action.
The plant world is filled with all kinds of marvelous adaptations to stressful living conditions. What is your favorite plant adaptation?

For more information on the Nantucket Conservation Foundation and our projects, please visit our website.

Horseshoe Crabs on Nantucket - Ancient and Fascinating

Spring on Nantucket means the arrival of peepers, daffodils blooming and American oystercatchers on the beach.  It also means the arrival of one of our more interesting marine species - the horseshoe crab, which begins showing up on protected and sheltered beaches to mate and spawn in May and June.
Mating Horseshoe Crab pair at Warren's Landing
Mating Horseshoe Crab pair at Warren's Landing
These prehistoric looking animals aren't actually crabs - they are most closely related to trilobites which were around 400 million years ago.  Fossil records show that the horseshoe crabs we see on our beaches today do not look very different from the horseshoe crabs that swam around when dinosaurs walked the earth!
These unique and fascinating creatures may be in trouble - anecdotally, populations are much lower than they were 30 years although it's only recently that serious efforts have been made to document how large horseshoe crab populations actually are.  People that grew up on Nantucket can remember a time when the beaches were covered with horseshoe crabs in the spring! Horseshoe crabs are in high demand as bait for conch and eel fisheries and for use in the medical industry.  Some states currently have a moratorium on horseshoe crab harvesting but the populations may still be in trouble. Check this great website for more information on threats to horseshoe crab populations.
So, to try and get a handle on horseshoe crab populations on Nantucket, in 2009, a group of island researchers from the Nantucket Conservation FoundationMaria Mitchell Association and the UMASS Boston Nantucket Field Station began monitoring horseshoe crabs.  The monitoring work we do now will help establish a baseline of information so in the future we can see if populations are dramatically increasing of decreasing.  In May and June we start visiting beaches on and around the days of the full and new moons at high tide and count the numbers of horseshoe crabs we see near the shore.
NCF Board Member Nathan Allan helping survey horseshoe crabs
NCF Trustee Nathan Allen helping survey horseshoe crabs
We use PVC poles strung with rope to help us define a survey area and count all males, females, and mating pairs within the area.  Because of the timing of high tides, we are sometimes out surveying beaches in the middle of the night - if you see flashlights out on the beach at Warren's Landing at 2 am over the next two months - it's most likely us searching for crabs! Luckily we aren't alone in these late night endeavors - this effort is being performed all along the East Coast by various conservation, university and government groups.
Male and female horseshoe crabs are fairly easy to distinguish.  Females tend to be quite a bit larger than males, going through 2-3 more molting cycles before reaching maturity.  Additionally, the front set of walking claws on male horseshoe crabs are modified into pinchers that look a lot like boxing gloves which allow the males to hold on to the back of the female crabs shell during mating.
NCF Trustee Dale Hamilton and wife..... determine the sex of a horseshoe crab.
NCF Trustee Dale Hamilton and his wife Susan determine the sex of the horseshoe crab.

We monitor horseshoe crab populations in May and June at high tides around the new and full moon due to the unique reproductive biology of these animals. Horseshoe crabs become mature adults in deep ocean waters with males reaching sexual maturity around 9 years old and females around 11 years old. Once mating season starts, typically in May and June, the horseshoe crabs move to shallow areas, particularly around sandy protected beaches near intertidal sand flats.  Mating takes place in shallow water where many males seek out and court a few females.  Females spawn and lay eggs in nests in the sand from the low water up to the spring high-tide and each nest can contain up to 4,000 eggs which each female producing ~80,000 eggs in one season!  The highest amount of spawning occurs with the evening high tides during the full and new moon cycles - this is when we target our beach surveys to help document the largest amount of crabs on the beach.
Horseshoe crab underside - it's a male!
Horseshoe crab underside - it's a male!
In addition to counting the number of crabs - male and female that we encounter, we are also tagging each crab with an individual tag to help us identify them.  White circular tags are placed on the back of the crab's main shell and each tag has an individual identification number.  This can help us figure out how crabs move around the island.  Most of our crabs are being tagged in Madaket Harbor and we tend to see them there again but a few of those crabs have made their way into Nantucket Harbor as well.  Now this is something you can help us out with!  When you see a crab - alive or dead, with a tag on it - write down the tag number and remember where you found it.  Reporting tag numbers is very very easy - just visit this website and fill out the online form - you will get information back on where the crab was tagged!
Keep you eye out for these white tags on horseshoe crabs around Nantucket
Keep you eye out for these white tags on horseshoe crabs around Nantucket

New England Plant Conservation Program - Surveying Rare Plants

Last week, Jen Karberg (NCF's Research Supervisor) attended the annual New England Plant Conservation Program (NEPCoP) MA Task Force Meeting to discuss rare plants and the state of rare plant populations and management in Massachusetts. NEPCoP is a collection of professional botanists, conservation organizations, universities and state agencies organized in order to document New England's rare plants and assist in managing and maintaining populations of rare and endangered plants.  In 1996 NEPCoP published the first Flora Conservanda - a list of the plants of conservation concern (rare, threatened and endangered) in each of the New England States.  NEPCoP recently released an updated version of that list for 2012.
Each state in New England has an organized NEPCoP Task Force to managing the monitoring of rare plants across the state.  The Task Force for Massachusetts meets annually in January to discuss review rare plant surveys from the previous year and plan rare plant surveys and management actions like seed collection for the coming field season.  The meeting also gives us a chance to touch base on botanical news in New England!
One of the most exciting projects we talked about this year was the GoBotany website - if you haven't see this website yet, please check it out!  GoBotany is a fantastic tool developed by the New England Wildflower Society to make plant identification accessible to everyone.  The website is complete with wonderful photographs and very clear illustrations as well as detailed plant characteristics to help everyone from the very beginner to the experienced botanist.  If you are new to learning plants - visit the website's Simple Key: a very user-friendly guide to 1,200 of the most common plants in New England.  For all of you Botany-nerds out there: very soon, GoBotany will be unveiling the Complete Dichotomous Key to ALL of the plants in New England (over 3500 plants).  This detailed key will allow you to interactively key out plants anywhere you are as long as you have access to the internet!  Also - if you want a list of which plants you can find in your particular county, check out the Vascular Flora of Massachusetts Checklist complied by the Massachusetts Natural Heritage Department
The GoBotany Complete Dichotomous Key to all New England plants is based on the new book released last spring:
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Flora Novae Angliae - the new definitive plant ID book for New England written by Arthur Haines; research botanist for the New England Wildflower Society and and instructor with the Delta Institute of Natural History.   This new flora of New England would be a great addition to any botanist's library!
Does all of this plant talk make you want to run out and start searching for new and rare plants?  Consider becoming a Plant Conservation Volunteer for the New England Wildflower Society! We are always looking to energetic and dedicated people to assist in the work of locating and surveying rare plant populations.
Slender Marsh Pink - Sabatia campanulata 01
Slender rose-gentian
Follow the links below to learn about some of the rare plants that NCF staff will be searching for on our properties this coming field season.
Remember, if you happen to be out walking the properties and see one of these plants please contact Jen and we can add the information to our inventory!

Thinking about Deer Browse because it's Hunting Season

There are a few local legends about how deer first came to live on Nantucket that range from deer swimming from the Cape (16 miles at the shortest point) to deer being purposefully brought to the island in the 1920s for hunting.  Looking at archaeological evidence, deer have likely been present since Nantucket became an island but over hunting drastically decreased populations until deer were re-introduced for hunting purposes. However they officially got to our little island, deer are definitely here to stay.
The Massachusetts Division of Fisheries and Wildlife estimates 45-55 deer per square mile on Nantucket – no matter how you slice it, that’s a lot of deer in one place.  Increasing deer populations are having negative impacts on native plant communities across New England and the Midwest states.  Impacts range from decreasing native and rare plants to increasing populations of invasive plants.  Scientists typically study the impacts of deer by constructing deer exclosures – tall fences designed to keep deer out of an area.  While those exclosures are in place, typically for 5-10 years, researchers monitor plant populations inside and outside of the fence.  We can see if some plants grow inside the exclosure but not outside of it where deer browsing pressure is high – we can also see if plant density is higher inside the fence.
On Nantucket, we have been observing high deer densities and hence, high deer pressures for a long time now – long enough that we don’t have a good idea of what many plant communities on island would look like without deer grazing. Some of the unique habitats that we study on Nantucket, the sandplain grasslands and coastal heathlands tend to be disturbance driven – they thrive when disturbance is present, prescribed fire, grazing, etc.  We started to wonder what/if any effect deer browsing might be having on these unique communities so we decided to set up a deer browse experiment.
In 2011, the NCF maintenance staff constructed a 50x50ft fence, tall enough to keep deer out.  If you hike at our Sanford Farm property, you can’t miss this large fence – located on the shorter hiking loop from the parking lot.  For the next 5 years (at least) we will be monitoring vegetation plots both inside and outside of this fence to see what happens to the plant communities when deer can no longer browse them.
Sanford Farm is a perfect place to study the effects of deer browsing – as anyone who walks this area can tell you, there are a lot of deer and a lot of deer sign (deer trails, scat,etc.).  Additionally, this area has a high abundance of several rare plants species palatable to deer – sandplain blue-eyed grass, bushy rockrose, New England blazing star).    Hopefully this study will help us understand how deer are influencing this unique landscape.
On a side note: As the shotgun hunting season starts on Nantucket this week, please be aware of the Foundation's hunting regulations and restrictions.

Salt Marsh Construction at Medouie Creek

The Medouie Creek Wetland is a large wetland along the north side of Polpis Harbor on Nantucket Island.  This wetland was historically one large salt water marsh, directly connected to the harbor, getting daily tides washing over it.  Sometime in the 1930s, a dike was created to build a road, allowing people access to the harbor - you can see the Eastern Dike Road in the GIS map below.
medouie-site-overview1
This dike road completely cut off the flow of salt water into the back part of the marsh, and over time it converted to a freshwater marsh with plants and wildlife associated with freshwater wetlands.
A couple things came together all at once to prompt NCF to consider trying to restore this wetland to a salt marsh.
The first was a large population of Phragmites australis (the common reed) that was continuing to expand in the freshwater marsh (see the area in yellow on the above GIS map).  Now if you haven't heard of Phragmites yet - I'll tell you its a very aggressive invasive wetland plant and some studies have shown that it doesn't do well in salt water.  Instead of spending a lot of time and lots of herbicide trying to get rid of the Phragmites by spraying it - we thought it might be smart to restore the salt marsh and  hopefully decrease the Phragmites by increasing salinity.
The second reason we started this restoration was purely to try and restore an important historic salt marsh back to its original function with all of the vital ecological benefits of a salt marsh. The Massachusetts Office of Coastal Zone Management Wetlands Restoration Program (MWRP) designated Medouie Creek as a high priority wetland restoration site increasing our desire to try and restore this important wetland.
Our restoration plan was actually fairly simple - we just set out to alter/restore tidal hydrology and let the vegetation and soils take care of themselves.  Our actual construction method had three components:
1) Install a culvert under the current dike road
culvertThis culvert first allowed all of the freshwater that was impounded in the previous freshwater marsh to drain out and then it also allowed daily tides to push salt water into the previously restricted marsh.
To facilitate saltwater moving back into the wetland...
2) We dredge out an existing tidal creek and an old ditch in the restricted marsh to connect to the newly installed culvert.
ditchSalt water can flow through this ditch into the back part of the marsh and move laterally out of the ditch into the rest of the marsh, bringing salt water to, hopefully, a large part of the marsh.
3) The last thing we did was lower the grade of the dike road to allow water of extreme high tide events to sheet flow over the road, further pushing salt water into the marsh.
grade
All of this construction work took place in December of 2008 and the restoration has progressed rapidly since then, aided by some extreme high tide/storm events!