The Winter Life of the Salt Marsh

*Please note, this blog post was originally published in The Inquirer and Mirror on January 19, 2017  in the article series called Island Ecology. The Foundation’s Science staff will be regularly contributing to our local newspaper and reprinting articles here the following week.*

As the shortest day of the year has passed and we officially enter the winter months, the natural world around us seems to be hibernating. Leaves have fallen off deciduous trees and grasses and flowers are mostly dormant, waiting for spring like the insects and many other creatures of the natural world – hunkered down until warm weather returns.

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Snow and ice along a salt marsh creek bank

Looking out over the expanses of salt marsh at the Creeks or in Polpis Harbor, you might think that the salt marsh was completely dormant also – resting and waiting for spring but looks can be deceiving. The winter salt marsh is actually quite ecologically active, even if most of that is hidden from view.

Salt marshes, the boundary between salty oceans and freshwater inlands and uplands comprise one of the most biologically productive ecosystems in the world. These oft overlooked transitional zones provide nursery grounds for many of the commercially and recreationally important shellfish and fish in New England, as well as being home to a variety of wildlife and birds. The unique placement of salt marshes, getting salt water from the oceans and freshwater from the uplands, makes these areas rich in a variety of minerals and nutrients. One of the biggest values of a salt marsh for human settlement is the ability to buffer the surge and waves created by large storms and to trap and hold excess water, slowing its release while filtering out excess nutrients like nitrogen and phosphorus from reaching our harbor areas.

Measure tide water levels during winter storms in a salt marsh

Measure tide water levels during winter storms in a salt marsh

In recent years, the biggest storms to hit Nantucket have come in the winter months – Nemo (Feb 2013), Sandy (Oct 2012), Juno (Jan 2015) etc. – and with each of these storms have come highest tides and storm surges, inundating our downtown streets where the salt marsh had long ago been filled in. In harbors where salt marshes still thrive, storm surge and high tide water was taken in, the rush of water slowed down and halted before reaching upland infrastructure. Salt marshes provided the barrier to protect areas of the island from more severe impacts.

 

 

And in winter, those higher tide storm events arrive at just the right time to help facilitate the next biggest function of the salt marsh. As winter comes, the dominant plant in the salt marsh, Smooth Cordgrass (Spartina alterniflora) goes dormant, waiting for spring to grow again. Cordgrass leaves brown and dieback to the salt marsh surface, slowly decaying and breaking off with the help of big storms and shifting ice sheets. Insects and microbes (detritivores) early work on consuming and breaking down this abundance of dead vegetation. An acre of salt marsh can produce up to 10 tons of cordgrass each year! Some of it stays on the salt marsh surface, helping build new organic soil layers. Some of the nutrients and minerals stored in the dying vegetation moves out of the salt marsh on retreating high tides, transporting much needed nutrients to nearby ocean areas.

The nursery of the sea, this rich detritus provides food for young fish and shellfish in the spring. A variety of amphibians, insects, snails and crustaceans find their way to the salt marsh in the spring to feast on the rich detritus released each winter.

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The mummichog, a diminutive salt marsh resident, lasting out the cold winter in small tidal pools.

Salt marsh tide pools, pockets of salt water held up on the surface of the marsh, away from the daily tidal pull, act as refugia for small fish and hunting grounds for birds in the winter. The diminutive mummichog or mud minnow (Fundulus heteroclitus) hunkers down in these sheltered, warmer pools in the winter until migrating to the salt marsh creeks in the warmer spring weather. Waterfowl and wading birds particularly haunt the winter salt marsh, foraging and grazing, searching out their invertebrate prey. You may not see fiddler crabs in the winter but they are still in the marsh, burrowed down deep in the soil, waiting for warm spring.

Covered in ice, the salt marsh is busy preparing for spring.

Covered in ice, the salt marsh is busy preparing for spring.

Through the long, cold, dark winter months the salt marsh is still functioning, protecting our coastlines and providing shelter and food for a diversity of species. And waiting, prepping for the warm weather of spring for the grass to grow again and brighten our coastlines with a swath of yellow/green!

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The Nantucket Conservation Foundation is a private, non-profit land trust that depends 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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Northern Long-eared Bat Alive, Well and Hibernating on Nantucket!

*Please note, this blog post was originally published in The Inquirer and Mirror on December 1st, 2016  in the article series called Island Ecology. The Foundation’s Science staff will be regularly contributing to our local newspaper and reprinting articles here the following week.*

Earlier this summer in our Island Ecology column, we reported on the discovery of a new species for the Island – the Northern Long-eared Bat. We’re back to give an update and to send out the bat signal to ask for help from Nantucketers!

Adult female Northern long-eared bat captured on Nantucket

Adult female Northern long-eared bat captured on Nantucket

If you missed our column in the September 1, 2016 edition of the Inquirer and Mirror, here’s a brief recap. The Science and Stewardship Department at the Nantucket Conservation Foundation, with support from the Nantucket Biodiversity Initiative, has been working with Zara Dowling, a Ph.D. student at UMass-Amherst, to study the bat populations on Nantucket, as very little is known about the bat species that call our island home. In particular, Dowling was hoping to find evidence of the northern long-eared bat (Myotis septentrionalis), a small, insectivorous, forest-dwelling bat. Historically common, populations of this species have declined by over 90% in the northeastern United States over the last 10 years because of the spread of a fungal disease, White Nose Syndrome (WNS).  This fungus grows on the bodies and wings of bats during hibernation, leading to unusual behavior including awakening and activity in the winter, which leads to loss of water and fat reserves, and eventually, death. The northern long-eared bat typically hibernates in caves in high densities – up to several thousand individuals. The cool, moist environment of a cave is conducive to the spread of the fungus and is very easily passed among bats during hibernation. Because of the devastating impacts of white-nose syndrome, this once very common bat is now listed as “Threatened” federally and “Endangered” in the Commonwealth of Massachusetts.

Before the outbreak of WNS, northern long-eared bats were common on Cape Cod, Martha’s Vineyard and Long Island but were not known to occur on Nantucket. While bat populations were declining rapidly in the northeast, it appeared that they were doing fine in these other coastal areas. Healthy, breeding female bats and juveniles were documented on Martha’s Vineyard which led researchers to wonder what is it about these coastal areas that seem to be protecting them and could they be found on Nantucket too? Could they possibly be hibernating on the islands rather than in large colonies in caves where WNS is so prevalent?

Beginning in 2015, in an effort to determine whether Nantucket might be providing a safe haven for these bats, Dowling placed acoustic detectors in several locations across the island to listen for bat calls. Dowling confirmed that northern long-eared bats were present in almost every location in which she placed the detectors. The next step was to discover whether the bats were breeding and successfully rearing pups here. To accomplish this, in July of 2016, we set up nets made of a very fine mesh near the acoustic detectors that had picked up high levels of activity from what we believed to be northern long-eared bats. Within just a couple hours after sunset, we had captured 10 northern long-eared bats! All captured bats were either adult lactating females or juvenile bats, providing solid evidence indicating a breeding population here on island. Not only had we just confirmed the presence of a new species for the island of Nantucket, but we also confirmed a healthy, breeding population too!

female northern long-eared bat caught in net on Nantucket

female northern long-eared bat caught in net on Nantucket

Dowling placed tiny transmitters, called nano-tags, on the backs of three of the largest female bats. The frequency of each nano-tag has an individual signature that allowed us to track each bat to its roost. In the late summer, bats roost either singly (usually males or non-reproductive females) or in what are known as maternity colonies composed of female bats (usually related), and their pups. Once the roost structure was identified, we returned at sunset to watch and count the bats as they emerged for the evening.

Pitch pine snags are used for maternity roost sites by northern long-eared bats.

Pitch pine snags are used for maternity roost sites by northern long-eared bats.

We are now at the point of identifying one more very important piece to our bat puzzle – are these bats hibernating on Nantucket? While everyone else was trick or treating on Halloween night, we were once again back out setting up nets and capturing bats. We were lucky enough to capture one male northern long-eared bat that evening and placed a nano-tag on it. Just having this bat present on island at this time of year is pretty solid evidence that they are likely hibernating here. But this little bat took us one step further – we were able to track this bat to the crawl space of a house, where we found five more of adult northern long-eared bats. We believe this to be a hibernacula and will continue to follow these bats through the winter.

Zara Dowling places a nano-tag transmitter on a female northern long-eared bat on Nantucket

Zara Dowling places a nano-tag transmitter on a female northern long-eared bat on Nantucket

This is big news for Nantucket and the conservation world. Nantucketers, we still need your help in order to build up more evidence of the importance of the island to the preservation of this species! If you suspect that you have bats hibernating in your crawl spaces, basements, old well, etc. please give us a call at the Nantucket Conservation Foundation and let us know! (508) 228-2884.

We understand that many of you may have some reservations about discovering that you have a threatened species on your property. Because the decline of this species was directly caused by the spread of white-nose syndrome and not due to habitat loss or destruction, this species was listed with special rules and exemptions that are not nearly as restrictive as those for other critically endangered species. Specifically, there are no regulations restricting what can be done to human structures even if they contain northern long–eared bats.  You can find more information about rules and regulations as well as the natural history of these animals on the US Fish and Wildlife website – http://www.fws.gov.

 

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The Nantucket Conservation Foundation is a private, non-profit land trust that depends 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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Northern long-eared bats call Nantucket home!

The Nantucket Biodiversity Initiative (NBI) is a collaboration of scientists from local conservation organizations, government agencies, and educational institutions. One of our main goals is to support and facilitate biodiversity research on Nantucket, Tuckernuck and Muskeget Islands and surrounding waters and share results with the scientific community and the general public. Each year, the NBI awards small research grants to scientists wishing to include Nantucket as a study site on wide variety of topics ranging from algal blooms in our ponds, to gall-forming insect diversity, and salt marsh invertebrates, all in an effort to increase our knowledge on the incredible biodiversity of the island we love.

Most recently, NBI has awarded Zara Dowling, a Ph.D. student at UMass-Amherst, a grant to study the bat populations on Nantucket. While the Maria Mitchell Association housed a few bat specimens in their collection that had been found on island, very little was known about the bat species that call Nantucket home. In particular, Zara was hoping to find evidence of the northern long-eared bat (Myotis septentrionalis), a small, insectivorous, forest-dwelling bat.  Historically common, populations of this species have declined by over 90% in the northeastern United States over the last 10 years because of the spread of a fungal disease, White Nose Syndrome (WNS). This fungus grows on the bodies and wings of bats during hibernation, leading to unusual behavior including awakening and activity in the winter, which leads to loss of water and fat reserves, and eventual death. The northern long-eared bat typically hibernates in caves in high densities – up to several thousand individuals. The cool, moist environment of a cave is conducive to the spread of the fungus and is very easily passed among bats during hibernation. Because of the devastating impacts of white-nose syndrome, this once very common bat is now listed as “Threatened” federally and “Endangered” in the Commonwealth of Massachusetts.

I suppose owing to their nocturnal behaviors, humans have construed all sorts of evil ideas about bats, most of which are unfounded. The benefits of having bats in the area far outweigh their drawbacks. They are very important consumers of insects, providing far greater services to agricultural areas than any pesticide ever could. They are voracious mosquito-eaters, protecting us from annoying bites and mosquito-borne illnesses– if only we could get them to acquire a taste for ticks! In many places, bats are important plant pollinators and their guano is still used for fertilizer.

Before the outbreak of WNS, northern long-eared bats were common on Cape Cod, Martha’s Vineyard and Long Island but were not known to occur on Nantucket. While bat populations were declining rapidly in the northeast, it appeared that they were doing fine in these other coastal areas. Healthy, breeding female bats and juveniles were documented on Martha’s Vineyard which led researchers to wonder what is it about these coastal areas that seem to be protecting them and could they be found on Nantucket too? Could they possibly be hibernating on the islands rather than in large colonies in caves where WNS is so prevalent? Indeed, Zara Dowling reported that “In February 2016, a healthy female northern long-eared bat was found roosting under the rakeboard of a house on Martha’s Vineyard, supporting the notion that at least some individuals are remaining on the island over the winter”. It seems plausible that these coastal areas might be providing refuge for this species from White Nose Syndrome.

In 2015, in an effort to determine whether Nantucket might also be providing a safe haven for these bats, Zara placed acoustic detectors in several locations across the eastern end of the island including Squam Farm, Medouie Creek, Milestone Cranberry bogs, and Norwood Farm. The recorded sounds are processed by software that can recognize the particular calls of each bat species – after manually vetting these results, Zara confirmed that northern long-eared bats were present on island in almost every location in which she placed the detectors. Adding further evidence, a single dead bat was found on a trail in a pitch pine forest on the northeastern edge of Hummock Pond that same summer. That specimen was given to a US Fish and Wildlife bat researcher and was determined to be a female northern long-eared bat!

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Acoustic  bat detector at Squam Farm

The next step in 2016 was to discover whether the bats were breeding and successfully rearing pups here and, if so, document what structures female bats used for roosting and maintaining maternity colonies. To accomplish this, Zara set up nets made of a very fine mesh across trails near the acoustic detectors that had recently recorded calls from probable northern long-eared bats. The nets were checked every 15 minutes beginning just after sunset in mid-July. Within an hour, Zara had captured her first northern long-eared bat on Nantucket! By 10:30pm, she had so many bats, the nets had to be closed. Each bat was identified, weighed and measured. The largest bats weighed a mere 7 grams! All captured bats were either adult lactating females or juvenile bats, providing solid evidence indicating breeding populations here on island. And none showed any sign of damage from White Nose Syndrome.

Adult female Northern long-eared bat captured on Nantucket

Adult female Northern long-eared bat captured on Nantucket

Zara placed tiny transmitters, called nano-tags, on the backs of three of the largest female bats. The frequency of each nano-tag has an individual signature that allowed us to track each bat to it’s roost tree, or house, in one case. Once the roost was identified, we returned at sunset to watch and count the bats as they emerged for the evening. The roosts had 10-12 bats each and it was fascinating to watch them emerge and begin to feed, often circling right over our heads, feasting on the plethora of mosquitoes. Their flight is fast, silent and fascinating.

Pitch pine snags are used for maternity roost sites by northern long-eared bats.

Pitch pine snags are used for maternity roost sites by northern long-eared bats.

From just a small amount of money invested by the Nantucket Biodiversity Initiative to fund some of Zara’s research, we now know so much more than we did just a year ago about what bat species share the island with us and that our protected conservation lands as well as private homes are providing critical, breeding habitat for a threatened species. Next, we would like to determine whether the bats are also actually hibernating here. We would love to know if you find bats under the shingles or trim boards of your house, or in your basement or old wells. Please contact the Nantucket Conservation Foundation to share this information!

As for White Nose Syndrome, researchers believe they have identified a bacterium that will attack the fungus, which provides hope of a cure if we can find and inoculate bats before it is too late. Given that some European bat species also have been exposed to, and survive, WNS, there is hope that given enough time, US bats may recover if enough of them are naturally resistant to WNS. In the meantime, hopefully, our coastal islands will continue to provide some refuge for northern long-eared bats.

You can help! If you, or anyone you know, finds bats in your barns, basement, old well or cisterns, in the late fall or winter, PLEASE call us here at the Nantucket Conservation Foundation at (508) 228-2884 or email dodell@nantucketconservation.org. Evidence such as this could help us determine if bats are hibernating on Nantucket through the winter – a major missing piece of our bat puzzle!

 

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The Nantucket Conservation Foundation is a private, non-profit land trust that depends 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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Rare Wetlands in the Midst of an Old Trash Dump

*Please note, this blog post was originally published in The Inquirer and Mirror on August 11th, 2016  in the article series called Island Ecology. The Foundation’s Science staff will be regularly contributing to our local newspaper and reprinting articles here the following week.*

On the southeast end of Nantucket Island there is a large tract of open land with no real access roads or trails. Just south of the Milestone Road and east of Tom Nevers, before you get to ‘Sconset is a Nantucket Conservation Foundation property called the ‘Sconset Dump. Unless you’re a hunter, birder or hard-core plant enthusiast, you probably haven’t wandered through this area and with good reason. This property is dense shrubby, scrubby, boggy wetlands with few upland areas and no walking trails – but it represents one of the more unique wetland properties owned by the Nantucket Conservation Foundation.

Named the ‘Sconset Dump as a nod to its history, this property hosts the highest variety of wetland communities on island, including a unique man-made wetland with numerous rare plants. From the north-side of the Milestone Road, the ‘Sconset Dump receives water from Gibbs Pond and the Milestone Cranberry Bog. Water from the bogs flows under Milestone Road, moves through this property as a mix of flowing surface water and groundwater that occasionally springs up to the surface and all this water eventually makes its way south to Tom Nevers Pond. In between the Bogs and the Pond exist a dense network of shrub swamps, Tupelo and Red Maple swamps, sandy open fens with carnivorous plants and Sphagnum mossy wetlands with a stream or two running through. Pulses of increased water during and just after cranberry harvest times helped create this vast wetland network of open water, streams and boggy land. All of these different wetlands leads to many unique and even rare plants and also is what makes this a hard place to walk through!

Sconset Dump Map

Map of our Sconset Dump Property, Showing the Scrape Wetland and extensive wetlands.

So you might be wondering why this gorgeous and unique property has the name ‘Sconset Dump? Right in the center of the property is a small upland area, surrounded on all sides by wetlands and, at some point, this higher ground started serving as an informal dumping ground for the southeast end of the island. The origination of this dump is lost in the memory of Nantucketers, but a glance at the Nantucket aerial photos from 1938 so the dump area in operation. The actual dump officially closed in 1971 with the Foundation assuming ownership in 1979. Over the years it was open, the Sconset Dump received everything from refrigerators and large metal appliances to everyday household waste. This is one reason no trail network exists on this property; the only upland area is covered in broken glass and rusting metal as a remnant of this unmanaged dump. Common historic practice at the ‘Sconset Dump was to conduct occasional controlled burns to reduce household trash, with the larger, unburnable debris pushed into piles around the dump. Eventually a wide but shallow firebreak was bulldozed in a horseshoe surrounding the upland dumping area to help contain the management fires. This single action of a bulldozer created one of the most botanically unique and rarest wetland types on island!

The wetland in this central bulldozer scrape has very acidic, sandy soil which doesn’t hold a lot of nutrients for growing plants. Additionally, as you many have noticed in your garden, sand soil is porous, making it difficult to hold water. This wetland was formed by a series of groundwater springs and surface water from surrounding areas running right through the scrape, keeping the soil at least moist if not covered in standing water all year long. Only a very select few plants can actually survive in the nutrient-poor and wet soils present in the scrape.

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The bulldozer scrape wetland in the Sconset Dump

Did you notice the mention of carnivorous plants above? Carnivorous plants – plants that attract, capture and digest prey – thrive in nutrient-poor wetlands. The prey they digest, typically insects, provide nutrients like nitrogen and phosphorus that these plants need to survive and can’t find in the soil. In the scrape at the ‘Sconset Dump, we can find two different species of sundews (Drosera) and a bladderwort (Utricularia), all carnivorous. Sundews use sweet but sticky nectaries on their leaves to attract prey while bladderworts use pressure bladders on their roots to suck in unsuspecting microbes for dinner. (We have blogged about carnivorous plants before – learn more here!)

Drosera NCF

Flowering Drosera linearis (Linear-leaved sundew)

In addition to the charismatic carnivorous plants, this unique wetland is home to at least 6 plants rare in Massachusetts. The plants that live in this wetland require not only wet, nutrient-poor soils, but also a lack of shade and competition to survive. In 2008, the Foundation got permission to cut and thin out woody shrubs that had begun encroaching into the scrape area. Since then, we have monitored the rare plant populations which have been increasing thanks to our management! Not everything is rare or carnivorous in these wetlands. One of this author’s favorite flowering plants can be found in and around this property, sheep laurel (Kalmia angustifolia) – keep an eye out for its birthday cake flowers in the spring!

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Birthday cake flowers of the Sheep laurel (Kalmia angustifolia). Photo Credit: K. Omand

From an unregulated dump and variable water flows from a large cranberry production to today, an area of the highest wetland diversity on island, thriving rare plant populations and the occasional carnivorous plant; the Sconset Dump represents one of the very important ways that the Nantucket Conservation Foundation not only protects rare pristine natural habitats but works to improve and promote the places that make Nantucket unique!

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The Nantucket Conservation Foundation is a private, non-profit land trust that depends 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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Voracious viburnum beetle has arrived

*Please note, this blog post was originally published in The Inquirer and Mirror on July 28th, 2016 on pg 11B in the article series called Island Ecology. The Foundation’s Science staff will be regularly contributing to our local newspaper and reprinting articles here the following week.*

Arrowwood in Bloom watermarked,KAO

Every year in midsummer, Nantucket’s conservation lands and roadside shrub thickets are suddenly abloom with lacy cream-colored flowers that resemble Queen Anne’s lace. Most of these flowers belong to arrowwood (Viburnum dentatum), one of the most common and important of the island’s shrub species. While this shrub typically grows in areas with moist soils and along pond shores, on Nantucket it can also frequently be found rubbing shoulders with bayberry and roses in our coastal heathlands, battered by salty sea air and wind, but tolerating the tough conditions.

Arrowwood does have a sworn enemy: the introduced viburnum leaf beetle (Pyrrhalta viburni). The beetle made its first North American appearance in Ontario in 1947, expanded as far as New York State by 1996, and reached Massachusetts by 2004. Each season since I moved here in 2008, I’ve been keeping an eye out for the characteristic leaf damage of this beetle, and each year breathed a sigh of relief when I didn’t encounter it.

Viburnum Beetle Larva, C Eiseman Viburnum beetle adults, C EisemanIn Maine, I’d been horrified to watch it skeletonize arrowwood, highbush cranberry, and nannyberry. The viburnum beetle was likely originally imported on a cultivated European or Asian viburnum bush, and has had an unwitting helping hand in its spread throughout the northeast via nurseries and garden centers. North American viburnums didn’t evolve with this beetle, so they never developed chemical defenses to deter these particular insects.

Unfortunately, viburnum beetle finally surfaced on island this season, reported during the biennial Nantucket Biodiversity Initiative (NBI) Citizen Science event in July by visiting entomologist and repeat NBI grant recipient Charley Eiseman and his wife Julia Blyth, the Maria Mitchell Association Biological Collections Manager; they observed the telltale viburnum leaf damage and some immature beetles at a home along Milestone Road, southwest of the area known locally as “The Serengeti.”

Since they started their search for another elusive viburnum bark mining insect in September of 2011, Charley and Julia have been keeping a close eye on Nantucket’s arrowwood populations.  The larval mines (empty spaces left behind as the larvae eat their way through the interior of plant parts) they found in both the leaves and bark of arrowwood revealed an entomological mystery. The task of identifying a mining insect can require a lot of detective work and patience. In this case, it included overwintering the larvae so that they could emerge as adults the following spring. For the viburnum bark moth, the process took five years from the time they first spotted the bark mines here on island, to getting live moths to emerge to begin the process of identifying the adult insects!

As for the exotic viburnum leaf beetle, Charley describes it as “abundant on arrowwood in places I’ve worked along the Maine coast and in mainland Massachusetts; its presence is immediately obvious because the leaves are riddled with irregular holes, to the extent that whole shrubs are partly or completely defoliated.”  On Nantucket, he believes it is not yet widespread, since they “spent many hours searching arrowwood all over Nantucket for the bark miner,” and “only found the [viburnum leaf beetles] on a couple plants along a driveway. Again, immediately obvious because of the tattered leaves. ”

What can we expect when a new insect arrives on a small island like Nantucket? Our local plant communities are definitely unusual, so the impact may be different here than elsewhere. Islands frequently have fewer species compared to the adjacent mainland, and species you’d expect to be common are sometimes conspicuously absent. Conversely, species that are rare on the mainland are often abundant on Nantucket, due to differences in the environment and past land use. Since arrowwood is so widespread and common on Nantucket — with high food value for birds and insects — we suspect that the spread of the introduced leaf beetle across the island may lead to dramatic changes. Winterberry holly, pepperbush, highbush blueberry, and swamp azalea are all likely to fill empty spaces if the arrowwood declines rapidly. But invasive non-native shrubs like bush honeysuckle (Lonicera morrowii) and autumn olive (Elaeagnus umbellata) could also rapidly gain a foothold in new areas of the island that are currently dominated by natives.imageedit_1_9904200684

With fewer species to start, retaining the ones we do have becomes even more important in protecting diverse native ecosystems.  The abundant dark purple or black fruit of arrowwood start ripening in August, perfect timing to fuel migratory bird species on their long fall journeys. Researchers have discovered that the fat content of the fruit of native shrub species is typically much higher compared to that of non-natives. So although birds will eagerly gorge on the fruit of non-native autumn olive or bush honeysuckle like candy, a meal of arrowwood and bayberry provides a much more beneficial balance of nutrients to fuel migrating birds. Think of it as the difference between eating a candy bar on a long hike, instead of snacking on high-energy trail mix containing a balance of sugars, carbs, proteins, and fat. Migrating birds are already often running on fumes as they approach their winter homes, and a lack of high quality nutrition could tip the balance away from survival. The impact on native insects could be even more dramatic, although harder for us to see and appreciate. Many rely on arrowwood, feeding on vegetation or visiting the flowers for nectar or pollen, meanwhile providing an important protein source for the birds.  Charley notes that “another viburnum leaf-mining moth (Phyllonorycter viburnella), is common on Nantucket despite being rare off-island— in fact, I’ve never seen it anywhere else.”

Sometimes plants can survive in reduced numbers and gradually evolve protective mechanisms, like toxins that deter herbivores. It’s possible that Nantucket might be home to some disease or high populations of predatory insects (like parasitoid wasps) that will keep beetle populations low, or maybe our salty sea air will limit where it can thrive. Unless these scenarios play out, we can expect beetle populations to initially explode as they have elsewhere in New England. Let’s hope that something will help keep the viburnum beetle from taking a big bite out of our island ecosystem! More info on how to identify viburnum beetle is readily available online, along with info about how to manage it in your yard.

Kelly Omand is a botanist and an Ecologist/Field Supervisor with the Science and Stewardship Department of the Nantucket Conservation Foundation. Insect photos included in this article were contributed by naturalist and author Charley Eiseman — follow his explorations of the insect world (including his ongoing Nantucket research) in his “Bug Tracks” blog (http://charleyeiseman.com/).

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The Nantucket Conservation Foundation is a private, non-profit land trust that depends 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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Rare Plants and Unique Wildlife on our Coatue Property

*Please note, this blog post was originally published in The Inquirer and Mirror on July 21th 2016 pg 6B in the article series Island Ecology. The Foundation’s Science staff will be regularly contributing to our local newspaper and reprinting articles here the following week.*

As we all know, Nantucket is unique in so many ways – our history, our quirky customs, our people. Each of us has a reason why we believe Nantucket is so special. As one who is inclined to be outdoors, what I find most fascinating about our island is our unique geologic and natural history.

The shape of Nantucket itself is quite unique, beloved and easily recognizable. One of the most recognizable landscape features of our island is the northern barrier beach known as Coatue. How this piece of land came to have its characteristic scalloped shape is quite rare geologically-speaking too. After the last glacier retreated, Great Point was an island itself, disconnected from the rest of Nantucket. Over time, with shifting shoals and drifting sand, dunes eventually filled in between the two islands, connecting Great Point to Coskata and Wauwinet. Coatue is believed to have developed after Nantucket and Great Point became connected, as this long, northward reaching spit of land interrupted the flow of the strong currents from the Atlantic towards the north part of the island. Sands drifted in on slower moving currents and were deposited from the east to the west creating the north-facing barrier beach. The scalloped shape of the cuspate spits that form the six points on the inside of Coatue facing Nantucket Harbor are an unusual feature that geologists believe formed and are maintained by just the right combination of the northeasterly prevailing winds in the winter versus the southwesterly winds of the summer along with the constant daily flux of tides in and out of the Nantucket Harbor. The prevailing winds and currents build up the points, while the tidal fluctuations move sand from the points and deposit it along the bends between them.

Today, most of Coatue from the fifth point, known as Bass Point, westward to Coatue Point at the east Jetty, is owned by the Nantucket Conservation Foundation and managed as a wildlife refuge. The Coatue Wildlife Refuge is a summer home for many rare, nesting bird species including American oystercatchers, piping plovers, least terns as well as songbirds like the saltmarsh sparrow, ground-nesting northern harriers, as well as herons and egrets. Over the last few years, we’ve also seen the development of some very unusual behavior by a colony of double-crested cormorants, which have begun nesting right in the dunes among all the gull nests!

Double-crested cormorant colony on the north shore of Coatue

Double-crested cormorant colony on the north shore of Coatue

Managing Coatue as a wildlife refuge also provides us an opportunity to protect some amazing habitat for very rare or unusual plants as well. While not a rare species, the dwarf red cedars on Coatue are thought to be quite old trees, perhaps upwards of 100 years. Other places across the island, cedars grow upright as normal trees. On Coatue, of course, they must do it differently! Due to constant wind and salt spray, their upright growth is stunted but they have adapted by growing prostrate to the ground, often with their trunks running along under the sand. As you move from north to south in the wider sections of Coskata and Coatue, the height of the cedars begins to increase as they are less influenced by the strong coastal winds. Researchers from UMass Amherst have been using ground-penetrating radar to study how the Coatue cedars are growing under the sand and questioning whether the parts of the tree that are above the ground are actually just multiple branches of the same individual. How many actual individual cedars are there on Coatue? Could they be growing similarly to how clonal species such as Aspen grow in the western US, where each tree is a genetic clone?

Clearly the plants that thrive on Coatue must be hard and able to withstand frigid winter temperatures, occasional ocean overwash during nor’easters, salt spray and the nearly constant wind. That anything survives out there is a miracle to me, but there are a few plant species whose tolerance to such harsh conditions is baffling. As child growing up in Connecticut, I would scour the dark, conifer forests in the late spring in hopes of finding a single, pink Lady’s Slipper. These members of the orchid family are rare and generally known to inhabit mossy or rocky slopes in pine and hemlock forests. Nothing at all like what is found on Coatue! I still am shocked when, year after year, large patches of these amazing orchids pop up in the sandy, dry, exposed soils of Coatue among all the bearberry!

Pink lady's slipper (Cypripedium acaule) in flower on Coatue

Pink lady’s slipper (Cypripedium acaule) in flower on Coatue

Having lived for many years in the desert southwest, I still find it most bizarre to see cactus – lots and lots of eastern prickly pear cactus (Opuntia humifusa) – in amongst the dunes and beach grass of Coatue. Indeed, Coatue is one of the only places you can find the eastern prickly pear in the Commonwealth and it is quite easy to spot right now as it is in full bloom with bright, showy, yellow flowers. To see it though, you’ll need to wade through the fields of poison ivy and swarms of greenhead flies so beware! In my opinion, it’s worth the fight to see this plant that just seems so oddly out of place and you just have to see it to believe it! It has bright green pads that grow along the ground so as to avoid the wind, and tends to lack the long, sharp spines of your classic western prickly pear species. It does however have many small, irritating hair-like spines called glochids that can become imbedded in your skin and are a nightmare to remove, so best to admire without touching. Bright red edible fruits will develop later in the summer. This is a plant that does not tolerate shading by other taller species so does quite well on Coatue as the constant wind keeps most plant growth quite stunted. The eastern prickly pear is afforded the highest level of protection by the Massachusetts Endangered Species Act and is listed as Endangered due to its very limited distribution within the state. I encourage people to go see this rare and beautiful plant but please leave it right where it is.

The rare Eastern prickly pear cactus (Opuntia humifusa).

The rare eastern prickly pear cactus (Opuntia humifusa).

Coatue is certainly a gem that we are so lucky to have. From so many places on island it seems just a stone’s throw away, yet is actually quite remote and hard to access without a boat or sturdy four-wheel drive vehicle. If you can get there, we at the Nantucket Conservation Foundation welcome you to enjoy what we think is one of Nantucket’s truly unique landscapes and all the natural wonders it has to offer. Remember, we are nearing the end of shorebird nesting season and many of the chicks are just now learning to fly. If you see fencing along the beach, please steer clear and view the birds from afar. Maybe you’ll be lucky enough to witness the first flight of one of our oystercatcher chicks!

 

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The Nantucket Conservation Foundation is a private, non-profit land trust that depends 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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Nantucket Coastal Plain Pond Hydrology and Globally Rare Plants

*Please note, this blog post was originally published in The Inquirer and Mirror July 14th 2016 pg 4B in the article series Island Ecology. The Foundation’s Science staff will be regularly contributing to our local newspaper and reprinting articles here in the following week.*

Alamanc Pond, a large Coastal Plain Pond on Nantucket, full of water in mid-summer

Alamanc Pond, a large Coastal Plain Pond on Nantucket, full of water in mid-summer

After a long spring drought with weeks of no rain in June, Almanac Pond in the Middle Moors sat full to the brim with water.

Wait, what?

Of all of the questions I hear about wetlands each year, the water levels in the smaller ponds throughout the island tops the list, usually because the pond levels seem so different from expectations based on weather. On Nantucket Island, our thoughts about water focus on the harbors and the Great Ponds where water levels make intuitive sense – high with high tide, low with low tide or, in the case of the Great Ponds, low when the beach opens and high when closed. But the little ponds throughout the inland parts of the island; Almanac, No-bottom, Wigwam, Jewel, the Pout Ponds and many more, are an entirely different kind of pond.

Coastal plain ponds: small, shallow freshwater ponds found throughout the Northeastern US and Canada and concentrated in coastal areas of southeastern Massachusetts and Rhode Island are home to one of the highest concentrations of rare plants in the region!

Why do these ponds behave so differently from the other water bodies on Nantucket? Located in areas covered thousands of years ago by the last glacier, these ponds are depressions in sandy or gravelly soil and receive all of their water because they intersect the water table, meaning that groundwater runs directly into these depressions, independent of tides, streams or other surface water. Groundwater? On an island, fresh drinking water is key so you’ve probably heard of our sole source aquifer, the reservoir of freshwater contained under the island. This aquifer is our groundwater which is, on average, 10-20ft below the soil surface but can be as shallow as 0ft and as deep at 100ft below the soil. Where groundwater intersects the soil, water can well up out of the ground – you may have encountered a small burbling pool in Squam Swamp or seen water trickling out of the side of Sconset Bluff – these are springs of groundwater reaching the surface. Where the groundwater seeps up in depressions, coastal plain ponds form. Because of the glacial history of our island, which created pockets, valleys and kettlehole depressions, these groundwater-dependent coastal plain ponds are abundant on Nantucket.

Groundwater fed ponds behave differently than primarily surface water fed ponds (ponds that depend mostly on precipitation, streams or a coastal connection). Surface water pond levels change almost instantly because their water source is instantaneous water, leading to short term changes in water levels. Basically, when it rains, water levels in surface water fed ponds rise almost immediately, when it’s dry for a few weeks, water levels drop. Groundwater, on the other hand is a bit more complicated. Groundwater levels draw down due to pumping for drinking water and uptake by plant roots, but this response is buffered by soil and the amount of groundwater present. Our aquifer is so large, that drawdowns in the aquifer happen slowly over time – although they do happen! Because of the sandy soil on Nantucket, which allows water to move quickly through it, our aquifer can get quickly recharged (refilled so to speak) by precipitation as rain or snow. Water levels in groundwater fed ponds like Almanac Pond don’t change in the same way as more predominantly surface water fed ponds like Hummock Pond. Which is why this summer, after weeks of drought, Almanac Pond is still full to over flowing!

Almanac Pond with lower water levels and abundant coastal plain pondshore vegetation.

Almanac Pond with lower water levels and abundant coastal plain pondshore vegetation.

Typically, groundwater fed coastal plain pond water levels are highest in spring and begin drawing down very slowly over the summer and into early fall. As fall rains begin and recharge the groundwater, these ponds will start filling again in the early winter months. How full a pond is in the spring depends on the previous fall and winter precipitation, not that spring’s rain – so some years the ponds are very full and possibly over flowing their banks and in some years they can start out the spring already 5ft lower than usual.

This variability in water levels over a season is what makes coastal plain ponds so ecologically interesting. Coastal plain pond shores – the edges of these ponds that are variably wet or dry depending on the season and year – host one of the highest concentrations of both locally and globally rare plant species in northeastern US and Canada. The state of Massachusetts has more than 40 state-listed plants and animals that are found almost exclusively in these ponds. The plants that emerge, flower and set seed each year depend almost entirely on water levels, meaning the seeds of plants that come up when the pond is at its lowest might have to survive 5 or more years underwater, a unique adaptation for most plants. In a low water year – rare plant stalkers in New England rush to the coastal plain ponds hoping to see some of the more unique and seldom seen plants in flower. This year, our ponds seem extra high so the possibility of seeing some of these rare plants this summer is not likely but in low pond years you might get a chance to glimpse the lovely, very rare and unique Rhexia mariana (Maryland meadow-beauty). Most years you can find this plant’s cousin Rhexia virginica (Virginia meadow-beauty) higher up on the pond shore.

Rhexia virginica (meadow beatuy) found on the pondshores.

Rhexia virginica (meadow beatuy) found on the pondshores.

What else might you find along the edge of these unique wetlands? Carnivorous sundews often hide along the shoreline, waiting to capture tasty ants or flies for a snack – Drosera filiformis (Thread-leaved sundew) and Drosera intermedia (Spatulate-leaved sundew) can both be found on Nantucket! And, I’m still waiting to stumble upon the very rare and beautiful Sabatia campanulata (Slender rose gentian) – maybe next year will be a low water year!

The rare and carnivorous Drosera filiformis (thread-leaved sundew).

The rare and carnivorous Drosera filiformis (thread-leaved sundew).

These unique coastal plain ponds provide a direct link to our precious aquifer, hosting a range of rare and unique species. The canary in the coal mine of the quality of our island’s freshwater resources, these ponds are susceptible to any groundwater contamination through fertilizer and other nutrient inputs as well as over pumping of the islands aquifer. Luckily, most of these ponds are on protected conservation lands, allowing us to monitor and study them into the future.

Jen Karberg, Ph.D., is a wetland and plant ecologist and the research program supervisor in the Science and Stewardship Department of the Nantucket Conservation Foundation

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The Nantucket Conservation Foundation is a private, non-profit land trust that depends 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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