Nantucket Conservation Foundation's Science and Stewardship Department

American cow-parsnip (Heracleum maximum) growing in disturbed soil around a paper birch near the intersection of Milestone and Turner Roads.

If you’re out and about on Nantucket this month and see super-sized umbels of white flowers that resemble Queen Anne’s lace but are the size of dinner plates, topping plants with beefy stems and large coarse leaves, it’s likely you have come across American cow-parsnip (Heracleum maximum). Typically found at the edges of wetlands and salt marshes, this native wildflower can also pop up unexpectedly in clearings where the soil has been disturbed and the soil is fairly rich and damp.

A compound leaf of American cow-parsnip.

American cow-parsnip flies under the radar its first season, producing only a bunch of leaves, but in the second spring it makes a grand entrance by sending up flower stalks usually 3-6′ tall, and producing umbels that are around 8″ in diameter. While a plant of this size is sure to make a splash no matter what, American cow-parsnip produces an added frisson of fear in a lot of people, because it is a close relative to giant hogweed (Heracleum mantegazzianum), which is a serious invasive weed introduced from Eurasia. Giant hogweed was introduced as an ornamental by Victorian gardeners, who also brought us such delights as Japanese knotweed (Fallopia japonica) and black swallow-wort, also known as dog-strangling vine (Cynanchum louiseae). The Victorians loved novelty in the form of oversized plants, particularly ones with a sinister twist, apparently. Giant hogweed (also called giant cow-parsnip by some) causes a severe blistering skin reaction that leaves permanent scarring, so it has made the blacklist of “Most Dangerous Weeds” in a lot of places.

American cow-parsnip showing off its compound umbels and compound leaves.

So, if you stumble across an enormous white-umbeled plant that looks like a Queen Anne’s lace from the Little Shop of Horrors, how can you tell whether it’s giant hogweed or American Cow-parsnip? And why should you care?

First off, it’s wise not to handle ANY plants in the Apiaceae (Carrot & Parsley Family) casually, so take a look rather than wading right in. Did you know that even home garden plants like parsley, carrots, and parsnip all produce harmful furanocoumarins in their vegetation? These are chemicals that when rubbed on your skin followed by sun exposure, can cause blistering burns, a condition called phytophotodermatitis. Handling carrots or parsley is not always a problem, but if the plants are wet, or if you get the oils on sensitive skin, or in large quantities, you can wind up with fluid filled blisters like poison ivy, only less itchy. The oils quickly bond to your skin, and spending even a short time in the sun afterwards can cause blisters to form. The giant hogweed reaction is much, much more serious and debilitating.

So, take a look at your Apiaceae carefully, and hands-off. Assuming your plant has the characteristic large coarse-lobed leaves and big white umbels, the next step is to assess the number of branches in the inflorescence. An American cow-parsnip will have up to 45 primary branches in its umbels, while the invasive and much more hazardous giant hogweed will have 50 or more branches. You can figure out the number of primary branches by looking at the top of the flower head, and counting the round bunches or clumps of flowers. Each bunch of flowers in an umbel equals one primary branch.

If your plant has umbels with 45 or less branches, you have a native American cow-parsnip, and the only thing you need to do is avoid handling or weed whacking the plants to prevent possible skin reactions, the same sort of precautions you would take with poison ivy or poison sumac. American cow-parsnip is a great pollinator plant feeding many species of native bees, flies, and wasps, and greatly enhances the biodiversity of its surroundings. Biodiversity goes way beyond pollinators, and this plant offers habitat for many other invertebrate species that feed on the leaves, and spiders that lie in wait for prey.

If on the other hand you’ve discovered a plant with 50 or more primary branches on an inflorescence, you may have found giant hogweed. This species has never been recorded as occurring on Nantucket, and we would love to keep it from ever becoming established. Please get in touch with one of the co-chairs of the NBI Invasive Plant Species Committee: either Kelly Omand at Nantucket Conservation Foundation (komand@ nantucketconservation .org) or Sarah Bois of the Linda Loring Nature Foundation (stbois@ llnf. org) to let them know about your find. Pictures and an exact location will help us determine if your plant is a concern.

Each year, the Nantucket Conservation Foundation’s Science and Stewardship staff hires 2 Seasonal Ecology Field Assistants to help completely all of our many research and management related objectives over the summer and early fall season. Each year we look for people with strong experience in plant research, wildlife monitoring, invasive species management and an overall love and drive for conservation and ecology. We have had some amazing field assistants over the years and 2018 is no exception. Laurel Martinez and James “Mack” McGraw are this year’s Field Assistants. Read a little more about them below and if you see them out on our properties working hard this summer, feel free to say Hi!

Laurel Martinez

Laurel Martinez holding a ring neck snake at Squam!

After spending several months in the dry mountains of New Mexico, the lush greenery and ocean views of Nantucket are a welcome sight. I am originally from Rockville, Maryland and I attended the University of Vermont where I received a B.S. in Environmental Science and a minor in Plant Biology. Over the course of my time at UVM, I was an intern at the Smithsonian Environmental Research Center where I designed an experiment examining the effect of low dissolved oxygen and pH on oyster growth. I also studied abroad in Botswana with Round River Conservation Studies where I did a project on elephant demography. However, I discovered a love of botany and began to pursue a minor in plant biology.

Soon after graduation, I got a job at the Joseph W. Jones Ecological Research Center where I conducted vegetation surveys under a canopy of longleaf pines. I was thrilled to be able to learn how to identify the plants of the Southeast and put a name to the amazing flora of the longleaf-wiregrass ecosystem. Nantucket offers an entirely new suite of plants to identify, and I am looking forward to the challenge of familiarizing myself with these new species and understanding their role in the sandplain-grassland community. When I’m not avidly searching for plants in the wilderness, I enjoy drawing and baking!

With only two weeks gone by, I have already experienced so many parts of the incredible natural world of Nantucket. During my first week I was surveying horseshoe crabs under the light of the full moon as they emerged from the ocean to the shore, ready to ensure their prehistoric legacy. I also got to wade through the wetlands of Squam Farm, searching for spotted turtles under waist-high ferns and a bed of Sphagnum moss. On a clear, windless night we set up mist nets to catch endangered long-eared bats. Carefully, we examined delicate membranous wings for tears and swabbed a tiny nose for disease as the bat squeaked his protests. Traveling to Coatue was another highlight, where outside the ranger house, rare geraniums brighten the front walkway with magenta petals, seals bask on the beach, and (if you know where to look) lady’s slippers dot the landscape. I am so grateful to be on this beautiful island for the field season and look forward to the new experiences and excitement I am sure to encounter!

Mack McGraw

Mack McGraw and a spotted turtle at Squam Farm

Born and raised on the North Shore of Massachusetts, I’ve been nurturing a love for the outdoors since I could walk. I loved picking up rocks and boards to see what critters might be hiding under them, or catching frogs and snakes in ponds nearby with friends. I always had a million different questions about the natural world, and when given the answers, they only made me think of a million more. Little did I know, my endless curiosity would be gas to the fire for my interest in ecology, and I was lucky enough to attend a vocational high school where I could major in environmental science. I took classes such as forest ecology, marine biology, wetland and soil science, and so much more. I went on many trips including an eight day canoe trip down the Merrimack River and a five day stay at a field station on the Bay of Fundy in Canada. It allowed me to not only observe the ecosystems I had been studying, but employ the surveying and experimental skills I was being taught and synthesize everything I was learning.

This program fine-tuned my love of nature to focus on wildlife sciences, and led me to attend the University of Maine to study wildlife ecology. There I was introduced to the true rigors and wonders of field research, of wildlife and habitat management, and of the ever growing conservation problems that challenge our biologists every day. Seeing more of the natural world from Maine to Peru through my studies, I felt a calling even stronger to try and save it all. That’s when I took to field research, starting with bird surveys in the forests, then saltmarshes. Then I took on a job conducting forest inventories in southern Indiana that afforded me the chance to also work with banding ornithologists, bat biologists, and botanists to help build my skills as a well-rounded wildlife biologist. Now working with NCF, I have this amazing opportunity to work with an array of plants and animals in a suite of different ecosystems, all with the goal of conservation and management in mind.

When I am not working, I enjoy bird watching, mountain biking, kayaking, or any number of other outdoor activities. I try to be outside as much as I can and here on Nantucket there is nothing holding me back!

**Update February 2019: Project Report on Hither Creek Hither Creek Washover and Salt Marsh Monitoring Report 2018 **

The photos and videos on social media October 30^th, 2017 were dramatic. Ocean waves in Madaket washing over the dune separating Hither Creek from the Atlantic Ocean, swirling under and around the stilt house and pushing sand into the southern end of Hither Creek. For a while during this story, it looked like Hither Creek would open to the Atlantic Ocean and the water rushing in threatened Millie’s Bridge, sending Nantucket DPW workers out to shore up the bridge. When the storm cleared, luckily the bridge was stable, the stilt house was still standing and the Atlantic Ocean was back on the other side of dune, now much shorter than before. But there were still dramatic changes to the landscape. All that rushing ocean water had significantly eroded the sand dune separating the ocean and Hither Creek and that sand had been push into Hither Creek, filling in most of the small circular salt pond closest to the silt house and blanketing the surround salt marsh with a thick layer of sand.

Water rushing over from the Atlantic Ocean, depositing sand into Millie’s Pond

After the storm: sand covering shrubs and salt marsh and filling most of Millie’s Pond

Once the storm subsided, waves have occasionally washed over from the Atlantic Ocean only during extreme high tide/wave events, but under normal conditions, the southern end of Hither Creek is reconnected to tidal flow from Madaket Harbor. Significant sand remained deposited on top of the salt marsh and within the salt pond.

NCF’s Research Program Director, Jen Karberg became very interested in what that thick layer of sand would do to the salt marsh underneath it. Salt marshes typically respond well to sand additions of an inch or two, small scale wash over events are vital for building up marsh elevation, encouraging growth of marshes grasses and helping salt marshes respond to climate change. Very little research has documented the response of salt marshes to this much sand deposition. Events like this are likely going to increase and salt marshes play a vital role in stabilizing our eroding shorelines and buffering our uplands from intense storm events. Understanding how large sand washover events can impact salt marshes will help NCF and other island organizations prioritize management and protection on Nantucket.

Sand over existing Salt marsh

So, with permission of the Massachusetts Audubon and the Town of Nantucket (owners of the majority of the salt marsh at the southern end of Hither Creek), NCF set out to study how the salt marsh would respond to these deep sand deposits as well as how long those sand deposits stay in place. Over the next year, NCF staff will be documenting sand extent and depth over the salt marshes, tracking the movement/retention of sand and examining salt marsh vegetation growth in response to the sand deposits.

In November, Jen established randomly located plots at the site, measured sand depth over the marsh and documented any vegetation that was still present. The response of salt marsh vegetation will depend on how much sand remains in place come spring when the plants start growing again. This is just the beginning of this monitoring work, which we will continue for at least a year but a few observations can already be made. In November, sand depth over the salt marsh ranged from 1/3 of a meter to up to 2 meters in some places. Interestingly, the sand deposit within the creek rises so much higher than the remaining salt marsh that incoming tides preferentially cover the remaining salt marsh which has already lead to the death of much of the grasses in some places. This also means the tide is flowing right around the base of Millie’s Bridge so the concrete blocks put in place to protect the bridge will likely remain for a while!

Observing the area at low tide, significant amounts of sand appear to be washing off of the big sand deposit and out into Hither Creek. Where these new deposits of sand fall out in the creek may end up may changing the navigational bottom of the creek. Between November and January, the sand deposits have been advancing over the salt marsh and closer to the bridge with each major storm and the loss of salt marsh is already being felt. Salt marshes both buffer large water flows and can hold on to water, keeping it from flooding uplands during large storm events. A neighbor on the pond had their basement flood with water during the most recent winter storm. This had never happened before to them before, with the only difference being that the salt marsh in front of their house was swamped with sand. These are just some small changes already being seen as a result of this major landscape change. Continued monitoring over the next year will help us understand how this area is changing and how future storm changes will impact Nantucket.

Column author:

Dr. Jen Karberg, wetland and plant ecologist and the Research Program Supervisor in the Science and Stewardship Department for the Nantucket Conservation Foundation.

*Please note, this blog post was originally published in The Inquirer and Mirror  in February 2018 in the article series called Island Ecology. The Foundation’s Science staff regularly contribute to our local newspaper and reprint the articles here soon after.

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