Tag Archives: Invasive Species

Marsh Madness: Restoration of Iona Marsh from Invasive Phragmites

Iona Island, located along an elbow of the Hudson River in Bear Mountain State Park, is technically an archipelago of three islands connected by marshlands. Iona has had many owners in its storied history, prior to being bought by New York State in the 1960s. The Island was host to Native American tribes for thousands of years, who took advantage of the plentiful shellfish along its shores. In the last few hundred years, it has been the site of an unsuccessful vineyard, a hotel and weekend destination for NYC residents, a U.S. Navy arsenal, and a partially built park recreation area. The eastern side of the island past the railroad tracks has been closed to the public since the 1980s, but a small portion of the island consisting of the five remaining Navy buildings is used for storage for the Palisades Interstate Park system. The rest of the island has returned to a more natural state of woods, meadows, and rocky outcroppings and serves as a sanctuary for wintering bald eagles.  The island achieved National Natural Landmark status in 1974, and was designated a NYS Bird Conservation Area and Audubon Important Bird Area shortly thereafter.

A key natural feature at Iona is the extensive marshlands, 153 acres in all, flanking its western side.  Part of the Hudson River National Estuarine Research Reserve (HRNERR), this brackish tidal marsh (marshes with water that has different concentrations of salt depending on the tides) teams with life including fish, waterfowl, waterbirds, plants, and crustaceans. In recent times, the rich biodiversity of the marsh, including a number of state rare species, has been threatened by Phragmites australis, or as it is more widely known, common reed.

Common reed (Phragmites australis) is a plant that was likely brought to the US from Europe and Asia in the 1800s through ship ballast or the water taken in by ships to allow them to balance on long voyages. Commonly referred to as just Phragmites, this non-native plant is invasive in the U.S., displacing and crowding out native plant species, such as cattails, rushes, asters, and many others. In turn, the presence of this species has undermined the complex web of marsh dependent organisms.

The non-native Phragmites is identifiable by its tall stature, dark blue-green leaves, and tendency to form dense stands, with little to no possibility for native species to grow in the areas that they occupy. A native species of phragmites (Phragmites americanus) occurs in NY as well, but this smaller plant with reddish stems grows with less density so it does not crowd out other flora.

Pre20018 Iona
Iona Island Marsh in 2008 before treatment. Phragmites dominate the background.

The phragmites problem at Iona Marsh began in the early 1960s, when the first small colony appeared near a pipe draining into the marsh. Over the next 40 years, phragmites steadily expanded until it covered nearly 80 percent of the marsh area. Researchers tracking these changes noted a concurrent decline in marsh specialist birds and specialized brackish marsh plants, including state rarities.  In an effort to reverse these trends, the Palisades Interstate Park Commission, while partnering with Hudson River National Estuarine Research Reserve and the Highlands Environmental Research Institute, started a New York State Department of Environmental Conservation (NYSDEC) funded management program in 2008 focused on a 10-acre test area. The goal was to reduce the invasive phragmites, and make room for native plants to once again occupy the area. If the program was successful in this small area (1/15th of the marsh), it could be expanded to additional marshlands.

A multi-faceted control and monitoring program has been developed and implemented and the results have been dramatic. More than 90% of the phragmites was eliminated within one year and nearly 97% by the third year. Researchers saw the return of huge meadows of annual native marsh plants, including some state-threatened species, followed by perennial cattail stands. Marsh specialist birds such as Virginia rail, least bittern (State-threatened), and marsh wren followed soon thereafter.  Based on this success, the project was expanded to an adjacent 32-acre area of the marsh known as Ring Meadow. Both areas now have less than five percent Phragmites cover, an overall success on the journey to reestablish native vegetation.

2017 Image
Map of the Iona Island Marsh Treatment Areas

While complete eradication of the Phragmites may be impossible to achieve, success can be maintained through continued monitoring and spot treating remaining and new patches.  Bird and vegetation surveys are conducted annually, as are measurements of sediment build-up on the marsh surface, as it relates to sea level rise.  The goal remains to restore the native plant communities in the marsh to promote biodiversity. A healthy, native marsh community will lead to increased productivity and habitats for fish, birds, and mammals – many of them specially adapted to the brackish conditions at Iona.  With continued management, the long-term outlook is positive for this Hudson River jewel, one of only four large brackish marshes on the Hudson.

RingMeadow
Ring Meadow in 2016. Cattail and blooming Rose Mallow have regrown where phragmites once were.

Interested in seeing Iona Marsh for yourself? While public canoeing and kayaking are not allowed in the marsh itself to protect this unique place, through collaboration with the State Parks, NYS DEC offers free public canoe programs each summer.  Not a fan of getting on the water? Iona Island is accessible by road. There is a parking lot approximately ½ mile onto the island, right before the railroad tracks (the boundary of the public accessible areas), where you can park and view the marsh. Lucky visitors may spot waterfowl, muskrats, frogs, turtles, wetland birds, deer, or even bald eagles!

Photo credit:   PIPC Archives

Dr. Ed McGowan,  2017 Annual Report Iona Island Marsh

Post by Jesse Predmore, SCA

Edited by: Dr. Ed McGowan & Chris O’Sullivan

Featured image: lulun & kame accessed from Flickr

Excelsior Conservation Corps Works Alongside Parks to Conserve Historical Site

The New York State Office of Parks, Recreation and Historic Preservation (State Parks) staff members at Ganondagan State Historic Site recently worked with members of the Excelsior Conservation Corps (ECC). The ECC is a non-profit organization within the Student Conservation Association (SCA). The members involved in this program range from ages 18-25 and learn skills and methods to help restore, protect and enhance New York’s natural resources and recreational opportunities.

Ten members of the ECC were tasked with invasive plant species removal from various locations and GPS monitoring of certain invasive plant species within the Ganondagan State Historic Site located in Victor, NY. Invasive plant species are non-native species that can cause harm to the environment, the economy, or to human health. Because these plants are not native in these habitats, they can cause or contribute to habitat degradation and loss of native species.

Wild Parsnip
Wild parsnip in full bloom, notice the yellow-green flowers that look like Queen Ann’s lace and dill.. Photo by ECC

Giant hogweed (Heracleum mantegazzianum), which is a tall flowering invasive plant that is infamous in many areas of New York, not only disrupts the environment in which it grows but can also be very harmful to humans. If the sap from the stem comes into contact with the skin, it can cause severe burns and make skin more sensitive to ultraviolet radiation provided from the sun.  Fortunately, no giant hogweed has been found at Ganondagan State Historic Site, but the site has become a host to a closely related and invasive plant called wild parsnip. Wild parsnip (Pastinaca sativa), has similar effects to giant hogweed when it comes into contact with unprotected skin.

When the members of the ECC arrived, they were informed they would be participating in the Parks’ annual wild parsnip picking day. Each year the staff members from the Environmental Field Office dedicate one day to pick as many wild parsnip plants as they can in hopes of clearing out fields and minimizing the possibility of more growing in the future. Everyone was instructed to wear long sleeve shirts, pants and gloves in order to protect their skin. Starting early in the morning, the group of 10 ECC members joined forces with six State Parks’ staff to venture out into the fields of wild parsnip. Throughout the day everyone hiked through trails and sections of the property, pulling the plants out and piling them up they could be removed from the area. The members were instructed to get as close to the ground as possible to pull the roots up by hand. After walking through 30 acres of fields, the total tally of plants removed came out to be 13,439!

Wild Parsnip field
ECC and State Parks crew in one of the many fields. Note the tall yellow plants that are all wild parsnip. Photo by ECC.

After the wild parsnip adventure, there was still more for the ECC members to do at Ganandogan. State Parks has been closely monitoring a field full of invasive plants for the past few years with GPS devices.  These devices enable the staff to map the location and the amount of invasive plants within the area. The ECC team helped record data on six different plants while walking across a 70-acre field. To cover the area efficiently, the ECC members were required to stand in a line about 14 paces apart and walk due North across the field in a straight line, using compasses as their guide. Staying straight was not easy while walking over hills and through tall grass, stepping over and through every obstacle in their path.

gps.jpg
GPS monitoring device used to mark invasive species in the area. Photo by ECC

The plants they were looking out for were Canada thistle, bull thistle, multiflora rose, autumn olive, swallowwort and non-native honeysuckles. Each observer would stop at every 15 paces to observe the area they were in and mark each location for any of these six invasive plans within a five-foot radius. In total, the team collected over 20,000 points that will be used to create maps in ARC GIS to show the extent of the invasives and to help guide management plans.

 

Post by Amber Goodman, ECC member

Invasive Species Spotlight – Elongate Hemlock Scale

Name: Elongate Hemlock Scale (Fiorinia externa Ferris)

Origin: Native to China and Japan and was first observed in New York City in 1905. It is believed that it was unintentionally introduced from Japan.

NYS Presence: Elongate hemlock scale (EHS) is present throughout the state, with the highest density within a 185 mile radius of New York City.

Identification: EHS is an armored insect most commonly found on the underside of hemlock needles. They show up as small (1.5-2 mm) and flat brown or white patches that hide the female and male insects, respectively. Underneath the brown scale, you may find the tiny yellow eggs.

Kristopher Abell, University of Massachusetts, Bugwood.org
Female EHS, look for small eggs, accessed from Kristopher Abell, University of Massachusetts, Bugwood.org

Life Cycle: “Crawlers” hatch from eggs under the female scale and emerge in the spring and summer. At this point they are mobile and can crawl to a new needle or be transported by wind or birds. Once they find a suitable site for feeding, they burrow under the waxy cuticle of the needle for protection, and insert their feeding tube into the mesophyll cells of the needle, just under the epidermis or surface layer of cells on the needs. The females will never leave this site as they go through their three stages of development. The males, however, will emerge from their five stages of development as winged adults. They will fly to a mature female, mate, and die without ever feeding. EHS overwinters either as fertilized females or eggs (typically 16-20 are laid). (Jill Sidebottom, Elongate Hemlock Scale, ncsu.edu).

Damage Pennsylvania Department of Conservation and Natural Resources -ugwood.org
EHS damage, photo accessed from Pennsylvania Department of Conservation and Natural Resources – Forestry , Bugwood.org

As EHS feeds on the hemlock needs they remove the plant’s nutrients, the needles take on a yellow color as they dry out and drop, leading to branch dieback and ultimately death in as little as ten years.

Control: One option of control is to remove highly infested trees. EHS can also be controlled chemically. The two most consistent chemical controls for EHS are Safari (a neonicotinoid) and Talus (an insect growth regulator). Safari is also used to control hemlock wooly adelgid, another invasive pest from Japan that often appears alongside EHS as white wooly ovisacs on the underside of hemlock needles. EHS can also be treated with biological agents, such as the parasitic wasp Encarsia citrina, and predatory beetles like the twice-stabbed ladybird beetle, Chilocorus stigma and Microweisea misella (Mark S. McClure, The Connecticut Agricultural Experiment Station). These biological controls have provided inconsistent results and are also susceptible to pesticides, so pesticide should be applied with that in mind. To report sightings of EHS in New York State Parks, visit  iMap Invasives or for other questions regarding invasives, email the Invasive Species Management Team at invasives@parks.ny.gov

The Invasive Species Management Team consists of Strike Teams and Forest Health Specialists. Strike Teams travel statewide for various invasive plant removal projects. Forest Health Specialists travel statewide as well, monitoring trees for the presence of forest pests like EHS and HWA among others.

Post by Sarantia Mitsinikos, Invasive Species Project Steward

Featured image photo by Irene Brenner

Invasive Species Spotlight – Leafy Spurge

Name: Leafy Spurge (Euphorbia esula)

Origin: Eurasia

NYS Presence: Leafy spurge has been identified in more than 15 counties across the state. It is found in grasslands, meadows, and riparian areas.

Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Yellow-green leafy spurge plants in a field, photo by Leslie J. Mehrhoff, University of Connecticut, assessed from Bugwood.org

Species Profile: Leafy spurge is a perennial plant that spreads by both seed and its extensive root system. These roots have little pink buds that produce new shoots or roots. The root system can reach depths of 30 feet into the soil, making it a tough invasive to control.The leaves are narrow and linear with lengths as long as 4 inches. They are arranged alternately on the pale green stems of the plant.

Euphorbia esula
A yellow-green leafy spurge flower, photo by Matt Lavin from Bozeman, Montana, USA, accessed from Wikicommons

Two key characteristics to look for when trying to identify leafy spurge are:

  1. the plant’s tiny yellowish-green flowers, which grow in groups of three. Each one is enclosed by a pair of heart-shaped bracts (leaflike structure beneath the flower). Flowering begins in mid-May and will in some cases last until mid-Autumn.
  2. The second is the white, milky sap within the plant. Any stem or leave breakage will result in the release of this sap. There are a number of similar species of spurge species in the state, some which are also non-native and invasive.
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Leafy spurge plants, photo by Leslie J. Mehrhoff, University of Connecticut, accessed from Bugwood.org

The leafy spurge’s ability to spread at a fast pace make this invasive plant highly competitive. Dense stands will often smother or shade out other native species, therefore decreasing biodiversity. This species is a threat to native grasslands, meadows, and agricultural lands. Although cattle are not particularly fond of leafy spurge, sheep and goats have been known to snack on it and spread the seeds around in the process.

Resources:

New York Invasive Species leafy spurge

Colorado Department of Agriculture Leafy spurge identification and management

Featured image: Matt Lavin from Bozeman, Montana, USA, accessed from Wikicommons

Invasive Species Spotlight – Mugwort

Name: Mugwort or Common Wormwood (Artemisia vulgaris)

Origin: Mugwort is native to Europe and Asia, where it was utilized as a medicinal and culinary herb. It was introduced to North America through ship ballast and continues to spread across the continent via nursery stock, turf grass and roadways.

NYS Presence: Widespread throughout the state and often found in ditches, roadsides, pastures and other disturbed areas.

Species Profile: Mugwort is a perennial that flowers in late summer to early fall. Its alternating dark green leaves are smooth on top and have silvery-white hairs underneath. When the foliage is crushed it is known to release a pungent odor. One plant can produce as much as 200,000 seeds which are roughly 1mm in diameter and are spread by the wind and easily moved around on tires, mowers and construction equipment. As a result, Mugwort can be found along miles of roadside.

Mugwort
Note the difference in color from the top (green) and the bottom (gray), image from https://extension.umass.edu/landscape/weeds/artemisia-vulgaris

Although seed dispersal plays a large role in the spread of this invasive weed, its root system is also a culprit in increase this weed’s introduction to new sites. Nursery stock including ornamental plants, turf grass, and orchard stock are easily contaminated by these root fragments and carried into new places. Mugwort’s rhizomatous roots – an extensive and dense underground network — and the abundance of seeds make this species very hard to control.

ArtemisiaVulgaris_Christian Fischer, accessed from Wikicommons
Mugwort in flower, photo by Christian Fischer, accessed from Wikicommons.org

Mugwort has displaced many native plants, especially those that thrive in sunny, open habitat. Cleaning equipment, using clean fill (e.g., at construction or landscaping sites), and removing and disposing of any new infestations of Mugwort are some of the ways to reduce the spread of this plant.

Resources:

Barney, J.N. and A. DiTommaso. 2003. The biology of Canadian weeds. 118. Artemisia vulgaris L. Canadian Journal of Plant Science 83:205-215.

https://www.forestandwatersolutions.com/uploads/3/6/3/1/3631108/japanese_knotweed_mugwort_pale_swallowort.pdf

http://www.nyis.info/index.php?action=invasive_detail&id=63

http://www.nrcresearchpress.com/doi/pdf/10.4141/P01-098

Featured image, mugwort growing along a forest edge, photo by Ansel Oommen, Bugwood.org