LIISMA has approved six invasive species subcontracts with funding from the New York State Environmental Protection Fund (EPF). EPF is administered by the New York State Department of Environmental Conservation. The projects involve invasive species management and outreach across the LIISMA region, from Staten Island to Montauk. This month, we are highlighting a project in our own backyard: comparative invasive viburnum management research and tier 2 invasive species eradication at the Sisters of Saint Joseph in Brentwood!
Knowing that almost 40% of the invasive plants now in the US were brought in initially as horticultural plants, it’s no surprise that the LIISMA region has an astonishing number of tier 5 invasive plants (460 according to our records). If you’re not familiar with the New York State PRISM tier ranking system for invasive species prioritization, a tier 5 invasive species is one that is already found in a given area, but requires more information on its spread and ecological impact. Two such plants on this section of the tier list are tea Viburnum (Viburnum setigerum) and linden viburnum (Viburnum dilatatum).
Historically, these plants native to Asia have been introduced through the horticultural trade as easy and fast growing shrubs with attractive red fruits. Like many invasives, the characteristics that made them favorable to gardeners are the same ones that have led to their success as forest invaders. They seem to thrive in disturbed soils, have suckering tendencies, and are rather shade tolerant. What’s more, they hang on to their berries late into the season, and with few other fruiting plants in the midst of winter, this characteristic allows their seeds to be easily dispersed by overwintering birds.
It wasn’t long before The Sisters of Saint Joseph (CSJ) Landscape Ecologist Amanda Furcall pointed one out to me on a warm December morning, still bearing it’s red fruits. This marked the beginning of our survey in the 40 acres of pitch pine/oak/heath woodland in the middle of Brentwood. We would continue to click the respective buttons for tea viburnum and linden viburnum on ArcGIS quick capture, our map quickly filling with colored data points. Furcall stewards all of the natural habitats within the CSJ property – from forest to agricultural easement, to the solar array and the newly constructed treatment wetland. With her wide brimmed hat, she can be found replacing hedgerows of invasive Miscanthus with natives like red-osier dogwood, or discussing watering plans with any one of the 8 farms on the property. But now, armed with a subcontract granted by LIISMA, she has traded her sunhat for a knitted one and has set out to survey the forest where invasive viburnums have been popping up.
The management of these viburnums was an easy decision for Furcall. In her proposal she says: “In order to avoid the ‘invasive treadmill’ where removal of one species causes the rise of another, we intend to rapidly control the invading viburnum, plant natives in their place and support a healthy forest ecosystem so that it will be resilient to future invasions.” But what started the ‘treadmill’ at this site? It was a forest disturbance, triggered by an insect that targets our native pines.
Like much of the pine barrens found further east on Long Island, southern pine beetle (Dendroctonus frontalis; SPB) has been documented here at CSJ in recent years. With Furcall on the lookout, early symptoms have been quickly followed up with cutting and splitting of the infested pitch pines (Pinus rigida) to prevent SPB’s further spread. While the rapid response of this tier 2 species has allowed other pines to stay SPB-free, it has prompted new management questions. The open spots in the canopy create opportunities for invasive species to take hold in the understory. In this case, tea viburnum and linden viburnum are the culprits.
At CSJ, these invasive viburnums are found growing in and around native viburnums, including maple leaf viburnum (Viburnum acerifolium), blackhaw (Viburnum prunifolium), and southern arrowwood (Viburnum dentatum), as well as other native shrubs like blueberries (Vaccinium spp) and huckleberries (Gaylussacia spp).
Furcall goes on to say: “There is a need to have [tea viburnum] mapped to assess its invasiveness and to weigh control methods. In fact, this species is showing signs that it will become a significant management challenge in the future as it has been observed spreading in the Long Island Central Pine Barrens Invasive Species Management Complex.” This past year, these viburnums have been seen within the Rocky Point Natural Resource Management Area, near Sears Bellows and West Hills county parks. As well, a quick glance at reports of these species on iNaturalist generates a handful of points from Queens to Middle Island. Unfortunately, their full extent is probably underreported. However, this is why we are so excited about the work being done at CSJ through this subcontract; it directly implements the actions recommended by the NYS Tier Ranking list: research and collect information.
This project will map the viburnums’ occurrences on the Brentwood campus, which will be entered into iMapInvasives. Along with mapping, different management techniques will be tested for efficacy: comparing the effects of pulling, cutting, cutting and painting stumps with a 20% glyphosate solution, and lastly a foliar spray of a 3.75% Glyphosate solution.* Creating size classes of small, medium and large individuals will hopefully help to further inform management strategies for invasions of various sizes and ages. The resulting maps and research data will enable other land managers across LIISMA and the rest of NYS to manage their populations of invasive viburnum species.
Aside from mapping and treating invasive viburnums within the property, the subcontract will assist CSJ in controlling other invasive species on the property that have become established due to landscape dumping. Some of these include wintergreen barberry. (Berberis julianae) and fuzzy deutzia (Deutzia scabra); tier 2 species that have been recently detected within the woodland in low abundance, making the goal of eradication still feasible. Often invasive species removal efforts on the property are conducted by Furcall herself, her team of seasonal interns, and the occasional group of willing volunteers. In areas adjacent to high quality woodland, there are considerable amounts of poison ivy, making quick and skilled removal by contracted landscapers a necessity.
Walking through the woodland with Furcall, it’s easy to forget where we are standing. I zig-zag beside her, collecting more points. It isn’t until I am confronted with a fence line abbuted by a colorful plastic playground, or hear the sound of traffic or church bells in the near distance that I am reminded that this is but a small refugia in a greater suburban landscape. “Brentwood is considered an Environmental Justice area by New York State; a low-income and minority community that suffers from disproportionate exposure to potentially hazardous land uses” Furcall’s proposal recalls. Conducting environmental restoration here isn’t simply an ecological service, but it is a service to the many people that engage with the woodland, either intentionally on the cosmic walk, or inadvertently, by breathing the air these trees produce. In this way, Furcall describes the property as a, “Counteracting force,” that the, “Healthy forest sequesters carbon, purifies the air, cleans and replenishes drinking water and provides a meditative location for passive outdoor recreation.”
The Sisters of Saint Joseph land ethic statement reinforces this sentiment through their devotion not only to ecological restoration, but also to restorative justice; as one tennent points out: “Every member of the Earth community has intrinsic value in its being, and the right to live in its natural habitat, and to fulfill its role in the ever-renewing processes of Earth.” It’s why we’re grateful to work alongside Furcall and the Sisters – they remind us that invasive species work isn’t just for the blueberries and butterflies, but for the people we get to share them with, now and into the future.
*Herbicide rates as recommended by Lower Hudson Prism’s fact sheet for linden viburnum; with use as per label directions.
