Poison sumac grows in rich shrub fens. Like poison ivy and poison oak, poison sumac contains the chemical urushiol, which can cause a skin rash upon contact by sensitive people. If ingested or inhaled, the urushiols attack the mucous membranes of mouth, nose, and intestines and can cause death. However, the fruit is non-toxic to, and is commonly eaten by, birds and other animals.
There are about one hundred occurrences statewide. Some documented occurrences have good viability and several are protected on public land or private conservation land. This community is limited to the calcareous areas of the state and is restricted to wetlands that gain most of their moisture from underground sources that flow through calcareous substrates. There are a few large, high quality examples. Most sites are small and some are very disturbed. The current trend of this community is probably stable for occurrences on public land, or declining slightly elsewhere due to moderate threats related to development pressure or alteration to the natural hydrology.
The number and acreage of rich shrub fens in New York have probably remained stable (or have slightly declined) in recent decades as a result of wetland protection regulations.
The number and acreage of rich shrub fens in New York have probably declined substantially from historical numbers likely correlated with the onset of agricultural and residential development. While the historical range and number of occurrences are unknown, two-thirds of our currently known examples of this community are smaller than 11 acres. These small wetland patches are most likely to be filled or otherwise altered. Thus, we estimate that there are many fewer examples today than 100 years ago.
Agricultural and residential development pressures are the greatest threat to this community. Aside from direct mowing, tilling, or filling of these wetlands, non-point source pollution from adjacent agricultural and residential lands can significantly alter the water chemistry or hydrology of the natural community. Additional threats include other alterations to the local hydrology and invasion by non-native invasive exotic plants, especially purple loosestrife (Lythrum salicaria) and common reed (Phragmites australis ssp. australis).
Consider how water flows around and into this wetland. As most of the water inputs are from underground, management for the prevention of altered water quality and quantity is particularly difficult for this natural community, but should be of the utmost priority. Projects that occur near this community must consider the proximity of the development to this wetland and the potential for changing how water flows, both aboveground and belowground, into this wetland. Terrestrial buffers provide nesting habitat for resident salamanders, frogs, and turtles, and additional food sources for locally nesting birds, and thus should be retained. Consultation with a hydrologist is important to determine patterns of run-off and underground water sources for the wetland; in addition, the construction of impervious surfaces that would rapidly deliver water to the wetland should be avoided. Rapid influxes of surface water dilute the limey, mineral rich waters, decrease the robustness of the native fen species, and increase the likelihood of invasion by non-native species.
When considering road construction and other development activities minimize actions that will change what water carries and how water travels to this community, both on the surface and underground. Water traveling over-the-ground as run-off usually carries an abundance of silt, clay, and other particulates during (and often after) a construction project. While still suspended in the water, these particulates make it difficult for aquatic animals to find food; after settling to the bottom of the wetland, these particulates bury small plants and animals and alter the natural functions of the community in many other ways. Thus, road construction and development activities near this community type should strive to minimize particulate-laden run-off into this community. Water traveling on the ground or seeping through the ground also carries dissolved minerals and chemicals. Road salt, for example, is becoming an increasing problem both to natural communities and as a contaminant in household wells. Fertilizers, detergents, and other chemicals that increase the nutrient levels in wetlands cause algae blooms and eventually an oxygen-depleted environment where few animals can live. Herbicides and pesticides often travel far from where they are applied and have lasting effects on the quality of the natural community. So, road construction and other development activities should strive to consider: 1. how water moves through the ground, 2. the types of dissolved substances these development activities may release, and 3. how to minimize the potential for these dissolved substances to reach this natural community.
Additional inventory efforts in regions with calcareous bedrock and promising wetlands will likely turn up a few additional sites. Re-inventories of known sites will provide important information to help assess short- and long-term changes. Survey fens that provide habitat for rare species. For example, extant bog turtle sites should be surveyed to determine the type and quality of the natural community if it is unknown.
Research better ways to accurately and efficiently measure and understand groundwater hydrology of fens. Further research into determining the proportion of fen water inputs is needed (e.g., groundwater vs. surface). If a fen is strongly groundwater influenced, traditional wetland buffers aimed at reducing surface water run-off may not sufficiently protect fen groundwater hydrology.
This community is currently known from the Hudson Valley, the St. Lawrence Valley, and scattered locations within the limestone belt that runs from Albany to Niaraga Falls. Additional occurrences may be located elsewhere in the state where similar environmental conditions are present.
The physically broadly-defined community may be widespread in areas of the United States and worldwide with calcareous peats. Examples with the greatest biotic affinities to New York occurrences are suspected to extend north into Ontario, south to the Central Appalachians of North Carolina and Tennessee, west to Wisconsin and Iowa, east to western New England, and northeast to New Brunswick. Few examples are suspected east of the Appalachian Divide, where the bedrock is mostly acidic.
A strongly minerotrophic peatland in which the substrate is a woody peat, which may or may not be underlain by marl or limestone bedrock. Rich fens are fed by waters that have high concentrations of minerals and high pH values, generally from 6.0 to 7.8. The dominant species in rich shrub fens are shrubs, which form a canopy and overtop most herbs. Some rich shrub fens are dominated by low shrubs (under 4 ft or 1.2 m) that collectively have 80 to 90% cover in the community. Other rich shrub fens are dominated by taller shrubs (over 4 ft or 1.2 m) that collectively have 50 to 70% cover in the community with low shrubs and graminoids locally dominant in openings. The rich shrub fen community is somewhat broadly defined to include both the low shrub and taller shrub examples as well as regional variants distinguished by variations in their flora such as the lack of shrubby cinquefoil (Dasiphora fruticosa ssp. floribunda) in northern examples. In rich shrub fens, peat mosses (Sphagnum spp.) are either absent or a minor component, with only the most minerotrophic species present. Other mosses may be common.
Look for sites that seem to be wet from groundwater, not from adjacent streams or ponds. A typical example has a high abundance of shrubs that like such "rich" or "sweet" water. Characteristic shrubs and small trees include red maple (Acer rubrum), red osier dogwood (Cornus sericea), speckled alder (Alnus incana ssp. rugosa), sweet-gale (Myrica gale), shrubby cinquefoil (Dasiphora fruticosa ssp. floribunda), swamp fly honeysuckle (Lonicera oblongifolia), black chokeberry (Photinia melanocarpa), alder-leaf buckthorn (Rhamnus alnifolia), and poison sumac (Toxicodendron vernix). Characteristic herbs include marsh fern (Thelypteris palustris), royal fern (Osmunda regalis), sedges (Carex stricta, C. interior), common cat-tail (Typha latifolia), bluejoint grass (Calamagrostis canadensis), tall meadow-rue (Thalictrum pubescens), water horsetail (Equisetum fluviatile), and marsh St. John's-wort (Triadenum virginicum). Characteristic nonvascular species include the mosses Brachythecium oedipodium, Campylium polygamum, Eurhynchium pulchellum, Helodium blandowii, Scorpidium cossonii, the rare scorpion feather moss (Scorpidium scorpioides), the peat moss Sphagnum teres, the leafy liverwort Calypogeia sphagnicola, and the thalloid liverworts Pallavicinia lyellii and Pellia epiphylla. The moss Calliergon giganteum becomes characteristically abundant in this community. Additional rich shrub fen bryophytes common to other rich fen types include the mosses Aulacomnium palustre, Bryum pseudotriquetrum, Calliergonella cuspidata, Campylium stellatum, Cratoneuron filicinum, Fissidens adianthoides, the peat moss Sphagnum warnstorfii, the rare golden moss (Tomentypnum nitens), and the thalloid liverwort Aneura pinguis.
Known examples of this community have been found at elevations between 230 feet and 770 feet.
One of the best times to visit this community is when the showy yellow flowers of shrubby cinquefoil are in full bloom, usually from mid July to mid August.
This New York natural community encompasses all or part of the concept of the following International Vegetation Classification (IVC) natural community associations. These are often described at finer resolution than New York's natural communities. The IVC is developed and maintained by NatureServe.
This New York natural community falls into the following ecological system(s). Ecological systems are often described at a coarser resolution than New York's natural communities and tend to represent clusters of associations found in similar environments. The ecological systems project is developed and maintained by NatureServe.
Alnus incana ssp. rugosa (speckled alder)
Fraxinus pennsylvanica (green ash)
Toxicodendron vernix (poison-sumac)
Alnus incana ssp. rugosa (speckled alder)
Cornus amomum ssp. amomum (silky dogwood)
Cornus sericea (red-osier dogwood)
Dasiphora fruticosa ssp. floribunda
Ilex verticillata (common winterberry)
Larix laricina (tamarack)
Lonicera oblongifolia (swamp fly honeysuckle)
Rhamnus alnifolia (alder-leaved buckthorn)
Salix candida (sage-leaved willow)
Carex flava (yellow sedge)
Carex interior (inland sedge)
Carex lacustris (lake-bank sedge)
Iris versicolor (blue flag)
Parnassia glauca (common grass-of-Parnassus)
Symplocarpus foetidus (skunk-cabbage)
This figure helps visualize the structure and "look" or "feel" of a typical Rich Shrub Fen. Each bar represents the amount of "coverage" for all the species growing at that height. Because layers overlap (shrubs may grow under trees, for example), the shaded regions can add up to more than 100%.
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Langdon, Stephen F., M. Dovciak, and D.J. Leopold. 2020. Tree Encroachment Varies by Plant Community in a Large Boreal Peatland Complex in the Boreal-Temperate Ecotone of Northeastern USA. Wetlands. https://doi.org/10.1007/s13157-020-01319-z
Motzkin, G. 1994. Calcareous fens of western New England and adjacent New York State. Rhodora. 96(885): 44-68.
NatureServe. 2015. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer.
New York Natural Heritage Program. 2023. New York Natural Heritage Program Databases. Albany, NY.
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New York State Department of Environmental Conservation. 1995. Freshwater Wetlands: Delineation Manual. July 1995. New York State Department of Environmental Conservation. Division of Fish, Wildlife, and Marine Resources. Bureau of Habitat. Albany, NY.
Olivero, Adele M. 2001. Classification and Mapping of New York's Calcareous Fen Communities. A summary report prepared for the Nature Conservancy - Central/Western New York Chapter with funding from the Biodiversity Research Institute. New York Natural Heritage Program, New York State Department of Environmental Conservation. Albany, NY. 28 pp. plus nine appendices.
Olivero, Adele. 2002. Survey of Eastern New York's calcareous fens in the Mount Everett-Mount Riga landscape. A report prepared for the Nature Conservancy Eastern New York Chapter. New York Natural Heritage Program, New York State Department of Environmental Conservation. Albany, NY. 31 pp. plus appendices.
Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.
Slack, Nancy G. 1994. Can one tell the mire type from the bryophytes alone? J. Hattori Bot. Lab 75:149-159.
This guide was authored by: Aissa Feldmann
Information for this guide was last updated on: May 29, 2020
Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Rich shrub fen. Available from: https://guides.nynhp.org/rich-shrub-fen/. Accessed March 23, 2023.