Perched bogs are named because they occur in depressions and valleys where a perched water table is present. A perched water table is groundwater that is separated from the main groundwater table below it by an impermeable layer. Since this water is supplied by a shallow perched water table, perched bogs have lower pH values, lower specific conductivity, lower minerals, lower nutrients, and lower biodiversity than non-perched bogs.
There are very few occurrences of perched bogs statewide. Perched bogs are usually too small to be protected by the New York State freshwater wetland regulations. A few documented occurrences have good viability and are protected on public land or private conservation land. This community has limited statewide distribution and tends to be embedded within barrens or rocky summits that depend on fire to maintain an open habitat. 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, alteration to the natural hydrology, reduced protection regulations for isolated wetlands, and perhaps fire suppression. This community has declined moderately from historical numbers likely correlated with mining, logging, and development of the surrounding landscape.
The numbers and acreage of perched bogs in New York have probably remained stable in recent decades as a result of wetland protection regulations, but may decline in the future with reduced protection regulations for isolated wetlands.
The numbers and acreage of perched bogs in New York have probably declined moderately from historical numbers likely correlated with logging and development of the surrounding landscape (increasing nutrient run-off into bogs).
Perched bogs are threatened by development and its associated run-off, recreational overuse (e.g., snowmobiles, hiking trails that cause peat compaction), and habitat alteration in the adjacent landscape (e.g., mining, logging, pollution, nutrient loading). Alteration to the natural hydrology is also a threat to this community (e.g., flooding or draining). Since many perched bogs are embedded within barrens or rocky summits, fire suppression may be an additional threat to this community. Although invasive species are currently not a threat to perched bogs, reedgrass (Phragmites australis ssp. australis) and purple loosestrife (Lythrum salicaria) may become a problem in the future. Perched bogs are usually too small to be protected by the New York State freshwater wetland regulations.In 2001, the federal Supreme Court ruled that the US Congress did not give authority to the US Army Corps of Engineers (US ACE) under section 404 of the Clean Water Act to regulate the filling of isolated wetlands. This decision led US EPA and US ACE officials to issue guidance in January 2003 that made it more difficult for regulators to protect isolated wetlands, such as perched bogs (Comer et al. 2005).
Because perched bogs are naturally acidic and low in nutrients, they are particularly susceptible to alteration by elevated nutrient inputs. Bogs may require larger buffers than other wetland types because of their high susceptibility to changes in nutrient concentrations. Direct impacts are typically most serious within 300 feet (90 m) of wetland areas (Sperduto et al. 2000).
Where practical, establish and maintain a natural wetland buffer to reduce storm-water, pollution, and nutrient run-off, while simultaneously capturing sediments before they reach the bog. Buffer width should take into account the erodibility of the surrounding soils, slope steepness, and current land use. Wetlands protected under Article 24 are known as New York State "regulated" wetlands. The regulated area includes the wetlands themselves, as well as a protective buffer or "adjacent area" extending 100 feet landward of the wetland boundary (NYS DEC 1995). If possible, minimize the number and size of impervious surfaces in the surrounding landscape. Avoid habitat alteration within the wetland and surrounding landscape. For example, roads and trails should be routed around wetlands, and ideally not pass through the buffer area. If the wetland must be crossed, then bridges and boardwalks are preferred over filling. Restore perched bogs that have been unnaturally disturbed (e.g., remove obsolete impoundments and ditches in order to restore the natural hydrology). Prevent the spread of invasive exotic species into the wetland through appropriate direct management, and by minimizing potential dispersal corridors, such as roads.
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.
Survey for occurrences statewide to advance documentation and classification of peatlands. A statewide review of the acidic peatlands including perched bogs is desirable, similar to the studies done in New Hampshire (Sperduto et al. 2000), Massachusetts (Kearsley 1999), and similar to what New York Natural Heritage did for rich fens (Olivero 2001).
Research is needed to fill information gaps about perched bogs, especially to advance our understanding of their classification, ecological processes (e.g., fire), hydrology, floristic variation, characteristic fauna, and bog development and succession. A comparison of perched bogs on various bedrock types is desirable (e.g., sandstone vs. conglomerate). This research will provide the basic facts necessary to assess how human alterations in the landscape affect peatlands, and supply a framework for evaluating the relative value of peat bogs (Damman and French 1987).
Perched bogs are currently known from the Champlain Lake region in Clinton County, the Indian River Lakes and eastern Ontario plain region in St. Lawrence County, and the Shawangunk Hills in Ulster County.
This community is possibly limited to low elevation portions of the Great Lakes basin and the eastern fringe of the High Allegheny Plateau, generally where the bedrock is sandstone. The range outside of New York is uncertain. This community may also occur in Quebec and Maine. Occurrences similar to those in New York are reported from Michigan, Pennsylvania, and West Virginia. The range is estimated to span north to central Canada, west possibly to Minnesota, south to West Virginia, and east to Maine.
An ombrotrophic or weakly minerotrophic peatland that occurs in shallow depressions in level or nearly level rock outcrops where there is a perched water table and shallow peat.
The plant community is typically dominated by peat mosses and dwarf ericaceous shrubs, but the herbaceous layer may be dense as well. The water is very acidic with a pH less than 5.0. The depth to bedrock is shallow compared to other open peatlands with the peat depth often under 0.5 meters, but may reach 1 meter on occasion.
Known examples of this community have been found at elevations between 760 feet and 2,200 feet.
During early to midsummer, plant species such as the ericaceous shrub species (leatherleaf, sheep laurel), the blueflag iris, and the insectivorous pitcher-plants come into bloom. During midsummer, the dark pink flowering spikes of hardhack spiraea appear, and highbush blueberries come into fruit. Autumn brings dramatic red coloration to many of the plants that inhabit perched bog communities.
Spiraea tomentosa var. tomentosa
Vaccinium corymbosum (highbush blueberry)
Chamaedaphne calyculata (leatherleaf)
Vaccinium corymbosum (highbush blueberry)
Carex lacustris (lake-bank sedge)
Drosera intermedia (spatulate-leaved sundew)
Eriophorum virginicum (tawny cotton-grass)
Iris versicolor (blue flag)
Juncus brevicaudatus (narrow-panicled rush)
Sarracenia purpurea (purple pitcherplant)
Scirpus cyperinus (common wool-grass)
This figure helps visualize the structure and "look" or "feel" of a typical Perched Bog. 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%.
Andrus, R.E. 1980. Sphagnaceae (Peat Moss Family) of New York State. Bulletin No. 442. New York State Museum. Albany, NY.
Comer, P. K. Goodin, G. Hammerson, S. Menard, M. Pyne, M.Reid, M. Robles, M. Russo, L. Sneddon, K. Sno, A. Tomaino, and M. Tuffy. 2005. Biodiversity Values of Geographically Isolated Wetlands: An Analysis of 20 U.S. States. NatureServe, Arlington, VA.
Cowardin, L.M., V. Carter, F.C. Golet, and E.T. La Roe. 1979. Classification of wetlands and deepwater habitats of the United States. U.S. Fish and Wildlife Service. Washington, D.C. 131 pp.
Damman, A.W.H. and T.W. French. 1987. The ecology of peat bogs of the glaciated northeastern United States: a community profile. U.S. Fish and Wildlife Service Biological Report 85(7.16). 100 pp.
Edinger, G. J., D. J. Evans, S. Gebauer, T. G. Howard, D. M. Hunt, and A. M. Olivero (editors). 2014. Ecological Communities of New York State. Second Edition. A revised and expanded edition of Carol Reschke’s Ecological Communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation, Albany, NY. http://www.dec.ny.gov/docs/wildlife_pdf/ecocomm2014.pdf
Edinger, Gregory J., D.J. Evans, Shane Gebauer, Timothy G. Howard, David M. Hunt, and Adele M. Olivero (editors). 2002. Ecological Communities of New York State. Second Edition. A revised and expanded edition of Carol Reschke's Ecological Communities of New York State. (Draft for review). New York Natural Heritage Program, New York State Department of Environmental Conservation. Albany, NY. 136 pp.
Johnson, Charles W. 1985. Bogs of the northeast. University Press of New England, Hanover, New Hampshire.
Kearsley, J. 1999. Non-forested acidic peatlands of Massachusetts: A statewide inventory and vegetation classification. Massachusetts Natural Heritage and Endangered Species Program, Westborough, MA.
New York Natural Heritage Program. 2019. New York Natural Heritage Program Databases. Albany, NY.
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.
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.
Sperduto, D.D. and W.F. Nichols. 2000. Exemplary bogs and fens of New Hampshire. New Hampshire Natural Heritage Inventory, Concord, New Hampshire.
Sperduto, D.D., W.F. Nichols, and N. Cleavitt. 2000. Bogs and fens of New Hampshire. New Hampshire Natural Heritage Inventory, Concord, New Hampshire.
This guide was authored by: Jennifer Garrett
Information for this guide was last updated on: March 22, 2017
Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Perched bog. Available from: https://guides.nynhp.org/perched-bog/. Accessed March 19, 2019.