Alvar is a Swedish term to describe barrens and grassland vegetation that grows on thin soils over level outcrops of limestone or dolomite bedrock. This community is limited to areas in Jefferson County underlain with Chaumont limestone (Galoo-Rock outcrop complex).
There are probably much less than 30 occurrences statewide. A few documented occurrences have good viability and several are protected on public land or private conservation land. This community is limited to areas in Jefferson County underlain with Chaumont limestone (Galoo-Rock outcrop complex), and there are only a few high quality examples. The current trend of this community is probably stable for occurrences on public land and private conservation land, or declining slightly elsewhere due to moderate threats that include conversion to pastureland, development, trampling by visitors, ATVs, and invasive species.
It is estimated that wet alvar grassland acreage has declined 10-30% within the last 100 years.
The current acreage is estimated to be less than half of the historical acreage.
Threats are the invasion of exotic plants (in particular pale swallow-wort, buckthorn and honeysuckles), grazing, trampling (especially ORV damage), hydrologic alterations, and development pressure in Jefferson County.
Maintain the mosaic proportional distribution of existing alvar communities by ensuring the the pavement areas and grasslands are kept open. Alvar communities seem to require seasonal flooding, and maintenance of the natural hydrologic regime is critical. Take measures to exclude use of sites by ORVs. Prescribed fire may be a useful tool to promote native plant species diversity (care should be taken in selecting sites for its introduction) and the maintanence of open site conditions (Kost et al. 2007). Develop and implement a prescribed burn plan at appropriate sites. Improve the condition of existing alvar communities by reducing and/or eliminating invasive species, such as black swallow-wort (Cynanchum louiseae), Morrow's honeysuckle (Lonicera morrowii), and buckthorn (Rhamnus cathartica). Identify and target areas with early infestations of invasive exotic plants for control and eradication. Improve the condition of the alvar communities by minimizing trail network and clearly marking existing trails. Improve the landscape context of the barrens by encouraging surrounding landowners to establish natural buffers and restore natural corridors to other larger natural landscape blocks.
Minimize road construction through or bordering these grasslands as their hydrology is very sensitive, easily altered and they are very susceptible to the introduction of invasive exotic plants. Soils are very thin or lacking in and around this community and the effect of clearing and construction on soil retention and erosion must be considered during any development activities. Similarly, these pavements have wide cracks and fissures and any nutrient enrichment (e.g., from septic leach fields and fertilized lawns) may rapidly decrease the water quality of underlying aquifers as well as altering the grassland community structure and function (White 1977).
The alvar communities in Jefferson County need to be inventoried and remapped using the current classification of alvar communities: 1) alvar pavement grassland, 2) alvar shrubland, 3) alvar woodland, 4) dry alvar grassland, and 5) wet alvar grassland. Survey for additional occurrences in Jefferson County and the surrounding region to advance documentation and classification of wet alvar grasslands. Continue searching for large sites in excellent to good condition (A- to AB-ranked). Periodic inventory of the wet alvar grasslands is needed, in order to keep occurrence data current. Quantitative data on composition and variability among patches within occurrences are needed from surveys throughout the growing season. Surveys for rare and characteristic invertebrate species (especially butterflies and moths, along with terrestrial molluscs) are needed for many sites.
Research the composition of wet alvar grasslands in Jefferson County in order to characterize variations and distinguish it from other alvar communities. Studies of the hydrology of alvar communities (a past study was conducted at Chaumont Barrens) and their immediately surrounding landscape are needed to better understand their hydrologic regimes. Continue long-term monitoring of deer browsing and grazing impacts. Establish a monitoring progam at various sites to understand and track the development of impacts from global climate change. Identify areas where fire can be implemented and evaluated as a management tool, including a flora and fauna monitoring component (Reschke et al. 1999).
Restricted to outcrops of Chaumont limestone (Galoo-Rock outcrop complex) in Jefferson County. New York's sites are at the easternmost edge of a narrow range extending across southern Ontario to the eastern edge of northern Michigan. There are about 54 square miles (34,368 acres) of Galoo-Rock outcrop complex mapped in Jefferson County in the Soil Survey Geographic (SSURGO) database for New York.
The wet alvar grassland occurs in the Great Lakes region of the United States and Canada, ranging from northern Michigan and southern Ontario to northern New York (NatureServe Explorer 2015).
The dominant grasses and sedges are tufted hairgrass (Deschampsia cespitosa), Crawe's sedge (Carex crawei), prairie dropseed (Sporobolus heterolepis), and flat-stemmed spikerush (Eleocharis elliptica var. elliptica). Other characteristic grasses and herbs include balsam ragwort (Packera paupercula), small rush grass (Sporobolus neglectus), sheathed rush grass (S. vaginiflorus), false pennyroyal (Trichostema brachiatum), and wild chives (Allium schoenoprasum). Typically there are several turf and weft mosses forming a patchy mat at the base of grasses and forbs; typical mosses are Bryum pseudo-triquetrum, Abietinella abietinum, Tortella tortuosa, and Drepanocladus spp.
This community is a grassland community that occurs on very shallow, organic soils that cover limestone or dolostone bedrock. Average soil depths in this grassland community are less than 10 cm. This community has a characteristic soil moisture regime of alternating wet and dry seasons; many of them have flooded or saturated soils in early spring and late fall, combined with summer drought in most years. Wet alvar grasslands occur on Chaumont limestone (Galoo-Rock outcrop complex).
Known examples of this community have been found at elevations between 339 feet and 377 feet.
In late May, visitors can enjoy a diverse succession of native wildflowers in bloom, especially prairie-smoke (Geum triflorum), which can be seen nowhere else in the northeast.
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.
Cornus racemosa (gray dogwood, red-panicled dogwood)
Rosa blanda (smooth rose)
Allium schoenoprasum (chives)
Bromus kalmii (Kalm's brome)
Carex castanea var. pilosum
Carex crawei (Crawe's sedge)
Carex granularis (limestone-meadow sedge)
Carex molesta (troublesome sedge)
Castilleja coccinea (Indian paint-brush, scarlet paint-brush)
Clinopodium vulgare (wild-basil)
Danthonia spicata (poverty grass)
Deschampsia cespitosa (tufted hair grass)
Muhlenbergia glomerata (spike muhly)
Packera paupercula (balsam groundsel)
Poa compressa (flat-stemmed blue grass, Canada blue grass)
Solidago juncea (early goldenrod)
Sporobolus heterolepis (prairie dropseed)
Sporobolus neglectus (small dropseed)
Trichostema brachiatum (false pennyroyal)
Zigadenus elegans ssp. glaucus
Zizia aurea (common golden Alexanders)
This figure helps visualize the structure and "look" or "feel" of a typical Wet Alvar Grassland. 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%.
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. https://www.nynhp.org/ecological-communities/
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.
Gilman, B. 1998. Alvars of New York: a site summary. Finger Lakes Community College. Canadaigua, NY.
Grossman, D. H., K. Lemon Goodin, and C. L. Reuss, editors. 1994. Rare plant communities of the conterminous United States: An initial survey. The Nature Conservancy. Arlington, VA. 620 pp.
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.
Reschke, C., R. Reid, J. Jones, T. Feeney, and H. Potter. 1999. Conserving Great Lakes Alvars: final technical report of the International Alvar Conservation Initiative. The Nature Conservancy, Great Lakes Program, Chicago, IL.
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.
This guide was authored by: Gregory J. Edinger
Information for this guide was last updated on: April 29, 2019
Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Wet alvar grassland. Available from: https://guides.nynhp.org/wet-alvar-grassland/. Accessed May 29, 2023.