Riverside sand and gravel bars provide favorable habitat for certain rare plants, such as swordleaf rush (Juncus ensifolius), dwarf bulrush (Lipocarpha micrantha), Carey's smartweed (Persicaria careyi), and low sand cherry (Prunus pumila var. depressa). However, these habitats are subject to multiple natural and human disturbances, making them particularly vulnerable to invasion by exotic plant species, such as Japanese knotweed (Reynoutria japonica var. japonica) and purple loosestrife (Lythrum salicaria). Ice scour and spring flooding from snow melt are natural processes that contribute to the dynamic nature of the plant communities and the substrate of riverside sand and gravel bars. In addition, artificial water-level fluctuation through the regulation of dams and reservoirs can influence these communities and the organisms that inhabit them.
There are probably several hundred 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 the rivers and streams with sand or gravel substrate in the state, and there are only a few high quality examples. The current trend of this community is probably stable for occurrences on public land, or declining slightly elsewhere due to moderate threats that include alteration to hydrology, shoreline development, instream gravel mining, and invasive species.
The number and acreage of riverside sand/gravel bars in New York have probably declined slightly in recent decades as a result of shoreline development, alteration to the hydrology, instream gravel mining, and invasive species.
The number and acreage of riverside sand/gravel bars in New York have probably declined moderately from historical numbers likely correlated to the alteration of natural hydrology from impoundments, shoreline hardening, and instream gravel mining.
Riverside sand/gravel bars are threatened by development (e.g., residential, agricultural, industrial) in the surrounding landscape. Structures built along the shoreline (e.g., riprap, boat launches) are a particular threat to this community. Other threats include habitat alteration (e.g., instream gravel mining, road crossings, logging in adjacent floodplain), and relatively minor recreational overuse (e.g., boating, ATVs, trampling by visitors, fishing, trash dumping). Threats to rivers may apply to the riverside sand/gravel bars (e.g., pollution, nutrient loading, sedimentation, impoundments, flooding, water release for rafting). Several riverside sand/gravel bars are threatened by non-native species.
Where practical, establish and maintain a natural riparian buffer to reduce storm-water, pollution, and nutrient run-off, while simultaneously capturing sediments before they reach the riverside sand/gravel bar. Avoid habitat alteration along the shoreline and surrounding landscape. Restore riverside sand/gravel bars that have been affected by unnatural disturbance (e.g., remove obsolete impoundments in order to restore the natural hydrology). Reduce or eliminate instream gravel mining from the best examples of riverside sand/gravel bar. Prevent the spread of invasive exotic species into the riverside sand/gravel bars through appropriate direct management, and by minimizing potential dispersal corridors, such as roads and bridges. Maintain or restore the natural flood and ice scour regime.
Where practical, establish and maintain a natural riparian buffer to filter storm-water, pollution, and nutrient run-off from surrounding uplands and to capture sediments before they reach the riverside sand/gravel bar. Avoid habitat alteration along the shoreline and surrounding landscape. Minimize potential dispersal corridors for exotic species, such as roads and bridges. Maintain or restore the natural flood and ice scour regime.
Survey for occurrences statewide to advance documentation and classification of riverside sand/gravel bars. Continue searching for large sites in good condition (A- to AB-ranked).
Research composition of riverside sand/gravel bars statewide in order to characterize variations and to clearly separate this community from cobble shore and cobble shore wet meadow.
Riverside sand/gravel bars are widespread throughout New York State. They are probably represented by different regional variants.
This physically broadly-defined community may be worldwide. Examples with the greatest biotic affinities to New York occurrences are suspected to span north to southern Canada, west to Minnesota, southwest to Indiana and Tennessee, southeast to Georgia, and northeast to Nova Scotia.
A meadow community that occurs on sand and gravel bars deposited within, or adjacent to, a river channel. The community can manifest in a variety of ways depending on rates of deposition and erosion of the sand or gravel substrate. Physiognomic variants include very sparse vegetation, tall or short herbs, dwarf shrubland, shrubland, or sparse woodland (Edinger et al. 2002).
Riverside sand/gravel bars can be found along streams throughout New York State. This community is identified by shoreline environments consisting of exposed, well-drained bars composed of sand and gravel (particles smaller than 10 cm in diameter). While the ratio of sand to gravel certainly varies from one occurrence to the next, a common proportion is roughly 70% sand to 30% gravel.
Known examples of this community have been found at elevations between 98 feet and 1,500 feet.
While this community can be indentified anytime during the snow-free seasons, it is most enjoyable to visit during the growing season, from late May through summer, when plants are flowering and water temperatures are conducive to wading.
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.
Acer saccharum (sugar maple)
Platanus occidentalis (eastern sycamore)
Salix interior (sandbar willow)
Platanus occidentalis (eastern sycamore)
Prunus pumila var. depressa (dwarf cherry)
Salix interior (sandbar willow)
Clematis virginiana (virgin's-bower)
Apocynum cannabinum (Indian-hemp)
Bidens frondosa (devil's beggar-ticks)
Daucus carota (wild carrot)
Doellingeria umbellata var. umbellata (tall flat-topped white-aster)
Dryopteris intermedia (evergreen wood fern, fancy wood fern, common wood fern)
Eupatorium perfoliatum (boneset)
Eutrochium maculatum var. maculatum (spotted Joe-Pye-weed)
Lycopus americanus (American bugleweed, American water-horehound)
Lythrum salicaria (purple loosestrife)
Melilotus officinalis (yellow sweet-clover)
Solidago gigantea (swamp goldenrod)
Veratrum viride (false hellebore, Indian corn lily)
This figure helps visualize the structure and "look" or "feel" of a typical Riverside Sand/Gravel Bar. 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.
New York Natural Heritage Program. 2021. New York Natural Heritage Program Databases. Albany, NY.
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: Aissa Feldmann
Information for this guide was last updated on: May 4, 2020
Please cite this page as:
New York Natural Heritage Program. 2021. Online Conservation Guide for Riverside sand/gravel bar. Available from: https://guides.nynhp.org/riverside-sandgravel-bar/. Accessed October 16, 2021.