Natural Communities of Rhode Island - University of Rhode Island

i 

Natural Communities 

of 

Rhode Island 

December 2006 

Richard W. Enser, Rhode Island Natural Heritage Program 

Department of Environmental Management 

and 

Julie A. Lundgren 

The Nature Conservancy of Rhode Island

Citation: Enser, R. W. and J. A. Lundgren. 2006. Natural Communities of Rhode Island. A joint 

project of the Rhode Island Dept. of Environmental Management Natural Heritage Program and The 

Nature Conservancy of Rhode Island. Web published by R.I. Natural History Survey, Kingston, RI. 

www.rinhs.org. 

Cover Photos © The Nature Conservancy: Oak – Hickory Forest (top right) & Oak – Holly Forest 

(lower right) by Julie Lundgren, TNC and Marine Intertidal Rocky Shore (lower left) & Upper 

Perennial Stream/River (upper left) by John Berg, TNC. 

Current contact information for authors: 

Julie Lundgren, P.O. Box 2077, South Burlington VT 05407 ecojal18@yahoo.com 

Rick Enser, rickenser@yahoo.com 

ii

Acknowledgements 

Rick Enser, coordinator of the RI Natural Heritage Program under RI DEM, authored the first 

edition of the Natural Communities of Rhode Island (Enser 2000) which is the platform for this 

revision. Thanks to many ecologists in the northeast network of state natural heritage programs, The 

Nature Conservancy, and NatureServe for their work on regional and state classifications which 

greatly informed the RI work. 

Among the first state-specific community classifications to be published and widely used in the 

northeast was Carol Reschke’s first edition of Ecological Communities of New York State (Reschke 

1990). This provided inspiration to all the northeastern Natural Heritage programs to create, expand 

and revise similar documents. Lesley Sneddon, Mark Anderson, Ken Metzler and Tom Rawinski 

contributed significantly to the development of regional and state classifications with the 

collaboration of state ecologists across the northeast. Frank Golet and the work of his many students 

added substantially to our understanding of wetlands in Rhode Island and the region. 

Thanks to reviewers and those who provided additional guidance for this revision: Peter August, 

Nels Barrett, Peter Burn, Gregg Cassidy, Helen Cottrell, Alex Frost, Frank Golet, Lisa Gould, Tom 

Kutcher, Hope Leeson, Joanne Michaud, Carol Murphy, Garry Plunkett, Chris Powell, Chris 

Raithel, Scott Ruhren and Pat Swain. We regret any omissions and acknowledge that earlier 

editions benefited from the insight and data from others not recognized here. In addition, the R.I. 

Natural History Survey (RINHS) has been instrumental in taking on the management of the R.I. 

Natural Heritage database and we thank Erik Endrulat for his skilled work in maintaining and 

expanding the natural community component of that database including integration of this 

classification. 

J. Lundgren 2006 

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Introduction to the Natural Community Classification of Rhode Island 

A natural community is an assemblage of organisms, their physical environment, the interactions 

among them, and the natural processes that affect them. Communities can be defined based 

primarily on plant species, geologic characteristics, animal assemblages, or other factors. This 

document defines natural communities primarily by dominant or characteristic plant species as they 

occur in assemblages repeated on the landscape. These are often tied to specific physical settings. 

This document provides a consistent language for describing and naming the natural communities of 

Rhode Island in an easily accessible format that is useful to a variety of users: land trusts, land use 

planners, biologists, hikers, land owners, consultants and others. The classification is organized by 

Systems, which refer to complexes of natural communities that share the influence of similar 

hydrologic, geomorphologic, chemical, and biological factors. There are six systems in Rhode 

Island: Marine, Estuarine, Riverine, Lacustrine, Palustrine, and Upland. Systems are divided 

into Subsystems (e.g., Open vs. Forested) that aid in the identification or categorization of a 

particular community type. 

The community types identified in each system and subsystem are distinguished by physiognomy 

(primary growth form of the vegetation), species composition, and ecological processes. The names 

assigned to each community type are descriptive labels and are not intended to describe all of the 

dominant species or the significant features. Communities may be named for a physiographic 

location (Maritime Beach Strand); the physiognomy of the vegetation (Dwarf Shrub Fen / Bog); or 

dominant species (Oak / Heath Forest). A diagnostic key is available to accompany the 

classification that will assist in identifying communities in the field. 

The descriptions of each community type include dominant species (most abundant or greatest 

percent cover) and characteristic species (commonly found in community occurrences, although 

not necessarily abundant). An individual community example or occurrence (i.e., site) may not 

contain all of the species listed in the description. Moreover, the description includes only a very 

small portion of the total number of species present in that community type. Natural communities 

are inherently variable and it takes experience in the field to become familiar with the range of 

variability within types. In addition, natural communities are dynamic; changing in age, structure 

and composition over time and in response to natural disturbances such as flooding, wind storms, 

wildfire, disease outbreaks, etc. 

The prevalence of non-native species in some locations can also add to the confusion in identifying 

a natural community occurrence. In general, one should rely on the physiognomy (structure) and 

native species composition to select the closest match. Sites dominated by non-native species are 

generally not included in this document (with a few exceptions such as Phragmites marsh) and the 

percentage of native versus non-native species is an important factor in identifying the best examples 

of a particular type. Sites with a higher percentage of non-native species are essentially poorer 

quality examples of a given community than sites strongly dominated by native species. 

1

Descriptions may include information on important environmental characteristics (hydrology, 

substrate, topography, etc.) and disturbance patterns (e.g., periodic flooding, fire). In addition, for 

each community type a generalized distribution within Rhode Island, and a few examples of places 

to view them is included. Organizations such as the Rhode Island Natural History Survey (RINHS), 

Audubon Society of Rhode Island (ASRI), The Nature Conservancy (TNC), Rhode Island Wild 

Plant Society (RIWPS) and others can provide opportunities to see and learn about the state’s natural 

communities. Contact information for these groups is included below. 

Natural community classifications may follow different structures and formats, with advantages and 

disadvantages to each. The full hierarchy is not outlined in this document and this classification is 

not intended as a hierarchiacal and numerical mapping tool; however, this classification can be 

adopted or cross-referenced to other schemes. For example, it can be linked to other systems such as 

the U. S. Fish and Wildlife Service wetland classification (Cowardin, et al., 1979), or to regional and 

national classifications developed cooperatively by The Nature Conservancy, NatureServe and state 

Natural Heritage Programs (e.g., Anderson, et al., 1998). A cross-walk to the RI Natural Heritage 

mapping names is included in this document. 

Plant taxonomy and nomenclature generally follows Gould et al. (1998), which is based on Gleason 

and Cronquist (1991), but some recent nomenclatural changes have also been adopted. Vertebrate 

animal taxonomy and names follow August et al. (2001). 

References Cited: 

Anderson M., P. Bourgeron, M. T. Breyer, R. Crawford, L. Engelking, D. Faber-Langendoen, M. 

Gallyoun, K. Gooden, D.H. Grossman, S. Landaal, K. Metzler, K.D. Patterson, M. Pyne, M. Reid, 

L.Sneddon,, and A.S. Weakley. 1998. International Classification of Ecological Communities: 

Terrestrial Vegetation of the United States.Volume II. The National Vegetation Classification 

System: List of types. The Nature Conservancy, Arlington, Virginia. 502 pp. 

(www.natureserve.org) 

August, P.V., R.W. Enser, and L.L. Gould (editors). 2001. The vertebrates of Rhode Island. Vol. 2 

of the biota of Rhode Island. RI Natural History Survey, Kingston, RI. 84pp. 

Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and 

deepwater habitats of the United States. Office of Biological Sciences, U.S. Fish and Wildlife 

Service, U.S. Department of the Interior, Washington, D.C. 131 pp. 

Enser, R.W. 2000. Natural communities of Rhode Island. Unpubl. report of the Rhode Island 

Natural Heritage Program, RI Dept of Environmental Management, Providence RI. 

Gleason, H.A. and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and 

adjacent Canada, second edition. The New York Botanical Garden, New York, NY. 910 pp. 

2

Gould, L.L., R.W. Enser, R.E. Champlin and I. H. Stuckey. 1998. Vascular flora of Rhode Island: a 

list of native and naturalized plants. Vol. 1 of the biota of Rhode Island. Rhode Island Natural 

History Survey, Kingston RI. 

Reschke, C. 1990. Ecological Communities of New York State. New York Natural Heritage 

Program, NewYork State Depatment of Environmental Conservation. 96 pp. 

3

SOURCES OF INFORMATION ON PLACES TO VISIT, FIELD TRIPS, SPECIAL 

PROGRAMS & OTHER RESOURCES IN RHODE ISLAND: 

RI Department of Environmental Management 

235 Promenade Street 

Providence RI 02908 

401-222-6800 general info 

www.dem.ri.gov (see Planning and Development, Water Resources and Natural Resources Bureau) 

Rhode Island Natural History Survey 

Room 101, Coastal Institute in Kingston 

1 Greenhouse Rd 

University of Rhode Island 

Kingston RI 02881 

401-874-5800 

www.rinhs.org 

The Nature Conservancy 

159 Waterman Street 


401-331-7110 

www.nature.org/rhodeisland 

Audubon Society of Rhode Island (Headquarters) 

12 Sanderson Road 

Smithfield RI 02917 

401-949-5454 

www.asri.com 

Rhode Island Wild Plant Society 

P.O. Box 2488 


401-453-3777 

www.riwps.org 

New England Wildflower Society 

180 Hemenway Road 

Framingham MA 01701 

508-877-7630 

www.newfs.org 

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TABLE OF CONTENTS 

I. Marine System ................................................................................................................................. 9 

A. Marine Subtidal ...................................................................................................................................... 9 

1. Marine Open Water _______________________________________________________________ 9 

2. Marine Subtidal Aquatic Bed________________________________________________________ 9 

B. Marine Intertidal .................................................................................................................................... 9 

1. Marine Intertidal Mud Flat__________________________________________________________ 9 

2. Marine Intertidal Sand/Gravel Beach_________________________________________________ 10 

3. Marine Intertidal Rocky Shore______________________________________________________ 10 

II. Estuarine System.......................................................................................................................... 11 

A. Estuarine Subtidal ................................................................................................................................ 11 

1. Tidal River/Stream _______________________________________________________________ 11 

2. Tidal Creek_____________________________________________________________________ 11 

3. Brackish Subtidal Aquatic Bed _____________________________________________________ 11 

4. Coastal Salt Pond ________________________________________________________________ 12 

B. Estuarine Intertidal .............................................................................................................................. 12 

1. Brackish Intertidal Flat____________________________________________________________ 12 

2. Brackish Marsh _________________________________________________________________ 12 

3. Low Salt Marsh _________________________________________________________________ 13 

4. High Salt Marsh _________________________________________________________________ 13 

5. Salt Panne______________________________________________________________________ 13 

6. Salt Shrub______________________________________________________________________ 14 

III. Riverine System (freshwater)..................................................................................................... 15 

A. Non-tidal River...................................................................................................................................... 15 

1. Upper Perennial Stream/River ______________________________________________________ 15 

2. Lower Perennial Stream/River ______________________________________________________ 15 

3. Intermittent Stream_______________________________________________________________ 15 

4. Blackwater Creek ________________________________________________________________ 16 

B. Tidal River (freshwater reach; see Estuarine System for brackish reach)...................................... 16 

1. Fresh Subtidal Aquatic Bed ________________________________________________________ 16 

2. Freshwater Tidal Marsh ___________________________________________________________ 16 

IV. Lacustrine System....................................................................................................................... 17 

A. Mesotrophic Lake ................................................................................................................................. 17 

B. Mesotrophic Pond ................................................................................................................................. 17 

C. Coastal Plain Pond................................................................................................................................ 17 

D. Eutrophic Pond ..................................................................................................................................... 18 

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V. Palustrine System ......................................................................................................................... 19 

(note: substrate is used as an organizing feature rather than a clear taxonomic division. When in 

doubt, refer to all the wetlands that match the physiognomy (open types/ A & B or forested types/ 

C&D). 

A. Open Wetlands (non-forested) on Mineral Soil..................................................................................19 

1. Common Pond or Lake Shore (herbaceous community) __________________________________19 

2. Coastal Plain Pondshore ___________________________________________________________19 

a. Seasonally Flooded Coastal Plain Pondshore_________________________________________20 

b. Semi-permanently Flooded Coastal Plain Pondshore __________________________________20 

3. Interdunal Swale _________________________________________________________________20 

4. Semipermanently Flooded (Deep) Emergent Marsh _____________________________________20 

a. Cattail Marsh _________________________________________________________________21 

b. Pickerelweed – Mixed Forbs Marsh________________________________________________21 

c. Phragmites Marsh (non-native) ___________________________________________________21 

5. Seasonally Flooded (Shallow) Emergent Marsh_________________________________________21 

6. Wet Meadow____________________________________________________________________21 

7. Shrub Swamp ___________________________________________________________________22 

B. Open Peatlands ......................................................................................................................................22 

1. Acidic Graminoid Fen ____________________________________________________________22 

2. Coastal Plain Quagmire ___________________________________________________________23 

3. Sea Level Fen ___________________________________________________________________23 

4. Dwarf Shrub Fen/ Bog ____________________________________________________________23 

5. Dwarf Tree Bog _________________________________________________________________24 

a. Black Spruce Shrub Bog_________________________________________________________24 

b. Atlantic White Cedar Shrub Bog __________________________________________________24 

C. Forested Mineral Soil Wetlands..........................................................................................................24 

1. Floodplain Forest ________________________________________________________________24 

a. Silver Maple - Sycamore Floodplain Forest__________________________________________25 

b. Red Maple - Pin Oak Floodplain Forest_____________________________________________25 

c. Red Maple –Ash Swamp (see below)_______________________________________________25 

2. Red Maple Swamp _______________________________________________________________25 

a. Red Maple - Deciduous Shrub Swamp______________________________________________25 

a1. Red Maple – Ash Swamp_____________________________________________________________ 26 

a2. Red Maple – Black Gum Swamp_______________________________________________________ 26 

a3. Rich Red Maple – Ash Swamp ________________________________________________________ 26 

b. Red Maple – Rhododendron Swamp _______________________________________________27 

3. Swamp White Oak Swamp _________________________________________________________27 

4. Hemlock – Hardwood Swamp ______________________________________________________27 

5. Vernal Pool ____________________________________________________________________27 

6. Forested Seep___________________________________________________________________28 

a. Headwater Seep _______________________________________________________________28 

b. Hillside Seep__________________________________________________________________28 

7. Spring_________________________________________________________________________28 

D. Forested Peatlands ................................................................................................................................28 

1. Atlantic White Cedar Swamp _______________________________________________________28 

a. Atlantic White Cedar / Rhododendron Swamp _______________________________________29 

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. Atlantic White Cedar – Hardwood Swamp __________________________________________ 29 

b1. Atlantic white cedar – swamp azalea type ________________________________________________29 

b2. Atlantic white cedar - hemlock - yellow birch type _________________________________________30 

2. Black Spruce Bog________________________________________________________________ 30 

VI. Upland System. ........................................................................................................................... 31 

A. Open Uplands (non-forested)............................................................................................................... 31 

1. Inland Sand Barren_______________________________________________________________ 31 

2. Maritime Beach Strand____________________________________________________________ 31 

3. Maritime Dune __________________________________________________________________ 31 

a. Beach Grass Dune Association ___________________________________________________ 32 

b. Beach Heather Dune Association _________________________________________________ 32 

c. Dune Shrub Association_________________________________________________________ 32 

4. Maritime Grassland ______________________________________________________________ 32 

5. Maritime Rocky Cliff_____________________________________________________________ 33 

6. Maritime Bluff __________________________________________________________________ 33 

7. Maritime Shrubland (also commonly known as “Coastal Shrubland”________________________ 33 

B. Woodlands ............................................................................................................................................. 33 

1. Maritime Woodland/ Forest _______________________________________________________ 34 

2. Pitch Pine / Scrub Oak Barrens _____________________________________________________ 34 

3. Red Cedar Rocky Summit _________________________________________________________ 34 

C. Forested Uplands .................................................................................................................................. 35 

1. Oak / Heath Forest _______________________________________________________________ 35 

a. Black Oak - Scarlet Oak / Heath Forest _____________________________________________ 35 

b. Chestnut Oak Forest____________________________________________________________ 35 

c. White Oak / Mountain Laurel Forest _______________________________________________ 35 

2. Oak – Hickory Forest _____________________________________________________________ 36 

3. Oak – Holly Forest _______________________________________________________________ 36 

4. Mesic Beech – Maple – Red Oak Forest ______________________________________________ 37 

5. High Terrace Riverside Forest ______________________________________________________ 37 

6. Pitch Pine - Oak Forest____________________________________________________________ 37 

7. White Pine – Oak Forest __________________________________________________________ 38 

8. Hemlock – Hardwood Forest _______________________________________________________ 38 

Note: The naming of community types follows a simplified version of the conventions adopted for 

the National Vegetation Classification (TNC and NatureServe): Title species are either dominant or 

simply characteristic of the community. Dashes and slashes between species names indicate similar 

or different physiognomic strata (tree, shrub or herb layer). For example Oak – Holly Forest 

indicates that these species are all in one strata compared to Oak / Heath Forest which is comprised 

of oaks in the tree layer and heath species in a lower strata (in this case shrub layer). 

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I. Marine System 

This system consists of open ocean, shallow saline coastal bays lacking significant freshwater 

inflow, and associated high-energy coasts. The limits extend from mean high water seaward, 

beyond the limits of rooted vascular vegetation. Salinity is greater than 18.0 parts per thousand (ppt) 

ocean-derived salts. 

A. Marine Subtidal. This subsystem includes the area below the lowest tide that is permanently 

underwater. Salinity levels are fairly constant within a range of 25.0 to 32.0 ppt. 

1. Marine Open Water. A broadly defined community describing life in the open ocean from 

the lowest tide level along the shore to the seaward limits of rooted vascular vegetation, or 

photic zone and adjacent deeper waters. This community includes all substrate types 

(ranging from rock bottom to unconsolidated bottom) and has sparse to no rooted vegetation 

or macroalgae. Associated fauna includes a large number of fish species and mollusks such 

as surf clam (Spisula solidissima) in near-shore waters and ocean quahog (Artica islandica) 

in deeper waters. 

Dist: Open ocean along southern coast, around Block Island, extending into 

Narragansett Bay. 

2. Marine Subtidal Aquatic Bed. Community of macroalgae and rooted vegetation occurring 

in quiet waters below the lowest tide level where fluctuations in salinity are minor. Includes 

“Eelgrass Beds” and macroalgae beds. Characteristic species include eelgrass (Zostera 

marina), sea lettuce (Ulva lactuca), kelp (Laminaria spp.), Irish moss (Chondrus crispus), 

and other macroalgae including other Ulva spp. (formerly Enteromorpha) and Cladophora. 

Many other algae species may be present. Green fleece (Codium fragile), a non-native algae, 

frequently invades this community. Characteristic fauna include bay scallops (Aequipecten 

irradians), northern quahog (Mercenaria mercenaria), Atlantic slippershell (Crepidula 

fornicata), and winter flounder (Pseudopleuronectes americanus). (See also, closely related 

Brackish Subtidal Aquatic Bed under Estuarine System). 

Dist: In lower Narragansett Bay and Long Island Sound, fringing shore and islands. 

The Eelgrass Bed association is extremely limited due to losses from eelgrass wasting 

disease. Eelgrass restoration efforts are ongoing. 

B. Marine Intertidal. This subsystem includes the area between the highest and lowest tide levels. 

The substrate is periodically exposed and flooded by semidiurnal tides, and salinity levels can 

fluctuate widely. 

1. Marine Intertidal Mud Flat. Quiet water community with a substrate composed of silt or 

sand rich in organic matter and poorly drained at low tide. Microalgae, including diatoms, 

are a key component of this community and the mud surface is often coated with a thin mat 

of algae. Characteristic organisms include sand worms (polychaetes), mudsnail (Ilyanassa 

obsoleta), softshell clam (Mya arenaria), and blue mussel (Mytilus edulis). This community 

is an important feeding area for shorebirds and some areas may be critical as migratory bird 

9

concentration areas. 

Dist: In salt ponds and coves along the seacoast and in Narragansett Bay. 

Examples: Quonochontaug Pond, Charlestown; Galilee Salt Marsh, Narragansett. 

2. Marine Intertidal Sand/Gravel Beach. Community washed by high-energy waves, with 

sand and gravel substrates that are well-drained at low tide and subject to high fluctuations in 

salinity and moisture. It occurs between the low and high tide lines, and the upper edge is 

often marked by a wrack line of plant debris washed up by the tide. This community is 

characterized by benthic invertebrate fauna including mole crabs (Emeritia talpoida), sand 

worms (polychaetes), and amphipods, and is an important feeding area for migratory 

shorebirds, a characteristic species being the sanderling (Calidris alba). The Marine 

Intertidal Sand/Gravel Beach lacks the vascular plants of the Maritime Beach Strand 

community which occurs above the intertidal zone (see Uplands section). 

Dist: Along the seacoast and lower Narragansett Bay. 

Examples: Moonstone Beach, South Kingstown; Goosewing Beach, Little Compton. 

3. Marine Intertidal Rocky Shore. Community of rocky shores exposed to high-energy waves 

and alternately exposed and inundated by the tides. Occurs below the high tide line and 

above the limit of the lowest tide. Organisms include those capable of withstanding wave 

impact and periodic desiccation, including attached algae, sea mussel (Mytilus edulis), sea 

star (Asterias spp.), sea urchin (Arbacia punctulata), and rock barnacle (Balanus 

balanoides). The community is typically species rich with over 60% of the substrate covered 

with attached organisms. Characteristic algae are rockweeds (Ascophyllum nodosum, Fucus 

spp.), Irish moss (Chondrus crispus), kelp (Laminaria spp.), and others (Ulva/ Enteromorpha 

spp., Rhizoclonium spp.). Used as winter foraging habitat for purple sandpiper (Calidris 

maritima), harlequin ducks (Histrionicus histrionicus) and eider ducks (Somateria 

mollissima). 

Dist: Islands and shore of lower Narragansett Bay. 

Examples: Sachuest Point National Wildlife Refuge, Middletown; Beavertail Point, 

Jamestown; Colt State Park, Bristol. 

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II. Estuarine System 

This system consists of deepwater tidal habitats and adjacent tidal wetlands that are semi-enclosed 

by land but have open, partly obstructed, or ephemeral access to the open ocean, and in which ocean 

water is partially diluted by freshwater influx. This system extends from the upstream limit of tidal 

influence seaward to an imaginary line closing the mouth of a bay or river. Salinity is >0.5 parts per 

thousand (ppt). 

A. Estuarine Subtidal. This subsystem includes the area below the lowest tide where the substrate is 

permanently flooded and continuously submerged. 

1. Tidal River/Stream. The aquatic community of continuously flooded substrates that 

supports no emergent vegetation. A vertical salinity gradient is maintained in which the 

surface layer of fresh water (0.5 ppt) floats over a deeper brackish layer (0.5 to18.0 ppt). 

Characteristic fish are anadromous species including alewife (Alosa pseudoharengus), 

blueback herring (Alosa aestivalis), and shad (Alosa sapidissima). 

Dist: Rivers within Narragansett Bay region. 

Examples: Pawcatuck River, Narrow River 

2. Tidal Creek. Aquatic community of a continuously flooded creek that drains the tidal 

waters of a coastal salt marsh. Water is brackish to saline (0.5 to 30.0 ppt). Water levels 

fluctuate with the tides; the creek bottom is permanently flooded, but the banks are exposed 

at low tide. Characteristic plants include widgeon grass (Ruppia maritima) and several 

cyanophyta. Fiddler crabs (Uca spp.) are common burrowers in the banks. Typical fish 

include mummichog (Fundulus heteroclitus), striped killifish (Fundulus majalis), and 

threespine stickleback (Gasterosteus aculeatus). 

Dist: Tidal marshes along the seacoast and Narragansett Bay. 

Example: Galilee Salt Marsh, Narragansett; Seapowet Marsh, Tiverton 

3. Brackish Subtidal Aquatic Bed. An estuarine community of continuously flooded 

substrates supporting rooted aquatic vegetation and associated macroalgae. Water is 

generally less than 6.6 ft (2 m) deep at low tide, and salinity ranges between 0.5 to 18.0 ppt. 

The characteristic plant of higher salinity beds is eelgrass (Zostera marina) with associated 

macroalgae including the genera Ulva (Enteromorpha), Chaetomorpha, Gracilaria, 

Agardhiella, Ectocarpus, and Pilayella. Lower salinity beds are characterized by widgeon 

grass (Ruppia maritima), wild celery (Vallisneria americana), horned pondweed 

(Zannichellia palustris), sago pondweed (Potamogeton pectinatus), clasping-leaved 

pondweed (Potamogeton perfoliatus), and naiads (Najas spp.), along with algal forms Ulva 

(Enteromorpha), Cladopora, and Chara. Aquatic beds serve as feeding grounds for 

American black duck (Anas rubripes) and brant (Branta bernicla), and nursery grounds for a 

wide diversity of fish and shellfish. Often adjacent to Brackish Intertidal Flat and/or Brackish 

Marsh. 

Dist: Brackish areas of Narragansett Bay and the permanently flooded portion of 

coastal salt ponds in Washington and Newport counties. 

11

Examples: Ninigret Pond & Trustom Pond in Charlestown. 

4. Coastal Salt Pond. This is a coarsely defined type that includes Intertidal and Subtidal 

habitats. These brackish ponds occur along the coastal edge, partially closed off from the sea 

by barrier beaches. Salinity may vary from nearly fresh to nearly saline depending on 

duration and extent of connection to the sea. Ocean waters enter the pond during storm 

events or when increased freshwater input on the landward side creates a breach to the ocean 

that may remain open for short or prolonged periods resulting in wide variations in salinity. 

Many ponds have been altered on the Rhode Island shore by the construction of permanent 

breachways. Two types of ponds are recognized: those with significant freshwater input 

from streams (restricted to eastern R.I.) and those with diffuse freshwater input and little or 

no stream connection (e.g., Washington County and Block Island). The vegetation is 

comprised of finer scale communities (which see) nested within this type, including Brackish 

Marsh, Subtidal Aquatic Bed, and/or Brackish Intertidal Flat. These ponds are also critical 

nurseries and havens for shellfish and finfish. 

Dist: South shore of state and on Block Island. 

Examples: Sachem Pond, Block Island; Ninigret and Trustom Ponds, Charlestown; 

Quicksand Pond, Little Compton. 

B. Estuarine Intertidal. This subsystem includes areas between the highest and lowest tide levels 

where the substrate is regularly exposed and flooded by semi-diurnal tides. Some areas are only 

irregularly exposed at low tide; other areas are only irregularly flooded at high tide. 

1. Brackish Intertidal Flat. A sparsely vegetated community characterized by low-growing, 

rosette-forming aquatic plants. This community occurs on exposed intertidal mud or sandy 

flats where vegetation is usually submerged only during highest tides. Water is brackish (0.5 

to 16.0 ppt). Flats subject to daily flooding and higher salinity levels may be devoid of 

macrophytes; characteristic plants of less frequently flooded and more brackish flats include 

mudwort (Limosella australis), horned pondweed (Zannichellia palustris), and spike rush 

(Eleocharis parvula), and microalgae. Two plant species typical of this community in 

Connecticut and Massachusetts but extirpated from Rhode Island are River-arrowhead 

(Sagittaria subulata), and Pygmy-weed (Crassula aquatica). 

Dist: Brackish ponds and edges of tidal marshes along the seacoast and Narragansett 

Bay. 

Examples: Narrow River, Narragansett; Hundred Acre Cove, Barrington. 

2. Brackish Marsh. A marsh community that occurs where water salinity ranges from 0.5 to 

18.0 ppt and water levels are 6 ft (2 m). This community consists of a combination of salt 

marsh and fresh marsh plants. Characteristic species include narrowleaf cattail (Typha 

angustifolia), freshwater cordgrass (Spartina pectinata), tall reed (Phragmites australis), salt 

marsh fleabane (Pluchea odorata), and rose mallow (Hibiscus moscheutos). The robust 

bulrush (Scirpus robustus), three-square bulrush (Spartina pungens), and spike rush 

(Eleocharis rostellata) may also be present. This community occurs in several 

environmental situations including the edges of tidal rivers, coastal ponds that maintain 

12

eachways to the ocean, and small barrier beach ponds that do not maintain permanent 

breachways, but exhibit higher salinity levels due to salt spray and occasional overwash. 

Additional study is needed to distinguish these types. This community provides nesting 

habitat for Virginia rail (Rallus limicola), sora (Porzana carolina), marsh wren (Cistothorus 

palustris), and other marsh birds. 

Dist: Coastal salt ponds and tidal rivers along the coast and Narragansett Bay. 

Examples: Trustom Pond, Charlestown; Narrow River, Narragansett; Lathrop 

Wildlife Refuge at Winnepaug Pond, Westerly; Providence River, Providence and 

East Providence; Tunipus Pond, Little Compton. 

3. Low Salt Marsh. A coastal marsh community in sheltered areas in a zone extending from 

mean high tide down to sea level, or to about 6.6 ft (2 m) below mean high tide. This 

community is regularly flooded by semidiurnal tides and is usually limited to the edges of 

tidal creeks and the borders of tidal flats. The vegetation is often a monotypic stand of salt 

marsh cordgrass (Spartina alterniflora) in combination with dense mats of marine algae such 

as sea lettuce (Ulva/Enteromorpha spp.), rockweeds (Fucus spp. and Ascophyllum nodosus) 

and blue green algae. Characteristic animals include fiddler crabs (Uca spp.), salt marsh 

snails (Littorina spp.), ribbed mussel (Geukensia demmisa), and seaside sparrow 

(Ammodramus maritimus). 


Examples: Galilee Salt Marsh, Narragansett; Touisset Marsh Wildlife Refuge, 

Warren; Seapowet Marsh, Tiverton; Providence River, Providence and East 

Providence. 

4. High Salt Marsh. A coastal marsh community in sheltered areas in a zone extending from 

mean high tide up to the limit of spring tidal flooding. This community is irregularly flooded 

by spring and flood tides. High salt marsh vegetation typically consists of a mosaic of 

patches, each dominated by a single graminoid species, including salt-meadow cordgrass 

(Spartina patens), spike grass (Distichlis spicata), and black grass (Juncus gerardii). Other 

characteristic plants include sea-lavender (Limonium carolinianum), salt marsh aster 

(Symphyothrichum tenuifolim; formerly Aster tenuifolius), seaside gerardia (Agalinis 

maritima) and spearscale (Atriplex patula). The salt marsh snail (Melampus bidentatus) is a 

common animal of this community, and nesting birds include clapper rail (Rallus 

longirostris) and sharp-tailed sparrow (Ammodramus caudacutus). 


Examples: Galilee Salt Marsh and Narrow River, Narragansett; Hundred Acre Cove, 

Barrington; Touisset Marsh, Warren; Emilie Ruecker Wildlife Refuge, Tiverton; 

Fogland Marsh Preserve, Tiverton 

5. Salt Panne. A poorly drained shallow depression within high or low salt marsh 

communities. Pannes in low marshes have substrates of soft, silty mud, drain irregularly and 

are usually unvegetated. High marsh pannes are occasionally flooded, the ponded water 

evaporating and raising salinity to extreme levels. Characteristic plants include dwarf salt 

marsh cordgrass (Spartina alterniflora), glassworts (Salicornia spp.), salt marsh plantain 

13

(Plantago maritima var. juncoides), and sea blites (Suaeda spp.). Typically, the surface is 

covered with a thin, dense algal mat comprised of cyanobacteria and chlorophyta that 

contributes significantly to biomass production in this community. Within pannes, small 

ponds may form that are permanently inhabited by fish including mummichog (Fundulus 

heteroclitus) and sheepshead minnow (Cyprinodon variegatus). 

Dist: Tidal marshes along the seacoast and Narragansett Bay 

Examples: Galilee Salt Marsh, Narragansett; Emilie Ruecker Wildlife Refuge, 

Tiverton. 

6. Salt Shrub. A shrubland community that develops at the ecotone of salt marsh and upland 

where the elevation is somewhat higher than the adjacent salt marsh community and salinity 

levels are lower. Characteristic shrubs are salt marsh elder (Iva frutescens), groundsel-tree 

(Baccharis halimifolia), and pasture rose (Rosa carolina), with salt meadow cordgrass 

(Spartina patens) and switchgrass (Panicum virgatum) in the herbaceous understory. This 

community usually occurs as a linear feature along the upper edge of salt marshes, or as 

shrub islands on higher elevations within large marshes. 


Examples: Galilee Salt Marsh, Narragansett; Fogland Marsh, Tiverton. 

14

III. Riverine System 

The riverine system consists of the aquatic communities of flowing waters where salinity is < 0.05 

ppt. This system is composed of deepwater habitats (> 6.6 ft) where persistent emergent vegetation 

is generally lacking, and shallow habitats where submerged or floating-leaved aquatic plants can 

occur. The Riverine communities are generally restricted to bottoms and aquatic beds in river 

channels, but may include vegetated shallow water communities along stream margins. 

A. Non-tidal River 

1. Upper Perennial Stream/River. Upper perennial streams have relatively steep gradients 

with well-defined riffles and pools. Water flow is constant, fast, and turbulent, and the 

normal water temperature is cold. Streambeds are narrow, shallow, and there is little 

floodplain development. Bottom substrates are composed of bedrock, boulder, stone, cobble, 

and occasional patches of sand. Characteristic fish include brook trout (Salvelinus 

fontinalis), longnose dace (Rhinichthys cataractae), blacknose dace (R. corporalis), and 

johnny darter (Etheostoma nigrum). Smaller streams may harbor amphibians including twolined 

salamander (Eurycea bislineata) and dusky salamander (Desmognathus fuscus). 

Mosses and periphytic algae are often present. Aquatic beds may occur locally with 

macrophytes such as waterweed (Elodea spp.), wild celery (Vallisneria americana), and 

pondweeds (Potamogeton spp.). 

Dist: Throughout Rhode Island. 

Examples: Queen, Upper Wood, Ponagansett, and Mossashuck Rivers. 

2. Lower Perennial Stream/River. Lower perennial streams have relatively low gradients and 

poorly defined pools and riffles. Water flow is constant but sluggish, and water temperature 

fluctuates widely. Streambeds are wide and there is usually a well-developed floodplain. 

Substrates are composed of finer sands and silts. Characteristic native fish include 

pumpkinseed (Lepomis gibbosus) and chain pickerel (Esox niger). Yellow perch (Perca 

flavescens) is a common introduced species. Aquatic beds may be well developed. Typical 

aquatic macrophytes include waterweed (Elodea canadensis), wild celery (Vallisneria 

americana), and linear-leaved pondweeds, such as sago pondweed (Potamogeton 

pectinatus). 

Dist: Larger streams/rivers in state, generally lacking in Bristol and Newport 

Counties, and Block Island. 

Examples: Pawcatuck River, Pawtuxet River, Blackstone River. 

3. Intermittent Stream. Channels of intermittent streams contain flowing water for only part 

of the year. When not actively flowing, water may be retained in isolated pools, or surface 

water may be absent. Faunal representatives include amphibians and invertebrates such as 

mayflies (Ephemeroptera), caddisflies (Tricoptera), stoneflies (Plecoptera), dragonflies 

(Odonata) and others that may inhabit the streambed only when water is flowing. 

Bryophytes such as Fontinalis spp. and Mnium spp. are characteristic. Intermittent streams 

are widely distributed throughout the Rhode Island landscape, but more inventories are 

15

needed to distinguish the plant and animal assemblages unique to this community. These 

reaches are often un-named and many are not shown on topographic maps or GIS stream 

coverages. 


4. Blackwater Creek. Slow-moving stream through or originating in acidic shrub swamp 

and/or forested swamps, typically on the coastal plain. Waters are darkly stained with 

tannins from plant debris. Pondweeds (Potamogeton spp.) and waterweeds (Elodea spp.) are 

common. Characteristic of this community is the Blackwater bluet (Enallagma weewa), a 

damselfly that reaches its northern limit in Rhode Island. More inventories are needed to 

define this community in RI. 

Dist: Southern Rhode Island. 

Examples: Burlingame State Park, Charlestown. 

B. Tidal River (freshwater reach; see Estuarine System for brackish reach) 

1. Fresh Subtidal Aquatic Bed. The aquatic community of continuously flooded 

substrates supporting rooted aquatic vegetation. This community occurs in rivers and 

streams within the upper limits of tidal fluctuation where salinity is < 0.5 ppt. Characteristic 

plants are waterweed (Elodea spp.), along with wild celery (Vallisneria americana), 

pondweed (Potamogeton perfoliatus), and naiads (Najas spp.). Note that non-tidal 

freshwater aquatic beds are included in river and creek communities described above. 

Dist: Rare community type in Rhode Island. 

Examples: Lower reaches of Pawcatuck River. 

2. Freshwater Tidal Marsh. A marsh community occurring at the upper limits of tidal flow 

along streams and rivers. Salinity levels are < 0.5 ppt and water levels are < 6.6 ft (2 m). 

This community forms a transition between brackish marsh and nontidal fresh marsh and 

includes a combination of species typical of both, including narrow-leaved cattail (Typha 

angustifolia), bulrushes (Scirpus robustus, S. pungens, and S. validus), pickerelweed 

(Pontederia cordata), arrowweed (Sagittaria latifolia), spatterdock (Nuphar variegata), 

saltmarsh hemp (Amaranthus cannabinus) and water-parsnip (Sium suave). In addition, 

several indicator species are found exclusively in these restricted habitats, most notably wild 

rice (Zizania aquatica). 

Dist: Very rare community type in Rhode Island; historically on most major rivers in 

the state before construction of dams. 

Examples: Mill Creek, Warwick; Runnins River, East Providence. 

16

IV. Lacustrine System 

The lacustrine system consists of waters situated in topographic depressions or dammed river 

channels. Persistent emergent vegetation is lacking, but areas with submerged or floating-leaved 

aquatic plants may occur locally. The communities within this system – lakes and ponds – are 

distinguished by trophic state, annual cycles of thermal stratification, morphometry (size and shape), 

and water chemistry. Two subcategories of this system that are of particular conservation interest 

are ponds and lakes that support only native fish (i.e., not stocked with non-native species) and those 

that are naturally fishless. 

A. Mesotrophic Lake. The aquatic community of a relatively nutrient-poor lake. These lakes have 

two periods of mixing or turnover, spring and fall; they are thermally stratified in summer and 

winter.. Waters are moderately clear with medium transparency (Secchi disk depths of 2 to 4 

meters), and are moderately well-oxygenated. Lake sediments have low to moderate amounts of 

organic matter. Characteristic native fishes include yellow perch (Perca flavescens), Eastern banded 

sunfish (Enneacanthus obesus), and pumpkinseed (Lepomis gibbosus). Introduced fish species 

include smallmouth bass (Micropterus dolomieui) and bluegill (Lepomis macrochirus). Pondweeds 

(Potamogeton spp.) and bladderworts (Utricularia spp.) are the most common submerged 

macrophytes. 


Example: Wallum Lake, Burrillville. 

B. Mesotrophic Pond. A clear, shallow, moderate to low nutrient pond. The substrate is usually 

sandy or rocky and the ponds are too shallow to become stratified in the summer. Aquatic 

vegetation is often sparse. Characteristic floating-leaved plants include water-shield (Brasenia 

shreberi) and water-lily (Nymphaea odorata), and submerged species include bladderworts 

(Utricularia spp.), pondweeds (Potamogeton spp.), and water milfoil (Myriophyllum spp.). In 

shallower waters, rosette-leaved aquatics may occur including pipewort (Eriocaulon aquaticum) and 

water lobelia (Lobelia dortmanna). Fish populations are either warm-water or cold-water species, 

depending on summer temperatures. Those ponds without fish are particularly important breeding 

sites for some invertebrate and amphibian species. This type grades into and may be hard to 

distinguish from some examples of the Coastal Plain Pond community (see below) which is 

characterized by higher plant diversity and greatly fluctuating water levels. 


Examples: Ashville and Blue Ponds, Hopkinton; Carr Pond, West Greenwich; freshwater 

ponds on Block Island. 

C. Coastal Plain Pond. The aquatic (permanently flooded) portion of shallow, clear, nutrient-poor 

ponds with seasonally fluctuating water levels. These are typically sandy- bottomed, occurring in 

glacial outwash or on the moraine and are best known for their unique pondshore flora (see Coastal 

Plain Pondshore community). Technically, some of the smaller or shallower coastal plain ponds fall 

strictly into the Palustrine System, but all are included here for ease of fuse of the classification. The 

pond community itself may be very similar to that of the Mesotrophic Pond above, but occurs in 

association with the Coastal Plain Pond Shore and/or Coastal Plain Quagmire Communities (which 

17

see). Odonates such as lateral bluet and pine barrens bluet (Enallagma laterale, E. recurvatum) are 

characteristic. 

Dist: Chiefly in Washington County. 

Example: Worden Pond, South Kingstown. 

D. Eutrophic Pond. The aquatic community of shallow, nutrient-rich ponds. These ponds are too 

shallow to become stratified in the summer. Water clarity is usually reduced due to accumulations 

of algae, and bottom substrates are usually mucky. Aquatic vegetation is abundant with 

characteristic submersed species including coontail (Ceratophyllum demersum), waterweed (Elodea 

canadensis), duckweed (Lemna spp.), and pondweeds (Potamogeton spp.). Fish populations are 

comprised of warm-water species. Note this type refers primarily to ponds with naturally high 

nutrient levels rather than culturally eutrophied waters. 


18

V. Palustrine System 

The palustrine system includes all non-tidal perennial wetlands characterized by emergent 

vegetation, including wetlands permanently saturated by seepage, permanently flooded, and those 

seasonally or intermittently flooded (these may be seasonally dry). Vegetative cover is dominated 

by hydrophytes and the soil types are hydric. Wetland communities are generally distinguished by 

their plant composition, substrate, and hydrologic regime; however, the boundaries between 

wetlands are not often discrete and several types may occur together at the same site in a complex 

mosaic. [User note: substrate (mineral versus organic) is used here as a common organizing feature; 

but is not critical to identifying the correct community. If uncertain of the substrate type, browse 

through all of the options under the correct physiognomy (open or forested wetland) to find the best 

match.] 

Open (non-forested) - Trees absent or less than 50% cover or in rare cases, trees > 50% cover but 

shrub-like; less than 5 m (16 ft) tall. 

Forested - Dominated by > 50% canopy cover of woody vegetation, greater than 5 m (16 feet) in 

height. Vernal pools, forested seeps and springs are included here as these small communities 

generally occur within forested habitats. 

A. Open Wetlands (non-forested) on Mineral Soil. Trees absent or less than 50% cover (or in rare 

cases, tree species > 50% cover but shrub-like, less than 3m tall). Dominant vegetation is shrub 

and/or herbs. Substrates are on mineral soils (not peat or muck) or close to bedrock. Fluctuating or 

variable water levels allow seasonal aeration of the substrate and promote plant litter decomposition, 

minimizing peat accumulation. 

1. Common Pond or Lake Shore (herbaceous community). Sparsely to densely vegetated 

shoreline of ponds on sand to gravel soils with thin or no peat or muck accumulation. The 

common Pond or Lake Shore type captures the herbaceous shores of the majority of ponds in 

Rhode Island, and is characterized by a variety of sedges, annuals and perennials and is 

habitat for a number of odonates, aquatic invertebrates, amphibians and other species. The 

rarer subtype of Coastal Plain Pond Shore (below) is characterized by Atlantic coastal plain 

species or regional endemics and subject to the dramatic fluctuations in water level. Little 

attention has been paid to the common lake or pond shore community type and the ecological 

role; additional field data is needed to better describe this type. 

Dist: throughout Rhode Island. 

Examples: Beach Pond, Hopkinton; Watchaug Pond, Charlestown. 

2. Coastal Plain Pondshore. The gently sloping sandy/gravelly shores of ponds in morainal 

kettle holes, and depressions in glacial outwash plains within the coastal region. 

Representative floras include a high percentage of species typical of the Atlantic Coastal 

Plain; several odonates are also characteristic of this community such as New England Bluet 

and Pine Barrens Bluet (Enallagma laterale and E. recurvatum). Two variants are described 

19

that may co-occur at some Coastal Plain Ponds and in rare instances the seasonally flooded 

variant may occur as a wet meadow without a noticeable aquatic community. 

a. Seasonally Flooded Coastal Plain Pondshore. Vegetated shores of basin ponds that 

do not receive above ground inflow. Water levels fluctuate widely in response to 

water table change, and pond shores and bottoms may be exposed during the growing 

season. In such cases plants germinate from seeds banked in pond substrates 

producing vigorous populations that develop as concentric zones of vegetation, from 

shallow open water to upland shrub borders. More densely vegetated examples have 

the appearance of wet meadows. Characteristic plants include pipewort (Eriocaulon 

aquaticum), golden-pert (Gratiola aurea), umbrella-sedge (Cyperus dentatus), 

narrow-leaved goldenrod (Euthamia tenuifolia), mud-rush (Juncus pelocarpus), and 

Virginia meadow beauty (Rhexia virginica). Notable rare species include rose 

coreopsis (Coreopsis rosea), narrow-leaved arrowhead (Sagittaria teres), New 

England boneset (Eupatorium leucolepis var. novae-angliae), horned rush 

(Rhynchospora macrostachya), nutrush (Scleria reticularis), bald-rush (Rhychospora 

scirpoides), umbrella grass (Fuirena pumila), rattlebox (Crotalaria sagittalis) and 

tiny-flowered sedge (Hemicarpha micrantha). 


Examples: Matunuck Hills, S. Kingstown and other isolated examples; most 

on private lands accessible via guided walks with RIWPS or TNC. 

b. Semi-permanently Flooded Coastal Plain Pondshore. Vegetated shores of ponds 

that maintain relatively constant water levels from perennial stream inflow or 

recharge from bordering wetlands. Permanent emergent plant communities develop 

in the littoral zone in water depths of 0 to 3.3 ft (1 m). Characteristic plants include 

threesquare (Scirpus pungens), bayonnet rush (Juncus militaris), water lobelia 

(Lobelia dortmanna), pennywort (Hydrocotyle umbellata), yellow-eyed grass (Xyris 

difformis). Horsetail spike-rush (Eleocharis equisetoides) may be present. (See also 

related Coastal Plain Quagmire). 


Examples: Tucker Pond and Worden Pond, S. Kingstown. 

3. Interdunal Swale. Small wetlands that occur in low areas and blowouts within coastal sand 

dunes where the water table is at or near the surface. Soils are sand to peaty sand and water 

levels fluctuate seasonally and annually, corresponding to changes in groundwater levels. 

Vegetation ranges from sparse to dense, and from graminoid-dominated to low shrub mats. 

Characteristic species are rushes (Juncus canadensis, J. greenei), beakrush (Rhynchospora 

capitellata), yellow-eyed grass (Xyris torta), cranberry (Vaccinium macrocarpon), sweet gale 

(Myrica gale), and northern bayberry (Morella pensylvanica; formerly Myrica pensylanica). 

Dist: Rare community type along the south shore and Block Island. 

Example: Quonochontaug Beach, Charlestown. 

4. Semipermanently Flooded (Deep) Emergent Marsh. Marsh community on mineral soils 

20

with water depths ranging from 6 in. to 6.6 ft (15 cm to 2 m). Water levels may fluctuate 

seasonally but the substrate is rarely dry. May occur as fringe marshes along rivers, pond 

margins, or in basins. Characteristic vegetation is composed of emergent aquatics including 

cattails (Typha latifolia and T.angustifolia), bayonnet rush (Juncus militaris), softstem 

bulrush (Scirpus tabernaemontani), pickerelweed (Pontedaria cordata), arrow arum 

(Peltandra virginica), and burreed (Sparganium spp.). Floating-leaved plants include 

spatterdock (Nuphar variagata), water lily (Nymphaea odorata) and pondweeds 

(Potamogeton spp.). The non-native common reed (Phragmites australis) is a frequent 

invader of this community. Species composition of each community is highly variable 

depending on hydrologic regime, topographic position, and substrate. The Typha dominated 

“Cattail Marsh” is the most familiar form of this community. Red-winged blackbird 

(Agelaius phoenicus) and Virginia rail (Rallus limicola) are common residents along with 

several state-rare species including marsh wren (Cistothorus palustris) and pied-billed grebe 

(Podilymbus podiceps). 


Examples: Simmons Mill Pond, Little Compton; Lonsdale Marsh/Valley Marsh 

Conservation Area, Lincoln. 

Several common types are based on the dominant species are: 

a. Cattail Marsh 

b. Pickerelweed – Mixed Forbs Marsh 

c. Phragmites Marsh (dominated by the non-native invasive variety; the native 

Phragmites is known only from small patches) 

5. Seasonally Flooded (Shallow) Emergent Marsh. Marsh community on mineral or muck 

soils that are permanently saturated and seasonally flooded. Water depths range from 6 in. to 

3.3 ft (15 cm to 1 m) during flood stages, but levels usually drop in mid to late summer 

exposing the substrate. Dominant plants include rice cutgrass (Leersia oryzoides), cattails 

(Typha spp.), soft rush (Juncus effusus), Canada rush (Juncus canadensis), reed canary grass 

(Phalaris arundinacea), bluejoint (Calamagrostis canadensis), arrow arum (Peltandra 

cordata), manna grass (Glyceria canadensis), wool grass (Scirpus cyperinus), three-way 

sedge (Dulichium arundinaceum), tussock sedge (Carex stricta), and wild iris (Iris 

versicolor). Faunal associates include common yellowthroat (Dendroica petechia), redwinged 

blackbird (Agelaius phoenicus), marsh wren (Cistothorus palustris, state-rare), wood 

frog (Rana sylvatica), spring peeper (Pseudoacris crucifer), a wide diversity of odonates 

(dragonflies and damselflies), and other species. 


Examples: Blackstone Valley Marshes, Cumberland and Lincoln. 

6. Wet Meadow. Graminoid and forb dominated meadows on soils that are seasonally 

saturated or flooded, but are drier and without standing water for most of the year. In a 

21

natural setting, the high water table prevents tree species from taking hold; however, wet 

meadows are often associated with agricultural settings, where woody species are kept at bay 

in part by grazing and/or mowing practices. Species composition is highly variable, but 

typically co-dominated by several species. Characteristic plants include Joe-pye-weed 

(Eupatorium spp.), wool-grass (Scirpus cyperinus), soft rush (Juncus effusus), sensitive fern 

(Onoclea sensibilis), marsh fern (Thelypteris palustris), St. Johnswort (Hypericum spp.), 

sedge (Carex stipata), tussock sedge (Carex stricta), and bluejoint grass (Calamagrostis 

canadensis). Goldenrods (Solidago spp.) may be conspicuous in some meadows. Scattered 

shrubs may occur, but comprise less than 30% percent cover. Wet meadows are rich habitats 

for invertebrates, especially butterflies and other nectar feeders. 

Dist: Throughout the state. 

Examples: Pardon Gray Preserve, Tiverton; Sprague Hill Farm, Glocester. 

7. Shrub Swamp. Wetland communities dominated by shrubs 0.5 to 5 m tall that occur along 

the margin of a pond or river, isolated in a wet depression or valley, or as a transition 

community between a marsh and upland communities. The substrate is usually mineral soil 

or muck. This type is highly variable with the dominant shrub species dictated by local 

conditions, including water depth, topographic position, and microclimate. At wetter sites 

buttonbush (Cephalanthus occidentalis) or water willow (Decodon verticillatus) may 

dominate with over 90% cover. Sites not permanently flooded may support a mix of shrubs 

with characteristic species including highbush blueberry (Vaccinium corymbosum), sweet 

pepperbush (Clethra alnifolia), winterberry (Ilex verticillata), alders (Alnus incana and A. 

serrulata), silky dogwood (Cornus amomum), maleberry (Lyonia ligustrina), spicebush 

(Lindera benzoin), meadow-sweet (Spiraea latifolia), steeplebush (Spiraea tomentosa), and 

swamp azalea (Rhododendron viscosum). When present, trees form an emergent canopy of 

less than 26% cover. 

Dist: Widespread across state. 

Examples: Ten Mile River bikepath, East Providence; Chapman Pond, Westerly. 

Examples of more common types, based on the dominant species are: 

1. Buttonbush Swamp (Cephalanthus occidentalis) 

2. Water Willow Swamp (Decodon verticillatus) 

3. Alder Swamp (Alnus spp.) 

4. Red-osier Dogwood – Willow Swamp (Cornus sericea – Salix spp.) 

5. Highbush Blueberry Swamp (Vaccinium corymbosum) 

B. Open Peatlands. Includes wetlands with < 50% canopy cover of trees, the dominant vegetation 

being shrubs, herbs, and mosses. Substrates consist of accumulated organic deposits consisting of 

coarse fibrous or woody peat, or well-decomposed organic soils (mucks). Permanent saturation 

reduces aeration of the substrate, thereby slowing decomposition of plant litter and allowing 

accumulation of peat. Areas with longer-term flooding tend to accumulate more peat. 

1. Acidic Graminoid Fen. A weakly minerotrophic peatland fed by groundwater containing 

minerals obtained during passage through or over mineral soils or aquifers. The substrate is 

22

peat composed primarily of Sphagnum. Sedges dominate, characterized by one or several of 

the following: slender sedge (Carex lasiocarpa), bog-sedge (Carex exilis), beaked sedge 

(Carex urticulata or C. rostrata), and twig-rush (Cladium mariscoides). Less common 

species include grasses such as mannagrass (Glyceria canadensis, G. striata, and Puccinellia 

pallida), or rare species such as Walter’s sedge (Carex walteriana) and Long’s bulrush 

(Scirpus longii). Associates are white beakrush (Rhynchospora alba), three-way sedge 

(Dulichium arundincea), marsh St.Johnswort (Triadenum virginicum), cranberry (Vaccinium 

macrocarpon) and round-leaved sundew (Drosera rotundifolia). Mosses (Sphagnum spp.) 

are frequent and may form solid mats or are suspended in the water. Shrubs such as 

leatherleaf (Chamaedaphne calyculata), sweet gale (Myrica gale), highbush blueberry 

(Vaccinium corymbosum) and others are often present but at < 50% cover. 


Examples: Great Swamp, South Kingstown; Diamond Bog, Richmond; Sprague Hill, 

Glocester. 

Variants: The Three-way sedge / Sphagnum Association (Dulichium arundinaceum / 

Sphagnum spp.) is well represented in Rhode Island, often occurring at the edges of larger 

fens as well as in small, isolated, woodland basins that are prone to fluctuating water levels. 

This association is characterized by a suspended layer of sphagnum mosses (S. fallax, S, 

cuspidatum, and others). 

2. Coastal Plain Quagmire. Community of shallow depressions on permanently 

flooded muck soils with water depths ranging from 16 cm to 0.6 m. Deeper 

water sections may be devoid of emergent vegetation, but shallow sections usually support 

dense patches of emergent plants. Characteristic species include twig rush (Cladium 

mariscoides), white beak-rush (Rhynchospora alba), drowned beak-rush (R. inundata), 

yellow-eyed grass (Xyris smalliana), horsetail spikerush (Eleocharis equisetoides), water lily 

(Nymphaea odorata), threesquare (Scirpus pungens), and Canada rush (Juncus canadensis). 

See also related Coastal Plain Pond Shore. 

Dist: Southern Rhode Island; a rare community type. 

Examples: Grass Pond, Richmond; Phantom Bog and Shumunkanuc Bog, Hopkinton. 

[Note: these areas are not readily accessible to public except by guided trips.] 

3. Sea Level Fen. A rare community type that develops in the upper border of tidal marshes 

where there is freshwater influx usually from groundwater seepage. The best Rhode Island 

example is found on the inland side of a coastal salt pond that receives freshwater percolating 

from the adjacent moraine. Characteristic species include twig-rush (Cladium mariscoides), 

spikerush (Eleocharis rostellata), and threesquare (Scirpus pungens). 

Dist: Two examples known in Westerly and Narragansett. 

4. Dwarf Shrub Fen/ Bog. An oligotrophic peatland usually occurring in a basin fed directly 

by rainfall, with little or no stream inflow. Water is nutrient-poor and acidic. This type is 

dominated by Sphagnum and > 50% cover of shrubs < 1 m tall, the principal species being 

leatherleaf (Chamaedaphne calyculata). Other shrubs may include sheep laurel (Kalmia 

23

angustifolia), highbush blueberry (Vaccinium corymbosum), cranberry (Vaccinium 

macrocarpon), black huckleberry (Gaylussacia baccata), and dwarf huckleberry (G. dumosa 

var. bigeloviana). Herbs include pitcher plant (Sarracenia purpurea), round-leaved sundew 

(Drosera rotundifolia), rose pogonia (Pogonia ophioglossoides), cotton grasses (Eriophorum 

spp.), and white beak-rush (Rhynchospora alba). Scattered saplings of white cedar 

(Chamaecyparis thyoides) and red maple (Acer rubrum) may be present. Rare plants are 

represented by species of northern affinities, including pod-grass (Scheuchzeria palustris), 

pale laurel (Kalmia polifolia), and bog rosemary (Andromeda glaucophylla). 


Examples: Great Swamp, South Kingstown; Diamond Bog, Richmond; Schwindel’s Swamp, 

Glocester. 

5. Dwarf Tree Bog. An oligotrophic peatland dominated by tree species that are in dwarf 

form (not simply young trees). Rare community type in RI; see Forested Wetlands for more 

common version of bogs dominated by conifers. 

a. Black Spruce Shrub Bog. An ombrotrophic or oligotrophic peatland, occurring in a 

basin fed directly by rainfall with little groundwater influence or as floating islands in 

man made reservoirs. The dominant woody plant is black spruce (Picea mariana) 

with most individuals < 5 m (16 feet) tall. A well-developed shrub layer is 

characterized by leatherleaf (Chamaedaphne calyculata) and rhodora (Rhododendron 

canadense), and herbaceous plants generally include species listed for dwarf shrub 

bog. (see Black Spruce Bog for forested type) 

Dist: Rare community type, several examples in Providence County. 

b. Atlantic White Cedar Shrub Bog. An oligotrophic (low-nutrient) peatland in a 

basin setting. The dominant woody plant is Atlantic white cedar (Chamaecyparis 

thyoides) with all individuals growing in a dwarfed form < 2 m tall (6 feet) and 10 cm 

(4 inches) diameter. Associated shrubs include dwarf huckleberry (Gaylussacia 

dumosa var. bigeloviana), leatherleaf (Chamaedaphne calyculata), and small 

cranberry (Vaccinium oxycoccus), and predominant herbs include cotton-grass 

(Eriophorum spp.), white beak-rush (Rhynchospora alba), yellow-eyed grass (Xyris 

torta), pitcher plant (Sarracenia purpurea), and horned bladderwort (Utricularia 

cornuta). (See related type: Forested peatland – Atlantic White Cedar Swamp). 

Dist: This community is represented by one Rhode Island example at Factory 

Pond, S. Kingstown. 

C. Forested Mineral Soil Wetlands. This subsystem includes seasonally flooded forests and 

permanently flooded or saturated swamps on mineral soils, well-decomposed mucks or shallow to 

deep peat. These wetlands are dominated by a > 60% canopy cover of woody vegetation, 5 m (16+ 

ft.) in height. 

1. Floodplain Forest. Hardwood forest on river floodplains. Low areas receive annual 

overbank flooding, usually in the spring but occasionally in fall as well. The water table may 

24

e well below ground surface for much of the growing season. A broadly defined 

community, floodplain forests are variable based on frequency and duration of flooding, size 

of river, topography, and substrate. 

a. Silver Maple - Sycamore Floodplain Forest. Typical of floodplains along main stem 

of rivers in northern part of state. Silver maple (Acer saccharinum) is almost always 

present. Other characteristic trees include, box elder (Acer negundo), sycamore 

(Platanus occidentalis), cottonwood (Populus deltoides) and elm (Ulmus americana, 

U. rubra). Red maple (A. rubrum) and green ash (Fraxinus pensylvanica) are often 

present but not the dominant species. Characteristic herbs include wood nettle 

(Laportea canadensis), jack-in-the-pulpit (Arisaema triphyllum) and ostrich fern 

(Matteuccia struthiopteris, rare in RI). 

Dist: Most characteristic along the larger rivers such as the Blackstone, but 

also characteristic of main stems of smaller rivers in Providence County. 

Occasional in other parts of the state. 

Examples: Blackstone River, Cumberland; Ten Mile River, East Providence. 

b. Red Maple - Pin Oak Floodplain Forest. Typical of floodplains in the lower 

Pawcatuck River system. Dominant trees include red maple (Acer rubrum), pin oak 

(Quercus palustris), and green ash (Fraxinus pensylvanica). Associates are swamp 

white oak (Quercus bicolor), hickory (Carya sp.), white oak (Quercus alba), 

winterberry (Ilex verticillata), sensitive fern (Onoclea sensibilis) and a sedge (Carex 

crinita). 

Dist: Pawcatuck River, Washington County 

Examples: Pawcatuck River, Bradford. 

c. Red Maple – Ash Swamp (variant of Red Maple Swamp; see below). This type is 

common on floodplains as well as in shallow basins. 

Examples: Fort Nature Refuge, N. Smithfield; Weetamoo Woods, Tiverton; 

Fisherville Brook Wildlife Refuge, Exeter. 

2. Red Maple Swamp. Dominated by hardwoods with the dominant tree species being red 

maple. Small percent cover (less than 25%) of conifers may be present, including hemlock 

(Tsuga canadensis), Atlantic white cedar (Chamaecyparis thyoides), and white pine (Pinus 

strobus). 

a. Red Maple – Deciduous Shrub Swamp. Overstory dominated by red maple (Acer 

rubrum) with an understory of mixed deciduous shrubs including highbush blueberry 

(Vaccinium corymbosum), spicebush (Lindera benzoin), sweet pepperbush (Clethra 

alnifolia), winterberry (Ilex verticillata), elderberry (Sambucus canadensis), and 

swamp azalea (Rhododendron viscosum). Associated tree species include black gum 

(Nyssa sylvatica), yellow birch (Betula alleghaniensis), green ash (Fraxinus 

pensylvanica), white ash (Fraxinus americana) and scattered conifers. Skunk 

cabbage (Symplocarpus foetidus) and cinnamon fern (Osmunda cinnamomea) are 

25

nearly always present. Others herbs are Turk's-cap lily (Lilium superbum), tussock 

sedge (Carex stricta), false hellebore (Vertatrum viride), jewelweed (Impatiens 

capensis), false nettle (Boehmeria cylindrica), royal fern (Osmunda regalis) and 

others. Sphagnum mosses are common on hummocks but rarely form extensive 

carpet. Occurs in basins, seepage swamps, and on floodplains of small rivers across 

the state. 


Examples: Burlingame State Park, Charlestown; Great Swamp Management 

Area, Kingston; Wickaboxet State Forest, West Greenwich; Fort Nature 

Refuge, N. Smithfield. 

Variants: The first 2 variants often co-occur and can be hard to distinguish in some 

cases. All species occur in both settings to some degree and one must rely on the full 

suite of characteristics to help distinguish intermediate examples. The third variant is 

restricted to sites with calcareous influence and is very limited in the state. 

a1. Red Maple – Ash Swamp: Red maple (Acer rubrum), green ash (Fraxinus 

pensylcanica), white ash (F. americana), spicebush (Lindera benzoin), skunk 

cabbage (Symplocarpus foetidus), and false hellebore (Vertrum viride) are 

characteristic; the spicebush often forming a conspicuous shrub layer. This 

community is frequent along small streams and in seasonally flooded basins. 

Hummocks and a conspicuous moss component may be present or absent 

depending on flooding regime. Lacking calcareous indicators in the herb layer 

in contrast to the Rich Red Maple – Ash Swamp variant below. 

a2. Red Maple – Black Gum Swamp: Red maple (Acer rubrum) and black gum 

(Nyssa sylvatica) dominate the canopy. Other tree species may occur in less 

abundance. Associates include highbush blueberry (Vaccinium corymbosum), 

swamp azalea (Rhododendron viscosum), winterberry (Ilex verticillata), 

cinnamon fern (Osmunda cinnamomea), tussock sedge (Carex stricta). Moss 

covered hummocks (Sphagnum mosses and others) are typical. Typically 

occurs in shallow basins subject to seasonal flooding, with soils remaining 

saturated longer than in the Red Maple – Ash Swamps. 

a3. Rich Red Maple – Ash Swamp: Deciduous or mixed swamp that is 

somewhat enriched by groundwater flow through circumneutral to calcareous 

substrate. Co-dominants are red maple and white ash and/or green ash 

(Fraxinus americana, F. pensylvanica) with lower abundance of yellow birch 

(Betula alleghaniensis), hemlock (Tsuga canadensis), Atlantic white cedar 

(Chameacyparis thyoides) and/or white pine (Pinus strobus). In adjacent 

states, black ash (F. nigra) is typical, but this species not documented in RI. 

The groundlayer tends to be quite diverse, including species such as swamp 

saxifrage (Saxifraga pensylvanica), golden ragwort (Senecio aureus), royal 

26

fern (Osmunda regalis), and mosses (e.g., Sphagnum spp., Campylium sp., 

etc.). 

Dist: Rare in RI, limited to northern part of state. 

Example: Ash Swamp, Cumberland 

b. Red Maple – Rhododendron Swamp. Overstory dominated by red maple (Acer 

rubrum) with Atlantic white cedar (Chamaecyparis thyoides) usually present. 

Understory dominated by great laurel or rhododendron (Rhododendron maximum) 

with lesser representation by sweet pepperbush (Clethra alnifolia) and swamp azalea 

(Rhododendron viscosum). Herbs are sparse, with most common species being skunk 

cabbage (Symplocarpus foetidus), Jack-in-the-pulpit (Arisaema triphyllum), and 

cinnamon fern (Osmunda cinnamomea). 

Dist: Washington County, north of Charlestown recessional moraine. 

Example: Ell Pond Preserve, Hopkinton. 

3. Swamp White Oak Swamp. A hardwood forested swamp community dominated by swamp 

white oak (Quercus bicolor). Associates may include black gum (Nyssa sylvatica) and red 

maple (Acer rubrum). Understory is sparse and patchy, with highbush blueberry (Vaccinium 

corymbosum), swamp azalea (Rhododendron viscosum), buttonbush (Cephalanthus 

occidentalis), cinnamon fern (Osmunda cinnamomea) and/or royal fern (Osmunda regalis). 

Water levels are seasonally high, but draw down for much of the year. The extent of the 

flooding can often be discerned from water marks left on tree trunks and trees may show a 

buttressing effect at the base. 

Dist: Not well documented in Rhode Island; presumed to be uncommon. Known 

from northern part of state; needs more study. 

4. Hemlock – Hardwood Swamp. A mixed coniferous/ deciduous swamp occurring on 

mineral soils in depressions receiving groudwater discharge. Characterized by a closed 

canopy (70 to 100% cover), sparse shrub layer, and low species diversity. Canopy is 

dominated by hemlock (Tsuga canadensis) (usually > 50% cover), with lesser representation 

by yellow birch (Betula alleghaniensis) and red maple (Acer rubrum). The most common 

shrub is highbush blueberry (Vaccinium corymbosum). Characteristic herbs include 

cinnamon fern (Osmunda cinnamomea) and sensitive fern (Onoclea sensibilis). Water levels 

fluctuate seasonally. 


Example: George Washington Management Area, Glocester. 

5. Vernal Pool. A wetland in a small, shallow depression within an upland forest, usually 

less than 0.25 acres and flooded for only a portion of the year. These pools are typically 

flooded in the spring (vernal), occasionally only in the fall or after heavy rainfall, and usually 

dry during summer. Some spring-flooded pools are filled again in autumn. This community 

includes invertebrates and amphibians that depend on temporary pools as breeding areas 

because they do not support fish populations that would prey on eggs or larvae. 

Characteristic obligate amphibians include wood frog (Rana sylvatica), mole salamanders 

27

(Ambystoma spp.), and Eastern spadefoot (Scaphiopus holbrookii - rare). Other species may 

include green frog (Rana clamitans), spring peeper (Pseudacris crucifer), and American toad 

(Bufo americanus). Fairy shrimp (Eubranchipus spp.) are characteristic, but more data is 

needed on other invertebrates and plants. These communities are generally missing from 

wetland map coverage due to their small size. 


Examples: Francis Carter Preserve, Charlestown RI; Weetamoo Woods, Tiverton; 

Fisherville Brook Wildlife Refure, Exeter. 

6. Forested Seep. Small, often overlooked wetland community at the site of small springs, or 

where groundwater seeps to the surface at the base or middle of a slope. Seeps are usually 

small (

(Chamaecyparis thyoides) comprises > 50% of the canopy cover; in mixed stands, red maple 

(Acer rubrum) is the codominant. A characteristic invertebrate is Hessel's hairstreak 

butterfly (Mitoura hesseli), an obligate Chamaecyparis feeder. Recognized community 

variants include the following: 

a. Atlantic White Cedar / Rhododendron Swamp 

Shrub layer dominated by great laurel or rhododendron (Rhododendron maximum). 

Tree canopy is dominated by white cedar, with lesser associates including red maple, 

yellow birch (Betula alleghaniensis), hemlock (Tsuga canadensis) and black gum 

(Nyssa sylvatica). Herbaceous layer is depauperate beneath a closed canopy, with 

mosses (primarily Sphagnum) predominant. Sites supporting this type are seasonally 

saturated and have potential for considerable water level fluctuation. Basin swamps 

overly stratified drift, glacio-lacustrine deposits, and till with low pH, and a high 

level of organic decomposition. 

Dist: Washington County. 

Example: Ell Pond/Long Pond, Hopkinton 

b. Atlantic White Cedar – Hardwood Swamp 

Mixed association of evergreen/deciduous trees with Atlantic white cedar 

predominating, but canopy always includes significant amounts of red maple, yellow 

birch, and/or hemlock. White pine (Pinus strobus) may also be present. The shrub 

layer is diverse with sweet pepperbush (Clethra alnifolia) and highbush blueberry 

(Vaccinium corymbosum) being the most frequent components. Other sporadically 

occurring shrubs include winterberry (Ilex verticillata), maleberry (Lyonia 

ligustrina), mountain laurel (Kalmia latifolia), smooth winterberry (Ilex laevigata), 

and fetterbush (Eubotrys racemosa, formerly Leucothoe racemosa). Common in the 

herb layer are starflower (Trientalis trifolia), goldthread (Coptis groenlandica), 

several sedges (Carex trisperma, C. stricta, C. folliculata), skunk cabbage 

(Symplocarpus foetidus) and marsh fern (Thelypteris palustris). 

Dist: across the state; largest examples in Washington County. 

Examples: Great Swamp, Kingston and Crandall (Chapman) Swamp, 

Westerly. 

Two expressions have been described in RI and CT, but are not consistently 

distinguishable in the field, therefore they are not split into separate variants in this 

document. Based on analysis of plot data, understory composition appears to vary 

depending on canopy composition. In addition to the typical suite of species listed 

above (especially sweet pepperbush and highbush blueberry), characteristic species 

are noted below. 

b1. Atlantic white cedar – swamp azalea type tends to be dominated by white 

cedar with a small percentage of red maple, and is characterized by swamp 

azalea (Rhododendron viscosum) and/or mountain holly (Nemopanthus 

mucronata). Sites supporting this association occur in semipermanently to 

29

seasonally flooded streamside or lakeshore habitats where water levels remain 

high into the growing season and fluctuation is lessened. 

b2. Atlantic white cedar - hemlock - yellow birch type is typically co-dominated 

by cedar and either hemlock (Tsuga canadensis) and/or yellow birch (Betula 

allegheniensis). Characteristic understory species are mountain laurel 

(Kalmia latifolia), cinnamon fern (Osmunda cinnamomea) and/or royal fern 

(Osmunda regalis), and three-seeded sedge (Carex trisperma). Occurs in 

seasonally saturated basin swamps and seasonally flooded streamsides. 

2. Black Spruce Bog. A conifer swamp of acidic peatlands in cool, poorly-drained 

depressions. The dominant tree > 5 m (16 feet) tall is black spruce (Picea mariana). A welldeveloped 

shrub layer is characterized by leatherleaf (Chamaedaphne calyculata) and 

rhodora (Rhododendron canadense). (This community differs from the Black Spruce Shrub 

Bog by the height and density of trees.) A widespread type of northern New England, this 

community is represented by only one example in R.I. 

Dist: Limited to Washington County. 

Example: Arcadia Management Area, Exeter. 

30

VI. Upland System. 

This system consists of upland communities, forested and non-forested, which have well-drained 

soils that are xeric to mesic (never hydric), and a vegetative cover that is never dominated by 

hydrophytes, even if the soil surface is seasonally flooded or saturated. Communities described as 

Maritime are those restricted to areas along the coastal edge that are regularly influenced by salt 

spray. 

A. Open Uplands (non-forested). Dominated by shrubs and/or herbaceous species, or sparsely 

vegetated communities. 

1. Inland Sand Barren. Sparsely vegetated community on shifting sands that are not along 

the ocean shore. Occurs within pitch pine forest or woodland types, generally occurring as 

patches of < 2 acres. Vegetation is patchy, usually on < 75% of surface area, consisting of 

lichens (especially Cladonia spp.), heather (Hudsonia tomentosa), little bluestem 

(Schizachyrium scoparium), umbrella sedge (Cyperus filiculmis), and sand jointweed 

(Polygonella articulata). The sand star fungus (Astraeus hygrometricus; formerly Geaster 

hygrometricus) is typically present. Characteristic insects include tiger beetles (Cicindela 

spp.) and parasitic wasps (Hymenoptera). This is a very rare community type, many 

examples across the region have been lost to development but several high quality examples 

occur on protected lands in Rhode Island. 

Dist: Washington, Kent and Newport Counties. 

Examples: Pawcatuck River Barrens, Hopkinton; Queens River Preserve (TNC), 

Exeter. 

2. Maritime Beach Strand. A sparsely-vegetated community that occurs on unstable sand, 

gravel or cobble beaches above mean high tide and in overwash zones, where the shore is 

modified by storm waves and wind erosion. Vegetation may be scarce and ephemeral due to 

the instability of substrates. Characteristic plants include sea-rocket (Cakile edentula), orach 

(Atriplex patula), seabeach sandwort (Honkenya peploides var. robusta), common saltwort 

(Salsola kali), and seabeach knotweed (Polygonum glaucum). Tiger beetles (Cincindela 

spp.) are notable invertebrate residents and the federally threatened piping plover 

(Charadrius melodus) feeds and nests in this community. Co-occurs with the Marine 

Intertidal Sand/Gravel Beach (see Marine System) which is below the tide line 

Dist: Rhode Island coast; best represented on RI’s southern shores and Block Island. 

3. Maritime Dune. A community dominated by grasses and low shrubs on sand dunes inland 

of and adjacent to maritime beaches. Vegetation occurs in patches resulting from past 

disturbances such as erosion, sand deposition, and dune migration. The composition and 

structure of the vegetation is dependent on dune stability, degree of deposition and erosion, 

and distance from the ocean. 

Dist: On barrier beaches along south shores of RI and Block Island. Examples: 

Block Island; Moonstone Beach, South Kingstown; Roger Wheeler Beach, 

Narragansett; Goosewing Beach, Little Compton. 

31

a. Beach Grass Dune Association. A sparse to densely vegetated grass-dominated 

association on the active portions of primary dunes where sand shifting is the 

greatest. Along with beach grass (Ammophila breviligulata), characteristic species 

include beach-pea (Lathyrus japonicus), seaside goldenrod (Solidago sempervirens), 

sandy sedge (Carex silicea), and several non-native (introduced) species including 

dusty-miller (Artemisia stellariana) and sand rose (Rosa rugosa). Switchgrass 

(Panicum virgatum) may be dominant in patches. The non-native strain of 

phragmites (Phragmites australis) also invades this community, often becoming 

established first in adjacent water bodies and wetlands and spreading by rhizomes 

into open uplands. 

b. Beach Heather Dune Association. Association dominated by dwarf shrubs or 

perennial forbs on the more stabilized portions of primary and secondary dunes where 

sand shifting is reduced. Characteristic species include beach heather (Hudsonia 

tomentosa), bearberry (Arctostaphylos uva-ursi), jointweed (Polygonella articulata), 

and beach pinweed (Lechea maritima). 

c. Dune Shrub Association. Dominated by medium height woody vegetation in the 

somewhat protected areas of sandy maritime dunes and atop coastal bluffs. 

Vegetation includes northern bayberry (Morella pensylvanica; formerly Myrica 

pensylvanica), beach-plum (Prunus maritima), and poison ivy (Toxicodendron 

radicans). The non-native sand rose (Rosa rugosa) has become naturalized in this 

setting, sometimes crowding out native species. 

(for Interdunal Swale see Palustrine System) 

4. Maritime Grassland. A sparsely vegetated community on rolling morainal topography of 

Block Island, generally on areas exposed to periodic wind and salt spray. Small examples 

likely occurred on exposed south shores of bay islands (e.g., Aquidneck and perhaps some 

smaller ones) but have been altered by land use and encroachment of invasives. This 

community is dominated by grasses and forbs and is generally found on upper slopes and 

crests of hills. Examples are relatively small in area (< 1 acre) and tend to be surrounded on 

downslope sides by maritime shrubland communities. Characteristic plant species include 

little bluestem (Schizachyrium scoparium), grass-leaved goldenrods (Euthamia graminifolia 

and E. tenuifolia), bitter milkwort (Polygala polygama), white-topped Aster (Sericocarpus 

asteroides; formerly Aster paternus), rush (Juncus greenei), and grasses. Rare species found 

in this setting include bushy rockrose (Helianthemum dumosum), northern blazing-star 

(Liatris scariosa var. novae-angliae), Maryland golden aster (Chrysopsis mariana), and 

purple three-awn (Aristida purpurescens). Note: This community type should not be 

confused with the large grasslands and hayfields on Block Island that are anthropogenically 

maintained. 

Dist: Primarily on Block Island 

Example: Lewis/Dickens Farm; Turnip Farm. 

32

5. Maritime Rocky Cliff. A community on exposed bedrock outcrops along the shore 

receiving direct impacts of wind and salt spray. Plant communities vary from sparse on dry 

sites, to more diverse in patches where freshwater seepage emerges near the crest of cliffs 

and trickles down rock crevices. Characteristic plants include threesquare rush (Scirpus 

americanus), pearlwort (Sagina procumbens), rush (Juncus marginatus), and seaside plantain 

(Plantago maritima var. juncoides). The exotic (non-native) scarlet pimpernel (Anagallis 

arvensis) is a notable inhabitant of this community. 

Dist: Along the rocky shore of Washington and Newport Counties. 

Example: Beavertail Point, Jamestown; Cliffwalk, Newport. 

6. Maritime Bluff. A community on exposed clay and glacial till substrates of steep faces 

(bluffs) along the immediate coast of Block Island and some areas around Narragansett Bay. 

Generally sparsely vegetated, with the highest diversity of plants occurring in patches of 

freshwater seepage. Representative plants include common horsetail (Equisetum arvense), 

orach (Atriplex patula), poison ivy (Toxicodendron radicans) and Virginia creeper 

(Parthenocissus quinquefolia). The clay banks tiger beetle (Cicindela limbalis) and nesting 

bank swallows (Riparia riparia) are characteristic animals of this community. 

Dist: Largest examples are on Block Island, smaller examples occur along the East 

Bay / Sakonnet shoreline and Aquidneck Island. 

Example: Mohegan Bluffs, Block Island; Sachuest Point NWR, Middletown. 

7. Maritime Shrubland. Commonly referred to as “Coastal Shrubland”, this community is a 

maritime feature limited to dry seaside bluffs, headlands, coasts, and islands exposed to 

ocean winds and salt spray. It is generally low in species diversity, tending to be dominated 

by a few species of shrubs and scattered small trees. Characteristic shrubs are northern 

bayberry (Morella pensylvanica; formerly Myrica pensylvanica), beach plum (Prunus 

maritima), wild rose (Rosa virginiana), and poison ivy (Toxicodendron radicans). Slightly 

inland, where maritime climatic influences are reduced, additional species may include 

shadbush (Amelanchier spp.), arrowwood (Viburnum dentatum), eastern red cedar (Juniperus 

virginiana), black cherry (Prunus serotina), and highbush blueberry (Vaccinium 

corymbosum). Non-native invasives are often present, such as honeysuckles (Lonicera spp.), 

oriental bittersweet (Celastrus orbiculatus), rugosa rose (Rosa rugosa), and multiflora rose 

(Rosa multiflora). Canopy height can range from 1 to 3 meters. (On sites where trees 

become dominant and the canopy is over 3 meters, see Maritime Woodland/Forest.) 

Dist: Coastal edge and on Block Island and islands in Narragansett Bay. 

Examples: Lewis/Dickens farm, Block Island; Sachuest Point, Middletown; 

Beavertail Point, Jamestown. 

B. Woodlands. Upland community structurally intermediate between forest and open barren. 

Woodlands exhibit a sparse canopy (25 to 60% cover), or one dominated by stunted trees < 16 ft (5 

m) tall. The term “barren” is often applied to woodlands on sterile soils (e.g., pitch pine barrens), or 

to wooded communities occurring on shallow soils overlying bedrock. 

33

1. Maritime Woodland/ Forest. Community of tall shrubs or small trees from 3 to 6 meters 

(10 to 20 feet) in areas exposed to occasional salt spray and on-shore winds. Characteristic 

species are shadbush (Amelanchier spp.), black cherry (Prunus serotina) and sassafras 

(Sassafras albidum). Other associates are black, scarlet oak and/or white oak (Quercus 

velutina, Q. coccinea, Q. alba)), beech (Fagus grandifolia), black gum (Nyssa sylvatica) and 

red cedar (Juniperus virginiana). Common shrubs and vines include bayberry (Morella 

pensylvanica), arrow-wood (Viburnum recognitum), poison ivy (Toxicodendron radicans) 

and Virginia creeper (Parthenocissus quinquefolia). The understory may be open or reflect 

the composition of the Maritime Shrubland Community, the two communities often 

intergrading and difficult to distinguish. More inventory of this type is needed. Both 

communities provide an abundance of fruit that is a critical food source for coastal resident 

and migratory songbirds. 

Dist: Block Island and bordering Long Island Sound and lower Narragansett Bay. 

Examples: Trustom Pond NWR, Charlestown; Rodmans Hollow, Block Island. 

Note: Young examples of this type may be dominated more by early successional species 

such as sassafras and red cedar and overall composition may be dramatically skewed by past 

land use. For example, a Beech - Black Gum Forest variant occurs locally, but is an artifact 

of past clear-cutting and subsequent elimination of typical overstory species such as oak and 

hickory. 

2. Pitch Pine / Scrub Oak Barrens. Woodland community typically found on well-drained 

sandy soils of outwash plains. Pitch pine (Pinus rigida) is the dominant tree varying from 25 

to 60% cover, and the shrub layer is dominated by scrub oaks (Quercus ilicifolia and Q. 

prinoides), often forming dense thickets. The low shrub canopy typically includes sweetfern 

(Comptonia peregrina), late lowbush blueberry (Vaccinium angustifolium), and black 

huckleberry (Gaylussacia baccata). Sandy openings within the woodland may be sparsely 

vegetated with lichens and mosses, and may also include patches of bearberry 

(Arctostaphylos uva-ursi), heather (Hudsonia ericoides and H. tomentosa), and wild indigo 

(Baptisia tinctoria). Early sedge (Carex pensylvanica) is typically found in the understory, 

and other herbs present may include goat’s-rue (Tephrosia virginiana), sickle-leaved golden 

aster (Pityopsis falcata), and wild lupine (Pityopsis falcata). Fauna of this community 

includes Alleghany mound ant (Formica exsectoides) and lepidoptera (moths and butterflies) 

such as buck moth (Hemileuca maia), frosted elfin (Incisalia irus), and hoary elfin (Incisalia 

polios) that are dependent on specific food plants that occur in this habitat (e.g., scrub oak, 

wild lupine, wild indigo). This community is typically maintained by periodic wildfire which 

reduces competing woody species and stimulates (but is not required for) reproduction of 

pitch pine. 

Dist: Washington and Kent Counties. 

Examples: Nicholas Farm, Coventry; Arcadia Management Area, Exeter. 

3. Red Cedar Rocky Summit. A community on warm, dry, rocky ridges and summits where 

vegetation may be patchy within areas of exposed bedrock. Eastern red cedar (Juniperus 

virginiana) is the characteristic tree, with understory vegetation dependent on site conditions. 

34

Sparse shrubs may include scrub oak (Quercus ilicifolia) or lowbush blueberries (Vaccinium 

angustifolia and V. pallidum). Herbaceous plants include hairgrass (Deschampsia flexuosa), 

oat-grass (Danthonia spicata) and early sedge (Carex pensylvanica). At inland sites, little 

blue stem (Schizachyrium scoparium), ebony spleenwort (Asplenium platyneuron), and a 

sedge (Carex eburnea) are common. This community is generally widespread in R.I. but 

occurs as very small patches. 


Examples: Diamond Hill and Miller's Oak, Cumberland. 

C. Forested Uplands. Upland communities with more than 60% canopy cover of trees, occurring on 

substrates with less than 50% rock outcrop or shallow soil over bedrock. Hardwood types are listed 

first, followed by coniferous and mixed forests. 

1. Oak / Heath Forest. Deciduous forest on well-drained, acidic soils. Black oak and/or 

scarlet oak (Quercus velutina, Q. coccinea) are generally dominant, but in less common 

instances chestnut oak (Q. prinus) or white oak (Q. alba) are the dominant trees. Common 

associates include white oak (Quercus alba), black birch (Betula lenta), black gum (Nyssa 

sylvatica), red maple (Acer rubrum) and sassafras (Sassafras albidum). Pitch pine (Pinus 

rigida) and white pine (Pinus strobus) may be present in small amounts. American chestnut 

(Castanea dentata) was a common associate prior to the chestnut blight; saplings are still 

found in the understory. Total percent canopy cover can range from 60 to 100% (woodland 

to forest). The shrub layer is ericaceous with characteristic species including black 

huckleberry (Gaylussacia baccata), mountain laurel (Kalmia latifolia), and lowbush 

blueberries (Vaccinium pallidum and V. angustifolium). Plants in the ground layer include 

early sedge (Carex pensylvanica), wild sarsaparilla (Aralia nudicaulis), and wintergreen 

(Gaultheria procumbens). Three types are recognized based on the dominant oak species. 

Dist: Statewide, but most abundant in southern half of state. 

Examples: Weetamoo Woods, Tiverton; Francis Carter Preserve, Charlestown; 

Arcadia Management Area, West Greenwich and Exeter. 

a. Black Oak - Scarlet Oak / Heath Forest. This is the dominant type of oak / heath 

forest in the state, covering large areas intermixed with smaller patches of other forest 

types. This type fits the main description above with black and/or scarlet oaks being 

the dominant tree species and heath shrubs characterizing the understory. See below 

for forest dominated by chestnut oak or white oak. 

b. Chestnut Oak Forest. A deciduous forest occurring on well-drained upper slopes 

and ridgetops where the dominant canopy tree is chestnut oak (Quercus prinus) with 

lesser representation by other oaks (Q. rubra, velutina, and alba). Additional trees 

may include red maple (Acer rubrum) and pitch pine (Pinus rigida). Examples: 

Ell/Long Pond and Blue Pond, Hopkinton; North-South Trail north of Route 6 in 

Foster. 

c. White Oak / Mountain Laurel Forest. Dominated by white oak with an understory 

35

of mountain laurel and sparse herbaceous cover. This type is typically found on welldrained 

coarse or gravelly soils such as on moraine deposits and eskers. Tends to 

occur in small patches within larger context of oak and oak – pine forests. 

2. Oak – Hickory Forest. A deciduous forest community on well-drained soils of ridgetops 

and slopes. Soils are usually loams/sandy loams and slightly more mesic and nutrient rich 

than in Oak - Heath Forests. Red oak (Quercus rubra) is typically dominant or co-dominant 

with lower densities of white oak (Quercus alba) and hickories (pignut hickory, Carya 

glabra; shagbark hickory, C. ovata; and, mockernut hickory, C. tomentosa). Occasionally 

black oak is dominant. Other associated trees include white ash (Fraxinus americana), red 

maple (Acer rubrum), tulip tree (Liriodendron tulipifera), and white pine (Pinus strobus). A 

tall shrub subcanopy is typically present with saplings of the canopy trees along with witch 

hazel (Hamamelis virginiana) and flowering dogwood (Cornus florida), which are fairly 

good indicators of this community. Maple-leaved viburnum (Viburnum acerifolium) is a 

characteristic shrub and other low shrubs include lowbush blueberries (Vaccinium pallidum 

and V. angustifolium), and sheep laurel (Kalmia angustifolia). Typical plants in the herb 

layer are wild sarsaparilla (Aralia nudicaulis), wood ferns (Dryopteris spp.), and early sedge 

(Carex pensylvanica). The herb layer is usually more diverse than in the Oak – Heath Forest. 

The American chestnut (Castanea dentata) was formerly a co-dominant canopy tree species 

in this community prior to the infestation of chestnut blight; today chestnut sprouts remain 

common in the understory. 

Dist: Throughout state; more prevalent farther from the coast. 

Examples: Sprague Farm, Glocester; Canonchet Trail, Hopkinton; Lincoln Woods 

State Park, Lincoln. 

Variant: Rich Oak – Hickory Forest. Occurs on soils overlaying calcareous bedrock 

such as limestone. The herbaceous layer reflects the calcareous influence and is more 

diverse than the typical Oak – Hickory Forest. It is characterized by “rich soil 

indicators” such as ebony spleenwort (Asplenium platyneuron), maidenhair fern 

(Adiantum pedatum), bloodroot (Sanguinaria canadensis), dogtooth violet 

(Erythronium americanum), and red trillium (Trillium erectum). Flowering dogwood 

and shagbark hickory are more frequent in this association than in the typical Oak – 

Hickory type as well. 

Dist: Uncommon and local in northern part of state 

Examples: Limerock Preserve and Lincoln Woods, Lincoln. 

3. Oak – Holly Forest. This is an oak-dominated forest with a prominent sub-canopy of 

American holly (Ilex opaca). It occurs on moist, moderately well-drained silt and sandy 

loam soils, often at the upper edge of forested wetlands (e.g. red maple swamps or red maple 

– ash floodplain forests). Upslope it often grades into Oak – Heath Forest. Black oak 

(Quercus velutina) and/or scarlet oak (Quercus coccinea) are typically dominant, but red 

maple (Acer rubrum) can be prevalent. Frequent associates are white oak (Quercus alba), 

beech (Fagus grandifolia), serviceberry (Amelanchier sp.) and ironwood (Carpinus 

carolinana). The understory includes highbush blueberry (Vaccinium corymbosum), sweet 

36

pepperbush (Clethra alnifolia), New York fern (Thelypteris noveboracensis), cinnamon fern 

(Osmunda cinnamomea), greenbriars (Smilax spp.), and wild grape (Vitis spp.). Holly may 

be present at low percents in other oak forest types, but here is > 25% cover. 

Dist: Predominantly near the coast, but occurs locally inland. 

Examples: Wilbur Woods, Little Compton; Pardon Gray Preserve, Tiverton; Great 

Swamp Management Area, South Kingstown. 

4. Mesic Beech – Maple – Red Oak Forest. A hardwood forest on generally moist, welldrained 

acid soils, broadly defined with several regional and edaphic variants. The canopy is 

co-dominated by American beech (Fagus grandifolia), sugar maple (Acer saccharum) and/or 

red oak (Quercus rubra). Common associates are white ash (Fraxinus americana), yellow 

birch (Betula alleghaniensis), hop hornbeam (Ostrya virginiana), red maple (Acer rubrum), 

basswood (Tilia americana), and American elm (Ulmus americana). White pine (Pinus 

strobus) and hemlock (Tsuga canadensis) are occasional. Represented in the tall shrub layer 

are ironwood (Carpinus caroliniana), witch hazel (Hamamelis virginiana), and occasionally 

flowering dogwood (Cornus florida). In the northern part of the state, striped maple (Acer 

pensylvanicum) and hobblebush (Viburnum lantanoides) occur in the tall shrub layer. The 

ground layer is generally high in species diversity with characteristic plants including 

Christmas fern (Polystichium acrosticoides), jack-in-the-pulpit (Arisaema triphyllum), white 

baneberry (Actaea pachypoda), and false Solomon’s seal (Smilacina racemosa), with rarer 

representatives being blue cohosh (Caulophyllum thalictroides), wild leek (Allium 

tricoccum), and bloodroot (Sanguinaria canadensis). Many herbaceous plants are spring 

ephemerals that flower before the canopy trees leaf out. (Includes types also known as 

“Northern Hardwood Forest” and “Red Oak – Northern Hardwood Forest”). 

Dist: mostly in northern and western part of state. 

Examples: George Washington Management Area, Glocester; Tefft Hill and 

Stepstone Falls in Arcadia Management Area, Exeter. 

5. High Terrace Riverside Forest. Forest communities on upper slopes and terraces of rivers 

and streams that are flooded only during peak high water events and for short durations. 

Soils are well-drained and the community is typically mapped as an upland type. 

Characterized by tree species typical of upland mesic forests, including American beech 

(Fagus grandifolia), sugar maple (Acer saccahrum), white ash (Fraxinus americana), red 

oak (Quercus rubra), basswood (Tilia americana), and ironwood (Carpinus caroliniana), and 

with ferns, spring ephemerals, and other herbacesous plants characteristic of floodplains. A 

rare community in Rhode Island that was historically more prevalent along the Blackstone 

River, but creation of dams and alteration of the hydrological regime severely altered the 

frequency of flooding of these reaches. 

Dist: Ravines on Blackstone and Pawcatuck River systems. 

Examples: Blackstone River, Cumberland; Stepstone Falls, Arcadia Management 

Area, Exeter. 

6. Pitch Pine - Oak Forest. A mixed coniferous/deciduous forest community that typically 

37

occurs on well-drained, sandy soils of glacial outwash plains and moraines, and also on thin, 

rocky soils of ridgetops. Dominant trees are pitch pine (Pinus rigida), comprising over 25% 

cover, mixed with one or more oaks including scarlet oak (Quercus coccinea), white oak (Q. 

alba), and black oak (Q. velutina). The relative proportions of oak and pine are highly 

variable within this type. The shrub layer is well-developed with scrub oak (Quercus 

ilicifolia), late lowbush blueberry (Vaccinium angustifolium), and black huckleberry 

(Gaylussacia baccata), and the herb layer is generally sparse, with bracken fern (Pteridium 

aquilinum), wintergreen (Gaultheria procumbens), early sedge (Carex pensylvanica), and 

pink lady’s-slipper (Cypripedium acaule). This community is common in R.I. and often 

develops in the absence of fire as a transition type between pitch pine/scrub oak barren and 

forest types dominated by oaks. Where white pine is a significant co-dominant, also see 

White Pine – Oak Forest. 

Dist: Providence, Kent, and Washington Counties. 

Examples: Kingston Pine Barrens, South Kingstown and Wickaboxet State Forest, 

West Greenwich. 

7. White Pine – Oak Forest. A mixed coniferous/deciduous forest on sandy soils or on slopes 

with rocky well-drained soils. The canopy is co-dominated by a variable mixture of oaks and 

white pine (Pinus strobus). Oaks include one or more of the following: black (Quercus 

velutina), chestnut (Q. prinus), red (Q. rubra), white (Q. alba), and scarlet (Q. coccinea). 

Pitch pine (P. rigida) may be frequent, but usually at lower percent cover. Other common 

associate trees include red maple (Acer rubrum), hemlock (Tsuga canadensis), American 

beech (Fagus grandifolia), and black cherry (Prunus serotina). The shrub layer is 

predominantly ericaceous with blueberries (Vaccinium spp.), and black huckleberry 

(Gaylussacia baccata). The ground layer is generally sparse and low in species diversity, 

with species including bracken fern (Pteridium aquilinum), wintergreen (Gaultheria 

procumbens), early sedge (Carex pensylvanica), and pink lady’s-slipper (Cypripedium 

acaule). Disturbance such as fire, insect and disease outbreaks, and windstorms can allow 

white pine to seed in or remain dominant for years; otherwise oaks eventually make their 

way into the canopy and the forest may transition to Oak / Heath Forest or Oak – Hickory 

Forest. 


Example: George Wasington Management Area, Glocester; Arcadia Management 

Area, Exeter. 

Variant: White Pine Forest – in areas that have been cleared (e.g., old pastures) or were 

subject to fire or severe canopy die-off from pathogens, white pine may seed in heavily and 

become the dominant tree. Eventually, oaks may become established and shift the 

composition towards the mixed forest type. (This differs from the White Pine Plantation, 

considered a cultivated or managed type that is usually easy to identify by even spacing and 

arrangement of the trees). 

8. Hemlock – Hardwood Forest. A mixed coniferous/deciduous forest that typically occurs on 

middle to lower slopes of ravines, on cool mid-elevation slopes, and moist uplands on the 

38

edge of swamps. Hemlock (Tsuga canadensis) is a co-dominant in the canopy with the 

following: American beech (Fagus grandifolia), sugar maple (Acer saccharum), red maple 

(Acer rubrum), black cherry (Prunus serotina), yellow birch (Betula alleghaniensis), black 

birch (B. lenta), and red oak (Quercus rubra). Tuliptree (Liriodendron tulipifera) may also 

be present. The relative cover of hemlock is highly variable, ranging from nearly pure stands 

to as little as 20% of the canopy. In closed canopy stands the shrub and herb layers are 

sparsely vegetated. Characteristic plants in the understory include cucumber root (Medeola 

virginiana), Canada mayflower (Maianthemum canadense), shining clubmoss (Lycopodium 

lucidulum), starflower (Trientalis borealis), bellwort (Uvularia sessilifolia), common woodsorrel 

(Oxalis acetosella), partridgeberry (Mitchella repens), and painted trillium (Trillium 

undulatum). Some examples of this community have been severely impacted by hemlock 

woolly adelgid (Adelges tsugae), a non-native insect pest, that weakens or kills hemlocks. 


Example: Durfee Hill Management Area, Glocester; Beach Pond, Exeter. 

HAPPY TRAILS! 

39

NOTES 

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Natural Communities of Rhode Island - University of Rhode Island

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