Freshwater Communities

In each of the communities covered, a photograph of the community is accompanied by a description of the soil conditions favored, the distribution of the community, and other points of interest. This summary is followed by two lists; the list entitled 'typical indicator species' includes plant species which tend to be dominant and typify the community. The second list, entitled 'Species to watch for' includes some of the rarer species which - in our area at least - tend to favor this community. Becoming familiar with the commoner species and their association with each other can be a good step toward finding rarer or more interesting plants.

Cranberry Bogs

Cranberry Bogs Cranberry Bogs
Early successional cranberry bog, with
a very rich plant community.
A mid-successional cranberry bog, with
open bog and areas that are scrubbing

In a Cape May sense, this section covers only abandoned cranberry bogs, since there is no longer any active cranberry production in the county. The production of cranberries has a long history in New Jersey and, during the time that this activity was occurring in the Cape May area, production was relatively low key, with local businesses operating on a small scale - very different to the industrial-strength production of Burlington and Ocean Counties today. Cranberries occur naturally in the state and their numbers were increased in part by planting and in part by providing conditions that favored the species. The original cranberry bogs were formed by simply building earth banks across suitable streams and allowing the water to back up behind the bank. Water control mechanisms in the banks allowed the water to be raised or lowered as required. Thus, most cranberry bogs in our area were originially wet savannas (see below) and the plant communities of the two have much in common.

Old cranberry bogs generally have one of two outcomes, dependent on how they are left. In some cases after abandonment (such as at Lake Nummy and Tarkiln Pond) the drainage gates are left closed and the bogs become permanent ponds. In other cases, the drainage gates are left open, or perhaps fall apart over time, and the bog returns to a seasonally flooded savanna-type habitat. In the case of the latter, old cranberry bogs quickly revert to an important collection of plant communities, rich in wetland species. Such communities are also important for a wide range of often local or scarce invertebrate species, such as Bog Coppers and Dion Skippers.

After abandonment, cranberry bogs readily dry out over time and all of the Cape May examples are being rapidly colonised by Pitch Pine, Red Maple and other woody perennials. None of the sites are managed for their important plant communities and it seems likely that all will eventually disappear over time unless habitat succession is halted by appropriate managament.

Typical indicator species
  • Foxtail Clubmoss
  • Engelmann’s Arrowhead
  • Rose Pogonia
  • Trifid Flat-sedge
  • White Beak-sedge
  • Dense-flowered St. John’s-wort
  • Purple Pitcherplant
  • Leatherleaf
  • Large Cranberry
  • Species to watch for
  • Slender Clubmoss
  • Tuberous Grass-pink
  • Goldencrest
  • Bog Aster

  • Savannas

    Savannas are often dominated by a
    range of grasses and grass-like plants.

    In a New Jersey sense, savannas relate not to open, grassy, prairie-like plains, but to areas along permanent freshwater systems that receive regular inundation. Wet savannas are common along the meandering rivers and streams of the pine barrens and tend to be most often flooded during the winter months. Regular flooding helps to prevent encroachment of woody perennials and these plant-rich habitats form perhaps the most important of the pine barren communities and contain many of the region's rarest plants. In Cape May, these are rare habitats, partly because conditions for forming these habitats are restricted to the northern third of the county, and partly because many of the original savannas were converted to cranberry bogs.

    Typical indicator species
  • American Yellow Water-lily
  • Rose Pogonia
  • Carolina Redroot
  • Tawny Cotton-grass
  • Smooth Saw-sedge
  • Species to watch for
  • Goldencrest
  • Tuberous Grass-pink
  • Bog Hair-grass
  • Maidencane Panic-grass
  • Sugarcane Plume-grass
  • Comb-leaved Mermaidweed
  • Creeping St. John’s-wort
  • Eastern Purple Bladderwort
  • Canby’s Lobelia
  • Pine Barren Thoroughwort

  • Vernal Ponds

    Vernal Ponds Vernal Ponds Vernal Ponds
    High water levels in spring give vernal
    ponds an impoverished look, with only
    grass-like plants in evidence.
    As water levels drop in vernal ponds,
    the exposed, bare earth is rapidly colon-
    ized by an abundance of low flowering
    plants, such as Golden Hedge-hyssop,
    here with the white flowers of Slender
    Arrowhead in front.
    Species-rich plant communities typical
    of vernal ponds may also develop as
    marginal communities of freshwater
    ponds if the summer water levels fall
    sufficiently enough to provide the right
    growing conditions.

    Vernal ponds can occur on a range of different soils and in a range of situations; they may be deeply shaded by thick woodland, or they may occur fully in the open with no shade at all - and anywhere in between. But their one common feature is that they are not wet year-round, usually drying our for at least some of the hotter, drier months of the year. This is an important feature of vernal ponds since it means they contain no fish populations and this fact makes them important breeding habitats for amphibians, since there are fewer predators to eat their eggs and young. From a plant communities perspective, vernal ponds create special problems to overcome. True aquatics such as water-lilies and pondweeds cannot survive the dry periods, while those plants that do occur, need to survive prolonged periods under water.

    Despite these seemingly difficult problems, vernal ponds often have species-rich plant communities in them, most often dominated by grasses, sedges and rushes of various species. Because of the inundation by freshwater, vernal pond plant communities tend to consist largely of species that grow and flower later in the year, and such ponds may appear rather barren before mid-summer. A number of the plant species are annuals and often survive by growing rapidly in great profusion in the summer months, then setting seed and dying down before the autumn frosts.

    True vernal ponds will be wet in winter and completely dry in summer, but similar conditions can form around the upper edges of freshwater ponds and plant communities that are typical of vernal ponds are also often found as marginal communities around the edges of ponds that draw down during summer, or as a mosaic with aquatic communities in ponds and depressions that have uneven bottoms. In addition, some ponds vary in their water content from year to year, according to the amount of precipitation received during the winter. Such ponds can form interesting, dynamic plant communities and require regular visits from year to year before their full speciers content can be assessed.

    Typical indicator species
  • Rafinesque’s Pondweed
  • Canadian Rush
  • Wool-grass
  • American Bulrush
  • Small-fruited Spikerush
  • Blunt Spikerush
  • Warty Panic-grass
  • American Brookweed
  • Golden Hedge-hyssop
  • Long-stalked False-pimpernel
  • White-bracted Thoroughwort
  • Umbellate Marsh Pennywort
  • Species to watch for
  • Square-stemmed Spikerush
  • New Jersey Hair-grass
  • Blue Maidencane
  • Maidencane Panic-grass
  • Wrinkled Joint-grass
  • Lowland Rotala
  • Lance-leaved Marsh-pink
  • Lavender Bladderwort
  • Canby’s Lobelia
  • Aster-like Boltonia

  • Freshwater Ponds

    Freshwater Ponds Freshwater Ponds
    Mature freshwater ponds usually have
    well-developed communities of aquatic
    plants below the surface and often good
    populations of water-lilies.
    Water-lilies can dominate the surface
    of freshwater ponds by late summer.

    Freshwater ponds are plentiful in Cape May County, but their value to wildlife - and especially to plant communities - may often depend on the ponds history. Ponds that originate due to human activity, such as sand diggings or areas flooded after cranberry bog abandonment, tend to be species-poor compared with those that have formed naturally over a longer period of time. Ponds that continue to receive relatively heavy human influence, such as ponds used for fishing, also tend to have relatively poorly-developed plant communities, especially at their margins, and such ponds may also be limited in their wildife value due to the presence of alien plant species which can become dominant and crowd out, or prevent the development of, native species.

    Plant communities of freshwater ponds consist of two sub-sets of communities; those that consist of emergent species in shallower water, and those that consist largely of submerged aquatics in deeper water. Good communities of emergent plants may only evolve in ponds that have relatively stable water levels, while submerged aquatic communities generally require ponds with clear water and may not develop in the 'blackwater' ponds found in areas of peaty soils, or where there is high tanin content from the leaves of nearby trees. A third sub-community of plants also may develop, consisting of floating species on the water surface. In some instances, especially where the water receives high nutrification, floating aquatics can be detrimental to other plant communities by shading out light and preventing it from reaching submerged species.

    Typical indicator species
  • American White Water-lily
  • Common Duckweed
  • Common Cattail
  • Floating Bladderwort
  • Species to watch for
  • Carolina Mosquito-fern
  • Spatter-dock
  • Golden-club
  • Rigid Hornwort
  • Low Water-milfoil
  • Pinnate Water-milfoil

  • Herb-rich Marshes

    Herb-rich Marshes Herb-rich Marshes
    Herb-rich marsh with a good floral
    A species-rich marsh but with signs of
    early colonization by Common Reed.

    Perhaps one of the habitats that has disappeared most rapidly and most extensively in the Cape May region is open, freshwater wetlands that hold species-rich communities of herbaceous plants. These plant communities develop at the back, or upper, edge of saltmarsh areas, where freshwater springs emerge from ridges of higher ground, or where wet ground is high enough up a gradient that it does not receive saltwater inundation, even on the highest tides. Over the past 50 to 100 years, such areas have been extensively colonized by Common Reed, which was introduced from Europe and the tall, dense stands of this species rapidly crowd out existing plant communities. In addition, construction of the Garden State Parkway through Cape May County took place extensively through this ecotone and displaced the overwhelming majority of these habitats and communities in the region - both directly by the physical presence of the road and indirectly by the disturbance caused, which allowed alien plant species to become established and outcompete the natives. In more recent years, the increasing occurence of higher storm surges and the greater number of saltwater inundations during the course of the yearly cycle has further reduced herb-rich marsh communities.

    Herb-rich marshes typically have a wide range of plant species from a number of plant families, living in close association. Typically, grasses, sedges, rushes, and members of the mint and aster family tend to be well represented and flowering is at its height in these communities during late summer.

    Typical indicator species
  • Marsh Fern
  • Large Blue Flag
  • Common Cattail
  • Narrow-leaved Cattail
  • Canadian Rush
  • Wool-grass
  • Trifid Flat-sedge
  • Smooth Saw-sedge
  • Sallow Sedge
  • Virginia Marsh St. John’s-wort
  • Seedbox
  • Swamp Rose Mallow
  • Seashore Mallow
  • Swamp Dock
  • Mild Water-pepper
  • Stiff Marsh Bedstraw
  • Swamp Milkweed
  • Giant Sunflower
  • Common Boneset
  • Climbing Hempweed
  • Hemlock Water-parsnip
  • Mock Bishopweed
  • Spotted Water Hemlock
  • Species to watch for
  • White Fringed Orchid
  • Yellow Fringed Orchid
  • Meadow Garlic
  • Northern Sweet-grass
  • Bearded Sprangletop
  • Purple-leaved Willowherb
  • Lake Loosestrife
  • Blunt-leaved Bedstraw
  • Blue Mistflower
  • Rattlesnake-master

  • Reedbeds

    The invasive Common Reed rapidly
    colonizes wetlands and forms dense
    single-species stands in many wetlands
    throughout the area.

    Much confusion exists over the presence of Common Reed (often referred to as 'Phragmites', its scientific name) in Eastern North America, with disagreement as to whether it is native here or alien. The confusion comes from the fact that Common Reed is native to the region, but a different clone or variety of the species was introduced from Europe (probably accidentally) and it is this non-native form that has become invasive, having displaced the native form, and many other wetland species. As an after note, it should be stated that the American and European species are generally now considered to be different species, and this taxonomic change adds more confusion to the situation.

    Vast swathes of invasive Common Reed can now be found throughout the area, dominating the fringes of freshwater wetland areas (including free-standing ponds, lakes and open, marshy areas) as well as the higher reaches of saltwater areas, where the parts per million of salt in the water do not exceed levels that can be tolerated by the reed. Sadly, the tall, dense stands of reed stems, with their deep thatch of dead material that build up each year, produce a habitat that cannot be successfully colonized by any other plant species. Locally, there may be a few plants that manage to survive, especially along open edges of the reed stands but often these are relics of the plant community that formerly occurred before the reed invasion.

    In areas where dredging material is dumped, broken pieces of reed root can regrow, and the steep, clayey banks of dredging inpoundments are usuallycarpeted in this species. Linear stands of Common Reed also grow along the edges of streams, ditches, canals and other wetland sites and the only limitations to its spread appear to be saltwater inundation, or dense shade, with the species typically not penetrating far into wooded swamps.

    Typical indicator species
  • Common Reed
  • Eastern Poison-ivy
  • Spear-leaved Orache
  • Spotted Touch-me-not
  • Hedge Bindweed
  • Bittersweet
  • Climbing Hempweed
  • Spotted Water Hemlock
  • Species to watch for
  • American Germander

  • Rivers and Streams

    Rivers and Streams
    The Tuckahoe River holds some good
    freshwater plant communities along its
    mid-section, here dominated by large
    rafts of Pickerelweed.

    Open rivers and streams are uncommon in Cape May County, mostly because of a lack of altitudinal range, meaning that saltwater incursion can reach throughout much of the wetlands of the region. Thus, there is an abundance of saltmarsh habitats but a relative scarcity of good freshwater plant communities, exept where manmade lakes or ponds have been colonized. The one major exception is the Tuckahoe River which, for much of its lower length, forms the border between Cape May and Atlantic Counties. For most of its lower reaches, the river is bordered by saltmarsh, but this is progressively replaced by plant communities of freshwater habitats from around the region of the Rout 50 bridge at Tuckahoe - though a true gradient from saltwater to freshwater communities is sadly interrupted by stands of Common Reed. Interesting plant communities can be found on both sides of this river as tidal impact gradually lessens and swamp woodland gradually dominates in the upper reaches. The river is sluiced where it passes under Route 49 at Head of the River, and upstream of here, the communities are typical of those covered under maple and white Cedar swamps, cranberry bogs and other wetland and woodland communities.

    This midsection of the Tuckahoe contains plant communities that are more common further up the Delaware Bay and it is here that remnant stands of Annual Wild-rice can still be found - this is a species that is fast disappearing as it is squeezed out by Common Reed encroachment and increased saltwater inundation due to sea level rises.

    In a few other places, freshwater streams pass through species-rich wetland plant communities (especially on the bayshore side of the peninsula) and have distinctive streamside communities along their banks. These are are usually dominated by stands of various sedges, Green Arrow Arum, Pickerelweed and other associates, while Yellow Water-lily or Spatterdock may be found in the stream itself.
    Typical indicator species
  • Pickerelweed
  • Green Arrow Arum
  • Annual Wild-rice
  • Spotted Water Hemlock
  • Species to watch for
  • Golden-club
  • Water Bulrush
  • European Sweet-flag