Dunes are dynamic and constantly changingecosystems that form a natural buffer between sea andland. Depending on conditions, they can eitheraccumulate sand from the beach, growing the dunesand storing sand, or they can form a source of sand tothe beach as the dunes erode. e ecology of these

ecosystems plays a key role in mediating many of thefunctions of dunes, including their growth andstabilization. Similarly, the physical environment ofthis unique habitat strongly shapes the ecology of theorganisms living there.

20 Dune Manual

Lower Beach and Wrack Line

In the lower portion of the beach where sediments arecovered frequently by water, aquatic organisms thrive.However, in the areas at and just above the high tidezone, conditions are particularly harsh. e lack ofwater makes life nearly impossible for aquatic orterrestrial organisms, and the dry sand is easy to heatand cool, resulting in strong swings in temperaturefrom too hot to walk on during a sunny summer dayto bitterly cold during winter. e sand in this area ismoved by both wind and waves, creating a highlydynamic system in which the sand is in near constantmotion. In oceanfront dunes, this high beach area alsoexperiences strong swings in salinity, from highly saltyconditions during dry weather caused by salt spray

being concentrated byevaporation, to beingwashed almost free ofsalt during intenserains. As a consequence,except in specializedhabitats (such as thewrack line, whererotting organic materialforms both food and amechanism for waterstorage), very fewanimals and no trueplants can live in thiszone.

In this area of beach

(the base of what is known as the supratidal zone), thestrand or wrack line forms a small oasis of life in theotherwise dry and relatively barren sand. Here in thewrack line, the debris left by the high tide forms anarrow band along the shore. As many a beachcomberwill testify, all kinds of items can be found here, fromhuman garbage to seashells, animal remains,decomposing seaweed, sea grasses, and other naturalmaterials. e rich organic content of this areaprovides a reservoir of water and food for the animalsfound in this area. One common animal in this zoneare talitrid amphipods (Talorchestia longicornis), oftenknown as beach fleas or sand hoppers. ese animalslive in burrows under or near the wrack line. eburrow helps hold water to keep them moist as well asforming a chamber where they can lay their eggswithout them being washed away by the tide. eselargely nocturnal crustaceans feed on the decomposingorganic materials in the wrack line. Tiny white wormsthat are cousins of the earthworm (EnchytraeidaeEnchytraeus albidus) are other common residents here.Carrion beetles as well as the larvae of tethinid orcarrion flies (Tethina parvula; Sarcophaga carnaria) mayalso often be found under the decaying carcasses offish, horseshoe crabs, and other larger animals foundin the wrack line. In the past, the brightly metallic-colored northeastern beach tiger beetle (Cicindeladorsalis dorsalis) would also have been abundant here,especially on the warmest summer days. Unfortunately,these animals have become critically endangered inrecent years and are either absent or extremely rare on

Dune Ecology: Beaches and Primary Dunes

Wrack lineJeanne Heuser photo

New Jersey’s beaches today, despite several attempts toreintroduce them to the beaches and dunes at SandyHook. While the diversity of wrack-line organisms islow, their abundance can be really high. Attracted bythe abundance of food, lycosid spiders (Arctosalittoralis) hunt here, their pale color helping tocamouflage them in the sand. Robber flies (Alslidae)also patrol this area looking for carrion flies to eat,swooping in with their characteristically curved attackpaths whenever they detect their prey. e rich supplyof arthropods and worms makes the strand line afavorite foraging area for waders and beach-nestingbirds like piping plovers, particularly for unfledgedplover chicks that often lack access to their preferredfeeding areas (back bay tidal flats) due to humandevelopment. In addition, it is common to seeswallows swooping low over the strand in search ofrobber flies and other insects drawn to this area(http://www.vliz.be/imisdocs/publications/139188.pdf).e wrack line is also an important microhabitat forseabeach amaranth, where plants are less numerous buttend to grow larger and, therefore, produce more seeds(U.S. Fish and Wildlife Service 2007; Hancock 1995;Weakley and Bucher 1992).

Ghost or sand crabs (Ocypodidae) make deep burrows3 to 4 feet into the sand toward the top of the beach orinto the edges of the dunes, and spend most of the dayin these cool, damp hiding spots. Like many beachresidents, their shells are sand colored, which,combined with their tendency to be seen inmoonlight, contributes to their ghostly appearance.ey can grow to about 2 inches across the shell andcan run sideways remarkably fast as they move acrossthe beach in search of clams, insects, detritus, and evenother crabs to eat. While they spend much of theirlives on land, ghost crabs must periodically return tothe sea or to the water at the bottom of their tunnelsto wet their gills. e female carries her eggs on herundercarriage, and these too must be periodicallysubmersed in water to keep them moist. e larvae arealso released into the ocean when they hatch, spendinga brief period as fully aquatic animals beforemetamorphosing and moving to the land as juveniles.

Unfortunately, ghost crabs can prey onthe eggs and chicks of beach-nestingbirds such as terns and piping plovers.us it is important to avoid habitat

modifications that favor ghost crabs in or near areasthat support populations of rare, threatened, orendangered beach species (Barnegat Bay Shellfish2013; NPS 2015).

Many beachgoers will testify to the fact that the beachoften plays host to a variety of biting insects,particularly greenheads and stable flies. As may beguessed by its name, the salt marsh greenhead fly(Tabanus nigrovittatus) breeds in salt marshes that areoften found near beaches, especially in the barrierisland and peninsula systems that dominate the NewJersey shoreline. Larval greenflies eat a wide variety ofinvertebrates found in the decomposing thatch of thesalt marsh. ey overwinter as pupae and thenmetamorphose to adults in late spring. Adult flies matein the marsh areas, and the female lays her first batchof eggs without need of a blood meal. However, to fueladditional laying, she needs to obtain energy andprotein by biting warm-blooded prey. Blown from themarshes to the beaches by the west winds, their strongbite and persistence can make them a serious pest forbeach-loving humans in the summer. Stable flies areanother familiar bane of summer beachgoers. eseflies look similar to house flies, but they have a verysimilar life cycle to greenheads, with the larvae feedingand maturing in the rotting thatch of the salt marshand the adults feeding on the blood of warm bloodedanimals (Cilek 2008; Hansens and Race 2008).

e use of off-road vehicles can have significantnegative effects on this habitat. Vehicles can crushghost crabs when not in their burrows, and vehicletraffic has also been found to decrease the numbers ofinvertebrates within the strand lines (Steinback andGinsberg n.d). It has also been suggested that off-roadvehicle use on ocean beaches was a key reason for theprecipitous decline in populations of the northeasternbeach tiger beetle in the past century (Hill and Knisley1994). In addition, wrack removal, which is often

Dune Manual 21

High Beach and Embryonic Dunes

Moving up the beach, away from the water, conditionsstabilize a little and life becomes possible. Organismsliving in this zone must have a high tolerance for beingblasted with and buried by the constantly moving sand.is sand has little or no organic material in it, whichmeans that nutrient supplies for plants are low. Withoutorganic materials to absorb water, rain drains rapidlythrough the coarse sand grains after a storm, so plantsmust have a strategy for obtaining water rapidly when itis available and storing it within their tissues for lateruse. ey must also have strategies to deal with the oftenhigh amounts of salt in their habitats.

At the very front of the living dune, a small number ofhighly specialized species with high tolerances to theconditions that this environment presents eke out anexistence. Many of the plants and animals in this zone,such as piping plover (Charadrius melodus), seabeachamaranth (Amaranthus pumilus), and seaside knotweed(Polygonum glaucum) are endangered due to habitat lossfrom coastal development, beach stabilization, and (forbird species) high levels of predation associated withhuman activities. In addition, these species are highlyintolerant of being trampled or disturbed by the foot orvehicular traffic that commonly occurs there. Making

things worse for such species is the increase in floodingfrequency resulting from rising sea levels and theencroachment of the invasive Asiatic sand sedge (Carexkobomugi), which grows further down the front of thedune toward the ocean than native dune species.

e narrow strip of beaches along New Jersey's Atlanticcoast supports a considerable number of rare,threatened, and endangered species, including federally-listed, state-listed, and other rare, declining, orimperiled species (Table 2). Iconic among these is thepiping plover, a small, sand-colored shorebird with darkbands across its forehead and around its neck and brightorange legs. ese birds breed on beaches throughoutthe Atlantic coast and on lake shores and river sand barsin the interior of the United States. ey winter in thesouthern Atlantic and Gulf coasts and even northernMexico, as well as in the Bahamas. ese birds createnests that are little more than scrapes in the sand on thehigh beach. ey prefer to nest in flatter areas withsparse vegetation to allow maximum ability to detectapproaching predators. e adult plovers and theirchicks are visual predators eating small crustaceans andmarine worms in the intertidal zone and wrack line, aswell as foraging for insects and other food in the dunes,

22 Dune Manual

done via beach raking toincrease the aesthetics ofbeaches to bathers,strongly lowers thediversity and abundanceof beach invertebrates inboth wrack and on opensand (e.g., De la Huz etal. 2005; Dugan et al.2003). Beach rakes alsoremove wrack materialas well as rare plants andtheir seed banks (Kelly2014).

Dune raker Jim Birkitt photo

Tire tracks. Jeanne Heuser photo

dune swale ponds, and back bay areas. When their nestsor young are threatened by a predator, adult plovers willoften put on elaborate displays, feigning a broken wingand crying loudly to try to draw the threat away fromtheir young. Piping plovers are solitary nesters,defending their territories from other plovers, thoughthey often nest in or near colonies of other birds such asterns. Piping plover chicks are mobile shortly afterhatching and follow their parents to feeding areas. esesmall, flightless chicks are camouflaged and highlyvulnerable to threats such as predators attracted tohuman trash, human disturbance that prevents themfrom getting enough to eat, being run over by vehicles,and even getting stuck in vehicle ruts.

Common and least terns also nest in the high beachareas of New Jersey’s coasts. Although visually similar

(with light grey and white body plumage as adults andblack caps on their heads) the least tern (Sternulaantillarum) is much smaller than the related commontern (Sterna hirundo) and has a yellow rather thanorange beak. Smaller and more delicate than gulls, ternshave the distinctive habit of hovering over water andthen plunging down to pick up a small fish or otherprey item from just below the water’s surface. Likepiping plovers, both least and common terns nest at thetop of sandy beaches in areas with little or novegetation, above the normal high water line. Both birdstend to nest in colonies, which provide some protectionfrom predation from gulls and other predators(Kaufman n.d.). Two very different black and whitebirds also nest on New Jersey beaches. With itsdistinctive long orange beak and haunting cry, theAmerican oystercatcher (Haematopus palliatus) wasalmost wiped out in the nineteenth century by huntersand egg collectors. Oystercatchers use their long beaksto search for bivalves in shallow water and to crack themopen. When in low densities, as in current-day NewJersey, oystercatchers often mate for life, whereas at highdensities they may form trios with one male and twofemales tending one or two nests (Kaufman n.d). eblack skimmer (Rynchops niger) gets its name from itsdistinctive black and white coloration and its method offeeding, which is to glide along the water’s surface withthe lower mandible skimming the water until it hits a

Dune Manual 23

Nesting terns Kevin Knutsen photo

Federally Listed

Piping plover (Charadrius melodus), threatened

Red knot (Caldris canutus ruia),threatened

Northeastern beach tiger beetle(Cicindela dorsalis dorsalis), threatened

Seabeach amaranth (Amaranthus pumilus)

State Listed

Least tern (Sterna antillarum)endangered

Black skimmer (Rynchops niger),endangered

Seabeach knotweed (Polygonumglaucum), endangered

Seabeach sandwort (Honckenya), threatened(Peploides), endangered

Other Species of Concern

Common tern (Sterna hirundo)

American oystercatcher(Haematopus palliatus)

Horned lark (Eremophila alpestris)

Seabeach evening-primrose(Oenothera humifusa)

Sea-milkwort (Glaux maritima)

Seabeach purslane(Sesuvium maritimum)

Table 2: Rare, Threatened, and Endangered Species that depend on New Jersey’s coastal beaches for habitat (Courtesyof FWS NJ)

fish, at which point the beak slams shut (Meyers n.d.).Like terns, skimmers nest in colonies, and all of these(terns, plovers, oystercatchers, and skimmers) nest inoverlapping areas and have experienced similarpopulation declines as a result of habitat loss duelargely to the incompatibilities between their nestingrequirements and the management of dunes andbeaches for human use and protection of humaninfrastructures.

Several other rare and threatened plants and animalsdepend on the narrow strip of sand between the dunesand the ocean for habitat. Northeastern beach tigerbeetles used to be very common on New Jerseybeaches, but were very sensitive to human uses of thebeach, including use of off-road vehicles. As a result,they were wiped out from the state in the early 1900suntil being reintroduced at Sandy Hook in the mid-1990s. As larvae, the beetles live in burrows in parts ofthe intertidal zone that are regularly inundated by tidesand hunt for prey such as amphipods near the entranceof their burrows. Larvae metamorphose into adultsafter two years, and adults are formidable predators,capturing amphipods, flies, and other arthropods withtheir long mandibles (USFWS NJ 2014).

Seabeach amaranth(Amaranthus pumilus) is

another species thatwas wiped outfrom New Jersey’scoastal ecosystemsfor much of thetwentieth century.

It is believed tohave been restored to

the state from seeds insand pumped onshore

during beach replenishment activitiesin 2000. is annual plant has red stems and small,bright green, fleshy leaves. It grows as a rosette closeto the sand and is often quite small (just a few inchesin diameter). It starts flowering in early summer andcontinues producing flowers and seeds until it dies in

Another distinctive, but much more common, speciesgrowing in the high beach at the dune edge is searocket (Cakile edentula). Its lobed, fleshy leaves helpkeep it moist in the hot dry sand. It has yellow orwhite 4-petaled flowers and forms bulbous seed podsthat stay on the stem after the leaves drop. Both theflowers and green pods are edible, and are both saltyand spicy in flavor (it is a member of the mustardfamily). e most seaward sea rocket plants tend togrow largest and most vigorously. ey also tend to

24 Dune Manual

Seasideknotweed

late fall or early winter. Although it grows in the highbeach, lower foredunes, and overwash areas wherecompetition with other plant species is low or absent, itis limited in how far down the beach it can grow by astrong intolerance to even occasional tidal inundation.

Seabeachamaranth

Seaside knotweed (Polygonal glaucoma) is another lowgrowing annual plant found in the high beach area. Ithas blue-green needle-shaped leaves that are coveredwith a waxy coating and tiny white to pale pinkflowers. Its shiny dark-brown seeds get larger as theseason progresses, from about 2.5mm at the start ofthe season to as much as twice that by the end of thefall (NHESP 2015). Other imperiled plants of thishabitat include seabeach sandwort, seabeach eveningprimrose, and seabeach purslane. All of these, alongwith the beach-nesting birds described earlier, arethreatened by a number of human activities, includingbeach stabilization (and especially beach armoringsuch as sea walls and riprap), intensive recreational use,and mechanical beach raking, as well as naturalpredation (which can also be intensified by humanactivities in some cases).

make the mostseeds. Sea rocketseed pods consistof two sections.e larger, distalarea of the pod isdesigned to breakoff, and its cork-like structureallows it to floatwell, allowing forlong distance

dispersal, colonizing new areas, and replacing seawardpopulations. By contrast, the lower part of the pod tendsto stay attached to the mother plant, and seeds from itdisperse locally. ese seeds tend to be blown landwardby the prevailing wind, putting them into suboptimalhabitats where their growth is lower and herbivorestresses are higher. Such inland sea rocket populationstend not to replace themselves, but instead are replacedby seeds blown inland from plants at the front of thedune (Davy et al. 2006). Interestingly, this two-part seeddispersal strategy is also found in seabeach amaranth(Weakley and Bucher 1992).

Off-road vehicle use, as well as foot traffic, can dosignificant damage to this ecosystem. Vehicles andpedestrians can crush the delicate and often relativelyunobtrusive plants that grow in this area. ey can alsocrush the eggs of beach-nesting birds, as well as frightenbirds from their nests, opening the eggs to predation andlowering hatching success. us human activity in theseareas is strongly correlated with decreases in theabundance of federally endangered species such as pipingplover and seabeach amaranth. As they drive or walk onthe front of the dunes, pedestrians and drivers alike canalso crush the expanding dune grasses as they spreadseaward, preventing the growth of the dunes andincreasing erosion (Steinback and Ginsberg n.d.).

Because many of the species in this habitat are threatenedor endangered, effective management of these areas isparticularly important. Activities that affect or changethe natural processes of sand accretion and movement,

such as sand fencing, installation of jetties, beach raking,or other such practices, can have strong impacts on thesespecies and should be avoided when possible. Off-roadvehicles and mechanical beach rakes can crush bird eggsand chicks; create ruts that can trap unfledged chicks;disturb nesting, roosting, and foraging birds; crush theprey items used by shorebirds; and crush rare plants. Inaddition to removing wrack material, mechanical beachraking can directly remove rare plants and their seedbanks from the beach. As a result, beach raking isgenerally restricted in the “protected zones” and“precautionary zones” delineated in the BeachManagement Plans. On beaches where dune erosion is aconcern, managers should also consider suspending anyongoing mechanical beach-cleaning activities. Handpicking anthropogenic trash and leaving the wrack willfoster the natural dune development process. ispractice will also conserve wrack material, which is animportant foraging habitat for piping plovers and othershorebirds and an important microhabitat for seabeachamaranth.

Native or invasive vegetation, such as beach grasses andAsiatic sand sedge, compete with rare, threatened, andendangered species of plants and often make the habitatunsuitable for nesting birds. As a result, any fencing orplanting activities should be carefully coordinated withwildlife managers and carried out only as prescribed inthe approved Beach Management Plan for that area. Toprevent disturbance to beach- nesting birds, areas usedby them for breeding or foraging are often fenced off torestrict access to foot and vehicular traffic during thenesting season (March 15 through August 31). Similarly,beach raking that removes wrack materials within thestrand line that form an important foraging resource forbeach-nesting birds should also be avoided. Predatorsincluding foxes, raccoons, feral cats, and even visitingdogs can be another important source of disturbance andmortality. Predator control plans and restrictions on dogwalking may thus also be required in areas where beachnesting birds are active (USFWS NJ 2015).

In all developed portions of the New Jersey coast thatcurrently or potentially support rare, threatened, or

Dune Manual 25

Sea rocket

26 Dune Manual

adaptation to this habitat is the beach grasses’ extensivesystem of roots and rhizomes (underground stems) thatform a complex horizontal network that can extend 20feet deep below the dune and at least as far outhorizontally. e horizontal rhizomes connect relatedplant shoots, while the roots allow the plant to accesswater reserves deep in the sand. e root can also accessmoisture near the surface from brief rain events thatdon’t provide enough moisture to infiltrate deep into thedune.

Despite all of these challenges, American beachgrassgrows rapidly – as much as 6 to 10 feet a year. It canalso grow as many as 100 stems per clump each year(USDA 2006). e leaves of American beachgrass havedeep grooves on their top surface but are smoothunderneath. Arising from a relatively short stem, thestraight, stiff leaves are relatively narrow (1/4 to 1/3inch) but can grow to several feet in length, and tend tostand upright rather than drooping. e leaves ofAmerican beachgrass act as filters that intercept blowingsand. As the sand grains hit the plants’ leaves, aircurrents slow and sand grains fall to the dune surfacewhere the plants’ roots and rhizomes help to hold themin place, building and stabilizing the dune.

American beachgrass flowers are clustered into spikesthat grow from a central stem in early summer.Although the plant does set seed in late summer, in NewJersey the seeds it forms are not highly fertile, and theplant spreads primarily through vegetative propagationvia horizontal rhizomes. In the front of the dune, theserhizomes can be eroded by waves during storms anddispersed to other areas via water transport (USDA2014).

Primary Dunes

Moving inland from thehigh beach, the soil tendsto be made up of smallersand grains that are easierfor the wind to pick upand transport from thebeach. e smaller grainshelp improve the abilityof soil to hold water.is, combined with thehigh humidity of thishabitat when winds areblowing onshore and thefact that few species cansurvive the salt, heat, and

water stresses of this habitat, means that the few speciesthat can grow there have few competitors and can growquite abundantly. In New Jersey, one plant species inparticular tends to dominate the first fully vegetatedareas of the dune (the primary dune). Americanbeachgrass (Ammophila breviligulata) is uniquely suitedto life in this habitat in a number of ways. For example,while burial is usually a negative factor for many typicalterrestrial plants, sand burial is actually stimulatory tothe growth of this and many other primary dunespecies. e constant supply of fresh sand thatcharacterizes the primary dune brings nutrients(attached to the sediment grains) and is pathogen free,having been sterilized by the ocean, so it reduces thedensity of parasites and disease-causing organisms in thesoil (Maun 2004). To save water, the stomata (poresused for gas exchange in plants) are located in deepgrooves on the leaf surface, and the long narrow leavescan be rolled or folded and held in such a way as tominimize exposure to wind (USDA 2006a). Another

American beachgrass

endangered species, Endangered and Non-Game Species(ENGS) and Fish and Wildlife Service representativesshould be consulted before any changes in managementare implemented. Managers should work with ENGSand FWS representatives to develop effective Beach

Management Plans that balance the need for stormprotection and other human uses of this area with therequirements of the rare, threatened, and endangeredspecies that depend on this narrow band of habitat fortheir survival.

Dune Manual 27

While Americanbeachgrass seeds

often haverelatively lowgerminationrates, theyare still animportant

food sourcefor birds and

small mammals,including snowbuntings and theendangered

Ipswich sparrow. In addition, many other species,including snowy and short-eared owls and a number ofgull species, use American beachgrass for habitat(Eastman 2003). Beach-nesting birds such as pipingplover are restricted to habitats with very sparse (<10%cover) beachgrass and other vegetation (Eastman 2003).

Part of the reason that American beachgrass is able tosurvive the challenging conditions of the primary dunesis that it usually grows in association with mycorrhizalfungi (Koske et al. 2004). ese fungi obtain water andnutrients from the soil and provide them to plants inreturn for sugars and other organics from the plantroots. In one study of another dune grass (sea oats orUniola paniculata) in Florida, the ratio of hyphae (thefungus equivalent of roots) to plant root was found tobe over 45,000:1. Clearly, these fungal extensionsmassively increase the surface area through whichnutrients and water can be absorbed for use in growthby the plant. Not surprisingly, studies show that duneplants with mycorrhizae grow better (get taller, makemore leaves, etc.) than those without, especially underdrought stress. Mycorrhizal associations can also increasesalt tolerance and help plants ward off parasites (Koskeet al. 2004). When plants disperse via rhizomes, theyactually travel with mycorrhizal spores, so that whenthey get to their new destination, both the plant and itsassociated fungal partner can sprout together. Typically,dune soils contain a variety of different species ofmycorrhizal fungi. e more spores there are of those

fungi in the soil, the more likely they are to beencountered by a sprouting seed to help with its growthand survival. Not all mycorrhizal fungi work equallywell, although American beachgrass plants grow betterwhen inoculated with spores from fungi collected fromdunes rather than those from other sites.

Compaction, such as that caused by humans driving ortrampling on the dunes, can destroy the root-likehyphae of the mycorrhizal fungi, which can impairplant growth (Koske et al. 2004). In addition, copingwith the stressful environment of the dunes leaves dunegrasses little energy in reserve to dedicate to mounting aresponse to infection. When humans walk or drive onthe dunes, their weight crushes the delicate rhizomesrunning just below the surface of the sand. Such damagecreates a pathway for pathogenic bacteria and fungi toenter the tissues of the plant, sickening or killing it. Inaddition, since each of the clumps of beachgrass isconnected to others through the rhizomal network, onceone plant becomes infected, the pathogen can spreadrapidly to interconnected clumps, creating a widespreaddieoff. is is why it is so important to avoid travelingthrough dunes in areas where dune grass is growing(Nickerson and ibodeau 1983).

As mentioned earlier, American beachgrass needs aconstant supply of sand accumulation to remain healthy.Away from the dune front, the species starts to lose vigorand becomes susceptible to infection by diseases such asMarasimus blight caused by a fungal infection. isdisease creates characteristic circular dead patches in thegrass (USDA 2014). Insects are the primary herbivoresin dunes, with grasshoppers, aphids, and the soft-scaleinsect (Ericoccus carolinae) becoming increasinglycommon with distance from the ocean, feasting on theplant’s tissues. Similarly, rabbits, deer, and otherherbivores that graze on beachgrass leaves becomeincreasingly common with distance from the water.Nematode worms, like the root-knot nematode(Meloidogyne sasseri), are another culprit, attacking dunegrass roots (Rogers and Nash 2003). As a result, growthof American beachgrass becomes increasingly sparsebehind the dune crest.

Buntings on beachgrass Kevin Knutsen photo

28 Dune Manual

An increasingly common sight in the primary dunes inNew Jersey is Asiatic sand sedge (Carex kobomugi). isinvasive species, as its name suggests, has its origins incoastal areas around the Sea of Japan. Like Americanbeachgrass, this species has a high tolerance for salt sprayand heavy winds. It typically grows to about a foot tallin large, dense beds. Its usual color is bright green toyellow-green, although yellow and brown leaves aremore common in the spring and fall. e relatively stiff,grass-like leaves curl over the plant, giving it a lowprofile. On the edges of the leaves are small, spinyridges that make the leaf edge feel like a serrated steakknife. e plant forms many flowers on a single stem.Each stem contains either male or female flowers. emale flowers form distinctive white pollen tubes duringthe early spring but die after pollen production ends.e female flowers are relatively unobtrusive in spring,but by fall they develop into a large seed headcharacterized by a triangular set of spikes attached to along stem with distinctive brown scales. Below theground, Asiatic sand sedge forms spike-tipped rhizomesthat spread out quickly from the plant. It also buildslong roots that can grow several feet into the sand.While the species does produce numerous seeds eachfall, the viability of those seeds seems to be low, and the

plant is believed to spread largely through creation ofnew clumps along its rhizomes, some of which canbreak off and be transported to new habitats by wind,erosion, or transport by ocean waves and currents.Unlike American beachgrass, this species is relativelyresistant to damage from trampling. Being non-native,few species recognize Asiatic sand sedge as potential preyand do not attempt to eat it. It also tends to be resistantto pathogens. ese characteristics, along with its sharpseeds and rhizomes that form a natural deterrent topedestrian traffic, caused this species to be planted inNew Jersey’s dunes for several decades. Unfortunately,the species’ tendency to form a monoculture –outcompeting the native species and significantlychanging the biology and geomorphology of the dunes– resulted in discontinuation of its use for dunerestoration by the late 1980s. However, the species stillspreads through natural propagation, and it is rapidlybecoming the dominant species within many primarydunes in New Jersey and beyond.

Moving up the dune and away from the ocean, theimproving soil quality and decreasing stress from saltspray and sand scour mean that other species are able tothrive. One such species is seaside goldenrod (Solidagosempervirens). Seaside goldenrod is a perennial, meaningthe same plant grows back year after year. Its broadleaves are arranged alternately on the stem, which growsas much as 3 feet tall. e fleshy leaves store water andhave a shiny wax coating to protect the leaf fromevaporative water loss and the drying effects of the saltspray. In late summer and early autumn, seasidegoldenrod produces large clusters of bright yellowflowers at the top of its stems. e individual flowers inthese clusters are larger than those of other New Jerseygoldenrods. Seaside goldenrod pollen grains are heavyand sticky, so the species is largely insect-pollinated. eheavy pollen also means that, contrary to commonperceptions, this plant is not responsible for the miseryof allergy sufferers in the fall. Ragweed, a plant withunobtrusive flowers that create pollen designed for airdispersal, is the real villain in this regard. e sugarynectar of seaside goldenrod is an important food sourcefor migrating monarch butterflies, the common buckeye

Asiatic sand sedge (Carex kobomugi)Louise Wootton photo

Dune Manual 29

butterfly, and otherssuch as the silver-bordered fritillary. Eachflower cluster gives rise toseeds that look similar tothe fuzzy parachutedseeds of a dandelion.ese seeds are food for

mice and songbirds. eplant hosts a number of gall-

producing insects, which in turnare an important winter food

resource for birds like chickadees.Deer and rabbits will also occasionally

graze its leaves. As well as increasing thespecies diversity of the dunes, goldenrod – likeAmerican beachgrass – can be one component of asuitable habitat for bird species such as killdeer(Charadrius vociferous), common terns (Sterna hirundo),and black skimmers (Rynchops niger) (Safina and Burger1983).

Together, American beachgrass and goldenrod make up90 to 95% of the plants in the foredune. A smallnumber of other species is also present, including searocket, seaside spurge, panicgrass, purple sandgrass,saltmeadow hay, beach pea, trailing wild-bean, and thenon-native dusty miller (Hosier 2003). Beach pea andtrailing sand bean plants, like other legumes, have asymbiotic relationship with nitrogen-fixing bacteriawithin swollen “nodules” in their roots. ese bacteriaare able to take atmospheric nitrogen (which is notusually available to plants) and turn it into ammonia(the same ingredient found in store-bought fertilizers).is is particularly important in the nutrient-poor soilsfound in sand dunes. Beach peas have pretty pink orpurple flowers reminiscent of those of cultivated sweetpeas. e flowers are important nectar sources for beesand butterflies, and once pollinated, form seed podsfilled with small peas which are eaten by deer, mice,birds, and a number of insects (Mass.gov. 2015).Burrowing under the roots of the grass to escape theheat and foraging for plant material and any carrionthey can find are a variety of ant species. Similarly, the

dunes are home to numerous burrowing wolf spiders.ese spiders’ deep burrows (up to 3 feet deep) create arefuge from the daytime heat. e wolf spider huntsmostly at night and preys on other dune insects.Another common dune species, the seaside grasshopper,is exquisitely camouflaged to look like sand. eseanimals are one of the few insects that prey on Americanbeachgrass, which forms their major food source. iswarmth-loving insect sometimes buries itself under thesand at night with just its head exposed in order tomake use of the heat stored in the sand grains of thedune. On a warm day, the chirps made by the malesrubbing their legs against their wings in order to attractfemales may be heard throughout the primary andsecondary dune systems (Hammond 2009).

e fact that there seems to be sand everywhere on adune makes it look like a very uniform habitat to thecasual observer. However, the direction and strength ofthe wind and the supply of sand from the beach makefor strong differences between sites. e height of thedune also varies. is in turn can affect the temperatureby varying the timing and amount of shade experiencedby plants on the dune surface, as well as affecting accessto water supply from ground water. Even smalldepressions in the dune can make an importantdifference to the plants growing there by collectingorganic material (which holds water and forms anutrient source as it decomposes), as well as providing ashaded area that may be an important nursery area(Garcia Novo et al. 2004). Similarly, the shade providedby beachgrass and goldenrod can help promotegermination and establishment of seeds in the sandbelow. Consequently, beachgrass may be planted alongwith other species in areas behind the dune crest, even

Seaside grasshopper Louise Wootton photo

30 Dune Manual

though it is unlikely to persist there long term, becauseits presence can help promote the establishment of theother plants sown along with it.

Coastal dunes form sand reservoirs that can play an important role in maintaining sand for the beaches in front of them as well as in protecting thecommunities behind them. In storms, wave erosioncan become focused on one area of dune and canoverwhelm the stabilizing effects of the dunevegetation. e sand released helps replace sand lostfrom the beach, but allows the ocean waters to floodlandward, creating areas of flat sand known asoverwash fans. Although overwash fans as well asblowouts (gaps in the dunes caused by wind erosion)can be problematic for human infrastructure (becausethey provide pathways for flood waters to movelandward behind the dunes’ defenses), they form animportant habitat for many threatened and endangeredspecies. In particular, they create safe nesting andforaging areas for beach-nesting birds, being well abovethe usual high tide mark but lacking in vegetation thatmay provide habitat and cover for their predators.

Where they occur, wide, dynamic, and complex naturaldune systems support a diversity of native plants andanimals. ey provide a rare habitat type that is fullycompatible with rare, threatened, and endangered(RTE) beach species. However, the dunes themselves arenot the primary habitats for any of New Jersey's RTEbeach species, which thrive more in the strip of beachbetween the water’s edge and the edge of the vegetateddune, although many RTE species will utilize duneblowouts or washovers when they are present. Evennatural, dynamic dune complexes are only a secondaryhabitat for RTE beach species, and stabilized dunes arenot habitat at all. Unfortunately, few beaches in NewJersey support natural dune systems (e.g., northernSandy Hook, Edwin B. Forsythe National WildlifeRefuge, North Brigantine Natural Area, and StoneHarbor Point). ese few natural areas support theoverwhelming majority of nesting piping plovers in thestate, as well as important concentrations of other RTEspecies. Along developed coastlines, there is typically

limited space for dunes to shift inland, limiting thepotential for the development of a secondary dune.Instead, much of New Jersey's coast features steep,stabilized dunes that are maintained by human activitiessuch as bulldozing, sand fencing, and vegetationplanting, as well as by direct placement of dredged sandduring project construction or renourishment. Whilesuch activities may be necessary for protection of humaninfrastructure in many areas, they often reduce habitatsfor RTE species, promoting the formation of heavilyvegetated berms and dunes that replace gently slopingand sparsely vegetated foredunes. Besides the directeffect of making habitat less suitable, these activities alsoindirectly affect RTE species. For example, stabilizeddunes can exacerbate conflicts with recreational beachusers by restricting both RTE species and people to anarrowed beach berm. Stabilized dunes can alsofacilitate predation of RTE birds by providing vegetativecover for predators, creating predator den sites orperches, and promoting a narrow linear band of nestinghabitat that is easily searched by predators.

American beachgrass (Ammophilia breviligulata) Juliana Pollara photo