U.S. Fish & Wildlife Service, 2006.

With the reintroduction of salt water, The modest increase in tidal exchange Native Plants the big change at East has in- between East Harbor and Cape Cod volved fish and nuisance insects. Be- has triggered a profound recovery of Flora and Fauna Respond fore the partial restoration of tidal estuarine animals. Besides the usual and Animals to Restoration Projects flushing and salinity, East Harbor was flock of gulls that have used the harbor by John Portnoy, PhD., Park Ecologist dominated by exotic common carp. for decades, it’s now common to see These hulking bottom feeders churned least and common terns, cormorants and ospreys, ever watchful for new op- Cape Cod National Seashore has an portunities, hunting the newly abundant active program of estuarine restoration mummichogs, silversides and shrimp. for the nearly 2500 acres of Outer Cape Even river otters, normally associated coastal marshes altered profoundly with freshwater environments, continue since the construction of tide-restrict- to fish East Harbor, having apparently ing dikes and causeways during the made the dietary switch from carp to nineteenth and early twentieth cen- carp perch and flounder. tury. Tides were restricted by roads and railways built across coastal wet- up sediment, muddied the shallow lands, and by dikes intended to limit water column and contributed to floodwater mosquito breeding and to chronic summer oxygen depletions, to promote lowland agriculture. With tide which they are largely immune. Low restoration under way since 1999 at 90- widgeon grass salinity, no tidal flushing and organi- acre Hatches Harbor in Province- cally rich bottom sediments led to mas- town, and just beginning in 700-acre Ruppia sive midge (a small non-biting fly) least tern East Harbor (also referred to as Pilgrim martima Lake) in Truro, both native and intro- duced plants and animals are respond- ing. At even higher elevations, and where PLANTSPLANTSPLANTS ditch drainage has lowered the water table, the normally waterlogged peat The blockage of seawater over many has become perennially drained, al- midge decades has had varying effects on lowing the near-total displacement of plants depending chiefly on site-spe- wetland plants by upland herbs, trees common tern emergences that episodically blanketed cific differences in marsh surface el- and shrubs. nearby homes and motels and even evation and distance from the ocean. obscured visibility on adjacent U.S. Some diked salt marsh plant communi- With the return of the tides at Hatches Route 6. As expected, partial restora- ties that are low in elevations, near and East , native salt marsh tion of the harbor’s tidal flow has creek banks and/or just upstream of plants are also returning. Unnoticed by caused the demise of most salt-sensi- leaky tide gates, still receive some sea- most of us, a slow and silent territorial tive carp and nuisance midges. The water, and salt marsh grasses (e.g. battle is raging among the plants of the reestablishment of native estuarine fish smooth cord grass, Spartina marsh surface. By restoring high salin- has greatly exceeded expectations. alterniflora) persist. ity and water levels, we tip the battle- Where once only introduced carp, ale- field in favor of native salt marsh veg- wives, American eels and white perch Further upstream, and at slightly etation by stressing and killing the could be found, East Harbor now sup- cormorant higher elevations, the water is only recent invaders with seawater flooding. ports a variety of native estuarine fish: brackish. The common phragmites mummichog, Atlantic silverside, winter reed (Phragmites australis), a highly Just above the Hatches Harbor Dike, flounder, nine-spine and four-spine invasive exotic plant, has typically where until recently vigorous stickleback, sand and shore shrimp and invaded this region, crowding out na- Phragmites stood 10 feet high, it now sand eels by the thousands. tive grasses. stands brown and stunted over an in- tensely green carpet of native salt marsh plants recolonizing the area: . seablite (Suaeda), pickle- weed (Salicornia), and Spartina -all native salt marsh plants.

common Much less conspicuous, but at least as mummichog osprey phragmites important to estuarine fish and shrimp, reed has been the sudden appearance last Scientific research conducted here and summer of large beds of widgeon grass salt marshes damaged by historic tide (Ruppia maritima) under the shallow restrictions can, to some degree, re- waters of East Harbor. The plant Atlantic silverside cover simply through the reestablish- Phragmites emerged after the seashore and the ment of tidal flow. Our management australis Town of Truro partially restored the approach is to restore the marine con- harbor’s native salinity, reduced by nection, and then to allow nature to diking since 1868. repair itself. Implicit in this approach is native salt marsh grasses the understanding that we have much to Ruppia is most abundant at moderate learn about salt marsh restoration. To salinities. At East Harbor, it teems with maximize what we learn, and to actively estuarine fish, shrimp and other inver- winter flounder manage any unanticipated problems, tebrates. As its name suggests, widgeon tide-restoration projects are accompa- grass attracts and feeds several species nied by intensive environmental moni- of migratory and wintering waterfowl. toring. Through systematic monitoring Black ducks have become very frequent we are seeing some dramatic, and often in Ruppia beds, even in summer. ANIMALS surprising, examples of the recovery of salt marsh flora and fauna. Tide restrictions also reduce or elimi- four-spine stickleback nate the marine connection for animals, Although plant and animal response to hindering estuarine and near-shore tidal restoration has so far been rapid fish, crustacean, shellfish, and benthic and encouraging, final results are not smooth cord grass pickleweed invertebrate migrations that are essen- yet in. Seashore scientists, along with tial to their life histories and contribute shrimp town, state and university cooperators, to fish and shellfish production. Tide Native plant and fish illustrations by Andrea will continue to monitor these restora- Sulzer are used with permission from the artist, restrictions also severely disturb natu- tion sites, as well as other marshes, both originally produced for the book Life Between ral chemical cycling in estuaries, with the Tides: Marine Plants and Animals of the undisturbed and human altered, Northeast, written for the Maine Sea Grant damaging effects on water quality and throughout Cape Cod. Program by Les Watling, Jill Fegley and John fish habitat. sand eel Moring, published by Tilbury House Publishers of Maine.