UPPER ECCLESTON BROOK WATERSHED-ECOSYSTEM
Proposed Site of “Four Winds at Mystic”
Application by Mystic Active Adult, LLC (Ron Bonvie)
| Existing Conditions by | Whitney Adams, Groton, CT Plant Scientist Independent Concerned Citizen |
Fall 2005 |
| Introduction by: | Sigrun Gadwa, MS, PWS Ecologist and Registered Soil Scientist Carya Ecological Services, LLC Cheshire, CT 06410 |
January 22, 2006 |
Introduction
As a long-time resident and naturalist familiar with this 160-acre property on the west side of Noank Ledyard Road, Whitney Adams has written a report (Existing Conditions section, below), to provide some detailed, location-specific information on the hydrology and plant communities of the Watrous portion of the Upper Eccleston Brook Watershed-Ecosystem, not included in the developer’s submissions. This introduction addresses the significance of his findings. The habitat information provided will, it is hoped, impress upon concerned regulatory agency staff, that this site warrants targeted inventories of plants and invertebrates, and serious consideration for open space purchase.
Functions and Values
It has already been established that this is a high-functioning, aesthetically attractive, noteworthy site with documented archaeological resources. The remarkably high vernal pool production export function confers scientific interest and a high level of wildlife support function, which, in themselves, in my professional opinion, warrant protection of pools and surrounding habitat setting as open space. Aquatic habitat function is also high in this unpolluted headwaters perennial stream with both low gradient and riffle habitats.
Mr. Adam’s field investigations also showed other factors conferring a high level of functions and values. There is unusually high production export function via nectar and pollen from abundant cardinal flowers along Eccleston Brook (used by hummingbirds), a large tulip tree stand, and diverse, flowering shrubs including fragrant Honeysuckle azalea. Their high aesthetic value increases the site’s potential for future recreational use by the public. Habitats on the site also include rock outcrops (elevated rare plant potential), massive trees bordering vernal pools (which may harbor rare bats), perennial seepage wetlands with remnant Atlantic White Cedar (restorable by means of deer control to a cedar swamp). Eccleston Brook supports Connecticut Special Concern Wood turtles and pollution-intolerant invertebrate species. The site has high rare species potential and uniqueness and heritage value.
Plant Biodiversity
Mr. Adams has described diverse, well-developed examples of plant communities for this ecoregion, undisturbed and lacking invasive species. William Moorhead, a noted Connecticut botanist, informed me that Groton is in the top 5% of towns in terms of numbers of historic records of rare plants (exceeded only by a few towns with traprock and marble geology). He noted that nodes of listed species are accompanied by other uncommon and poorly understood plant species, and that seep communities in this portion of the southeast coastal ecoregion are especially in need of scientific characterization. He also noted that historic records typically have poor locational information, so that they could appear in any undeveloped piece of land in Groton. He informed me that several recent searches in Groton and neighboring towns by qualified professionals (Mr. Moorhead and others) have in fact been quite fruitful, both rediscoveries of historic records and new finds, but that search effort has overall been low in this town. Although it is difficult to predict potential for particular rare species without a field investigation, he did mention the following possible species: Eupatoreum alba, a species of rocky outcrops as well as sandy sites, Hottonia inflata (featherfoil) along low-gradient headwaters streams, and yellow ladyslipper ( Cypripedium parviflorum ) and small, whorled Pogonia ( Isotria medeoloides ), a federally listed species, found in forested habitats. William Moorhead may be contacted to verify these statements by calling 860-567-4920.
Qualified professionals should conduct searches at this particular site during the growing season, before the onset of construction work. It is actually my professional opinion that any site over 50 acres should be inventoried with at least moderate intensity for plants, with identifications to species of the genera that include listed species (e.g. asters and sedges).
Seepage Wetlands and Headwaters Streams
These habitats are both on the CTDEP draft “List of 13 Imperiled Communities,” compiled by CTDEP Botanist, Ken Metzler and Dr. Dave Wagner (professor at UConn, Storrs), for their botanical and invertebrate rarities. Dr. Wagner may be contacted at 860-486-2139 regarding the particular listed invertebrates; they include a mayfly and a damselfly. Mr. Adams’ survey, in the driest part of the summer of 2005, showed water still present in stream and seepage wetlands. Plants and hydrologic information included in his wetlands characterizations show the white cedar wetland to be a seepage area, with a year-round water supply. Shrub species associated with the vernal pools are those of headwaters, low-nutrient wetlands (not a fertile, bottomland ecosystem.)
Eccleston Brook and on-site tributaries are headwaters streams with a forested watershed, habitat for pollution-intolerant aquatic insects; the applicant did not provide stream bioassessment data. This riparian corridor also supports a known population of Wood Turtle, a Connecticut Species of Special Concern. Wood Turtles benefit from an ecosystem with large numbers of tadpoles and salamander larvae, and aquatic insects, from excellent water quality. They are also usually found in very wide undeveloped riparian corridors such as this, as their summer terrestrial foraging habitat extends out many hundreds of feet from streams. Broad forested habitat blocks also support high avian biodiversity, including area-sensitive, disturbance-intolerant species, such as veery ( Catharus fuscescens ).
Potential Reference Wetland for CTDEP Baseline Nutrient Data
Lisa Wahle at the CTDEP Water Resources is collecting baseline data on nutrient levels and periphyton in undisturbed Connecticut wetland communities, as CTDEP has been directed to develop a set of nutrient standards modeled on natural wetland systems (not the health code standard of 10 mg/l). This would be a suitable site.
Summary
Mr. Adams report has further documented the high level of wetland function at this site. He has provided additional site-specific data because baseline information on fauna and flora was deficient in the application, and is by no means an adequate basis for planning for the future of this site. Thorough baseline botanical data is warranted due to the high ranking of the Town of Groton, in terms of numbers of records of historic listed plant species, and the productivity of recent listed plant searches. Additional ecological investigations are warranted, now that the perennial nature of the wetlands (seeps) has been observed. With completion of Whitney Adams’ report, we now know that there is a significantly increased probability of state-listed seep and headwaters invertebrates. In my professional opinion, there is a high likelihood that the targeted searches will reveal high plant, and potentially invertebrate, biodiversity. This site is well-suited to a “bioblitz.” It is also my professional opinion that the only way to achieve effective protection of the wetland functions and values on the site, including “uniquensss and heritage value” is to protect the site’s ecological integrity , through conservation not only of the wetlands but also the associated uplands on the Watrous property.
Existing Conditions
BY WHITNEY ADAMS
Hydrology
Upper Eccleston Brook runs north-south in a large drainage basin bounded by I-95, Noank Ledyard Rd., Route 1, and Flanders Rd. to the north, east, south and west respectively. This watershed contains an amazingly diverse group of wetlands and uplands with Upper Eccleston Brook flowing through the center of it.
The east of Upper Eccleston Brook toward Mystic is bordered by a north-south string of five extensive vernal pool systems flowing into the brook. Paralleling these is a prominent series of uplands including extensive rock cover and rocky ridges providing abundant upland habitat. The west of Eccleston Brook is bordered by an upland, which rises gradually toward Flanders Road and is the source of numerous intermittent streams and seeps, which also flow into Eccleston Brook.
Vernal Pools
Vernal pool 1 , which is the southernmost and smallest of the five vernal pools mentioned above, is approximately 100 ft. north to south and 50 ft. east to west. It receives water from significant wetlands to the north and drains into fairly extensive wetlands to the south before merging with the southern part of Upper Eccleston Brook where the brook approaches the first houses of the Bel Aire community.
Vernal pool 2, which is located slightly to the north of vernal pool 1 has the distinction of being the most productive known vernal pool in Connecticut . It sits on a slightly elevated upland in with no human habitation on the uplands that drain into it. Thus it is protected from drainage associated with human habitation, which often contains chemicals that are known to be very destructive to vernal pool ecosystems. Freedom from this detriment may account, in part, for the exceptional productivity of this vernal pool. Additionally these uninhabited uplands provide the necessary integral habitat for a highly productive ecosystem supporting high population densities and high species diversity.
Vernal pool 2 is ~500 ft. long east to west and narrower north to south. Uplands draining into the pool surround it on the east, north and south so that it drains intermittently westward into a large remnant Atlantic White Cedar ( Chamaecyparis thyoides ) swamp and then westward into Eccleston Brook.
The westernmost portion of this vernal pool system contains a relatively persistent body of open water (~50 by 100 feet), with a water depth of ~2-3 feet in deeper pockets when filled to capacity. This portion of vernal pool 2 lacks overhead tree cover, and dries up only during prolonged droughts. It is bordered on its south side by a massive three-trunk Black Tupelo ( Nyssa sylvatica ). Buttonbush ( Cephalanthus occidentalis ) is found around the margins, particularly on the north side, along with abundant native Water Oleander ( Decodon verticillatus ) with stoloniferous branches. Abundant Highbush-Blueberrry ( Vaccinium corymbosum ) and Summer-Sweet ( Clethra alnifolia ) are around the margins as well. A remnant Chestnut ( Castanea dentata ) grows on slightly higher ground to the southwest.
The remainder of the vernal pool system to the east, which constitutes the majority, tends to dry up more quickly than the westernmost pool mentioned above. It consists of a vast number of interconnected vernal pools dotted with multitudes of small islands. These islets are populated with Red Maple ( Acer rubrum ), Yellow Birch ( Betula alleghaniensis ), Tupelo ( Nyssa sylvatica ), Black Chokeberry ( Aronia melanocarpa ), Swamp Azalea ( Rhododendron viscosum ), Mountain Laurel ( Kalmia latifolia ), Highbush-Blueberry ( Vaccinium corymbosum ), Summer-Sweet ( Clethra alnifolia ) and tangles of Catbrier ( Smilax rotundifolia ).
Beneath each of these islets is a system of tunnels, which are submerged when the vernal pool is filled providing safe hibernacula for vernal pool reptiles and amphibians as well as small mammals. Above each islet there is a dense multilayered vegetational cover at low and medium levels. Both the tunnels below the islets and the multilayered vegetation above provide a rich series of microenvironments insuring species abundance and diversity.
Bordering the southeastern portion of vernal pool 2 is another notable tree specimen, a large Tulip Tree ( Liriodendron tulipifera ) approximately 4 ft. in diameter. This may close to the record size for Connecticut. Evolutionarily, it is also a very ancient tree, closely related to magnolias.
The functioning of this vernal pool system is currently threatened by proposed construction to the south and east as well as a road to the north.
Vernal pool 3 is located immediately to the north of the vernal pool 2 complex described above, on the same side of Eccleston Brook. It also drains into the remnant Atlantic White Cedar swamp and then into Eccleston Brook. This vernal pool system has a multitude of islets similar to vernal pool 2 and a semi-permanent stream that only ceases to flow during the drier part of the summer. The functioning of this vernal pool is currently endangered by a proposed bridge to be built across its junction with the cedar swamp as well as construction on rocky uplands immediately to the north.
Vernal pools 4 and 5 are located to the north of the currently proposed Four Winds development. Vernal pool 4 drains into Eccleston Brook slightly before the brook enters the remnant Atlantic White Cedar swamp. It extensive in area and similar to the multi-islet topography of vernal pools 2 and 3. Vernal pool 5 is a smaller discrete basin populated with islets, which drains into vernal pool 4 shortly before it empties into Eccleston Brook.
Uplands
The immediate uplands draining into vernal pools are of particular importance to many vernal pool species. These uplands are also particularly picturesque because of the abundant large rock outcroppings, Mountain Laurel thickets, American Beech ( Fagus grandifolia ) groves, pink, fragrant Honeysuckle Azalea ( Rhododendron roseum ) and Witch Hazel ( Hamamelis virginiana ). Vernal pool 2uplands are particularly notable because of their topographic and botanic diversity and are described in more detail below.
Topographically, the land surrounding vernal pool 2 is breathtakingly dramatic, somewhat resembling an amphitheater, with a relatively open level area midway between the vernal pool and the high rocky ridges. Northward of vernal pool 2 there is abundant boulder-cover over a large area of gradually upward sloping forest floor terminating in a high rock ridge at the border of the next vernal pool system. Rock-cover of this sort provides moist refugia and hibernacula for a range of species. Northeastward and eastward there are numerous additional high rock ridges. A permanent deepwater pond, adjacent to Noanck-Ledyard Road, occurs immediately to the east of these eastward high rock ridges. Southward, stone walls and man-made boulder piles provide additional abundant rock cover. The open field to the south of these rocks has abundant shrub cover as well.
Archaeologically , the site also has confirmed high value. The state historian has identified a number of sites in the rock ridge area containing Indian artifacts. Three of the sites have been recommended for preservation.
Botanically , a mesic forest surrounds vernal pool 2 on all sides with a forest floor thick with moisture-retaining leaf litter. The northward slope contains Summer-Sweet ( Clethra alnifolia ), Tupelo ( Nyssa sylvatica ), Witch Hazel ( Hamamelis virginiana ), extensive Mountain Laurel ( Kalmia latifolia ), and Highbush Blueberry ( Vaccinium corymbosum ). As the elevation increases there is Sassafras ( Sassafras albidum ), Tulip Tree ( Liriodendron tulipifera ), American Beech ( Fagus grandifolia ), abundant intensely fragrant Honeysuckle Azalea ( Rhododendron roseum ) (a.k.a. Rhododendron prinophyllum ) , Red, Black and White Oaks ( Quercus spp. ) and extensive communities of Dangleberry ( Gaylussacia frondosa ), which is a type of Huckleberry, on the relatively open level area midway between the vernal pool and the high rocky ridges. Eastward , many of the same plants occur along with a significant copse of Chestnut Oak ( Quercus prinus ) and a remnant Chestnut ( Castanea dentata ). Southward , there is a narrower belt of forest before transition to an abandoned upland field with heavy shrub cover.
Remnant Atlantic White Cedar Swamp
The Remnant Atlantic White Cedar Swamp into which vernal pools 2-5 drain directly or indirectly, and through which Eccleston Brook flows, contains two remnant Atlantic White Cedars. The largest approaches 70 ft. tall, and 16+ inches diameter at breast height. The height is quite unusual for this area and may be due to the partial protection from wind provided by the surrounding uplands. The other cedar is ~25 feet tall. Abundant seed production occurs from both cedars and many seedlings trees are apparent, but are unable attain adult size due to persistent herbivory. This is apparently the only remaining swamp containing Atlantic White Cedar in the town of Groton. With protection this remnant White Cedar swamp could be restored and appreciated by the community.
The vegetation in this Atlantic White Cedar Swamp is primarily composed of shrubs and is dominated by Winterberry ( Ilex verticillata ), Swamp Azalea ( Rhododendron viscosum ), Highbush Blueberry ( Vaccinium corymbosum ), and Summer-Sweet ( Clethra alnifolia ). Less common shrubs are Common Alder ( Alnus serrulata ), Swamp Rose ( Rosa palustris ), Black Chokeberry ( Aronia melanocarpa ), Mountain Laurel ( Kalmia latifolia ), Viburnum species, Poison Sumac ( Rhus Vernix ) and Poison Ivy ( Rhus radicans ) and tangles of Catbrier ( Smilax rotundifolia ) near the periphery.
The overhead tree cover is relatively open and is composed mainly of Red Maple ( Acer rubrum ) and occasional White or Black Ashes ( Fraxinus spp. ).
Herbaceous plants are mainly Skunk Cabbage ( Symplocarpus foetidus ), hummocks of Royal Fern ( Osmunda regalis ) and other ferns, various Sedges, Blue Flag ( Iris versicolor ), Sphagnum Moss ( Sphagnum sp. ) and other mosses. Large portions of the cedar swamp covered with spaghnum moss indicate a dependable water source. The moss-covered hummocks, as well as the dense multilayered vegetation, or Tangle, provide a rich collection of microenvironments, which foster species abundance and diversity.
Upper Eccleston Brook
Upper Eccleston Brook, which runs south through the center of this Remnant Atlantic White Cedar Swamp has a muddy bottom, indicating a slower water velocity. White or Black Ashes ( Fraxinus spp. ), Red Maple ( Acer rubrum ) are common along this slow-moving stream bank. Shrubs consist mainly of Winterberry ( Ilex verticillata ), Swamp Azalea ( Rhododendron viscosum ), and Common Alder ( Alnus serrulata ). Poison Ivy ( Rhus radicans ) and dense tangles of Catbrier ( Smilax rotundifolia ) and Wild Grape ( Vitis spp. ) are also common.
At the South end of the swamp, the brook abruptly changes to a sandy, sometimes pebbly bottom, with abundant larger rocks located both in the stream and for considerable distances on both sides of the stream. The rock surfaces are heavily covered with moss over much of the stream length indicating a reliable water supply. Water tumbles over and around many of these rocks indicating a higher slope and water velocity, with better water aeration. Seldom is the sound of tumbling water absent throughout the length of this lower portion of the brook. The water depth may reach 2-4 feet during the wet season. During heavy precipitation, the brook overflows its banks and scours the surrounding rocks and tree roots, often cutting new channels across the rocky forest floor. Fish, probably native trout, can be found in both the swamp portion and brook portion of Upper Eccleston Brook.
Trees bordering the brook consist of White or Black Ashes ( Fraxinus spp. ), Red Maple ( Acer rubrum ), Yellow Birch ( Betula alleghaniensis ), Black Tupelo ( Nyssa sylvatica ) Hornbeam ( Carpinus caroliniensis ), and occasional Sycamore ( Platanus occidentalis ). Shrubs on drier stream banks consist mainly of Summer Sweet (Clethra alnifolia ). Along wetter stream banks Northern Spicebush ( Lindera benzoin ), Winterberry ( Ilex verticillata) and Swamp Azalea ( Rhododendron viscosum ) are abundant. Tangles of Wild Grape ( Vitis spp. ) are very common. Similar Grape Tangles are common along many of the intermittent streams and seeps feeding into the brook from the western slope toward Flanders Road.
Amazingly profuse populations of Cardinal Flower ( Lobelia cardinalis ) are found along the lower two-thirds of Eccleston Brook until it intersects the first houses in the Bel Aire community. During the winter, when the water level of the brook rises, the green rosettes of Cardinal Flower leaves can be seen below the surface of the water with the dead, bleached flower stalk from the previous summer trailing downstream. The western side of this portion of the stream also has a large population of near one hundred Tulip Trees, which prefer moist soil. A small population of intensely fragrant pink Honeysuckle Azalea ( Rhododendron roseum ) is also found along the western side of the lower stream course.
It is our hope that, with your help, this extremely beautiful, compact, productive and varied series of ecosystems can be preserved for present and future generations.
—–
Whitney R. Adams
48 Bel Aire Dr.
Mystic, CT 06355
B.A. Chemistry-Biology, University of Delaware, Newark, DE, 1961
M.S. Natural Sciences. Rensselaer Polytechnic Institute, Troy, NY, 1968
Yale Biology Department., New Haven, CT, Plant Physiology, 1970-78
Charles Pfizer Co., Inc., Groton, CT, Plant Biochemistry, 1978-1990
Dekalb Genetics Corp., Mystic, CT, Plant Biochemistry, 1990-1999
Monsanto Co., Inc., Mystic, CT, Plant Biochemist, 1999-present