Clark Pond Plan - Association of Great Neck

A SUSTAINABILITY PLAN FOR CLARK POND
Building Local Stewardship through Conservation and Management
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Prepared by
The Clark Pond Group
Adopted by
The Association of Great Neck, Inc.
April 30, 2012
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Executive Summary
The Clark Pond Group, a subcommittee of the Association of Great Neck (AGN) Board
of Directors, prepared this report for AGN. This resource management plan for Clark
Pond is a comprehensive examination of the Clark Pond ecosystem that establishes its
ecological health and provides a framework for guiding the AGN Board of Directors in
conservation decisions. Also included are scientific data and, cultural and social values
that justify the need for monitoring and sustaining the Clark Pond ecosystem. The
recommendations in this plan are a guide to the management of the Clark Pond
ecosystem as well as opportunities for sustaining this landscape today and into the future.
A vital part of our landscape, the Clark Pond ecosystem deserves the time and resources
that we can provide to ensure its lasting vitality.
Preface
The effects of environmental change are challenging issues that confront our
society. Environmental change is driven not only by natural forces but also by human
impact on the landscape. For example, the dynamic interface between water and land are
areas of high-density residential development despite the frequent natural hazards that
can occur, such as flooding, storm impacts, and coastal erosion. Thus there is a pressing
need to respond to the challenges of environmental change as well as develop solutions
that address the complexity of the interactions between nature and mankind.
In addition, our understanding of ecosystems as natural landscapes is changing.
Anthropogenic, or man-made, factors are now robust players in ecosystems. Yet a key
aspect to our sustainability is recognizing the effects we have already had on ecosystems,
as well as predicting what future impacts may result from our actions. Recognizing the
overwhelming dominance of humans in ecosystems also makes us cognizant of the
responsibility we have to understand, manage, and steward our fragile landscapes.
In this document we use the term ecosystem to denote a specific place, Clark
Pond, and provide a plan to sustain the environmental quality of this ecosystem in a
rapidly changing interconnected world. Over the last 50 years ecosystems have changed
more when compared with any prior time in human history (MA, 2005). Ecosystems are
complex dynamic systems of plants, animals, and communities of microorganisms that
interact with the physical environment. Ecosystems also provide numerous beneficial
services for nature and for society.
The Great Marsh (~25,000 acres) is the largest continuous salt marsh in New
England, spanning from Gloucester, Massachusetts to Portsmouth, New Hampshire.
Clark Pond, though small in comparison, is a vital part of this landscape. While artificial
in origin, since its formation Clark Pond has become a major contributor to regional
biodiversity. Today however, pressure from increased human presence is contributing to
water and habitat quality issues for the Clark Pond ecosystem. As well, the threat of
biodiversity loss and disruption of the benefits, or ecological services, provided by Clark
Pond from factors such as invasive species and climate change are also concerns.
In the summer of 2010 The Association of Great Neck (AGN) Board of Directors
initiated the development of a conservation and management plan for Clark Pond. A
subcommittee, the Clark Pond Group, was assembled that included an interdisciplinary
team of residents of Ipswich representing the stakeholders abutting Clark Pond including
the Town of Ipswich and Great Neck residents. The objectives of the plan were to assess
the physical, chemical, and biological conditions of Clark Pond as well as its
contributions to human well being and, establish a scientific basis for actions needed to
enhance the conservation and sustainability of Clark Pond. The focus of the work was
integrating research with monitoring, assessment, and conservation strategies, which
include a combination of prevention measures, early detection, and management of
invasive species both flora and fauna.
The result is this document, a sustainability plan for Clark Pond that conserves
and enhances the flora and fauna and their related habitats while providing opportunities
for compatible wildlife-dependent recreational uses and facilitates environmental
stewardship both short (~1-5 years) and long term (~5-10 years). We do not, however,
provide a comprehensive summary of the complexity of the interactions between coupled
human-natural systems in this ecosystem and beyond. The intended use of this plan is as
a benchmark for future assessments, as a resource to identify priorities for decisions
affecting this ecosystem, to gain foresight concerning the consequences of past decisions
affecting this ecosystem, and to help build individual capacity to undertake ecosystem
assessments and act on the findings. Our intent is that this plan will provide valuable
insights into important issues, not that it will provide final answers.
Acknowledgements
This assessment would not have been possible without the extraordinary
commitment of the Clark Pond Group members and their in-kind contributions and the
in-kind support of their institutions, which enabled their participation. The diversity of
voices greatly enhanced the color of this report. I thank the Clark Pond Group for the
guidance and oversight they provided in this process: Wayne Castonguay, Michael
DeRosa, Jennifer Hughes, Beth O’Connor, and Joe Quinn. I also thank the Association
of Great Neck Board of Directors for their support in developing the plan.
In addition, I want to acknowledge the support of Marc Bellaud, Aquatic Control
Technologies, Sutton, MA for water sampling and aquatic vegetation identification;
Donohoe and Parkhurst, Inc. Land Surveying and Mapping, of Topsfield, MA for the
bathymetry plan; Ann McMenemy, Program Director Ecological Services,
Environmental Resources Management, Boston, MA for invaluable consultations on
environmental laws and regulations, and Clark Pond vegetation identification; Ann
Mollica for her contributions as a resident of Great Neck; and Stanley Wood, Great Neck
resident of 55 years, for providing an illustrated history of Clark Pond.
Cricket C Wilbur
AGN Board of Directors & Clark Pond Group
About the Authors
WAYNE CASTONGUAY is Director of the Center for Agriculture and the
Environment, The Trustees of Reservations. He has served on local, regional, state, and
federal committees related to environmental issues. Currently he serves on the Shellfish
Advisory Board, Agriculture Study Committee, and the Stormwater Committee in
Ipswich. He is also active in several local conservation organizations.
MICHAEL DEROSA is a wetland scientist and landscape ecologist specializing in
landscape restoration. He is a Licensed Site Professional (LSP Lic. No. 3452) and
manages hazardous waste site evaluations, assessments and remedial actions within the
Commonwealth. Also, he is a LEED Accredited Professional under the US Green
Building Council and consults on green building and LEED certification projects.
JENNIFER HUGHES is Director of the Conservation Department for the Town of
North Andover. She is a member of the Ipswich Conservation Commission since 2000
and currently serves as vice chairman.
BETH O’CONNOR is Open Space Stewardship Coordinator for the Town of Ipswich.
In her role for the Town she oversees the maintenance and management of Town
properties that are protected primarily for conservation purposes, many of which have
some form of public access for passive recreational enjoyment.
JOSEPH QUINN is a retired Senior Executive of retail. He has served on the
Association of Great Neck Board of Directors for the past six years and currently serves
as president.
CRICKET WILBUR is a doctoral candidate at Antioch University New England. Her
research interests include human-environment relationships past, present and future. In
addition to her dissertation research on environmental change in the Arctic, she
volunteers with conservation organizations in Massachusetts. She currently serves on the
Board of Directors of the Association of Great Neck.
TABLE OF CONTENTS
CHAPTER 1 Introduction………………………………………………………………..8
CHAPTER 2 Environmental Background……………………………………………….9
2.1 Physical……………………………………………………………………......9
2.2 Cultural…………………………………………………………………….…10
2.3 Biological…………………………………………………………………….14
2.4 Conclusion……………………………………………………………………15
CHAPTER 3 Site Assessment……………………………………………………...…..17
3.1 Clark Pond Survey………………………………………………………...….17
3.2 Clark Pond Watershed…………………………………………………...…...17
3.3 Flora Survey…………………………………………………………...…….18
3.4 Nekton Survey………………………………………………………...…......18
3.5 Pond Bathymetry…………………………………………...…………....…..19
3.6 Soils and Sediment Core Lithology…………………………….…………....19
3.7 Storm Water Drainage………………………………..……………………...20
3.8 Water Quality Analysis………………………………………………………21
3.9 Conclusion…………………………………………………………………...22
CHAPTER 4 Recommendations to Protect the Habitat & Sustain the Open Space...….23
4.1 Community Outreach and Education………………………………………....25
4.2 Water Quality………………………………………………………………...26
4.3 Invasive Species and Habitat Protection………………………………….….27
4.4 Habitat Restoration………………………………………………….….....….31
CHAPTER 5 Conclusions………………………………………………………….…..33
REFERENCES…………………………………………………………………..……...33
APPENDICES:
A. Deed of Conservation Restriction……………………………………….…..34
B. Clark Pond Survey Results……………………………………………...…...40
C. Soil Map……………………………………………………………………..41
D. Bathymetry Plan…………………………………………………………......43
E. Water Quality Report………………………………………………….…..…45
F. Rare Species/Priority Habitat 903……………………………………..…......48
CHAPTER 1: Introduction
To address potential adverse consequences for local and regional biodiversity yet
retain the passive recreational use of Clark Pond, we developed a conservation plan for
the coming years and decades that is based on history, current observations, and
experiments. We offer this management plan as a guide for the Association of Great
Neck (AGN) Board of Directors regarding issues that may impact Clark Pond. These
recommendations serve as a roadmap for the AGN Board to ensure the ecological
integrity of Clark Pond and the Great Marsh.
1.1 Study Site
Clark Pond is located on Great Neck, a 600 acre island in the Town of Ipswich,
Massachusetts, that is part of a parcel of land as shown on a “plan entitled “Plan of Land
in Ipswich, Massachusetts” dated May 10, 1983 by Hancock Survey Associates, further
described in a deed to the Association of Great Neck, Inc., from the Proprietors of Great
Neck, Inc., dated Sept 26 1985 and recorded with the Essex County Registry of Deeds
Book 8098 Page 247/2”. The Clark Pond Conservation Area, ~67 acres, is located on the
eastern shore of Great Neck (Figure 1) and consists of three primary regions, Clark
Beach, Clark Pond, and the surrounding marsh and shrub lands. Clark Beach is
approximately 1/3 of a mile in length and forms the eastern portion of the property.
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Figure 1. Aerial photo of Great
Neck, Ipswich MA.
Abutters to Clark Pond include the Town of Ipswich, AGN and individual
property owners. The Town of Ipswich owns ~1/3 of the land (Figure 2). The
Association of Great Neck via a conservation restriction owns Clark Pond and the
adjacent parcel known as A. B. Clark Beach (Appendix A). The remaining parcels
belong to nine individual property owners. In addition, this area is adjacent to and
contiguous with a larger conservation area of Great Neck totaling 85.5 acres owned and
managed by the Town of Ipswich (Figure 2). This area forms the hillsides and valley
between Northridge and Plover Hill, and is bordered by Pasture and Clark Ponds.
Figure 2. Great Neck Conservation Area,
Ipswich, MA (photo courtesy of the Town of
Ipswich).
Clark Pond is managed by AGN. AGN is a non-profit, charitable corporation
formed in part to protect the natural resources on the properties owned and managed by
the Association. The conservation of biodiversity in this area is a mission of AGN. In
general, an ecosystem-based approach to conservation has been utilized with a
management intervention in the fall of 2009 to control the invasive species Phragmites
spp. This approach to management enhances biodiversity of the pond, the beach and the
surrounding uplands.
Although a man-made feature of the landscape, Clark Pond has become an
important component to local and regional biodiversity.
Fresh water coastal ponds are exceedingly rare as well as
critically important habitat for plants and animals. For
example, the location of Clark Pond along the Atlantic
flyway attracts migratory shorebirds, waterfowl and
terrestrial birds (Figure 3). In the summer, the shrub land
Figure 3. Night heron at Clark Pond.
on the western shore of the pond is a staging area for herons and egrets. The
Massachusetts Audubon Society considers Clark Pond one of the most significant
waterfowl areas on the North Shore of Massachusetts (AGN Clark Beach Management
Program (2002)).
As well, the proximity of Clark Pond to Plum Island Sound is considered by many
as one of the closest fresh water ponds to the ocean on the eastern seaboard of the United
States. In addition, the intertidal flats along Clark Beach are mapped as suitable habitat
for soft-shelled clams. Clark Pond provides ecosystem services to humans, for example
by influencing water quality, and as a buffer to coastal hazards. However, much of the
region surrounding Clark Pond is densely developed residential area making the pond
susceptible to land management practices within the contributing watershed.
Due to the complexity of the Clark Pond ecosystem we begin this plan with
information about the environmental setting of Clark Pond and the surrounding area
through ancient, historic and modern times to establish reference conditions of this
ecosystem. Next we present data and maps used to assess the ecological integrity of
Clark Pond today and its significance to Great Neck residents. Lastly we offer
recommendations for monitoring ecosystem conditions at Clark Pond to protect the
habitat and sustain the open space into the future.
CHAPTER 2: Environmental Background
Shaped by glaciers
during the last the ice age, the drumlins of Great Neck and
Little Neck form the cornerstones of the Clark Pond landscape.
During the times of the
Indians and early European settlers, the pond and its immediate surroundings were used
as a source of food (shellfish, birds, and mammals) and drinking water. The pond may
have also served as a sheltered tidal bay for canoes and other small boats. More recently,
in the late 1800’s and early 1900’s, the pond was used for duck hunting and harvesting of
ice. Today, the Clark Pond area is appreciated for its scenic beauty and wildlife
inhabitants with the use of Clark Pond restricted to winter recreational activities (ice
skating and ice boating). In this section, we present physical, cultural and biological
information about Clark Pond and the surrounding area through ancient, historic and
modern times.
2.1 Physical
Clark Pond on the northeastern Massachusetts coast is situated within the
Seaboard Lowland section of the New England Physiographic Province (Fenneman,
1938). Approximately 15,000 years ago, ice sheets covered much of New England
extending as far south and east as Nantucket (Oldale, 1992). These ice sheets deposited
on bedrock ground moraine (till) and outwash deposits of variable thickness and sediment
type (boulders – clay). In some areas, till was shaped by ice sheets and formed drumlins.
As the ice sheets retreated sea level rose, and Holocene age deposits covered glacial
sediments and bedrock, forming salt marsh and barrier beaches seaward, except for
numerous partly drowned drumlins. Holocene transgression on the northern
Massachusetts coast associated with sea-level rise and isostatic rebound from glacial
retreat was variable until ~5000-6000 b.p. (Kelley et al, 1992). Sea level rise slowed
from 3,000 to 4,000 b.p. (Oldale and O’Hara, 1980) and was followed by sediment
deposition leading to the formation of our modern barrier coasts.
This formally glaciated coastline today is a mixed energy, tide-dominated setting.
The mean tidal range and average wave height are ~2.6 m and ~1.0 m respectively
(Abele, 1977; Smith and Fitzgerald, 1994). Also, the Gulf of Maine storm wave
approach is predominately east-northeast the consequences of which are a north to south
movement of sand. Erosion rates over the past 150 years for Atlantic beaches are
estimated at one and half feet per year (United States Geological Survey). However,
erosion rates and associated impacts are localized and variable. As well, increases in the
percentage of coastline eroding today
may be related to the impacts of rising sea level.
A relative youngster to the landscape, Clark Pond was formally established in the
early part of the 20th century through the construction of
two earthen dikes causing the drowning of a former bay
(Figure 4). Dikes were constructed at the outlet of a
former channel on the north end of the pond and atop the
former spit which connected the beach to the mainland on
the southwest portion of the
property.
Figure 4. Map of Great Neck
and Little Neck, Ipswich, MA
circa 1893.
2.2 Cultural
As sea level rose and salt marshes and barrier beaches formed, Indians used Clark
Pond and the surrounding area for camps. Clark Pond was ideal for this as a sheltered
tidal flat adjacent to a fresh water stream. Indians could pull their canoes out of reach of
the tide, and fish and clam within the basin. Excavations of shell heaps on the banks of
Clark Pond have produced well-documented evidence of Indians from as early as 6000
years ago to as recent as 1600’s.
During European settlement of the area, William Jeffery purchased the Great
Neck area from the Indians. The lands became known as Jeffries Neck and though
originally forested, it was primarily used as pastureland for grazing cattle. From 1634 to
1713 the Great Neck area were common grounds and administered by the Town of
Ipswich. In 1713 and until 1896 the Proprietors of Jeffries Neck Pasture administered the
land. By 1897, Alexander B. Clark had purchased sufficient rights to the land from the
Proprietors as well as inhabited and claimed land for his family. After a subsequent
division of portions of the land back to the Town, the property was subdivided, leased
and then sold as house lots for the present community.
A map of Essex County shows Clark Pond in 1893 open to the ocean at high tide
(Figure 4). Around 1897, A.B. Clark built a stone dam at the northeast corner creating a
fresh water pond for duck hunting. He also built gunning blinds into the bank (Figure 5).
Also around this time, ice was harvested from the pond
and stored in buildings for summer
use. In the 1930s, the pond was
drained by the State and ditched to
Figure 5. Great Neck,
Ipswich, MA as seen from
Clark’s Pond circa 1890.
limit the breeding of mosquitoes.
In the 1940s, the pond area was leased to Ben Moseley who repaired the dam and
created a roadway along the beach to access a gunning booth/duck blind in the vicinity of
what is now the middle parking lot. Use of the road diminished in the early 1950s, as it
was mostly overgrown (Figure 6). However, the 1940s and 1950s were the beginnings of
significant human development of the area. Many house lots were leased for summer
camps and land was sold and/or leased with rights to beach access. To accommodate
beach goers, and as an incentive to purchase house lots, in 1956 a parking lot was
enlarged at the southern end of the pond and the boat ramp to the ocean was paved.
Sometime around 1964 to improve beach access, the
former beach road (Belleau Woods Road) along the
eastern side of Clark Pond was reconstructed and a
second parking area in the vicinity of the Mosely
duck blind was constructed.
Figure 6. Clark Beach August 7, 1956.
On the western end of the pond, an extension of Clark Road (formerly Casino
Road) was constructed around 1960 to facilitate development and allow for the supply of
drinking water from the water tower to North Ridge Road. This road crossed the
freshwater stream to the pond with a culvert. A portion
of the wetlands associated with the northwest corner of
the pond was also filled to create the road. In 2007, the
Town as part of the Great Neck Conservation Area
acquired several parcels of land on the west and south
ends bordering Clark Pond that had remained with the
Proprietors (Figure 2). On one of the parcels on the west
Figure 7. Clark Pond Overlook,
Clark Road, Ipswich, MA.
end of the pond the Town of Ipswich constructed an observation deck that overlooks
Clark Pond (Figure 7).
2.3 Biological
Because of its geographic location and physical and biological diversity Clark
Pond can be considered a valuable ecological resource in eastern Massachusetts. Clark
Pond is one of only five coastal freshwater ponds in the State. The combination of
terrestrial, marine, and fresh water environments attracts many species of birds, small
mammals, fish, amphibians, reptiles, and insects.
Surrounding Clark Pond is an extensive freshwater emergent marsh as well as five
other vegetative community types, saltwater wetlands, dunes, maritime forest, grasslands,
and upland forest. These vegetative community types make up six of 23 major vegetative
types in Massachusetts. As well, five of these six are considered uncommon and/or
declining in Massachusetts.
Clark Pond is ecologically productive as evidenced by the biodiversity, plant and
animal, terrestrial and aquatic. For example, diverse fish populations of estuarine species
include mummichog, Atlantic silversides, and sheephead minnow; populations of waterdependent mammals include muskrat, river otters, and beaver; the presence of snapping,
spotted, and painted turtles, and abundant frogs. This may be related to the pond
functioning as early successional habitat. Early successional stages in many pond
systems often correlate to high levels of productivity due to the open ecosystem niches
that often exist and the lack of high levels of decaying organic matter that deprive the
water of oxygen. However, due to the extreme shallowness of the pond, anaerobic
conditions caused by high levels of decaying organic matter, which are typical in most
ponds, do not generally exist in Clark Pond.
Clark Pond and its adjacent wetlands, shrub land and forest also support a
diversity of bird life. Many species of fresh and salt-water shorebirds utilize the pond
during some part of the year, including the Piping Plover, and Least and Common Terns,
which are federally threatened species. American Bittern, King Rail and Virginia Rail
have been known to nest along the water’s edge (the King Rail is among the rarest
nesting birds in Massachusetts). During low water periods in the summer, thousands of
migratory shorebirds can be observed roosting along the waters edge or on exposed
bottom areas.
The area around the pond is also an important feeding area for raptors, e.g.
Coopers Hawks, Kestrels and Peregrine Falcons, a federally threatened species. As well,
Ospreys commonly fish the pond.
In addition, the coastal banks and steep hillsides adjacent to the wetlands along
Clark Road provide one of the most significant roosting and staging habitat for mixed
groups of herons during August and September in Essex County. Snowy and American
Egrets, black-crowned, Green, Little and Great Blue Herons can be observed at one time
in these areas during this period each year.
As well, most native species of songbirds
utilize the areas immediately adjacent to the pond. During migratory periods, the shrubs
and marshes along the pond function as an important “sink” due the proximity to the
ocean and salt marsh, the protection afforded by the dense vegetation, the steep
topography of the area, and the high density of seed/fruit producing shrubs and vines
common in the area. Marsh wrens are known to nest in the Typha surrounding the pond.
Invasive species, plants and animals, have been a part of the Clark Pond
ecosystem for many years. During the 1950s, the dominant vegetation around the pond
was purple loosestrife. This was gradually replaced by Typha spp. More recently
Phragmites spp began to replace Typha spp.
In addition, every year families of mute swans nest on the pond to raise their
young. The Mute Swan was imported to this country from Europe to Long Island, New
York in the late 1800’s. Since escaping into the wild, their populations have been
expanding. Today they are considered to be a significant nuisance due to their size and
aggressiveness by displacing and outcompeting native waterfowl as well as the amount of
physical and biological damage to ecosystems due to their voracious appetite for
submerged aquatic vegetation. Much of the coastal ecology of New York, New Jersey,
Connecticut and Rhode Island have been devastated as these regions support the highest
populations of mute swans. In an effort to combat this devastation, several states have
implemented swan control programs.
Mute Swans first began nesting on Clark Pond in the 1960’s and have become the
symbol of the Association of Great Neck, as they are the most recognized feature of
Clark Pond. Swans are extremely territorial and a single pair was successful at fending
off additional nesting pairs until the 1990’s when one additional pair successfully set up a
territory on half of the pond. Then, in 2007, a 3rd pair successfully established a third
territory such that as many as 3 pairs have been known to raise signets each year. At these
high population levels, the Swan’s are negatively impacting the native waterfowl
population such that other waterfowl typically do not nest or raise young in the pond. In
addition, the breeding pairs contribute to the expansion of the swan population in coastal
Massachusetts with negative impacts on other coastal areas. Because swans can live over
30 years in the wild, the Clark Pond swans are contributing to the growth of the local
population overall.
2.4 Conclusion
These historical and cultural perspectives establish reference conditions for
estimating how the current Clark Pond ecosystem differs from this ecosystem of the past.
These characterizations can also provide insights into possible future ecosystem
development by identifying disturbance agents, vegetation patterns, environmental
change, and the variability of biotic patterns and processes. A summary of the Clark
Pond ecosystem today is provided in the next chapter.
CHAPTER 3: Site Assessment
Ponds are major contributors to regional biodiversity. To assess the ecological
integrity of and establish base line data for Clark Pond, biotic and abiotic data were
collected as well as consulting with Great Neck residents to identify their relationship
with Clark Pond. In this section, we present findings of physical, chemical and biological
data about Clark Pond as well as cultural findings from Great Neck residents.
3.1 Clark Pond Survey
In November of 2010, the Great Neck community was consulted via an online
survey to identify their relationship with Clark Pond. The survey questioned residents
about environmental quality, environmental values and behaviors with respect to Clark
Pond, perceptions of Great Neck development, attitudes toward Clark Pond, and
demographic characteristics.
The results of the survey indicate Great Neck residents
value the aesthetic, wildlife, and recreational qualities of Clark Pond (Appendix B).
Some residents (21% of the respondents) noted they were dissatisfied with water quality
and 16% were dissatisfied with the accessibility for winter recreational activities.
3.2 Clark Pond Watershed
The Clark Pond ecosystem is supported by freshwater from runoff, groundwater
and two intermittent streams that drain the surrounding 150-acre watershed (Figure 8).
Delineation of the Clark Pond watershed is by those areas that due to their topography
influence water drainage toward or directly into Clark Pond. Streets included in the Clark
Pond Watershed are Clark Road, eastern portions of Northridge Road, southeast portions
of Skytop Road, Ploverhill Road, Dartmouth Road, northern portions of Chattanooga
Road, Bunker Hill Road, Appomattox Road, portions of Dunkirk and Bayview, and the
Clark Beach Road. Impervious areas within the Clark Pond watershed, e.g. the Air Force
facility on Skytop Road, also influence Clark Pond by contributing to faster rates of runoff and less infiltration of surface water. Among the land uses included in the Clark Pond
Watershed are medium and high density residential as well as a variety of “natural” uses
including forest, non-forested wetlands, and brushland/successional forest (MA GIS data,
2008). Of these uses, residential development accounts for the largest portion of land use
in the watershed.
Figure 8. The Clark Pond Watershed modeled using the United States Geological Survey (USGS)
StreamStats program.
3.3 Flora Survey
The fresh water conditions within the pond support a fringe of both narrow-leaved
(Typha, Phragmites, sedges) and broad-leaved (Pontederia) emergent plants and minor
amounts of purple loosestrife. Pickerelweed typically tolerates salinity levels no higher
than 3 ppt. The emergent fringe to the pond is supported on a very poorly drained
organic soil (Appendix C). Beyond the emergent fringe are meadows dominated by rice
cut grass, deciduous and coniferous trees, and shrubs. The pond itself is generally very
shallow (~1-3 feet) and supports beds of submerged aquatic vegetation (Potamogeton)
and low growing spikerush (Eleocharis sp.). In the fall of 2010, the aquatic vegetation
was dominated by muskgrass (Chara sp.), a microalgae.
3.4 Nekton Survey
The fish population in Clark Pond is dominated by brackish and low-oxygen
tolerant species such as killifish (Figure 9). Atlantic silversides and sheepshead minnows
were also present in Fall 2010 but not in May 2011. Three spine sticklebacks were
present in May 2011 but not in Fall 2010.
Number
of
*ish
Clark
Pond
Nekton
Survey
Data
200
180
160
140
120
100
80
60
40
20
0
2010‐Oct
2011‐May
Mummichogs
Altantic
Silverside
Sheepshead
Three
Spine
Minnow
Stickleback
Species
Figure 9. Clark Pond Nekton Survey Data collected with a minnow trap.
3.5 Pond bathymetry
Bathymetric data for Clark Pond were collected in the December of 2010. The data
was collected using survey equipment, and was referenced to both horizontal and vertical
datums. 110 points were collected and used to generate a bathymetric model of Clark
Pond. The bathymetric model indicates a uniformly shallow pond, average depth less
than 3 feet, that has an elevation of only 2 feet above mean high tide (Appendix D). Soft
sediment accumulations were thickest in the northwest section of the pond approximately
1.78 feet at the thickest. The thinnest accumulations of soft sediment are along the
eastern shore of the pond parallel to Clark Beach, the thinnest being .13 feet.
3.6 Soils and sediment core lithology
Soils surrounding Clark Pond as mapped by the Natural Resources Conservation
Service are Scitico silt loam, Boxford silt loam, and Ipswich and Westbrook mucky peats,
and Beach (Appendix C). The sediment in Clark Pond was determined from a sediment
core. A sediment core, approximately two feet in length recovered from Clark Pond with
a gravity corer in February 2011, exhibited a marked difference in sediment size from the
bottom of the core to the top. Several soil horizons could be identified by composition as
well as color. The bottom of the core was predominately sand, with both light and dark
colored grains. Sand grains were mostly rounded, macro organic material, or plant
fragments, were few, though this section was also enriched in micro organic material.
Approximately five inches from the core bottom was a distinct peat horizon. Above this
peat horizon the core was fairly uniform in color, mostly black, where the percentage of
sand grains decreased towards the top of the core being, which were replaced by silt and
clay sized particles. Brown organic fragments were abundant throughout this section, in
the form of stems, leafs, roots, and root hairs. Near the top of the core a pebble sized
rock fragment was found and which upon further examination appears to be a
conglomerate composed of sand and perhaps tar. In addition the core had the distinct
smell of hydrogen sulfide.
Figure 10. A portion of the soil
core recovered from Clark Pond
in February 2011.
3.7 Storm water drainage
Within the Clark Pond watershed are four storm drain outfalls that discharge into
Clark Pond. Most surface water runoff from a storm event or snowmelt flows down
gradient and is collected via catch basins, runs through the drain lines, then flows to the
outfall pipes, where it is discharged into Clark Pond. As represented on the bathymetry
plan the locations of storm water discharge are identified as SDO #11-14. The outfall
pipes are red lines, catch basins are blue circles, and yellow lines are the drain pipes
(Figure 10). SDO #11 is located behind the property at 68 Clark Road and is the outfall
pipe for water runoff and discharge collected in the general vicinity between Chattanooga
Road and Bayview Road north of Plover Hill Road. SDO #12 is near the storm drain in
the roadway just north of 44 Clark Road and is the outfall pipe for water runoff and
discharge collected in the general vicinity between Mulholland Drive and Chattanooga
Road north of Plover Hill Road. SDO #13 is near the fire hydrant by 28 Clark Road and
is the outfall pipe for water runoff and discharge collected in the general vicinity of the
hilltop between the Air Force facility and Clark Road. SDO #14 is across Clark Road
from Skytop Road and is the outfall pipe for water runoff and discharge collected in the
general vicinity of Skytop Road east of Merganser Road.
Clark Pond Storm Drain System
Rd
.
hrid
Nort
ay
Qu
Dartmouth Rd
d
ge R
SDO #13
SDO #14
SDO #12
SDO #11
Outfall pipes
Rd
xR
d
att
o
Rd
Ap
po
m
rH
ill
an
o
Bu
nk
e
Rd
500 Feet
og
aR
d
Hydrant
iew
yv
Ba
Rd
k
ar
Cl
0
ck
Ne
250
le
Litt
500
Legend
Hill R
d
Ch
a tt
Plov
er
Catch Basin/Manhole
Storm drain line
Parcels
Alam
oR
d
Figure 11. The storm drain system in the vicinity of Clark Pond, Ipswich, MA.
3.8 Water Quality Analysis
The pond has gradually been converted from brackish to fresh water. The water
quality of Clark Pond has been analyzed from a sample collected from mid-pond (42o
42.262’ / 70o 47.869’) in October of 2010 by Aquatic Control Technologies, Inc. and
processed by Microbac Laboratories, Inc. The results indicate mediocre water quality
with high conductivity and alkalinity (Table 1), which could result from the close
proximity of Clark Pond to Plum Island Sound and/or be indicative of non-point source
pollution in storm water runoff.
Table 1. Water Quality Analysis results of a mid-pond water sample from Clark Pond collected on
10/19/2010. See Appendix E for the full report.*sample was received outside of the recommended holding time for
analysis; † MA Class B water quality standards; ªU.S. Environmental Protection Agency (EPA).
RANGES FOR PARAMETERS
TEST
RESULT
pH
8.48 S.U.*
Alkalinity as CaCO3
72 mg CaCO3/l
6.0-8.3†
<1 - >20 mgCaCO3/lª
Turbidity
2.7 NTU
Conductivity
2630 umho/com
Nitrate Nitrogen as N
<0.1 mg/l^
<1 – 1000’s NTU; freshwater
lakes eastern MA: <5 NTU
<500 umho/cm freshwater
>225,000 umho/cm sea water
<0.3 - >1.5 mg/l
Phosphorus as P
0.028 mg/l
<3 - >150 mg/l
E. coli
10 CFU/100ml*
<200 organisms/100ml†
Salinity
1.4246
35 (sea water)
In the summers of 2005 and 2010, the pond experienced pronounced algal
blooms. Microscopic examination of algae film collected from the pond bottom in the
fall of 2010 identified both filamentous green algae and a colonial bluegreen algae (M.
Bellaud, Aquatic Control Technologies, Inc., pers. comm.). These blooms may have
been a result of the shallow water depth of the pond and/or the input of phosphorus.
3.9 Conclusion
In this section we have described the abiotic and biotic events that include
humans and human actions, which contributed to the development of the current
conditions of the Clark Pond ecosystem. Ecosystems are dynamic and attempts to
maintain them in a static condition can adversely affect them. Actions we believe could
be beneficial to the sustainability of the Clark Pond ecosystem are described in the
following chapter.
CHAPTER 4: Recommendations: Protect the Habitat/Sustain the Open Space
Virtually every ecosystem is directly or indirectly affected by human activities
and Clark Pond is no exception. The degradation of aquatic ecosystems can result from
stresses including excess nutrients, hydrological manipulation, siltation, exotic species
introductions, acidification and toxic contaminants. Our concern is that this ecosystem
will be further stressed by climate change and increased human activities within its
watershed, such as the development of the parcel between the Great Neck Conservation
Area and Clark Pond formally occupied by the US Government.
In this section, activities are outlined to manage Clark Pond in ways that benefit
society while minimizing both short- and long-term impacts on the environment. We
present recommendations on community outreach and education, water quality, invasive
species and habitat protection, and restoration (Table 2). The objective of these
recommendations is to minimize negative ecological impacts on Clark Pond by targeting
factors that are contributing to driving the Clark Pond ecosystem beyond the range of
normal variation or from its natural state.
4.1 Community Outreach and Education
As the governing body overseeing the sustainable management of natural
resources on Great Neck, AGN plays a key role in educating the public on environmental
issues, engaging the community through environmental education and advocacy, and
promoting environmental stewardship. To raise awareness of the importance of
sustaining the natural resources on Great Neck and to gain a deeper understanding of the
synergistic interactions among multiple stressors on the Clark Pond ecosystem, a
Conservation Committee, a subcommittee of the AGN Board of Directors, should be
established. The Conservation Committee becomes the liaison between the AGN Board,
AGN members, and other stakeholders to support the sustainable management of AGN
properties through leadership and partnerships with stakeholders while maintaining a
balance between people and our environment. The Conservation Committee is important
both to the development of management and restoration practices, and to progress in
improving our understanding of basic ecological processes of Clark Pond.
Table 2. Recommendations to protect the habitat and sustain the open space on Great Neck.
TOPIC
Outreach &
Education
ISSUES
Responsible use and protection of Great Neck
natural resources
RECOMMENDATIONS/ACTIONS
Establish a Conservation Committee within the AGN
Board of Directors to address conservation
management issues on Association of Great Neck
properties.
Communication
Educate Great Neck residents about environmentally
sound household, yard, and septic system practices
through advocacy e.g. AGN bulletin boards, newsletter
and website. Coordinate community awareness
campaigns, such as a storm drain marking project.
Citizen monitoring
Develop a Community Stewardship program to involve
and educate the community about management,
biodiversity, and conservation.
Water Quality
Nutrient management
Conduct water quality analysis of Clark Pond
periodically to monitor for nutrient influx.
Invasive Species &
Habitat Protection
Invasive species both flora and fauna
Control mechanisms for invasive flora and fauna need
to be determined on an individualistic basis. For
example, monitor purple loosestrife and if necessary
use beetles to keep in check. Monitor fauna
populations and recognize their activities in low
numbers can be beneficial to the ecosystem. For
example, control the mute swan populations in the
Atlantic flyway by participating in a swan control
program.
Wildlife habitat improvement projects
Remove by hand old stands and re-growth of
phragmites and plant native grasses, and bayberry,
sumac, and Virginia rose to encourage shady habitat.
Water level management and mitigation. Outlet
stream management and storm damage
mitigation.
Maintain dam/dike to spillway height or above to
ensure that the pond water level is high enough to
inhibit the spread of invasive species of flora.
State and Federal Endangered Species
Regulations
Any management activities require approval from the
State of Massachusetts and the Federal Government as
Clark Pond is listed as habitat for state and federal
protected shore birds (least tern, common tern, and
piping plover).
An integrated resource management plan for
AGN properties.
Update the Clark Beach Management Plan.
Rare/threatened/candidate Species
Encourage the growth of native plants and the
formation of habitat for rare/threatened/candidate
species, e.g. New England Cottontail, by limiting
landscape practices of mowing and weed whacking
along the pond side of the beach road and the outlet
stream upstream of the footbridge.
The residents of Great Neck are a significant influence on the ecological health of
Clark Pond. An important component to AGN management of Clark Pond should
include engaging with the community through education and advocacy. The development
of a Community Stewardship program can provide programs and services to strengthen
the conservation ethic of the Great Neck community. Engaging with volunteers of all
ages, or Community Stewards, could provide hands on awareness of management,
biodiversity, and conservation of Clark Pond and Clark Beach. Community workshops,
awareness campaigns such as a storm drain marking project and signage identifying the
Clark Pond watershed, and publications can create a heightened awareness of the
dynamic nature of natural resources and the impact of human stresses on the
environment, and assist AGN in research and monitoring efforts associated with the
management of Clark Pond and Clark Beach. For example, information about
environmentally sound practices of lawn care, car washing, septic management,
household cleaning supplies and pet waste should be communicated via the AGN bulletin
boards, website, and newsletter.
4.2 Water Quality
The water quality of Clark Pond is our primary concern as even minor increases
in nonpoint-source pollution to the pond from storm water runoff, septic systems and
landscape practices can cause increased loading of nutrients, such as nitrogen and
phosphorous, and the potential for eutrophication. Eutrophication is the process by which
continued nutrient loading stimulates excessive plant and algae growth resulting in the
accumulation of organic matter and the depletion of dissolved oxygen, which can lead to
biodiversity loss. Though eutrophication is a natural process in the evolution of lakes and
ponds, it is influenced by the characteristics of the basin, the watershed, climate, and
pollution, which can accelerate the rate at which this state is reached (Greeson 1969).
Total phosphorus values for Clark Pond
are 0.028 mg/l (28 ppb) that are not particularly
high, though total concentrations of 0.030mg/l
(30 ppb) or more are sufficient to stimulate algae
blooms or excessive plant growth (Figure 12).
Figure 12. Total phosphorus in parts per
billion (ppb) as related to lake tropic
state.
Potential sources of phosphorous entering into Clark Pond include decaying vegetation,
such as grass clippings and leaves in storm water runoff, soil erosion, household cleaning
products like automatic dishwasher detergents, lawn and garden fertilizers, pet waste and
failed septic systems. Another way that phosphorus can enter Clark Pond is from the
sediment at the bottom of the pond.
Nitrogen, like phosphorus, is an important nutrient for plant and algae growth.
Nitrogen levels in Clark Pond were below the instrument detection limit, though low
nitrogen levels do not limit algae growth as low phosphorus levels do. Blue-green algae
blooms are often associated with low nitrogen to phosphorus (N:P) ratios in lakes and
ponds (MA Water Watch Partnership). In Clark Pond, algae may be using atmospheric
nitrogen gas (N2) dissolved in the pond water as a nitrogen source for growth. However
because these parameters, P and N, can fluctuate over the year, multiple rounds of testing
by a licensed professional should be performed to establish meaningful average values to
be used as baseline data for future monitoring. Note once established in the pond,
removal of nutrients becomes tedious and expensive.
Although contaminants negatively affect the water quality of Clark Pond, the area
functions as a pollution retention pond and may mitigate pollution prior to impacting
coastal water quality. Without Clark Pond, the water quality of the adjacent Plum Island
Sound may be negatively impacted and important shellfish beds in the vicinity of Clark
Beach, known locally as “Richie’s Ground”, may need to be closed. Conducting water
quality analysis using a licensed professional at least once a year may provide sufficient
monitoring for nutrient influx. As well, using a standard Secchi Disk to monitor water
clarity, which can indicate the beginning of an algal bloom, should be done over the
summer months. If conditions indicate an algae bloom, samples can be collected for
algae identification and toxin analysis.
If water quality tests indicate compromised conditions in the pond or an algae
bloom occurs, multiple rounds of testing should be performed to identify the impact of
storm water and groundwater on pond water quality. If storm water is a problem, work
with the Town of Ipswich on storm water management improvements, such as using
stormceptors, and identify sources of funding for storm water management projects. Also
analyzing water samples from within Clark Pond and the outlet stream may determine
residence time of any nutrients. Pollutant levels leaving the pond as measured in the
outlet stream should be lower than the cumulative inputs. Multiple rounds of testing can
document the pond’s effectiveness at mitigating pollution.
4.3 Invasive Species & Habitat Protection
The Clark Pond ecosystem has been impacted by invasive species. While there
are a number of invasive, exotic plant and animal species which are part of the pond’s
ecosystem, three in particular are addressed here: swans, purple loosestrife, and
Phragmites. Although recommendations are provided for the above species, control
mechanisms for other invasive flora and fauna should be determined on an individualistic
basis through consultation with conservation professionals because many
control/repair/restoration efforts can have unplanned and undesirable consequences.
Although mute swans, Cygnus olor, are considered an invasive species, in limited
numbers, they may be beneficial to the pond’s ecology. As the only waterfowl able to
feed over the entire pond due to changes in water depth, swans may be indirectly
contributing to open water conditions by controlling submerged aquatic vegetation
(SAV). In addition, swans feed on the underwater rhizomes of Phragmites along the
water’s edge and may help to control the spread of the Phragmites into the deeper parts
of the pond. Thus, swans may be the primary reason Clark Pond has retained mostly
open water. Without the swans, the pond may develop into a marsh system.
However, one pair of swans is likely sufficient to provide these beneficial
ecosystem services. Allin and Husband (2003) determined that extensive grazing on
SAV by concentrations of mute swans during the summer months resulted in habitat
degradation impacting fish and macro-invertebrate populations
which
has
negative
consequences for waterfowl as the pond provides critical habitat for wintering ducks and
geese. To protect the habitat for other species, mute swans populations should be limited.
If swan pair numbers become greater than three for two or more years, management
activities, such as participating in the Massachusetts Division of Fisheries & Wildlife
swan control program, should be undertaken to limit the reproductive success of mute
swans and habitat degradation of the pond. By participating in the program we will be
reducing the impact of this breeding population on other areas of the State and attracting
other waterfowl, especially migrating waterfowl, to use the pond throughout the year.
As the photo of Clark Pond from the 1950’s illustrates purple loosestrife has been
a problem at Clark Pond for many years (Figure 6). Purple loosestrife prefers freshwater
marshes and/or intermittently shallow water areas. During extended periods of drought
or low water, purple loosestrife may colonize the edges of Clark Pond. However, due to
the relatively high water levels in the past few years, likely related to the beaver
population as well as maintenance of the spillway, purple loosestrife has been kept in
control. To maintain the existing positive influences on the control of purple loosestrife
the water levels in the Clark Pond should be maximized to the extent possible to
discourage the spread of this invasive plant, for example maintenance of the dam to
spillway height or above. In addition, monitoring of purple loosestrife should be done on
a yearly basis. If purple loosestrife becomes invasive, biological control (biocontrol) is
recommended using the leaf-feeding beetle, Galerucella spp., which is a widely used
technology for invasive plant management (Driesche et al., 2002).
Today Phragmites is the most significant invasive plant affecting the Clark Pond
ecosystem. The plant can create dense monocultures, which out compete native plants in
a relatively short period of time. These dense stands are generally unproductive habitat
for wildlife where a more native vegetative community could provide additional benefits
to the ecosystem. Though the extremely dense and tall “wall” of Phragmites, which
surrounded the pond historically, could have provided cover for birds and especially
waterfowl as these species are sensitive to human activity and predators. While the
Phragmites control program may be benefitting the overall ecology of Clark Pond, it may
also be negatively impacting the waterfowl population that uses the pond. Without the
protective cover of Phragmites, waterfowl and their young are susceptible to predators as
well as disturbance from human activity.
Monitoring of Phragmites on a yearly basis should be done to identify any areas
for treatment. If it is determined treatment is necessary, the methods should be used in
the following order: hand cutting, hand swiping of the leaves using an herbicide, spot
treatment with an herbicide. If Phragmites crowds out other native plants and the above
methods are shown to be ineffective, then the use of a mechanical device to spray
herbicide and cut dead stands could be considered. In addition, because removal of one
invasive species can open niches for other invasive plants, and the Phragmites
eradication project undertaken by AGN in 2009 did not address any restoration of the
habitat, native grasses and shrubs, such as bayberry, sumac, and Virginia rose that
encourage the development of shady habitat, should be planted to inhibit the spread of
Phragmites.
However, prior to any management activities at Clark Pond or Clark Beach, AGN
needs to address the Massachusetts Endangered Species Act (MESA) as this area is
mapped as Priority Habitat for two species of terns (Appendix F), the main focus being
foraging habitat. In addition the US Fish and Wildlife Service should be consulted as the
threatened species, piping plover, is listed as likely to occur in the Town of Ipswich. Any
management intervention at Clark Pond needs to demonstrate how the proposed
management activity fits the management exemption provisions in MESA so that a filing
or permit would not be necessary. Though it will require review/approval by the National
Heritage and Endangered Species Program. A request can be made for an extension on
the existing request for determination of applicability (RDA) from the Ipswich
Conservation Commission in order to complete a management plan, and have it reviewed
and approved by the State and Federal governments.
Because the Clark Pond ecosystem is contiguous with Clark Beach as well as the
Great Neck Conservation Area, it plays a vital role as habitat in an otherwise fragmented
landscape. In order to sustain the Clark Pond ecosystem, management should be
consistent with the manner of Clark Beach, to preserve its important functions as a
resource providing recreational opportunities; storm and flood protection for Great Neck
(especially as relative sea level continues to rise); and habitat for plants and wildlife,
which protects the ecosystem while including support for coastal dependent uses and
stakeholder interests. However, the management plan for Clark Beach was written in
2002. To maintain the vitality of our coastline today requires careful planning and the
evaluation of our progress, which is a continuous effort. A contribution on our part is to
update the Clark Beach management plan.
In addition it is our opinion that integrating the updated Clark Beach Management
Plan with the Clark Pond Management Plan thus creating a Clark Pond Conservation
Area resource management plan, would be beneficial to these ecosystems, biodiversity
and the Great Marsh. As these properties share boundaries, management on one property
impacts the other, as no ecosystem is an island. Many coastal and marine species utilize
these areas for food, shelter, and breeding grounds. Not only is wildlife dependent on
Clark Pond but Clark Beach is as well. Environmental changes, such as rising sea level,
will require the open space provided by Clark Pond in order to sustain the beach
ecosystem.
Habitat protection of the riparian zone surrounding Clark Pond is important for
the functioning of this ecosystem. A source of organic matter for ponds is litter fall from
riparian vegetation. In addition, large woody debris provides foraging habitat and
predation refuges for animals and insects. We recommend limiting the landscaping
practices of mowing and weed whacking along the pond side of the beach road and the
outlet stream upstream of the footbridge. The limiting of these landscape practices may
encourage the growth of native plants in these areas as wells as encourage the
introduction of rare/threatened/candidate species, such as the New England Cottontail,
into the Clark Pond ecosystem.
Input water level management is another human activity that can alter the Clark
Pond ecosystem. The water budget for Clark Pond was studied in the 1990’s
(unpublished MS Thesis) and indicated ~40% of the annual freshwater balance of the
pond was derived from storm drains and the remainder from watershed runoff and
groundwater. The storm drain system is a high percentage of the overall water budget
because, in addition to discharging storm water, the system intercepts large amounts of
groundwater due to the perched water table on Great Neck. Perched water tables are
typical on drumlins, such as Great Neck, that have an impermeable clay layer, which
prevents water from percolating through the soil to the water table. On Great Neck,
groundwater does not typically percolate vertically to the water table but rather travels
horizontally along the clay layer where it either intercepts the underground storm water
system, discharges on the hillsides surrounding Clark Pond, and/or discharges within the
Clark Pond.
The four storm drains that discharge into Clark Pond generally flow even during
periods of dry weather and as such are very likely a primary source of fresh water to the
pond especially during the summer months (Figure 11). In addition another source of
water to Clark Pond during dry weather periods may come from septic systems within the
Clark Pond watershed. Without inputs of water to Clark Pond via septic systems, water
levels in Clark Pond may be much lower especially in the summer months and/or during
extended droughts. Any activity on Great Neck that adjusts the present water budget of
Clark Pond, for example municipal sewer, needs to consider the impact of removing a
source, and perhaps a significant source, of Clark Pond’s water sources.
4.4 Restoration Potential
Because Clark Pond was historically a coastal brackish/salt water embayment and
marsh system, it has been considered as a potential site for restoration to its “natural”
state. However, the bottom elevation of the pond is higher than the mean high tide
elevation at Clark Beach, thus it is probably not feasible to restore a significant amount of
salt water to the system to support a natural salt marsh or embayment (Appendix D).
Moreover due to the significant amount of freshwater inputs, a restoration project may
exacerbate the nonnative plant invasions because the restoration may allow the majority
of the freshwater to drain from the system thus encouraging brackish water conditions
favorable to Phragmites and seasonally freshwater wetlands favorable to purple
loosestrife.
At this time we recommend that the current man made freshwater pond system be
preserved. Although this recommendation does not address the almost certain likelihood
that the frequency of inundation by seawater into the pond will increase as storm
frequency and severity increases and sea level rises. Clark Pond is accommodating space
for the inland transfer of sand that may be enabling sediment accretion rates to keep pace
with sea-level rise, a key requirement for the continued functioning of Clark Beach. Thus
let environmental change from rising sea level, coastal evolution, and ecosystem
succession occur naturally rather than prematurely through a restoration project.
CHAPTER 5: Conclusions
As a vital part of the landscape, the Clark Pond ecosystem deserves the time and
resources that we can provide to ensure its lasting vitality. The Clark Pond Sustainability
Plan provides a comprehensive examination of Clark Pond to establish its ecological
health and a framework for guiding the AGN Board of Directors in conservation
decisions. We provide a scientific basis and cultural and social values to justify the need
for monitoring and sustaining the Clark Pond ecosystem. In addition, the public should
play a role in the monitoring and management of Clark Pond because people are an
inseparable part of ecosystems.
The ecological assessment of Clark Pond indicates a relatively stable ecosystem
today with regard to its physical environment, biotic resources, and tropic networks, even
though residential development accounts for the largest proportion of influence on the
watershed. Clark Pond is located on Great Neck in the Town of Ipswich within the Parker
River watershed and unique for a 23-acre pond. It is shallow, averaging ~three feet in
depth, with a sand and silt bottom and minimal submerged vascular vegetation, abundant
algae, and high fish populations. These factors are likely related to the shallowness of the
pond, which can allow water to remain highly oxygenated due to mixing with the
atmosphere that aids in the breakdown of organic matter.
The mute swans may be responsible for the low levels of vascular submerged
plants (their primary food), which helps to keep the pond surface open. Migratory birds
visit the pond both spring and fall some of which choose to stay and nest. Because of its
proximity to Plum Island Sound, seawater and coastal sediments inundate Clark Pond
during high intensity coastal storms, though the ecosystem thus far has been able to
recover from these events. Because the human population on Great Neck continues to
grow which results in increased pressure on the landscape and the single water sample
indicated phosphorous values bordering on eutrophication, more information about the
water quality of Clark Pond is needed.
The stewardship of Clark Pond requires the partnerships among the AGN Board,
the residents of Great Neck, and the Town of Ipswich. The recommendations provided in
this plan include: increasing an awareness of the values of biodiversity and steps to
conserve it; minimizing negative impacts to biodiversity; pollution control (including
excess nutrients) to levels that are not detrimental to ecosystem function and biodiversity;
and invasive species control. By implementing the recommendations in this document we
are protecting the habitat, sustaining the open space and shaping the future of the Great
Marsh. A management approach that includes the community and science-based
processes can build long-term conservation strategies to meet ecosystem sustainability
and human needs.
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Vegetation and Macroinvertebrates in a Rhode Island Coastal Pond. Northeastern
Naturalist 10, 305-318.
Driesche, F., Blossey, B., Hoodle, M., Lyon, S., Reardon, R. (2002). Biological Control
of Invasive Plants in the Eastern United States. United States Department of Agriculture
Forest Service, FHTET-2002-04, 413 p.
Fenneman, N. M. (1938). Physiography of Eastern United States. New York: McGrawHill 714 p.
Greeson, P. (1969). Lake Eutrophication—A Natural Process. Journal of the American
Water Resources Association 5, 16-30.
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