The Ecology of Rhode Island’s Islands: Focus on Block Island
October 28, 2000
University of Rhode Island, Kingston, RI

Roger Williams Park Zoo: Research and Conservation Efforts in Rhode Island

Kemba Alexander, Suzanne Azar, Lou Perrotti, Ming Lee Prospero, and ZooPower Teens
Roger Williams Park Zoo, Providence, RI 02907

The Conservation and Research Department (CRD), under the direction of Lisa Dabek, at the Roger Williams Park Zoo (RWPZ) is committed to being a major player in the field of conservation biology. We actively participate in conservation research and education locally and internationally. The CRD assists in several local research projects, including the American Burying Beetle (ABB) Captive Breeding Program and the ZooPower Stewardship Program. Since 1994, RWPZ has collaborated with the United States Fish and Wildlife Service on the recovery effort of the ABB, playing a major role in the captive breeding and reintroduction of this endangered species. The ZooPower Stewardship Program involves teenagers from local schools. In recent years, these students have measured and evaluated the water quality of the Pawtuxet River Watershed with the assistance of the Pawtuxet River Authority. They have also learned Geographic Information Systems (GIS) techniques that were used to map and assess environmentally hazardous vacant lots in Providence, RI.

Eelgrass Monitoring Program

Glenn T. Almquist and Karen M. Hanecak
Environmental Science Services, Inc., 272 W. Exchange Street, Providence, Rhode Island 02903.
Email: galmquist@essgroup.com, khanecak@essgroup.com

Environmental Science Services, Inc. (ESS) was contracted to perform monitoring of eelgrass (Zostera marina) in the vicinity of a residential dock location in the East Passage of Narragansett Bay, Jamestown, Rhode Island. The dock extends seaward over the eelgrass bed for a length of 65 feet. An eelgrass monitoring program was designed by ESS in consultation with the Army Corps Of Engineers and the National Marine Fisheries Service to document potential impacts to the eelgrass bed from the dock structure and associated boating activities. The study examined eelgrass cover, shoot density, canopy height, epiphytes, and wasting disease for pre and post construction dock activities. Three monitoring events will be conducted during the boating season over the next 3 years, these will occur in the months of May, June, and September. Three transects have been established to document conditions near the landward edge of eelgrass, under and adjacent to the lower elevation access dock, the waterward side of the dock, and control areas beyond the area directly impacted by the dock and boating activities. Each of these transects will have nine quadrat stations to examine the eelgrass under the dock and at set distances on either side of the dock.

To date pre-construction monitoring has been completed as well as 2 post-construction monitoring events. Data from the first post-construction monitoring have been tabulated, construction activities appear to have had no significant impact on the health of the eelgrass bed. The second post-construction monitoring even was conducted in September, results from this event will be incorporated into a final assessment report.

Quaternary Geology and Landscape Development of Block Island and Adjacent Regions

Jon C. Boothroyd
Department of Geosciences and State Geologist, University of Rhode Island, Kingston, RI 02881, jon_boothroyd@uri.edu

Les Sirkin
Earth Science, Adelphi University, Garden City, NY 11530

Two known ice advances across Block Island are inferred from glacial stratigraphy. The first, Illinoian in age, probably occurred before 120,000 BP. The maximum advance of the second, Late Wisconsinan age (22,000 BP), ice is marked by low ridges and patches of boulder gravel south of Block Island. Laurentide ice then retreated to Block Island and paused long enough to form two recessional moraines correlative with moraines on Long Island. Ice in Block Island Sound then retreated to the Charlestown end moraine recessional position and a glacial lake formed in Block Island Sound. The Charlestown morainal position is correlative with Long Island moraines to the west and with the Buzzards Bay moraine on the east.

Block Island stratigraphy is comprised of two sediment bodies (“drift sheets”), an upper body overlying a lower. The sediment bodies, also distinguished by color and composition, contain a highly disturbed mix of diamict (till), stratified sand and gravel, and rhythmic silt and clay deposited in a number of environments.

The Odonata (Dragonflies and Damselflies) of Block Island

Virginia A. Carpenter
The Nature Conservancy, 159 Waterman St., Providence, RI 02906

The Odonata fauna of Block Island has been studied recently as part of the Rhode Island Odonata Atlas project, which was initiated in 1998. Thirty-one (31) of the stateês 130 species were documented on the island during the first three years of the project. The Block Island fauna is small but rich in abundance. The majority of species are of southern origin and all are species of ponds and stagnant waters. Because there are no rivers and streams or boreal wetlands on Block Island, 50 odonate species that require these habitats are absent. However, the island contains a high number and concentration of ponds. Thus, the species that occur there tend to occur in large numbers because the habitat is abundant and packed into a small land area. Block Island is witness to regular seasonal migrations of the larger wide-ranging dragonflies such as common green darners (Anax junius) and gliders of the genus Pantala. During a spring 1996 migration of giant swamp darners (Epiaeschna heros) along the northeast coast, the collection (by hand) of a weakened, exhausted individual on Block Island verified that some of these wanderers made an unusual long-distance flight over water to the island.

Freshwater Ecosystems of Block Island

Mark Chandler
New England Aquarium, Central Wharf, Boston, Massachusetts 02110; mwc@neaq.org

The freshwater ecosystem of Block Island consists of over 300 ponds, intermittent streams and moderate groundwater flow. Over the past 4 years, a study of 42 ponds has been undertaken to better characterize the fish, macroinvertebrates and aquatic plant communities present on the Island. A principal objective of the study has been to categorize pond types based on the biota, as well as the basic physical and chemical characteristics of their environment. The ponds of Block Island are generally small, shallow and endowed with significant amounts of aquatic plant growth. Based on the subset of ponds studied, Block Island ponds can be diffentiated based on proximity to ocean, presence of fish, macroinvertebrate community, pH, and water conductivity, among other factors. The relationship among these factors will be explored during the presentation.

Ecology of Morainal Grasslands on Block Island, Rhode Island

Jeffrey Collins
Field Naturalist Program, University of Vermont, Burlington, Vermont 05405
Current address: Center for Biological Conservation, Massachusetts Audubon Society, 208 South Great Road, Lincoln, Massachusetts 01773
jcollins@massaudubon.org.

Morainal grasslands are a globally rare biotic community identified in New England only on Block Island. Although these small communities (<2 acres) are host to the state species of special concern bushy rockrose (Helianthemum dumosum), and Northern blazing star (Liatris scariosa var. novae-angliae), little is known about what controls their distribution and extent on an island dominated by maritime shrubland. Analysis of soil samples collected from within the grasslands and from adjacent communities revealed no significant difference in texture. Investigation of land use and botanical inventory of 16 sites suggest they are primary successional communities recovering from intense grazing by sheep. Encroachment of shrubs and trees may be hindered by xeric conditions in the absence of an organic soil horizon, a condition which the shrubs themselves are altering as they deposit litter in the sites. Management recommendations include removal of woody species pioneering within the grasslands, monitoring populations of listed plants, and maintenance of shrubland/grassland border.

Postglacial Vegetation History of Block Island

Richard W. Enser
Rhode Island Natural Heritage Program, Rhode Island Department of Environmental Management, 235 Promenade Street, Providence, Rhode Island 02908
renser@dem.state.ri.us

Assessment of Block Island’s vegetational past is problematic. Botanical histories compiled for neighboring mainland and island locales may not be indicative of what transpired on Block Island because it was isolated soon after deglaciation. This early formation of aquatic barriers prevented some species from reaching Block Island. Another complication in determining the composition of natural communities was the complete alteration of habitats initiated by American indians and intensified with European colonization, a conversion so thorough that by 1875 none of the residents could recall when native trees grew on the island. The principal evidence for reconstructing Block Islandês botanical past is pollen analysis of sediment cores. These studies provide a rough approximation, but are complicated by several factors including the difficulty of identifying plants to species. Limited anecdotal evidence may also be gleaned from Livermoreês History of Block Island. An inventory of the Island’s flora was not conducted until 1897 when less than 300 species were cataloged. Today, Block Island’s uplands are chiefly vegetated in shrublands. Other natural communities include several estuarine and palustrine wetland types, and small patches of morainal grassland. Burgeoning populations of several invasive exotic plants are threatening the integrity of Block Island’s natural communities.

Bluff Erosion Rate on Block Island 1982-1999

Janet Freedman
Coastal Geologist, RI Coastal Resources Management Council, Stedman Government Center, Wakefield, RI 02879

The spectacular bluffs on the northeast and south shores of Block Island have been eroding episodically since their formation in the last ice age. Erosion is the result of a combination of geological processes that are dependent on the severity of coastal storms and wave action at the base of the bluff; composition, slope and degree of saturation of the sediment comprising the bluff; and even freeze/thaw cycles that cause small fissures to expand and eventually lead to slope failure. Because the bluff retreat rate varies from year to year, a long term average erosion rate is essential for determining the impact of erosion on coastal development. This study compares the bluff edge on geo-referenced vertical aerial photographs from 1972 and 1999. The edge of the bluff was interpreted on 1:12000 scale photo series using a four power stereoscope. The bluff edge was then delineated on the scanned, geo-referenced aerial photographs. Bluff edge overlays were used to calculate the bluff erosion rates along segments of the Block Island shoreline over the past 27 years. These rates were projected for the next 30 years to estimate risks to existing property and develop best management practices for future coastal development.

Researching and Restoring Block Island’s Pre-Settlement Natural Landscape

Bruce Hammond
The Nature Conservancy, Wakeman Center, RFD 319-XVineyard Haven, Massachusetts 02568;
bhammond@tnc.org

The pre-settlement vegetation cover of Block Island was researched by reviewing historical records, evaluating pollen coring data, surveying the flora and landscape history of nearby islands and mainland areas, and analyzing wood fragments buried in peat deposits. The evidence strongly suggests that Block Island supported an oak-dominated forest, although this forest appears to have been early-successional by the time of European settlement due to Native American clearing. The settlers used the forests for fuel, timber, and shelter for the first sixty years, but by 1721 the town declared a wood shortage. By 1885, farms occupied over 70% of the island, and centuries of intensive agricultural and peat mining had virtually eliminated trees from the landscape. With the decline of agriculture, abandoned fields were invaded by maritime shrubs, whose seeds were dispersed by the island’s dense populations of nesting and migratory birds; the absence of forest refugia and the intensity of agricultural use meant that neither tree seeds nor sprouts were present to recolonize the landscape. Restoring sections of the original forests would add to the island’s landscape diversity and demonstrate alternatives to exotic tree species. A forest restoration plan for Clayhead was developed which recommends planting native hardwoods under dying stands of exotic conifers.

Tick Fauna Diveresity on Prudence Island, Rhode Island

Kerwin E. Hyland, Jenifer Bernier, Daniel Markowski, Andrew MacLachlan, Zuhair Amr, Jay Pitochelli, James Myers, and Renjie Hu
Department of Biological Sciences, 100 Flagg Road, University of Rhode Island, Kingston, RI 02881

Early studies of the tick fauna from the islands of Narragansett Bay were very sparse and only a few records existed. In the 1950′s, a concerted effort to evaluate the ectoparasite fauna of Rhode Island mammals was begun and three new tick species were noted on Prudence Island (Dermacentor variabilis, Ixodes muris, and I. scapularis). With the emergence of Lyme disease, tick-related studies became more common and these ticks were collected from a variety of hosts. In addition, D. albopictus was collected on deer. For the next several decades, the tick fauna of Prudence Island was dominated by these tick species. In the early 1980′s, we first recorded what was to become a dramatic surge in the Amblyomma americanum population on the island. Beginning in 1984, birds were reported as hosts for a number of tick species on the island. Of 27 species of birds collected, 21 species were found to harbor preadult ticks. Ixodes scapularis, I. muris, I. dentatus, I. cookei, D. variabilis, and Haemaphysalis leporispalustris were taken in numbers ranging up to 69 larval I. scapularis on a single Carolina wren. Interestingly, no A. americanum have been taken from birds or small mammals. Deer appear to be the principle host for this species. Never-the-less, the lone star tick has assumed a major role on the island becoming, perhaps, the most abundant tick species.

Plant Conservation on Block Island: Status and Causes of Rarity of Liatris Borealis (Asteraceae)

Ailene Kane
Brown University Box 3021, Providence, RI 02912

Johanna Schmitt
Department of Ecology and Evolutionary Biology and Center for Environmental Studies, Brown University, Providence, RI 02912

About 350 of New England’s 2000 indigenous plant species are at risk of extinction (www.newfs.org, 10/3/00), due largely to anthropogenic activities. One of those species is Northern Blazing Star (Liatris scariosa var. novae angliae, or Liatris borealis, Asteraceae), a rare plant, endemic to the northeastern United States and endangered (rank = S1) in Rhode Island. L. borealis is an early successional species that inhabits Block Island’s morainal grasslands. To develop a conservation plan for the New England Plant Conservation Program (NEPCoP), the species biology and demography of L. borealis are being studied on Block Island. Baseline demographic data are being collected to determine the most sensitive life history stages of Liatris borealis. The impact of herbivory and the effects of patch size, patch density, and proximity to main population on reproductive success are also being studied. Deer grazing appears to be severely limiting reproduction of L. borealis on Block Island.

Designing a Protocol for Monitoring the Great Salt Pond and its Watershed, Block Island, Rhode Island

Leslie Maxon Katz
254 Hope St. #7, Providence, RI 02906 (Brown University Masterês Thesis, May 2000)

This study develops the foundation for a comprehensive data-gathering programãa monitoring protocolÝÝfor Block Island, Rhode Island’s Great Salt Pond and its watershed. Because humans influence all aspects of the Great Salt Pondês natural system, attempting to separate those processes which are “natural” from those which are responses to human influence is nearly impossible. There are four major processes that threaten to alter the present state of the natural system: loss of land and marine habitat; introduction of nonnative species; overfishing; erosion and sedimentation. In addition, I identify twelve variables that have the potential to affect human health and welfare in the Great Salt Pond and its watershed. Human influence is increasing: tourism has grown by 138 percent since 1978; car visitation has increased by 575 percent; 80 percent of all housing units built since 1960 are for seasonal use. Human influences that pose the highest risk to the watershed are household septic effluent, marine overboard sewage discharge, and underground storage tanks. I present twenty-five potential indicators, and rank these as highest priority: monitoring water clarity, tracking island summer populations, inspecting septic tanks, mapping habitat change, and establishing compliance with the Federal No Discharge Area. Implementation tactics are discussed.

Associations between Tick-Borne Infection on Block Island, Rhode Island

Peter J. Krause and Jaber Aslanzadeh
Departments of Pediatrics and Clinical Microbiology, University of Connecticut School of Medicine, Farmington, Connecticut 06030

Richard J. Pollack and Andrew Spielman
Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts 02115

In order to determine whether residents of an enzootic site who are exposed to one tick transmitted pathogen are likely to be exposed to other such pathogens, we surveyed the sera of a cohort of residents of Block Island, RI in 1997 and 1998. The sera of 166 of 756 participants reacted with the agents of human babesiosis, Lyme disease and human granulocytic ehrlichiosis. Of the seroreactive subjects, 29% reacted against the Lyme disease agent, 48% against the babesial agent and 5% against the agent of human granulocytic ehrlichiosis. Multiple infection was frequent. The sera of 13% of the subjects reacted against the agents of Lyme disease and human babesiosis, 2% against the agents of babesiosis and ehrlichiosis, 1% against the agents of Lyme disease and ehrlichiosis, and 1% against all three agents. We conclude that exposure to one tick transmitted pathogen implies exposure to other tick transmitted pathogens.

Protozoa in Block Island’s Freshwater Ponds

Gaytha A. Langlois
Science & Technology Department, Bryant College, 1150 Douglas Pike, Smithfield, RI; Telephone: 401-232-6145
langlois@bryant.edu

This paper will describe the protozoan fauna of ten freshwater ponds on Block Island, reflecting seasonal and locational differences. Emphasis will be placed on microbial food chains, and comparisons will be made with the microfauna found in similar ponds on Penikese Island, Prudence Island, and mainland Rhode Island. The underlying hypothesis, that microbial food chains found in island ponds will be different from those existing in similar mainland habitats, will also be discussed. Samples were collected in shallow sediments, examined by phase contrast microscopy, and photographically recorded. Future research will focus on determining the effects of changing land use patterns on the microfauna of island ponds in Rhode Island.

Community-Based Conservation on Block Island, Current Status and Future Trends

Christoper N. Littlefield and Scott B. Comings
The Nature Conservancy, Block Island Program, Box 1287 Block Island, Rhode Island 02807
clittlefield@tnc.org, scomings@tnc.org.

Block Island supports one of the most unique ecosystems in southern New England, as well as a dynamic human community which varies between 800 year-round residents in midwinter to over 15,000 inhabitants during the summer. Escalating land values and increasing popularity of the island as a summer destination have resulted in both intense pressure to develop open land and negative impacts from human disturbance to some of the island’s most sensitive ecological communities. With the support of virtually all segments of Block Island’s people, The Nature Conservancy works to preserve the islandês natural systems, in partnership with local and off-island NGOês, the USFWS, foundations, and individual supporters. Their science-based effort is focused in two main areas; habitat conservation and education. In spite of considerable challenges, the Conservancy remains optimistic that it can continue to make progress toward the long-term goal of preserving the islandês natural heritage.

Protecting Block Island’s Fragile Water Supply Through Cutting Edge Wastewater Management

James Lucht, Lorraine Joubert, George Loomis, David Dow, Dr. Arthur Gold
University of Rhode Island Cooperative Extension Water Quality Program, URI Woodward Hall, Kingston, RI 02881

Block Island’s fragile groundwater supply received federal designation as a Sole Source Aquifer (SSA) in 1984. Although water quality is good at present, ongoing development and outdated existing septic systems pose a serious threat. No feasible supply alternatives are available. The Town has a sewage treatment facility, but the Comprehensive Plan states that capacity expansions should be used to support a compact town center rather than extending service area. Treated septic effluent from on-site systems is also necessary to recharge the aquifer. In response to this issue, the Town adopted a Wastewater Management Ordinance in 1996. It quickly became apparent that additional detailed performance standards were needed. The URI Cooperative Extension Water Quality Program responded with technical assistance in developing Zoning Section 506: a cutting-edge technology-based treatment level system that proscribes appropriate wastewater technology for different natural conditions such as marginal soils or location in a resource protection area. Alternative wastewater technologies range from simple enhancements for conventional systems to advanced treatment systems for reducing nutrients and pathogens. The Town is currently in the process of adopting Zoning Section 506 with assistance from URI through the EPA National Community Decentralized Wastewater Treatment Demonstration Project. This poster is intended to help citizens understand how the management scheme effects them.

Status of our Knowledge of Macrolepidoptera on Block Island

Mark Mello
Lloyd Center for Environmental Studies, 430 Potomska Road, PO Box 87037, South Darmouth MA 02748

Recent surveys (Enser, Ellis, Comings, Mello) have documented 271 species of macrolepidoptera on Block Island. This is roughly half the number of species that likely inhabit the island, as spring and fall inventory work has been sparse as has been coverage of wetlands, dune and forested habitats. These inventories have documented several uncommon or declining species including Sphinx drupiferarum (Sphingidae); Schizura apicalis (Notodontidae); and Phalanostola hanhami, Catocala meskei, Oncocnemis riparia and Abagrotis nefascia (Noctuidae). These species are all associated with the early successional habitats that form the vegetative cover on much of Block Island.

No Place to Land? Stopover Ecology of Migrant Landbirds

Frank Moore
Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, Mississippi 39406
frank.moore@usm.edu

Migration is an energetically expensive, high-risk adventure. While en route, migrants must forage in unfamiliar habitats to replenish depleted energy stores, resolve conflicting demands of predator avoidance and food acquisition, compete with other migrants and resident birds for limiting resources, respond to unpredictable and sometimes unfavorable weather, and correct for orientation errors. How well these birds meet the energetic demands of migration and respond to the contingencies that arise en route depends on their ability to locate suitable habitat. Yet, favorable habitat, where a migrant can safely and rapidly accumulate energy stores, is probably limited, or effectively so because a migrant may not have the opportunity to select the best stopover habitat. This problem is exaggerated for those migrants that must negotiate large water crossings by the rapid development of the coastal zone. Hence, coastal islands may provide stopover habitat when most needed.

Marine Mammals and Sea Turtles of Block Island, Rhode Island

Robert Nawojchik
Department of Research and Veterinary Services, Mystic Aquarium 55 Coogan Boulevard, Mystic, Connecticut 06355
rnawojchik@mysticaquarium.org

The presence of marine mammals and sea turtles in southern New England has been well-documented. However, few reports relate specifically to Block Island. Our current knowledge of Block Island species stems primarily from stranding records, anecdotal reports, and occasional sightings from local biologists. Mystic Aquarium has responded to marine mammal and sea turtle strandings in Connecticut and Rhode Island since 1975. Since 1979, 28 pinnipeds, representing four species, have been accessioned into the Aquariumês stranding records from Block Island. Cetacean stranding records on Block Island date from 1983, representing 19 cases and six species. There have been 20 sea turtle strandings on Block Island, dating from 1987, all of which were leatherback turtles. Despite the paucity of systematic survey data, insights into the natural history of marine mammals and sea turtles in the waters around Block Island were still gleaned from the opportunistic data sets presented here.

Monitoring Migration on Prudence Island, Rhode Island, Fall 1999

Jason Osenkowski
University of Rhode Island, Kingston, RI 02881

Baseline information is lacking on avian distribution and use of Prudence Island. We monitored migration, via mist netting, on Prudence Island from 19 August to 28 October 1999. We operated three primary banding stations located at the northern (Coggeshall Cove), central (Nag Pond), and southern (Power Line) ends of the island. The Nag Pond banding station was by far the most productive. Landscape position and the life form of vegetation influenced the capture rates at this location. This station is surrounded by salt marsh habitat to the east and west with only a narrow shrub corridor along the road dividing these salt marshes. Migrating birds were attracted to this corridor for food and cover. This caused a ‘funnel effect’ and allowed us to capture a high percentage of the birds traveling through this corridor. During this study we determined the spatial distribution and abundance of migrants using Prudence Island as a fall stopover point. We also discovered that capture rates were high in comparison to other banding stations located in North America (314.46 birds per 100 net-hours at Nag Pond). In conclusion, Prudence Island is a valuable stopover point in Rhode Island and an excellent place to monitor fall migration.

Geology of Peat and Peat Resources on Block Island, Rhode Island

Colen R Peters
Duke Engineering & Services, Inc. 500 Washington Avenue, Portland, Maine 04101
crpeter1@dukeengineering.com

Jon C Boothroyd
Department of Geosciences and State Geologist, University of Rhode Island, Kingston, Rhode Island, 02881
jon_boothroyd@uri.edu

In response to OPEC oil embargos of the 1970s, US Department of Energy/RI Energy Office funding for alternative energy sources was obtained to determine fuel-grade peat resources of freshwater wetlands on Block Island. All wetlands on the island were mapped with 14 wetlands, ranging from 0.4 to 7.9 hectares, selected for coring, BTU analyses and computation of peat resources. Variations in successional pathways, including deforestation and historic peat harvesting cause modern wetland types on the island to be unreliable indicators of underlying peat stratigraphy. Peat in the 14 wetlands reaches maximum depths of 12 meters, which in descending typical sequence consisted of wood, moss or reed-sedge peat over basal sedimentary peat that accumulated in post-glacial open-water wetlands. BTU value has a significant inverse relationship to ash content and decreases with depth. Fuel-grade peat (>8,000 BTU/lb, <25% ash) resources range from 680 to 23,320 metric tonnes in the 14 wetlands and total 116,090 metric tonnes. This resource could supply 8 years of fuel to a one-megawatt power plant or 64 years of supplemental heat to 100 homes.

Small Island, Big Birds: Avian Biomass and the Persistence of the American Burying Beetle

Christopher Raithel
Principal Wildlife Biologist
Rhode Island Division of Fish and Wildlife, PO Box 218 West Kingston, RI 02982
401-789-0281

Burying beetles, of which there are 15 species in North America, are large orange and black species whose life histories depend on vertebrate carcasses. They bury carrion to feed the developing larvae and are unusual in exhibiting parental care of their young. In 1989, the U.S. Fish and Wildlife Service listed the American burying beetle as endangered because it had disappeared from most of its former range and was known to occur only in Oklahoma and on Block Island, R. I. Though it was not well studied prior to its demise, Andrea Kozol subsequently determined carrion preferences and certain demographic parameters of the species on Block Island. Kozol established that the species is not very fecund; broods of young typically range between 10-20 individuals. In addition, brood size was positively related to reproductive carcass weight, with a size range of 100-200 g optimizing reproductive output. It was reasonable to assume that the burying beetle persisted on Block Island because reproductive resources were stable there relative to the rest of its historical range. The peak reproductive season of the American burying beetle is in June and coincides with the peak of the nesting bird season. I therefore examined point count and Breeding Bird Survey data to compare the nesting avifauna of Block Island to that of the mainland. When I quantified nesting birds into “large” and “small” categories according to adult body weight (100 gram cut-off), I found that Block Island supported many more large birds than the adjacent mainland. The Ring-necked Pheasant contributed most of this “large” biomass. Besides its relative abundance, demographic parameters of the pheasant suggest that it is the primary carcass producer for the American burying beetle on Block Island.

Landbird Community Composition During Spring and Fall Migration on Block Island, Rhode Island

Steven E. Reinert
11 Talcott Street, Barrington, Rhode Island 02806
sreinert@lifespan.org

Kim Gaffet and Elise Lapham
Block Island Banding Station, P. O. Box 640, Block Island, Rhode Island 02807

Landbird migrants were trapped in mist nets during spring (15,016 captured) and fall (52,757 captured; >90% hatch-year birds) in shrub/scrub habitats of the north end of Block Island, Rhode Island from 1970 through 1994. During the 25-year study period 109 species were captured during the spring migration period (1 April-31 May) and 113 during fall (15 Aug-15Nov); 103 species were captured at least once in both seasons. Warblers, Mimics, and Emberizids, were the three most abundant taxa, respectively, in both seasons (Warblers 51% spring, 47% fall; Mimics 17% spring, 13% fall; Emberizids 13% spring, 10% fall). Thirty-four percent of spring captures were of species that typically winter in the neotropics, vs. 19% of fall captures. Thirty-eight percent of spring captures and 21% of fall captures were of Block Island breeding species which exceeded an average of 0.3 pairs per station at 104 point-count stations censused in June of 1990. The large between-season difference in the percentage of breeding species captured is due principally to the large number of non-breeding hatch-year migrants, principally the Yellow-rumped Warbler (Dendroica coronata; 11% of spring migrants, 35% of fall migrants) captured each fall.

Ecological Geography of Block Island

Laura Rosenzweig
Le Colombier, 1195 Bursinel, Switzerland
laurar@iprolink.ch

Roland Duhaime , Aimee Mandeville, Pete August
Department of Natural Resources Science, University of Rhode Island, Kingston, Rhode Island 02881
roland@edc.uri.edu; aimee@edc.uri.edu, pete@edc.uri.edu

Nine miles south of the Rhode Island mainland lies a 10 square mile piece of land known as Block Island. Considered by The Nature Conservancy to be one of the last great places in the entire US, Block Island contains a surprising variety of ecosystems and several rare and endangered species. Although it appears to be sparsely populated with under 1000 year-round residents, Block Island is an enormously popular summer tourist destination. The pressures brought by tourism and, increasingly, second home development are threatening to undermine the unique ecological qualities and community values which are critical to the protection of endangered species found nowhere else in Rhode Island. This chapter provides a general overview of Block Island. We describe the island’s physical and ecological geography, development history and economy, and introduce long-standing efforts being made to conserve the special nature of this place.

Beetles of Rhode Island: Rare Species

Derek Sikes
Department of Ecology and Evolutionary Biology, University of Connecticut, U-43, Storrs Connecticut 06269
dsikes@neca.com

With over 2,000 species of beetles occurring within Rhode Island, comparable to the species richness of Rhode Island’s flora, it is not too surprising that exciting discoveries are fairly common. Approximately 40% of the beetle species collected in Rhode Island during the last five years are new state records. Block Island, in particular, appears to harbor a significant number of unique elements of the Rhode Island beetle fauna. In addition to the federally listed American Burying Beetle (Nicrophorus americanus (Olivier)) the island is also home to the only population of the Clay Banks Tiger Beetle (Cicindela limbalis Klug) in southern New England and recently it has been discovered that a large and colorful hister beetle, Spilodiscus arcuatus (Say), which hasn’t been collected in over 50 years, occurs on Block Island. This presentation highlights these unique elements and attempts to address hypotheses which may approach an explanation for these observations. Among these hypotheses is the possibility that the beetle fauna of Block Island today shares more similarities with the mainland fauna of a century ago than does the mainland fauna of today.

Restoration of a Tidal Pond and Marsh Complex on Prudence Island

James Turek
NOAA Restoration Center, Narragansett, R

Kenneth Raposa
Narragansett Bay National Estuarine Research Reserve, Prudence Island, RI

Daniel Barnett
NRCS, West Wareham, MA

Joseph Bachand, Betsy Clarke
NRCS, Warwick, RI

Gregory Mannesto
USFWS, Charlestown, RI

A joint federal, state, and municipal agency effort is underway to restore a 3.5-acre tidal pond (Potters Pond) and contiguous salt marsh, located proximate to Potters Cove off Prudence Island, that are severely restricted from Narragansett Bay tidal flushing. Potters Pond is part of the Narragansett Bay National Estuarine Research Reserve (NBNERR), a site protected for ecological research and monitoring. A stone and gravel causeway presently hydrologically isolates Potters Pond from Potters Cove. Two culverts are present within the causeway, only one of which passes minimal flows to and from the pond. Minimal tidal exchange occurs with the normal pond tidal prism limited to less than two inches, as compared to the normal tide range of 3.5 feet for nearby Narragansett Bay. Field investigations revealed significant ecological effects resulting from poor tidal flushing including seasonal anoxia, dense mats of filamentous algae throughout the pond, and altered fish and macro-invertebrate assemblages. The salt marsh community bordering the pond has also been altered (e.g., plant species cover, composition and diversity; plant height; Phragmites invasion) by this severe tidal restriction. Installation of a properly sized and set culvert while still allowing use of the causeway will ensure restoration of the pond and wetland tidal hydrology, as well as allow increased fish access. Potters Cove is an important feeding, spawning and nursery area for various estuarine fish species based on surveys completed by the Rhode Island Department of Environmental Management, and restoration of Potters Pond may provide similar fish habitat functions.

Additionally, a culvert under the main island road at the upper end of Potters Pond is non-functional, thereby preventing any tidal exchange to up-gradient wetlands. This 0.5-acre marsh, previously dominated by Spartina alterniflora as recently as five years ago, is now a monotypic stand of Phragmites australis. Replacement of this culvert is expected to restore tidal flushing to this upper marsh, thereby greatly reducing Phragmites cover and re-establishing conditions favorable to a Spartina-dominated marsh community.

Pre-restoration monitoring has been completed by NBNERR staff, and will be compared with post-restoration monitoring data to document ecological changes within the pond complex. Monitoring parameters include tide range and marsh surface flooding frequency; water temperature, salinity, dissolved oxygen, and pH; sediment grain size and organic content; marsh vegetation cover, dominant plant height, and submerged aquatic vegetation cover; and fish and macro-invertebrate abundance and richness, Fundulus feeding patterns, and avifauna use. A nearby wetland (Coggeshall Marsh) is also being monitored as a reference marsh for this restoration project. Project implementation, with assistance from the Town of Portsmouth, Department of Public Works (DPW), is expected to be completed in Spring 2001. This project, with technical assistance and/or funding provided by the National Oceanic and Atmospheric Administrationês (NOAA) Restoration Center, NBNERR, Natural Resources Conservation Service (NRCS), and U.S. Fish and Wildlife Service (USFWS), will result in the restoration of approximately six acres of tidal pond and marsh complex.

Geologic Controls on the Ground-Water Resources of Block Island, Rhode Island

Anne Veeger
Department of Geosciences, University of Rhode Island, Kingston, RI 02881
veeger@uri.edu

The complex and often choatic stratigraphy of Block Island, an erosional remnant of the Late Wisconsinan terminal moraine, is exposed in detail along the island sea cliffs. The sediments include stratified meltwater deposits, till, sediment-flow deposits and glacially transported blocks of Cretaceous strata and pre-Late Wisconsinan glacial deposits. The relatively high permeability of the surficial deposits permits infiltration of precipitation with little surface run-off. Layers of low hydraulic-conductivity material, however, impede vertical flow of ground water permitting the formation of a thick lens of fresh water. Two chemically distinct ground-water types are recognized on the island: 1)high silica, high bicarbonate and high dissolved iron, and 2) low silica, low bicarbonate and low dissolved iron. High-silica ground water is found almost exclusively in the eastern portion of the island and is associated with the presence of blocks of Cretaceous coastal plain sediments that were incorporated into the Pleistocene glacial deposits.

Quantifying Body Condition of Songbirds at a Stopover Site During Autumn Migration

Megan L. Whitman, Dr. Scott R. McWilliams
Department of Natural Resources Science, University of Rhode Island, Kingston, R.I. 02881

Birds fuel migration primarily by storing fat before departure, although nonfat body components also may be stored in concert with fat. These fat and nonfat stores are used during flight and then replenished during layovers at stopover sites. We quantified dynamics of fat and nonfat components in songbirds during their stopover on Block Island, Rhode Island, using two nondestructive techniques, dilution of isotope-labeled water and total body electrical conductivity (TOBEC), for simultaneously estimating fat and lean mass in four species of migrant songbirds (Yellow-rumped Warbler, n = 21; Black-throated Blue Warbler, n = 21; Red-eyed Vireo, n = 18; and White-throated Sparrow, n = 19). TOBEC yielded estimates of lean mass within 3-7% of actual lean mass measured by chemical extraction. Estimates of fat mass in migratory songbirds using dilution of hydrogen isotope-labeled water have estimated fat mass with precision of 10-15% (Karasov and Pinshow 1998). We present similar results for the four passerine species in our study. Simultaneous use of these two nondestructive methods for measuring dynamics of body composition in small passerine birds should prove useful in evaluating quality of habitat at stopover sites.

Diet Preferences for Certain Fatty Acids and its Effect on Composition of Fat Reserves in Red-Eyed Vireos Captured on Block Island During their Fall Migration

Barbara J. Wilson, Scott R. McWilliams
Department of Natural Resource Sciences, University of Rhode Island, Kingston, RI 02881

Most birds accumulate large lipid stores as the primary source of energy for fueling their migratory flights. Typically 16-carbon and 18-carbon fatty acids comprise 50-90% of these lipid stores. We studied fatty acid preferences and the influence of diet on the composition of fat reserves in migratory red-eyed vireos using semi-synthetic diets that differed only in fatty acid composition. Using paired food-preference tests, we found that daily food intake of red-eyed vireos was higher on diets containing triolein (18:1) than tristearin (18:0), higher on diets containing tripalmitin (16:0) than tristearin (18:0), and higher on diets containing trimyristin (14:0) than tripalmitin (16:0) and higher on diets containing trilinolein (18:2) than triolein (18:1). These results suggest that red-eyed vireos prefer diets with mostly longer-chain and more unsaturated fatty acids. We also maintained vireos for one month on diets with different dietary fatty acids. The proportion of 16- and 18- carbon fatty acids in the depot fat of vireos was similar to that of their diets. However, the presence of very long-chain unsaturated fatty acids in the depot fat of vireos, despite its absence in the diets, suggests that selective metabolism of fatty acids is also important in determining the fatty acid composition of depot fat in migratory birds.