* Note that these projects were initiated long before the start of ENVS 1965 in January 2011. Most are senior honors theses. The goal of the capstone seminar in environmental change is for students to explore various means of communicating the significance and key results of their environmental scholarship to diverse audiences, including policymakers, journalists, and community partners.
In this study, we measured decomposition of the salt marsh cordgrass Spartina alterniflora along the latitudinal gradient of the U.S. East coast. Using latitude as a proxy for warming allows us to predict how decomposition rates may change with warming. Measuring the rate of belowground decomposition of S. alterniflora rhizomes is important for predicting whether or not salt marshes will be able to keep up with sea level rise (SLR), because accumulation of belowground biomass is the primary contributor to salt marsh elevation gain. The two main hypotheses for this study are (a) S. alterniflora belowground biomass decomposition rate will vary predictably along a latitudinal gradient, increasing toward the South and (b) locally derived root material will decompose at a different rate than introduced Northern root material, due to the specialization of local microbes. Belowground decomposition rates of S. alterniflora were measured at eight sites along the Atlantic coast between May and October 2010 using the litterbag technique (i.e. Benner et al 1991, Bertness 1985, Hackney and de la Cruz 1980). Samples were processed in the lab in October 2010 and average local and Northern source decomposition rates (grams/day) were calculated for each site. Because higher temperatures lead to higher rates of decomposition, there will be a decreased ability of all marshes to keep up with SLR induced by climate change as decomposition happens faster in the warming northern marshes. Understanding the ways in which decomposition varies will help to inform future comparisons across marshes and will help inform conservation and management decisions.
Since the Industrial Revolution, Rhode Island’s Narragansett Bay has experienced a rapid increase in nitrogen inputs from wastewater treatment facilities, farm runoff, and fossil fuel combustion. In the past decade, evidence for anthropogenic eutrophication has mounted, including dissolved oxygen surveys that proved summer hypoxia to be severe. In order to understand how excess nutrients have impacted the Narragansett Bay ecosystem in the past 150 years, I measured stable isotopes δ15N and δ13C and the total concentration of N and C in seven sediment cores along the Bay’s modern productivity gradient. The main questions I ask are, how has the increase in nitrogen inputs and organic matter impacted primary productivity in the bay? and, how have the resulting changes in nitrogen cycling impacted primary productivity? In addition, I discuss the current systems for managing Narragansett Bay’s eutrophication, the efficacy of these programs, and perspectives on NB nutrient management from Rhode Island scientists, environmental advocates, and policy-makers.
Since the January 2010 earthquake that reduced many of Haiti’s cities and towns to rubble, an international movement of governmental and aid organizations has called to attention the need for sustainable and structurally sound reconstruction efforts throughout the country. This project, developed for the benefit of the organization GOALS Haiti, is leading the design and construction process of a sustainable community center in the city of Leogane. In addition to providing a structure out of which GOALS may run its operations, a significant objective of the project is to engage the local community of Leogane in the development and building of the community center, and to promote the construction of environmental structures by other individuals and organizations in the area. Evaluating site conditions such as solar gain and storm water management, and encouraging the development and application of local building codes will connect the project to the larger reconstruction effort throughout the country. By establishing a local contingent of construction experts and workers skilled in the processes of low-impact, environmental design, the project aims to stimulate a dependable construction industry that is self-sustaining.
The intertidal barnacles (Jehlius cirratus and Notochthamalus scabrosus) co-occur across much of the Pacific coast of South America. Jehlius generally occurs higher in the barnacle zone than Notochthamalus but, with significant overlap of their tide heights, the species disobey conventional ecological thought about rocky intertidal species distributions. Previous studies of the interaction have neither directly addressed the role of physical stress nor come to conclusive results about the nature of the relationship (ie direct competition, ameliorative effects etc). Carried out on the central coast of Chile, my project tracked the growth and survivorship of the two barnacle species at two tide heights in shaded and unshaded plots. These data in conjunction with temperature and weather data collected throughout the 6 month study are used to consider the effect of physical stress, using temperature as a proxy, on the relationship. The ultimate goal of this study is to better understand the complex ways in which climate change will effect species interactions, particularly those that do not follow conventional ecological models, and thereby better inform future researchers and decision makers.
Susanna (Suzy) Mage
Nutrient limitation occurs when meaningful additions of an essential element in biologically available forms cause an increase in the rate of a biological process (such as primary productivity) and/or in the size of an important ecosystem compartment (such as biomass). In many ecosystems, phosphorus is the limiting nutrient. This is the case for the mountainous tropical rainforest of eastern Puerto Rico. Phosphorus inputs to ecosystems come from either the weathering of bedrock or dust deposition. Of the mechanisms that drive phosphorus limitation, low-phosphorus parent material often causes ultimate limitation because it controls the ecosystem mass balance of phosphorus. In this particular rainforest, there are two main types of underlying bedrock: volcaniclastic and granodiorite. In order to determine the soil nutrient availability of phosphorus in this ecosystem, I have collected over 400 soil samples. I collected soil samples within two different forest types, Tabonuco and Colorado, both of which are found on the two rock types. Since phosphorus is a rock-derived nutrient, and there are two different bedrock types, I am looking forward to finding out if the nutrient availability of the overlying soil is different depending on the parent material of the bedrock. If this is the case, with all else held constant, one can infer viable information on soil fertility from just knowing the parent material of the underlying bedrock.
Bárbara M. Santisteban
Sustained declines in marine fish harvest and the difficulty of managing a common pool resource have prompted a shift toward privatization strategies and ecosystem-based management for marine fisheries. Stewardship and attitudes toward nuisance species may have a significant impact on how stakeholders interact with marine stocks and consequently on the effectiveness of marine policy. In southern New England, many fishermen strongly support increasing quotas for spiny dogfish, which they perceive to be a ‘nuisance’. Therefore, recent government efforts to rebuild the spiny dogfish stock have heightened already existing mistrust between fishermen and scientists. This conflict raises interesting questions about how fishermen and managers perceive marine species, ecosystems and approaches to fisheries management. For example, how does stewardship of non-economically important marine resources vary under different management regimes? In what ways, if any, do fishermen, managers, and scientists understand the ecology of spiny dogfish differently and does this lead to different preferences for management? My goal is to map differences in knowledge between stakeholder groups and to assess attitudes toward spiny dogfish in order to see how knowledge and beliefs about a contested species such as the dogfish affect preferences for management. This information can contribute to a more resilient basis for management by allowing incorporation of multiple types of knowledge and stakeholder perspectives. My study includes four different approaches: a participatory mapping exercise; a survey of different user groups; and triangulation with data from vessel trip reports and observer data collected from the RI fluke sector. Findings are analyzed in the context of major southern New England fisheries to suggest new directions for the management of spiny dogfish and other nuisance species in which more impacts of regulations are considered.
Modern climate change is expected to be a major driver of species extinctions. Changing climatic conditions will cause the current habitats of many species to become unsuitable for survival, and species that cannot adapt to novel conditions or shift their distributions to new locations will be unable to survive. To prevent such climate-based species extinctions and the resultant ecosystem degradation, scientists have proposed a conservation strategy known as managed relocation, which involves the human-mediated movement of vulnerable species to more suitable habitat. A primary concern surrounding this controversial strategy is that managed relocation is unlikely to be successful based on the low success rates of past conservation-motivated species translocations. However, there are also many examples of successful species introductions in which species persist and even flourish in the recipient habitat. Given these conflicting examples, the determinants of a successful species relocation must be resolved before managed relocation can be considered a viable conservation strategy. This project evaluates the likelihood of success or failure of mammalian relocation programs based on past mammalian species translocations and identifies parameters that can predict the outcome of a given relocation. These findings will directly inform conservation decisions by allowing wildlife managers to predict whether or not a managed relocation program is likely to succeed for a given species, and to determine how to conduct the relocation to ensure the greatest chance of success.
Scientific research has demonstrated the toxicity of several classes of common flame retardants. As these flame retardants are slowly phased out, new chemicals are being developed to take their place. However, current United States chemicals policy allows many new chemicals to be implemented before thorough toxicity testing is conducted. The rapid development of novel chemicals, combined with lax regulation, leads to a risk for human exposure to toxic substances. This project will address the dual questions of scientifically assessing the toxicity of a novel compound, and understanding its regulation. The compound of interest is a component of Firemaster 550, a recently developed flame retardant that is already in use but has little data on possible health effects. The laboratory component of the project will use a rat model to assess developmental reproductive toxicity, due to the compound’s high structural similarity to a well-known male reproductive toxicant. The policy portion of the project will investigate flame retardant and general chemical regulation in Rhode Island. Through discussions with personnel at the Rhode Island Department of Health, preparation of a policy report and model legislation for the Rhode Island legislature, and publication of the data gathered in the laboratory portion of the project, an attempt will be made to increase awareness in the policy arena of potential health effects of novel, untested chemicals, and propose ideas for policy reform.
Eric Van Arsdale
Scientific communication has become an increasingly important component of effective environmental management and conservation. My research has focused on scientific communication surrounding salt marsh die-off on Cape Cod, and recent issues involving ecosystem health in the Gulf of Maine region. On Cape Cod, I developed an outreach program in order to determine the number of individuals aware of salt marsh die-off, and how die-off information can be best communicated to the Cape community. In the Gulf of Maine, my research is examining how decision-makers in the region view ecosystem health, and what types of communication can be used to address either misconceptions or knowledge gaps. Using these two studies and the broader communication debate, I aim to help conservation scientists better communicate research to society and other scientific circles. Better communication is not the panacea for all conservation dilemmas, but communication is undoubtedly an important part of developing more effective management strategies. Follow these links for an executive summary of my Cape Cod work, along with the full scientific report.
Since its approval in 1980, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), more commonly known as the Superfund Act, has been an important legal force in the effort to clean up the estimated 400,00 sites contaminated by toxic waste in the US (Berg and Raven, 2006). Several recent studies have used census data to investigate the relationship between population demographics and the presence of environmental health hazards, finding that certain demographic groups are more likely than others to move away from Superfund sites. Additionally, a recent study by Bennear et al. (2010) provides evidence that the form in which information about environmental health hazards is presented is important in determining the actions people take to protect themselves. Using census data and site evaluation reports from the EPA, my study will explore the related question of whether migration patterns of people living within census tracts containing Superfund sites differ depending on the types of contaminants found on-site, the environmental media contaminated, the way in which information about the site is communicated to the local community, and the education levels of the surrounding population. With human health at stake, it is important to further our understanding of how surrounding communities are affected by Superfund sites. I hope to help illuminate how scientists and policymakers can best communicate environmental health risks to the public to minimize exposure to hazards.
Narragansett Bay has been affected by nitrogen-rich wastewater discharge and land area runoff for many decades and the problem continues today. Excess nitrogen can cause eutrophication in shallow waters with resounding impacts on local fish populations, water quality, and overall bay health. Furthermore, as the effects of climate change are realized in New England and in Rhode Island specifically, the need for a more complete, region-specific, and mechanistic understanding of how coastal ecosystems function will be vital to making the best policy decisions to balance use and preservation of ocean resources. My research uses a novel mesocosm system to investigate the synergisms of multiple stressors like phytoplankton blooms and climate change on a simple coastal ecosystem, the rocky intertidal zone, to address a lack of understanding of cumulative impacts of environmental stressors.