Browsing by Subject "spatial analysis"
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Item Open Access Assessing the Importance of Frontal Zones on the Distribution of Upper Trophic Level Predators off Cape Hatteras(2006) LaBrecque, Erin AEffective conservation of upper trophic level marine predators requires a comprehensive understanding of their distributions and of the underlying biological and physical processes that drive these distributions. We investigated the spatial distributions of marine mammals and seabirds off Cape Hatteras, NC, in relation to positions of the shelf break and Hatteras Front system. We conducted transect surveys with synoptic, fine-scale oceanographic sampling in August 2004, and derived the daily position of the Hatteras Front from temperature, salinity, and pressure data collected by a scanfish. To account for the correlated and autocorrelated nature of the environmental data, we assessed the influence of the Front on species distributions using a suite of Mantel’s tests. Pure partial Mantel’s results show that marine mammal distribution over all survey days was influenced by salinity. Results of the daily Mantel’s tests show that no one variable consistently influenced the distribution of marine mammals. Pure partial Mantel’s results show that seabird distribution over all survey days was influenced by depth, distance from shelf break, fluorescence, and space. The significance of space indicates that another variable or variables with spatial structure influenced the distribution of seabirds but were not tested. Results of the daily Mantel’s tests show that different combinations of environmental variables influenced the distribution of seabirds on different days. However, one variable consistently influenced seabird distribution – fluorescence. These findings enable consideration of spatially explicit approaches to the conservation of marine mammals and seabirds and other upper trophic level predators in this region. Keywords: marine mammal distribution; seabird distribution; spatial analysis; Hatteras FrontItem Open Access Estimating the Lower Temperature Limit of Bottlenose Dolphins Along the North Carolina Coast(2004) Shoemaker, MandyDuring winter, the coastal ecotype of bottlenose dolphins are at the northern limit of their range off the coast of North Carolina. In this study, the distribution of coastal bottlenose dolphins in North Carolina was evaluated in response to variation in sea surface temperature to determine whether the distribution of dolphins was limited directly or indirectly by winter temperature minima. Observations of dolphin distribution were obtained from monthly aerial surveys conducted along the North Carolina coast during February 2000 through July 2001. Sea surface temperatures were obtained for each survey from NOAA’s Pathfinder satellite, using PO.DAAC Ocean ESIP Tool (POET). Where necessary, the sea surface temperature data was interpolated (krigged) over areas of cloud cover. The northern latitudinal and lower temperature distribution was determined for each survey. During winter months bottlenose dolphins were not distributed throughout their known range of 10-32 °C. Dolphins may be limited directly by temperature, due to the limits of their thermal neutral zone, or indirectly by temperature, through distribution of their prey. To determine how temperature is affecting dolphin distribution in the Western North Atlantic, future research should focus on determining the thermal neutral zone of dolphins in this region. In addition, it would be useful to build a model including other dynamic factors that may affect dolphin distribution. Although results suggest that more research is necessary, there is potential for using results from this type of analysis for management.Item Open Access GIS-based Association Between PM10 and Allergic Diseases in Seoul: Implications for Health and Environmental Policy.(Allergy Asthma Immunol Res, 2016-01) Seo, Sungchul; Kim, Dohyeong; Min, Soojin; Paul, Christopher; Yoo, Young; Choung, Ji TaePURPOSE: The role of PM10 in the development of allergic diseases remains controversial among epidemiological studies, partly due to the inability to control for spatial variations in large-scale risk factors. This study aims to investigate spatial correspondence between the level of PM10 and allergic diseases at the sub-district level in Seoul, Korea, in order to evaluate whether the impact of PM10 is observable and spatially varies across the subdistricts. METHODS: PM10 measurements at 25 monitoring stations in the city were interpolated to 424 sub-districts where annual inpatient and outpatient count data for 3 types of allergic diseases (atopic dermatitis, asthma, and allergic rhinitis) were collected. We estimated multiple ordinary least square regression models to examine the association of the PM10 level with each of the allergic diseases, controlling for various sub-district level covariates. Geographically weighted regression (GWR) models were conducted to evaluate how the impact of PM10 varies across the sub-districts. RESULTS: PM10 was found to be a significant predictor of atopic dermatitis patient count (P<0.01), with greater association when spatially interpolated at the sub-district level. No significant effect of PM10 was observed on allergic rhinitis and asthma when socioeconomic factors were controlled for. GWR models revealed spatial variation of PM10 effects on atopic dermatitis across the sub-districts in Seoul. The relationship of PM10 levels to atopic dermatitis patient counts is found to be significant only in the Gangbuk region (P<0.01), along with other covariates including average land value, poverty rate, level of education and apartment rate (P<0.01). CONCLUSIONS: Our findings imply that PM10 effects on allergic diseases might not be consistent throughout Seoul. GIS-based spatial modeling techniques could play a role in evaluating spatial variation of air pollution impacts on allergic diseases at the sub-district level, which could provide valuable guidelines for environmental and public health policymakers.Item Open Access Improving Equity through Passive Recreation in Northeastern North Carolina(2016-04-29) Pericak, AndrewViewing public parks as environmental goods that provide benefits to people, society should strive to equitably distribute parks so that all individuals, regardless of racial or socioeconomic background, can use parks. This project emphasizes passive recreation parks, public parks such as nature preserves or hiking trails that do not require built park infrastructure as would a soccer field or a baseball diamond. These parks provide opportunities for outdoor recreation, but importantly also maintain many ecosystem service benefits which a “built” park would eliminate. Prior research has analyzed the distribution of parks for city residents, inconclusively finding that poor and minority populations may or may not reside physically closer to parks than do wealthy, white populations. Generally, though, the environmental justice literature emphasizes how privileged members of society tend to reside near quality parks, so achieving distributional equity requires creating new parks near less-privileged people. Perhaps surprisingly, few studies have examined the distribution of parks in rural areas; parks are just as important here because rural residents contend with the extensive agricultural environment, one not necessarily conducive to outdoor recreation. A critical need exists to assess the distributional equity of passive recreation parks in low-income, rural, agricultural counties, and to determine whether establishing new parks in those counties would lead to greater equity. To address this need, I examined park access for residents of five rural counties in northeastern North Carolina: Beaufort, Edgecombe, Halifax, Nash, and Rockingham. I first created an objective definition of equity for this study; namely, an equitable situation results when residents of poor, high people-of-color (POC) Census block groups (BGs) have statistically equal drive times to their closest parks as do residents of wealthy, low POC BGs. Notably, this definition does not take into account some important determinants about how people choose what park to visit, such as park size, quality, or amenities. The definition also assumes people own a car and are willing to drive to their closest park, and presumes people actually know the location of their closest park and choose to visit it because of its proximity. Nonetheless, I employed this definition so as to take an objective survey of current park distribution. Using this definition of equity, I then ascertained the “local context” of each BG within all five counties. Using American Community Survey data, I compared a BG’s median income and percent POC population to the average values of those metrics for surrounding BGs; the local neighborhood for comparison derived from the average commute time of the target BG, with the assumption that people would willingly spend about the same amount of time to drive to a park as they would to their workplace. From this process, I categorized each block group as having higher or lower income and higher or lower percent POC in comparison to their local neighbors. I then located public, passive recreation parks within the five counties and within neighboring counties. An algorithm found the closest park in terms of shortest driving time for each BG within the five counties, correlating these drive times to the race and income categories derived from the local context operation. Per this study’s definition of equity, I found certain counties demonstrated inequities in park distribution. Beaufort County actually exhibited similar drive times from all BGs, suggesting parks are equitably distributed in that county. Contrastingly, Halifax County’s poor, high POC BGs had significantly longer drive times to their closest parks than did any other populations. Edgecombe, Nash, and Rockingham Counties showed the opposite result of Halifax; the poor, high POC BGs had significantly shorter drive times to their closest parks than did rich, white areas. Nonetheless, all counties but Beaufort demonstrate inequitable outcomes. Since Halifax County met the environmental justice assumption that environmental goods favor wealthy, white populations, I ran a series of case studies on that county to determine if establishing new parks would make drive times equal among the various BGs. In one model, I pinpointed the BG with the greatest drive time to its closest park, identified government-owned land within that county, chose one parcel to become a hypothetical park, and re-ran the closest park analysis. I repeated this process until there were no significant differences among the race and income categories; this required establishing 11 new parks. In another model, I replicated this process but only established new parks in the poor, high POC BGs; here, I only needed six new parks until an equitable outcome resulted. This study shows that rural counties tend to have inequities in park distribution, but that in some cases low-income, POC populations do have better access to parks than do wealthier, whiter populations. Careful planning about where to site new parks can eventually lead to distributional equity, at least in Halifax County, but the county’s limited resources may prevent it from establishing multiple new parks in a short time period. This study does not consider important variables that actually determine what parks people want to visit, or where local residents would want a new park. Future studies can combine the objective information generated from this study with community discussions and demands to decide where best to locate new parks. Future research can also use the local context operation to investigate different definitions of distributional equity—for example, is it equitable that residents of one must drive on average only 15 minutes to their closest park if it takes 30 minutes in another county? In sum, the distributional equity of passive recreation parks suffers for rural, agricultural counties, meaning that certain privileged individuals within those counties receive an unjust share of the parks’ environmental and health benefits. This finding holds especially true for residents living the farthest away from these counties’ towns and cities. By using the local context to identify specific areas within counties most in need of parks, however, this study shows that careful planning can lead to greater distributional equity.Item Open Access Potomac Watershed Priority Lands Strategy: Conserving lands to benefit drinking water quality(2009-04-24T17:09:17Z) Weidner, EmilyRapid development in the Potomac watershed – the conversion of forests to agricultural, suburban, and urban land — threatens water quality. Similarly, strategic land conservation can protect water quality. Inspired by examples of water purification through land conservation, the EPA Region 3 and the Potomac River Basin Source Water Protection Partnership (PRBSWPP) aim to prioritize areas of the Potomac watershed for conservation. To work toward this goal, I analyzed two questions: (1) How do land areas in the Potomac Watershed support stream water quality?; and (2) In a larger context, how should land conservation be prioritized to protect water quality? To assess the relationship between land use and water quality, I created a regression model to correlate land characteristics including land use composition, land use pattern, and hydrological connectivity, with water quality. The final regression shows that buffer capacity (i.e. the average percentage of downstream forest area) has the largest impact on water quality, followed by urban saturation (i.e. average percentage of downstream urban area), and two estimates of soil loss and erodibility. I mapped the output of this regression analysis. To identify priority lands for conservation, I developed a multi-object decision analysis (MODA) tool. I used the weighted averaging approach to combine a land parcel’s water quality protection value, water intake protection value, and ecological value, along with its vulnerability to future development. This resulted in a map showing areas of higher and lower conservation priority, which can be used to allocate funds for conservation, update local zoning to designate strategically located natural areas, assist developers in minimizing their environmental impact, and strengthen coalitions in developing a common understanding of the multiple benefits of land conservation.Item Open Access Spatial Ecology of the North Atlantic Right Whale (Eubalaena Glacialis)(2008-04-24) Good, CarolineDespite decades of protection, the endangered North Atlantic right whale (Eubalaena glacialis) has failed to recover, primarily due to interactions with fishing gear and ship strikes. Right whales range along the U.S. east coast, foraging year round in the Gulf of Maine while a subset of the population travels to the South Atlantic Bight each year to calve. The habitat requirements of the right whale are poorly understood. I investigated the relationship between the distribution of right whales and physical oceanographic conditions in an effort to create predictive models of essential right whale habitats. Additionally, the distribution of right and humpback whales (Megaptera novaeangliae) relative to fixed fishing gear was examined to assess spatio-temporal overlap. Habitat preferences were assessed using aerial survey data of whale locations and a range of topological and satellite derived physical parameters including bathymetry, sediment type, sea surface temperature, thermal gradients and surface roughness. A suite of non-parametric quantitative techniques including Mantel tests, log likelihood functions, Generalized Additive Models, Spearman Rank Correlations and the Williamson's spatial overlap index were used to assess relationships between whales and habitat variables. Our findings indicate that suitable calving habitat along the east coast may extend much farther to the north than is currently recognized. Our model correctly identified several well documented current and historic calving grounds in the eastern Atlantic but failed to fully identify a heavily used calving area off Argentina, which is characterized by lower surface water temperatures than the other calving regions. In the Gulf of Maine, right whale distribution was correlated primarily with sea surface temperature, sediment type and bathymetry. Predictive models offered insights into right whale habitat preferences for foraging but failed to wholly capture the physical factors underlying right whale distribution. I found the relative density of right and humpback whales and fixed fishing gear in the Gulf of Maine to be negatively correlated in most seasons and areas. These findings demonstrate that the regular co-occurrence of high densities of whales and gear is not a prerequisite for entanglement. Prohibiting entangling lines in areas where whales are known to forage could substantively reduce entanglement.Item Open Access The Impact of Socioeconomic Factors, Coverage and Access to Health on Heart Ischemic Disease Mortality in a Brazilian Southern State: A Geospatial Analysis.(Global heart, 2021-01-20) de Carvalho Dutra, Amanda; Silva, Lincoln Luís; Pedroso, Raíssa Bocchi; Tchuisseu, Yolande Pokam; da Silva, Mariana Teixeira; Bergamini, Marcela; Scheidt, João Felipe Hermann Costa; Iora, Pedro Henrique; do Lago Franco, Rogério; Staton, Catherine Ann; Vissoci, João Ricardo Nickenig; Nihei, Oscar Kenji; de Andrade, LucianoBackground
No other disease has killed more than ischemic heart disease (IHD) for the past few years globally. Despite the advances in cardiology, the response time for starting treatment still leads patients to death because of the lack of healthcare coverage and access to referral centers.Objectives
To analyze the spatial disparities related to IHD mortality in the Parana state, Brazil.Methods
An ecological study using secondary data from Brazilian Health Informatics Department between 2013-2017 was performed to verify the IHD mortality. An spatial analysis was performed using the Global Moran and Local Indicators of Spatial Association (LISA) to verify the spatial dependency of IHD mortality. Lastly, multivariate spatial regression models were also developed using Ordinary Least Squares and Geographically Weighted Regression (GWR) to identify socioeconomic indicators (aging, income, and illiteracy rates), exam coverage (catheterization, angioplasty, and revascularization rates), and access to health (access index to cardiologists and chemical reperfusion centers) significantly correlated with IHD mortality. The chosen model was based on p < 0.05, highest adjusted R2 and lowest Akaike Information Criterion.Results
A total of 22,920 individuals died from IHD between 2013-2017. The spatial analysis confirmed a positive spatial autocorrelation global between IDH mortality rates (Moran's I: 0.633, p < 0.01). The LISA analysis identified six high-high pattern clusters composed by 66 municipalities (16.5%). GWR presented the best model (Adjusted R2: 0.72) showing that accessibility to cardiologists and chemical reperfusion centers, and revascularization and angioplasty rates differentially affect the IHD mortality rates geographically. Aging and illiteracy rate presented positive correlation with IHD mortality rate, while income ratio presented negative correlation (p < 0.05).Conclusion
Regions of vulnerability were unveiled by the spatial analysis where sociodemographic, exam coverage and accessibility to health variables impacted differently the IHD mortality rates in Paraná state, Brazil.Highlights
The increase in ischemic heart disease mortality rates is related to geographical disparities.The IHD mortality is differentially associated to socioeconomic factors, exam coverage, and access to health.Higher accessibility to chemical reperfusion centers did not necessarily improve patient outcomes in some regions of the state.Clusters of high mortality rate are placed in regions with low amount of cardiologists, income and schooling.