Browsing by Author "Walter, Matthew"
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Item Application of field methods and remotely sensed satellite and aerial imagery in analyzing relationships between human activities and wetland health in the State of Delaware(University of Delaware, 2020) Walter, MatthewWetlands can be among the most productive ecosystems in the world, providing habitat, aiding in storm water management, and improving water quality. Even though their value is well known, there has still been a large-scale impact on wetlands through human activities such as agriculture and urbanization. Understanding how and where wetlands are being impacted by human activities may help in directing resources and policy to those wetlands. The State of Delaware in the United States is covered by 25% wetlands, making it very difficult to individually assess all wetlands. ☐ In this thesis, I use several methods based on field work, remote sensing, and geographic data to assess how and where humans are impacting wetlands in Delaware. In Chapter 3 I assess plant and soil characteristics in estuarine wetlands in urban, agricultural and natural settings to determine if surrounding land covers have an effect on wetland ecosystems. Next in Chapter 4, I develop a new stress indicator called “Rapidly Assessed Wetlands Stress Index” (RAWSI) by combining several natural and anthropogenic stressors of wetlands in Delaware to quickly assess wetlands using remotely sensed data. I compared two machine-learning algorithms, support vector machine (SVM) and random forest (RF), to quantify wetland stress by classifying satellite images from Landsat 8 and Sentinel-1 Synthetic Aperture Radar (SAR). Finally, in Chapter 5 with the use of high-resolution imagery from the National Agricultural Imagery Program (NAIP), the invasive plant species, Phragmites australis is mapped on the State-wide level in Delaware. ☐ Results from this work indicate that remote sensing data may be useful for assessing wetland health on a statewide level. Additionally, NAIP data can successfully be used to map Phragmites australis in wetland areas on a statewide level.Item Social media analysis reveals environmental injustices in Philadelphia urban parks(Scientific Reports, 2023-08-03) Walter, Matthew; Bagozzi, Benjamin E.; Ajibade, Idowu; Mondal, PinkiThe United Nations Sustainable Development Goal (SDG) target 11.7 calls for access to safe and inclusive green spaces for all communities. Yet, historical residential segregation in the USA has resulted in poor quality urban parks near neighborhoods with primarily disadvantaged socioeconomic status groups, and an extensive park system that addresses the needs of primarily White middle-class residents. Here we center the voices of historically marginalized urban residents by using Natural Language Processing and Geographic Information Science to analyze a large dataset (n = 143,913) of Google Map reviews from 2011 to 2022 across 285 parks in the City of Philadelphia, USA. We find that parks in neighborhoods with a high number of residents from historically disadvantaged demographic groups are likely to receive lower scores on Google Maps. Physical characteristics of these parks based on aerial and satellite images and ancillary data corroborate the public perception of park quality. Topic modeling of park reviews reveal that the diverse environmental justice needs of historically marginalized communities must be met to reduce the uneven park quality—a goal in line with achieving SDG 11 by 2030.