Date of Award
Campus Access Dissertation
Doctor of Philosophy (PhD)
Environmental Sciences/Environmental, Earth & Ocean Sciences
Alan D. Christian
Robyn E. Hannigan
Jose E. Martinez-Reyes
Ecosystems are continuously impacted by global change drivers. The Millennium Ecosystem Assessment defines drivers as “any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. Anthropogenic drivers influence ecosystems indirectly from demographic, economic, sociopolitical, cultural, religious, scientific, and technological pressures. Direct anthropogenic drivers include climate, plant nutrient use, land conversion, disease and invasive species. Natural drivers include climate variability, extreme weather events, or volcanic eruptions. This dissertation comprises three research objectives, which combine to inform a context for the Étang Saumâtre (ES), Haiti, lake and watershed. The context enables an understanding of the influence of global change drivers on this tropical system over the 30-year period 1984 to2014. There are far fewer tropical lakes than temperate lakes and information on tropical waters is diffuse and fragmentary.
As there is a paucity of data on Haiti, it was necessary to create and collect data to carry out this work. Landsat imagery provides a continuous set of satellite images at uniform spatial resolution and integrity to enable development of base layers. ArcGIS is the platform used for data creation, storage, and analysis. The first research objective correctly delineates the geographic spatial extent of the ES watershed, which defines the areal extent of the research. The second research objective develops a context for the temporal evolution of the lake and watershed. Base layers enable production of lake morphology, analysis and quantification of lake-level rise, and analysis of vegetation change. Base layers also support analysis of 25 soil samples collected at 13 sites across the south facing shore of the lake. Primary Constituent Analysis correlates soil elements and, organic and inorganic material with site location. The third research objective assesses and characterizes ES water column limnology and lake production by 1) conducting physical, chemical, and biological water analysis; 2) using the above analyses to characterize and assess the lake productivity. This research creates data and establishes a foundation for determining the influence of global drivers on the ES system, providing a basis for future research efforts in the region.
Hotz, Helenmary M., "Influence of Global Change Drivers on a Tropical Lake and Watershed, Étang Saumâtre, Haiti" (2019). Graduate Doctoral Dissertations. 525.
Available for download on Wednesday, June 23, 2021