Date of Award

5-31-2018

Document Type

Campus Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biology/Environmental Biology

First Advisor

Alan D. Christian

Second Advisor

Solange Brault

Third Advisor

Robert Chen

Abstract

Land use land cover (LULC) change is one of the top 5 drivers of global climate change. The River Continuum Concept was the first to relate variation in land cover along a natural stream gradient to the behaviors of the biota in least impacted, lotic ecosystems. Changes to these systems have been shown to influence water quality. The Boston Harbor has undergone changes in LULC over many centuries. Restoration efforts have improved its water quality and productivity; however, it is important to further understand and further reduce loadings in the harbor and warrants a comprehensive study of LULC influences on water quality in the Harbor’s watersheds. The Neponset River Watershed (NRW) is a 337 km2 urban watershed, services a population of about 300,000, and has 5 major land uses: forested, industrial, residential, wetlands, and golf courses. The goal of this research was to better understand the effects of these LULCs on the physical, chemical, and biological parameters of the NRW and use this information in a path analysis model to help determine management strategies to reduce LULC impacts. I hypothesized that LULCs altered from its natural state would be different than area left unaltered as shown through physical/chemical parameters, macroinvertebrates, and microbes, due to differential non-point sourced loadings. Physical/chemical analyses revealed that concentrations varied across treatments, and lower concentrations of indicator parameters were not specific to forested treatment stations and temporal variation was shown across all stations. Macroinvertebrate and habitat analyses showed habitat quality to have little impact on macroinvertebrate communities as some LULC treatments with better habitat quality had macroinvertebrate communities’ indicative of poor water quality. Microbial community structure was found to be not only a product of LULC, but also local conditions. Path analysis showed that local conditions such as percent impervious cover and percent development at the buffer scale were better predictors of physical habitat, water chemistry, and biological communities in the NRW. This study provides insight on the nature and vulnerability of urban watersheds making these systems ideal for showing the impacts of best management practices, further improving water quality in the watershed and Boston Harbor.

Comments

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