Date of Award

8-2020

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Biology/Environmental Biology

First Advisor

Alan D. Christian

Second Advisor

Jarrett E.K. Byrnes

Third Advisor

Michael P. Shiaris

Abstract

Streams are dynamic systems shaped by geographic location, hydrology, riparian vegetation, and in-stream habitat. Furthermore, ecosystem disturbance plays a major role in structuring stream communities and ecosystem processes. Disturbances include natural occurrences, such as flooding, drought, and fire events and anthropogenic disturbances such as land use changes, damming, and pollution. Agricultural use acts as a press disturbance regime, homogenizing the surrounding landscape and simplifying in-stream habitat, leaving legacy effects after farming ceases. Active restoration is intended to ameliorate these effects by reintroducing variation, with the goal of shifting the ecosystem into a more diverse and natural state. The act of restoration therefore acts as a pulse disturbance, attempting to shift the community from one system state to another through habitat and process alteration. Active restoration of an in-fallow (since 2010) flow-through cranberry bog in Southeastern Massachusetts occurred in late 2015, allowing the ability to set up a Before-After-Control-Impact (BACI) design to investigate the effects of restoration’s disturbance phase. Structural, compositional, and functional attributes of macroinvertebrate and habitat/ecosystem biodiversity were evaluated over a 3-year study at the restored site, with an active flow-through cranberry bog and a least-impacted stream acting as regional controls of high and low disturbance respectively. As expected, we saw compositional shifts in the macroinvertebrate assemblage and several measures of ecosystem function related to the perturbation of disturbance, but limited evidence of long- term shift away from initial conditions following restoration.

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