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Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv and Cons Biol) / Freshwater ecosystems are valuable to all components of biodiversity communities. Globally, these ecosystems are threatened by human activity and as a consequence, many vertebrates, including waterbirds, have become threatened. Wetlands are one of the most productive ecosystem types in the world. Yet, despite this, many protected area networks around the world fail to include this ecosystem type in their protected area networks. On a national scale, in South Africa, wetland loss and deteriorating wetland habitat quality continues to restrict and reduce the range of wetland waterbirds. For this thesis, Maximum Entropy (MaxEnt) species distribution modelling was used to identify additional areas of possible waterbird occurrence. The MaxEnt results noted that waterbirds rely on a combination of these environmental variables for their distribution ecology in their wetland habitat, with vegetation and humidity variables having the highest predictive powers. These would be considered important predictor variables for the distribution ecology of these waterbirds.

Damming disrupts natural sediment flow to downstream resulting in legacy sediment accumulation. Legacy sediments have been well investigated in streams throughout the Piedmont region; however, there is no research of legacy sediments following dam removal in low-gradient Coastal Plain streams. Research objectives were to: characterize legacy sediments in a low-gradient stream restoration, quantify pre-impoundment accretion and carbon dynamics, and assess current sediment deposition rates via 14C analyses within sediment cores and sediment collection tiles. Carbon accumulation and accretion rates of modern tidal sediment have reached that of the tidal relic benchmark and current sediment deposition rates are similar between the natural reference and restored tidal wetlands. At this site, the pattern of legacy sediment accumulation and stream incision was reversed relative to previous studies in higher gradient systems. Results suggest in dam impacted Coastal Plain streams, legacy sediment may become a benefit rather than a liability for downstream tidal wetlands.