Bird species (BS) of the Nakdong River estuary (NRE) were selected to suggest conservation and management strategies, taking habitats and major threats into consideration. Five BS (Cygnus spp., Calidris alpina, Sterna albifrons, Fulica atra, and Anser fabalis) were selected following analysis of their dominance, national importance, seasonality, taxonomic group, and distribution within the NRE. The BS comprise two winter birds, one summer, one passage bird, and one resident bird. They can also be classified into four taxonomic groups: two under ducks and geese (Anatidae), and one each under gulls (Laridae), shorebirds (Scolopacidae), and diving birds (Rallidae). The results show that BS could be a useful tool in guiding estuary management because their habitats are clearly distinct, and include important areas of the NRE. A reduction of feeding and resting places—such as tidal flats, Scirpus planiculmis habitat, and agricultural farmland—and climate change are major threats to BS, therefore countermeasures to such threats should be considered in future estuary management plans.

Access to clean and affordable water is one of the fundamental human rights because water is essential to life and a foundation for socioeconomic development of any country in the world. Despite the efforts to secure water supply in Burundi, the amount of water supplied by public utilities does not meet the demand of the population because population keeps increasing with fluctuation of weather conditions. This study selected north Bujumbura that is a sprawling new residential area in the western part of Burundi as a case to investigate the potential of rainwater harvesting in meeting water demand of the country. Based on a long-term average monthly precipitation in the region, the rainwater harvesting potential was assessed as a function of roof sizes, number of households, and runoff coefficients of roof materials. For the entire region of north Bujumbura, the current water supply capacity of the local water company combined with the rainwater harvesting potential resulted in the water surplus of 468,604.1 m3/yr. Although three communes among them still showed water deficit in dry season, they still got help from rainwater to relieve their water shortage. This suggests that at the regional scale, proper storages and water quality control for harvestable rainwater could contribute to relieving the regional water shortage and allow the population growth.

To understand the initial changes in the microbial activities of wetland soil after construction, dehydrogenase activity (DHA) and denitrification potential (DNP) of soil from 1 natural wetland and 2 newly constructed wetlands were monitored. Soil samples were collected from the Daepyung marsh as a natural wetland, a treatment wetland in the West Nakdong River, and an experimental wetland in the Pukyong National University, Busan. The results showed that the DHA of the natural wetland soil was 6.1 times higher than that of the experimental wetland and similar to that of the treatment wetland 6 months after wetland construction (fall). Few differences were observed in the DNP between the soil samples from the natural wetland and 2 constructed wetlands four months after wetland construction (summer). However, 6 months after the construction (fall), the DNP of the soil samples from the natural wetland was 12.9 times and 1.8 times higher than that of the experimental wetland and the treatment wetland, respectively. These results suggested that the presence of organic matter as a carbon source in the wetland soil affects the DHA of wetland soil. Seasonal variation of wetland environment, acclimation time under anaerobic or anoxic wetland conditions, and the presence of carbon source also affect the DNP of the wetland soil. The results imply that the newly constructed wetland requires some period of time for having the better contaminant removal performance through biogeochemical processes. Therefore, those microbial activities and related indicators could be considered for wetland management such as operation and performance monitoring of wetlands.

Aquatic and riparian vegetation of river ecosystems are very important both in ecological and management perspectives. Vegetation surveys were conducted to understand the characteristics of riparian vegetation in the mid and lower reaches of the Nakdong River, Korea. A total of 68 families and 260 species were identified at eleven survey sites. The numbers of taxa were similar to those reported in a previous survey in 1996,but the percentage of naturalized plants increased more than two times compared to that in the previous survey. Survey sites near Yangsan Bridge and Nambu Park in Yangsan showed the highest percentage of naturalized plant species. Urbanization indices of the survey sites were high at 18.8% on average. Therophytes were the most dominant plant life form at the survey sites with 39.2% of total plants identified, followed by phanerophytes (19.2%), hemicryptophytes (18.9%), aquatic plants (13.9%), cryptophytes (5.8%), and chamaephytes (3.1%). The relative composition of hemicryptophytes decreased whereas those of therophytes and chamaephytes increased compared to those in the survey in 1996. This may be due to increase in dryness of riparian soils or degradation of riparian areas. Plant compositions at sites near Jeokpo Bridge and Hwoicheon suggest that the composition and distribution of riparian vegetation are affected by land use pattern surrounding riparian areas or human accessibility to the areas.