Nutrient and sediment removal by a restored wetland receiving agricultural runoff

Few studies have measured removal of pollutants by restored wetlands that receive highly variable inflows. We used automated flow-proportional sampling to monitor the removal of nutrients and suspended solids by a 1.3-ha restored wetland receiving unregulated inflows from a 14-ha agricultural watershed in Maryland, USA. Water entered the wetland mainly in brief pulses of runoff, which sometimes exceeded the 2500-m3 water holding capacity of the wetland. Half of the total water inflow occurred in only 24 days scattered throughout the two-year study. Measured annual water gains were within 5% of balancing water losses. Annual removal of nutrients differed greatly between the two years of the study. The most removal occurred in the first year, which included a three-month period of decreasing water level in the wetland. In that year, the wetland removed 59% of the total P, 38% of the total N, and 41% of the total organic C it received. However, in the second year, which lacked a drying period, there was no significant (p > 0.05) net removal of total N or P, although 30% of the total organic C input was removed. For the entire two-year period, the wetland removed 25% of the ammonium, 52% of the nitrate, and 34% of the organic C it received, but there was no significant net removal of total suspended solids (TSS) or other forms of N and P. Although the variability of inflow may have decreased the capacity of the wetland to remove materials, the wetland still reduced nonpoint-source pollution.     

Food selection in larval fruit flies: dynamics and effects on larval development

Selecting food items and attaining a nutritionally balanced diet is an important challenge for all animals including humans. We aimed to establish fruit fly larvae (Drosophila melanogaster) as a simple yet powerful model system for examining the mechanisms of specific hunger and diet selection. In two lab experiments with artificial diets, we found that larvae deprived of either sucrose or protein later selectively fed on a diet providing the missing nutrient. When allowed to freely move between two adjacent food patches, larvae surprisingly preferred to settle on one patch containing yeast and ignored the patch providing sucrose. Moreover, when allowed to move freely between three patches, which provided either yeast only, sucrose only or a balanced mixture of yeast and sucrose, the majority of larvae settled on the yeast-plus-sucrose patch and about one third chose to feed on the yeast only food. While protein (yeast) is essential for development, we also quantified larval success on diets with or without sucrose and show that larvae develop faster on diets containing sucrose. Our data suggest that fruit fly larvae can quickly assess major nutrients in food and seek a diet providing a missing nutrient. The larvae, however, probably prefer to quickly dig into a single food substrate for enhanced protection over achieving an optimal diet.     

Sustainable development as a framework for developing country participation in international climate change policies

The paper presents a number of ideas on how climate change policy implementation in developing countries can be supported by alternative international cooperation mechanisms that are based on stakeholder interests and policy priorities including broader economic and social development issues. It includes a brief review of current development policies, technological research and promotion efforts, and climate change that demonstrates that mutual policy initiatives undertaken by governments and the private sector actually have major positive impacts on climate change without being initiated by this global policy concern. Furthermore a number of examples are given on how future development objectives in Brazil, China, and India jointly can support economic and social goals and global climate change concerns if these goals are taken into consideration and supported by international cooperative mechanisms. The paper proposes international cooperative mechanisms that can support the implementation of integrated development and climate change policies. The mechanisms include an international sustainable development (SD) and Climate Finance Mechanism (SDCFM), technology development and transition programmes, technology standards, and other measures.

Quantifying the climatic suitability for tourism in Namibia using the Tourism Climate Index (TCI)

Environment, Development and Sustainability - Tourism Climate Indices (TCIs) are the most widely used method to quantify climate suitability for tourism, yet remain more extensively applied in the...