Design standards within constructed wetlands for the reduction of mosquito populations in Clark County, Nevada

Wetlands are considered one of the most productive ecosystems in the world and provide many benefits to the environment. However, the slow moving and sometimes stagnant water created by the vegetation in the wetland creates an ideal environment for the proliferation of mosquitoes. Mosquitoes are the most important insect disease vector worldwide. The presence of mosquitoes within wetlands increases the risk of disease transmission among workers and visitors creating a public health concern. Effective design standards aimed at reducing mosquito breeding habitat should be implemented during the construction and planning phase of wetland development to effectively reduce the mosquito populations. This research evaluated the presence of mosquitoes within two wetlands in Clark County, Nevada; one constructed using the Environmental Protection Agencies suggested guidelines for mosquito reduction, the other not. During the peak mosquito season (March--October), traps were set at two wetland sites on a monthly basis. This trapping occurred for the span of two mosquito seasons in the Las Vegas valley. Trapping data were evaluated to determine if one location produced a lower mosquito population when compared to the other. It was found that the amount of mosquitoes produced between these two locations were statistically different. Furthermore, the same information was used to determine the dominant mosquito species within the wetland and then evaluate the possibility of disease transmission among this species. Culex (Cx.) tarsalis was the most common mosquito species from both wetlands making up 56% (2829 of 5059) of all mosquitoes captured and consequently the most important mosquito-borne disease vector in Clark County. However, 97% of the Cx. tarsalis samples originated from site one (2741 vs. 88). The results of this study showed that wetland location two, constructed using EPA supported guidelines and through the implementation of these designs, limited the overall mosquito population, thereby reducing the potential for disease transmission among known disease vectors within Clark County, NV.