Mosquito density, macroinvertebrate diversity, and water chemistry in water-filled containers: relationships to land use

The proliferation of disease-vector mosquitoes has been attributed to the effects of land-use change. We investigated the relationship between land use, macroinvertebrate communities, and water chemistry in water-filled containers in native forest, pasture land, and urban land at two locations (Waikanae and Paraparaumu) in the Kapiti region, New Zealand. Larvae of the endemic Culex pervigilans and exotic Aedes notoscriptus constituted 45.0% and 55.0% of all late-instar mosquito species collected. At Waikanae, fourth instar A. notoscriptus, pupal, and total mosquito densities were higher in native forest than in urban land and pasture land, and pupal density was higher in native forest than in pasture land. At Paraparaumu, fourth instar A. notoscriptus and pupal densities were higher in native forest and urban land than in pasture land. Macro invertebrate communities in human-modified land uses were dominated by two herbivorous chironomid species, consisted of fewer species, higher densities, and different composition than in native forest. Water chemistry was also associated with land use, with nitrate, nitrite, and acidity higher in native forest at both locations. Fourth instar A. notoscriptus, pupal, and total mosquito densities were negatively associated with non-culicid invertebrate density. Fourth instar A. notoscriptus density was also negatively associated with pH. Fourth instar C. pervigilans density was not significantly related to any water chemistry variables. These results indicate that land-use change may not necessarily lead to higher densities of mosquitoes in larval habitats by altering the associated macroinvertebrate community.