Increasing anthropogenic disturbance threatens the existence of species and habitats. Research is needed to help conserve biological diversity. Fresh water habitats are diverse and also threatened environments. Construction of new habitats has been used in wetlands, since they have been lost and degraded all around the world. In Finland these constructed wetlands are built to filter nutrients from the runoff from agricultural fields, but they also act as potential new habitats for wetland species. The biodiversity of these constructed wetlands has not been studied a lot in Finland. The aim of this study was to find out, whether these constructed wetlands are used by dragonflies (Odonata) as new habitats and what environmental variables might affect the number of individuals and the species richness of dragonflies. The study was conducted by collecting and identifying dragonfly larvae and exuviae from 20 wetland sites in Central Finland. The effects of environmental variables were analyzed with linear regression. Dragonflies were abundant in the wetlands. Over half of the regional lentic species were observed, and they seem to add to the local diversity of agricultural landscapes. The number of individuals was explained by the structural complexity of vegetation. Species richness was explained only by the number of individuals, and no explaining environmental factors were left in the model. However, the structural complexity of vegetation had an indirect effect on species richness via the number of individuals. Studying what features make an environment functional and diverse will help to reach the biodiversity goals of constructing new habitats.