Biodiversity effects of constructed and restored wetlands – an ecological and socioeconomical approach

Abstract

Wetlands are highly productive ecosystems with characteristics of both terrestrial and aquatic ecosystems. They have special biota adapted to inundation by water. Between 1970 and 2008, natural wetlands declined on average by about 30% globally and 50% in Europe. The severe loss of natural wetlands, as well as their degradation by agriculture, forestry and other human activity, has caused declines in natural wetland habitat types and specialized species, for example waterfowl populations in Finland. During the last decade, wetlands have been protected, restored and even constructed to save the diversity of wetland biota. Many studies show that constructed and restored wetlands can provide suitable habitats for waterfowl, waders and other wetland-dependent taxa. However, the biological characteristics of such wetlands often differ from natural ones and the habitat variables of constructed or restored wetlands affect the use of wetlands by waterbirds. My PhD project focuses on the biodiversity of constructed and restored wetlands on agricultural areas. The aims of the project are: 1) to investigate the effects of the characteristics, i.e. size, mean water depth, shoreline length and age of wetlands on vegetation, waterbirds and dragonflies, 2) to study the effects of regional land use and wetland connectivity on waterfowl diversity, densities and wetland suitability as breeding habitat, and 3) to study the motives of landowners to apply for EU-subsidies for wetland construction and the cost-effectiveness of such subsidies. I will present the results of the effects of several habitat characteristics of constructed wetland on waterbirds at 32 constructed agricultural wetlands in boreal zone, Finland. We use orthoimages generated from aerial photographs taken with an unmanned aerial vehicle (quadcopter) to estimate open water area and shoreline length of the sites, belt-line transect quadrat method for defining vegetation structure and standard Finnish waterbird census method for species, pair and brood counts. The results can be applied in cost-efficient construction and restoration of wetlands with high biodiversity values.