We compared morphometric and physico-chemical characteristics of farm ponds and natural wetlands in Andalusia (southern Spain) to determine whether artifi-cial waterbodies might act as alternative and/or complemen-tary habitats for aquatic biodiversity. Farm ponds were much smaller than natural wetlands, making them unsuit-able for species requiring large waterbodies. However, we observed high farm pond density in areas lacking natural wetlands, which suggests a prime role for the conservation of species with low dispersal capacities. Natural-substrate ponds were abundant in traditional extensive farming sys-tems and showed shoreline complexity as high as the most complex natural wetlands. Areas with more intensive agri-culture were dominated by artificial-substrate ponds and wetlands, with low physical complexity in both. The high copper load in sediments, due to the use of copper sulphate as biocide, differentiated the artificial-substrate ponds from natural-looking ponds and all natural wetland types. Aque-ous mineral levels in farm ponds were much lower than in natural wetlands. We can conclude that farm ponds might play a principal role in region-wide habitat complementarity, by providing a relatively high density of small, permanent, oligohaline waterbodies that is not matched by natural wet-land. To enhance this role, measures regulating both pond construction and management are needed, particularly for artificial-substrate ponds.