Anthropic wetlands: their contribution to biodiversity conservation in the subtropical and pampean dominia of Argentina

In low areas, civil works which are mostly regarded as actions of environmental negative effects, commonly generate barriers which favor wetlands formation. Conversely, we postulate that anthropic wetlands can, within special circumstances, contribute to biodiversity conservation. Terrepleins slope bases, defence enclosures against floodings, excavated areas and road drains, have generated, aided by rains and by ground water outcrops, important wetlands, considering their extent, number and permanence. Within the Subtropical Dominion and the Paraná-Paraguay System (Mesopotamia, Argentina) numerous civil works have been made to mitigate the deletereous effects of river pulses on human settlements. At the base of terrepleins in enclosed protected areas, it is frequent to observe the formation of wetlands which house high biodiversity. It is also worth considering the importance of other type of anthropic environments, e.g. rice irrigation systems. In the Pampas, the lithological characteristics and topography bring the basic conditions by which the elevations related to road construction interfere with superficial runoff, generating semi permanent wetlands. These limnotopes may contribute to preventlocalspecies extinctions. Furthremore, they house numerous biotic communities, and interact with other ecosystems, constituing faunal rearing sites, refuges and migratory scales. In these environments either on the coastal plain or in the interior areas permanent water bodies are originated by extractive activities.Their volume is maintained by rainfall and groundwater contribution. These limnotopes contain aquatic and emergent plant communities and associated macroinvertebrates. Among the latter there are species which are only found in stable and permanent aquatic environments. In addition it is remarkable the abundance of fishes and waterfoul fauna