A cost-effectiveness analysis was performed to evaluate the competitiveness of seminatural Free Water Surface (FWS) wetlands compared to traditional wastewater-treatment plants. Six scenarios of the service costs of three FWS wetlands and three different wastewater-treatment plants based on active sludge processes were compared. The six scenarios were all equally effective in their wastewater-treatment capacity. The service costs were estimated using real accounting data from an experimental wetland and by means of a market survey. Some assumptions had to be made to perform the analysis. A reference wastewater situation was established to solve the problem of the different levels of dilution that characterize the inflow water of the different systems; the land purchase cost was excluded from the analysis, considering the use of public land as shared social services, and an equal life span for both seminatural and traditional wastewater-treatment plants was set. The results suggest that seminatural systems are competitive with traditional biotechnological systems, with an average service cost improvement of 2.1-fold to 8-fold, according to the specific solution and discount rate. The main improvement factor was the lower maintenance cost of the seminatural systems, due to the self-regulating, low artificial energy inputs and the absence of waste to be disposed. In this work, only the waste-treatment capacity of wetlands was considered as a parameter for the economic competitiveness analysis. Other goods/services and environmental benefits provided by FWS wetlands were not considered.

BackgroundVenomous snakes are among the most serious health hazards for rural people in tropical regions of the world. Herein we compare the monthly activity patterns of eight venomous snake species (Elapidae and Viperidae) with those of rural people in the Niger Delta area of southern Nigeria, in order to identify the periods of highest potential risk for persons, and the human group actually at greater risk of snakebite.ResultsWe documented that above-ground activity of all venomous snakes peaked in the wet season, and that high snake activity and high human activity were most highly correlated between April and August. In addition, we documented that women and teenagers were at relatively higher risk of encountering a venomous snake than adult males, despite they are less often in the field than men.ConclusionsOur results suggest that future programs devoted to mitigate the social and health effects of snakebites in the Niger Delta region should involve especially women and teenagers, with ad-hoc education projects if appropriate. We urge that international organizations working on social and health problems in the developing world, such as IRD, DFID, UNDP, should provide advice through specific programs targeted at especially these categories which have been highlighted in comparatively potential higher threat from snakebites than adult men.

Researchers and practitioners in basic and applied ecology provide to private or public clients assessment documents on various concern topics, such as the state of ecosystem components, the type of threats and their regime or the level of pressure and impact on biodiversity. These assessments, carried out by ecological field studies, may be strategic in addressing conservation research, plans and actions. Therefore, data provided in these documents should be characterized by a high reliability, that is, they should be based on standard methods and protocols, independence of data samples, absence of pseudo-replication, control of different levels of detectability among sampled individuals or species, high level of precision and accuracy etc. In this paper we propose a simple two-data-sheet format for a data reliability assessment of a professional study that may facilitate a rapid check of the more important requirements of a correct ecological field research. This format may be useful to students, technicians, professionals and researchers as well as public or private commissioning agencies (e.g. to evaluate the suitability of the study, possibly suggesting additions or modifications).

Highlights We analyze citizens' shared ecological knowledge (SEK) of wetlands functions to describe its nature, its relation with the official knowledge, the relation between the motivations outlined by SEK and those expected by the standard economic model. Wetlands functions' SEK is related to wetlands living proximity and unexpectedly diminishing for some long since acquired critical services There is a separation between official knowledge and SEK on crucial aspects like wetlands' climate change role. Economic preferences are driven by multiple motivations well rooted in SEK social nature and not by simply consequential motivations. This approach helps to transfer a socio-cultural complex capital into a public decision making processes.

No abstract