Are PES and PWS programmes a good solution?
According to S. Wunder paper (2005), Payments for Ecosystem Services (PES) are usually defined as " voluntary transactions where a well-defined ecosystem service is ‘bought' by at least one ecosystem service buyer, from at least one ecosystem service provider, if and only if, the ecosystem service provider secures ecosystem service provision ". In the case of water, the equivalent to PES would be the Payments for Watershed (or Watershed Ecosystem ) Services ( PWS or PWES ). The principle is simple and therefore this mechanism should not have associated the uncertainties and the flaws that in fact it has. PWS are rapidly increasing, with more than 205 active programmes globally in 2011. However, the performance of PES (and by extension PWS) is still controversial and its initial laudable aims seem not so easy to achieve.
The first point is that the "voluntary transactions" have become into a kind of ecosystems and watershed marketization, subsequently functioning under market rules. This fact may shift the management´s aim from conservation to profitability, where there is not a clear regulatory framework and the private influence is strong. The goal of protecting the tampon and protection effects of watershed fades off, and PWS programmes process may end in a commoditization of water resources. The initial proposals for achieving the economic and resources redistribution from urban to rural areas and guarantee the interest of the poorest populations are not being clearly reached. And some articles (Kallis et al., 2005; Muradian et al., 2013) pointed out some of the negative aspects of these approaches, encouraging as an alternative, the public investment and control over the programmes.
Once more the questions are how to combine, rights, moral, values, education and ownership and public goods, with socio economic profitability and efficiency; and how to do PWS more reliable and efficient...