Today I listened to an old (2006) interview with E.O Wilson by Michael Novacek (thanks NYAS). Wilson had a few criticisms of economics - the heavy basis in mathematics for one - and he stated that this had come at the expense of building a microeconomic foundation based on evolutionary biology.
He also spent some time on the subject of valuation of diversity and ecosystem services. Much of this is a no-brainer. There is clear value to clean water, recreation etc. Where it gets more interesting is when we get to the value of a species. There might be some value in the genetic or biological information, the willingness to pay of some people to simply let it exist and some degree of moral obligation. A great example of this is gecko. In another NYAS podcast, Kellar Autumn laid out what had been learnt from the amazing properties of the hairs on gecko feet. There are applications from nanosurgery to aerospace that may come from this.
The flip side is, of course, that the value must have a limit. In the same way that the optimal healthcare system will see some people die, some ambulances arrive late and not every treatment is provided to everyone it could help, there is a limit to the costs that society can bear. At what point do we draw that line?