Google just launched Google Insights, which records how many times a term was used as a searching word over time (monthly data, from 2004 to present). In addition it also tells you "regional interest", aka, how many times a key word was used in different parts of the world.
Using the term "Ecosystem Services" I found:
1) People in Australia were interested in the term most (searched 100 times in the 4.5 years), followed by those from India, US, Canada and UK.
2) The first on the list of "rising searches" is "valuing ecosystem services" (55) (followed by"forest ecosystem services")!
p.s. I have nothing to do with either result :)