For a critique of ecotourism that may also provoke uncomfortable questions about academic conference travel and about anthropologically-oriented fieldwork ...

Rosaleen Duff. 2002. A Trip Too Far: Ecotourism, Politics and Exploitation.

It's available on google books.

There's a review of it here:

"The author was anguished to discover that ecotourism is like many other human activities. It is does not deliver on all the promises that people make for it, not all the people are nice and not everyone benefits. The biggest surprise to the author was that “ecotourists reveal that they are primarily concerned about the ways in which their holidays affect them as individuals (p. xi).” This point really disturbed the novice researcher as she exclaimed that “self-satisfaction is still the ecotourist's over-riding concern (p. 40).” "