Can someone confirm that, there is a data base of individuals which, for example, stays in accommodation related to special forms of tourism eg. eco-tourists, adventurers, backpackers?
If you are referring to a type of niche tourism world atlas or online database for eco-tourists, adventurers, backpackers, then you can look at SustainableTourismOnline
You probably need something like the latter stats but more on a global scale, like global statistics eco-tourists, adventurers, backpackers accommodation, correct ?
However, access to Mintel publications database requires subscription with user name or password which is usually purchased by the University or other affiliate institution.
I don’t know of such global systematic statistics by countries. You can search on UNWTO ELibrary and other international organizations sources such as OECD, UE or other bodies of United Nations (PNUMA), but the information is neither systematic nor segmented by niches. Other alternative would consist of searching on specific associations or NGO´s for example, The International Ecotourism Society (http://www.ecotourism.org/contact-us).
thank you all for answers and suggestions. I followed them and also reviewed some different sources. First, a short conclusion would be that at this moment there is no such a data collected at one place or source (including world reports and by country). So there is no global facts about alternative, niche or special interest tourism, only accounts and approximations. Second, instead of previous, I found many papers and resources with own statistics gathered by regions or by tourism themes (eg eco-turism, adventure forms, backpacking, wine, geo-tourism...).
In time to time I will share those facts here, so it can be reachable to everyone interested.