Compromising of land
Converting undeveloped land into profitable space for tourism is one disadvantage. National parks and wilderness areas may be compromised by an influx of tourists. Additionally, while ecotourism standards include traveling to natural areas while doing nothing to negatively impact those areas and providing cultural and economic advantages to the areas visited, there is no real way to enforce those standards. Sometimes, businesses that are not truly invested in the standards of ecotourism will still advertise as such.
Residents may leave
Ecotourism may displace some local residents. They either won't be able to afford to stay, or they may be forced by developers to leave. When prices in an area rise due to the inflated costs of living in a popular area, prices on everything from food to rents will increase. Often, corrupt governments take a large portion of ecotourism profits and leave little for the local communities impacted by the influx of people.
The industry of ecotourism attracts upper-class, urban tourists who may not be culturally sensitive and may alienate the local residents. Likewise, when an area of land is conserved, such as a natural park, the people that historically lived on that land can end up displaced and forced to abandon their means of sustenance and their cultural traditions associated with the land.
Lack of income prospects
Ecotourism jobs for local residents often don't pay well. And profits may spill into other nations' pockets as wealthy investors gain from the success of an ecotourism project. For example, if large hotels or chain restaurants move into an area it can put local mom and pop guest houses and restaurants out of business.
Ecotourism is susceptible to catastrophic downfalls, such as those that could come from worldwide economic instability. Tourism dollars that poor, foreign governments grow to depend on could easily disappear.