I'll take a stab at paraphrasing this:
Nature tourism and ecotourism are recognized as ways to improve the reputation of tourism.
Words like enriching and enhancing are synonyms for improving.
For something to improve in standing, it first needs to be low in standing for some reason. Given the term ecotourism, I can guess that the passage is talking about tourism that damages the environment – perhaps inadvertently, or perhaps through negligent planning.
For example, say a tourism company starts arranging tours through a rain forest. Such an industry could disrupt the habitat, because of new building development, because of an increased strain on natural resources, or simply because more people are going through the area. Some environmentalists may be aware of this, and get into a "tourism is bad" mindset.
However, such a company could be sensitive to the ecological impact of increased tourism, and design its tours accordingly. It might transport only a limited number of tourists into an area at any one time. It could confine the tourists to walking only in designated areas. It could donate some of its revenue into preservation efforts. Such steps would increase the standing of tourism in the minds of concerned environmentalists.