In an effort to conserve water, landscapers in Arizona have turned to the wild cacti of West Texas for decoration, creating an unsustainable demand that could imperil some species. According to a new report from the World Wildlife Fund, agaves and yuccas are being harvested from the Chihuahua Desert to feed a demand for drought-tolerant landscaping in Tucson and Phoenix. (Both species also grow closer to home, but Arizona boasts far stricter rules for gathering native plants than Texas.) Adding to the problem are rare-plant collectors in Europe and elsewhere, who will pay top dollar for cacti. All told, succulent plants had a market value of more than $3 million from 1998 to 2001. Roger Young of Desert Trees Nursery, which supplies retail nurseries and landscape contractors, acknowledged that the booming trade could spell trouble for the environment: “That’s almost like the days when we used to hunt buffalo. … It doesn’t take long for them to disappear if there’s a demand for it.”