The International Union for Conservation of Nature warns in a new report that about a third of the world's cactus species are threatened with extinction.

The study evaluated 1,478 species and determined that 31 percent are endangered due to factors such as the conversion of wilderness areas to farming and ranching, urban development and the harvest of cactus seeds and plants for trade and private collection.

The report identifies hotspots of endangered cactuses across the Americas, from the southern Brazilian state of Rio Grande do Sul and parts of neighboring Uruguay north to the Mexican states of Queretaro, San Luis Potosi, Oaxaca and Puebla.

The report was published in the journal Nature Plants.