south africa reveals. reporter: namaqualand is a semi-desert in northwestern south africa, with extreme heat and barely anyything that grows here needs to be hardy. like these unusual looking succulents, known as "living stones." their limited water source comes from dew that forms between the quartz stones and mist from the air. they grow slowly, some living for hundreds of years. wynand: this is a plant that really can withstand a great deal. it can survive with very little water, with almost no rain. this one is under stress -- you can see by the markings and colors. it's all about survival in this dry environment. reporter: the rangers in knersvlakte nature reserve are responsible for an area the size of berlin. they're trying to protect and preserve this unique ecosystem. because of the 190 species that grow only here, around 80% are at risk of extinction by poachers. they come in ever greater numbers, uprooting thousands of plants to sell to an international market that is constantly growing. zanne: it's something that people want, they want that, they want to see that plant that grows naturally and