Many visitors are surprised at the amount of vegetation in Arches. Plants are critical components of all ecosystems, and Arches is no exception. Plants capture particulate dust in the air, filter gaseous pollutants, convert carbon dioxide to oxygen, provide animal habitat and possess many raw materials useful to humans. Diverse plant communities thrive in patches of biological soil crust, while others seem to grow right out of cracks in the rock. Many adaptations enable desert plants to survive the extremes of temperature and aridity found in Arches. These adaptations are grouped in three categories: drought escapers, drought resistors and drought evaders.