Opuntia in shallow, loose soils, such as on mountain slopes. "Opuntia" spreads into large clonal colonies, which contribute to its being considered a noxious weed in some places. Animals that eat "Opuntia" include the prickly pear island snail and "Cyclura" rock iguanas. The fruit are relished by many arid land animals, chiefly birds, which thus help distribute the seeds. "Opuntia" pathogens include the sac fungus "Colletotrichum coccodes" and Sammons' Opuntia virus. The ant "Crematogaster opuntiae" and the spider "Theridion opuntia" are named because of their association with prickly pear cacti. Like most true cactus species, prickly pears are native only to
Opuntia ficus-indica the Mediterranean basin. Under those hedges and adjacent areas soil physical properties, nitrogen and organic matter are considerably improved. Structural stability of the soil is enhanced, runoff and erosion are reduced, while water storage capacity and permeability is enhanced. Prickly pear plantations also have a positive impact on plant growth of other species by improving severe environmental conditions which facilitate colonization and development of herbaceous species. Opuntia ficus-indica is being advantageously used in Tunisia and Algeria to slow and direct sand movement and enhance the restoration of vegetative cover, minimizing deterioration of built terraces with its deep and strong rooting