Neophytische Opuntien im Sukkulentenbusch auf Teneriffa

Abstract

Xerophytic scrubs dominated by succulents such as Euphorbia canariensis, E. balsamifera and Kleinia neriifolia are among the most famous plant communities of the Canary Islands. In these natural communities neophytic plants, particularly Opuntia dillenii and O. ficus-indica, are frequently present. In a one-day project students of the University of Basel and Potsdam explored the relationship between the presence of neophytes and the indigenous vegetation of the succulent scrub. In six plots at each of four sites from sea level to the upper end of the xerophytic scrub zone in Tenerife, the diversity and cover of indigenous and neophytic plants along with habitat conditions were assessed. Opuntia species were regularly present and of similar importance as characteristic indigenous succulents. Other neophytes were rare. There was a significantly positive relation of the cover of Opuntia species with the one of indigenous species, and also with plant diversity. Species composition changed with altitude and scree cover. Opuntia dillenii was present only below c. 400 m a.s.l., while O. ficus-indica occurred at higher elevation. The results indicate that Opuntia species nowadays are naturalized elements of the succulent scrub communities in Tenerife. Environmental conditions favorable for indigenous succulents apparently also enhance the presence of the Opuntia species. For a prediction, whether and to what degree Opuntia species will displace the indigenous elements of the succulent scrub in the future, experimental evidence will be needed.