Ecology Distribution Management Info Impact Info References and Links Contacts

General Impact One of the major impacts of Agave americana is its large leaves shading out native plant species. A. americana also has a very dense network of rhizome offshoots, which could draw resources away from native species. The rhizomatous nature of A. americana could also alter the nutrient status of the soil. A. americana may have adverse effects on human and animal health (Badano & Pugnaire 2004; Macdonald et al. 2003; NPPA 2008; Williams 2008).          Location Specific Impacts: Australia   Reduction in native biodiversity: A. americana ssp. americana has a negative impact on rangeland biodiversity in Australia; A. americana and A. americana var. expansa also pose a threat to native biodiversity (Martin et al. 2006; Vitelli & Pitt 2006). Malawi   Human health: May have adverse effects on human and animal health (Macdonald et al. 2003). Reduction in native biodiversity: Invades native ecosystems and displaces native species (Macdonald et al. 2003). Malta   Competition: On the island of Malta, Cape fig (Carpobrotus edulis), prickly pear (Opuntia ficus-indica) and American agave compete with and replace the 'Critically Endangered (CR)' National Plant of Malta, the Maltese Rock-centaury (Cheirolophus crassifolius) and the CR Maltase Cliff-orache (Cremnophyton lanfrancoi) (Santos & Lanfranco 2006). New Zealand   Human health: The spiked arms of A. americana can injure beach visitors, and can result in poisoning. (NPPA 2008). Inhibits the growth of other species: A. americana can smother small plants, especially in coastal and cliff areas. (NPPA 2008). Auckland Region (New Zealand)   Reduction in native biodiversity: Can replace vulnerable dune species. (ARC 2007). Northland Region (New Zealand)   Habitat alteration: A. americana causes rearrangement of mobile sands. (Williams 2008). Inhibits the growth of other species: A. americana shades out native plant species. (Williams 2008). Reduction in native biodiversity Spain   Competition: A. americana may compete with native species for resources at the top of dunes in sand dune populations. A. americana is known to be interfering with the native dominant species in at least one dune field in south-east Spain. (Badano & Puganire 2004). Reduction in native biodiversity: Assemblages of native species found among Agave sp. (including A. americana) were less diverse than those found in uninvaded sand dune areas (Badano & Pugnaire 2004). Canarias (Spain)   Competition: Agave sp. on the Canary Islands are a threat to the Critically Endangered (CR) Crambe wildpretii, the Endangered (EN), Crambe pritzelii and the Vulnerable (VU) Asparagus arborescens (Santos 2011). Isla Grossa (Spain)   Competition: A. americana competes with Salsola sp., Lycium intricatum, and Withania frutescens in Ilsa Grossa (Andreu et al. 2009).