As part of an island-wide project to identify and eradicate potentially invasive plant species before they become established, a program of inventories is being carried out in the urban and agricultural zones of the four inhabited islands in Galapagos. This study reports the results of the inventory from Puerto Villamil, a coastal village representing the urban zone of Isabela Island. We visited all 1193 village properties to record the presence of the introduced plants. In addition, information was collected from half of the properties to determine evidence for potential invasiveness of the plant species. We recorded 261 vascular taxa, 13 of which were new records for Galapagos. Most of the species were intentionally grown (cultivated) (73.3%) and used principally as ornamentals. The most frequent taxa we encountered were Cocos nucifera (coconut tree) (22.1%) as a cultivated plant and Paspalum vaginatum (salt water couch) (13.2%) as a non cultivated plant. In addition 39 taxa were naturalized. On the basis of the invasiveness study, we recommend five species for eradication (Abutilon dianthum, Datura inoxia, Datura metel, Senna alata and Solanum capsicoides), one species for hybridization studies (Opuntia ficus-indica) and three species for control (Furcraea hexapetala, Leucaena leucocephala and Paspalum vaginatum).
References
[1]
Fosberg FR (1972) Man's effect on island ecosystems. In: Taghi Farvar M, Milton J, editors. The Careless Technology. Chapter 46. New York, USA: The Natural History Press. pp. 869–880. Available: http://www.iucn.org/themes/ceesp/Publica?tions/SL/CT.htm [accessed 22-august-07].
Vitousek PM, D'Antonio CM, Loope LL (1997) Introduced species: A significant component of human-caused global change. New Zealand Journal of Ecology 21: 1–16.
[4]
Tye A (2007) La flora endémica de Galapagos: aumentan las especies amenzadas. Informe Galápagos 2006-2007. pp. 101–107. FCD, PNG & INGALA. Puerto Ayora, Galápagos, Ecuador.
[5]
Wiggins IL, Porter DM (1971) Flora of the Galapagos Islands. 998. Stanford: Stanford University Press..
[6]
Tye A (2006) Can we infer island introduction and naturalization rates from inventory data? Evidence from introduced plants in Galapagos. Biological Invasions 8: 201–215.
[7]
Mauchamp A (1997) Threat from alien plant species in the Galapagos Islands. Conservation Biology 11: 260–263.
[8]
Tye A, Atkinson R, Carrion V (2007) Incremento el número de plantas introducidas en Galápagos. Informe Galápagos 2006-2007. pp. 137–139. FCD, PNG & INGALA. Puerto Ayora, Galápagos, Ecuador.
[9]
Buddenhagen C, Yánez P (2005) The cost of quinine Cinchona pubescens control on Santa Cruz Island, Galapagos. Galapagos Research, 63: 32–36.
[10]
Rejmánek M, Richardson D, Higgins S, Pitcairn M, Grotkopp E (2005) Ecology of Invasive Plants: State of the Art. In: Mooney H, Mack R, McNeely J, Neville L, Schei P, et al., editors. Invasive Alien Species. Scope 63. Washington, USA: Island Press. pp. 104–162.
[11]
Randall JM (2000) Improving management of non-native invasive plants in wilderness and other natural areas. In: Cole DN, McCool SF, Borrie WT, O'Loughlin J, editors. Conference proceedings Wilderness ecosystems, threats and management, Missoula, USA. pp. 64–73.
[12]
Species Survival Commission (2000) IUCN guidelines for the prevention of biodiversity loss caused by alien invasive species. Auckland, New Zealand: IUCN, Species Survival Commission, Invasive Species Specialist Group.
[13]
Randall RP (2000) Which are my worst weeds? A simple ranking system for prioritizing weeds. Plant Protection Quarterly 15: 109–115.
[14]
Gravez V, Gelin A, Zurita L, Encalada E (2004) Contribución al conocimiento de la laguna Las Diablas (Isabela, Galápagos) para su manejo (cartografía, profundidad y parámetros físicos'químicos). Parque Nacional Galápagos, Ecuador 23p. Available: http://www.AquaticEcology.org [accessed 22-august-07].
[15]
Fryxell P (1992) Malvaceae. In: Harling G, Andersson L, editors. Flora del Ecuador Berlinas, Arlov- Sweden. Volume 118.
[16]
Swearingen J (2005) Alien Plant Invaders of Natural Areas. Plant Conservation Alliance, Alien Plant Working Group. http://www.nps.gov/plants/alien/list/a.h?tm [accessed 22-august-07].
[17]
Hussey B, Keighery G, Cousens R, Dodd J, Lloyd S (1997) Western weeds: A guide to the weeds of westhern Australia. Plant Protection Society of Western Australia. The Gordon Reid Foundation for Conservation. Australia. pp. 218–220.
[18]
Nel J, Richardson D, Rouget M, Mgidi T, Mdzeke N, et al. (2004) A proposed classification of invasive alien plant species in South Africa: towards prioritizing species and areas for management action. South African Journal of Science 100: 53–64.
[19]
Jorgensen P, León S (1999) Catalogue of the Vascular Plants of Ecuador. San Luis, Missouri: Missouri Botanical Garden Press.
[20]
Institute of Pacific Islands Forestry (2004) Pacific Island Ecosystems at Risk (PIER) database. Available: http://www.hear.org/pier/index.html [accessed 03-june-2006].
[21]
Staples G, Herbest D (2005) A Tropical Garden Flora. Honolulu, Hawaii, USA: Bishop Museum Press.
[22]
Mabberley DJ (1997) The Plant Book. Cambridge: Cambridge University Press.
[23]
WWF (2006) National list of naturalised invasive and potentially invasive garden plants. WA Department of Agriculture Plants Database. WWF-Australia. Available: http://wwf.org.au/publications/ListInvas?ivePlants/[accessed 22-august-07].
[24]
Wang X, Felker P, Paterson A, Mizrahi Y, Nerd A, et al. (1996) Crosshybridization and seed germination in Opuntia species. Journal Professional Association for Cactus Development 1: 49–60.
[25]
Wittenberg R, Cock MJW (2001) Especies exóticas invasoras: Una guía sobre las mejores prácticas de prevención y gestión. Wallingford, UK: CAB Internacional.
[26]
Proa?o ME, Epler B (2007) El turismo en Galapagos: una tendencia el crecimiento. Informe Galápagos 2006-2007. pp. 31–35. FCD, PNG & INGALA. Puerto Ayora, Galápagos, Ecuador.