How do invasive species travel to and through urban environments?
- 851 Downloads
Globalisation has resulted in the movement of organisms outside their natural range, often with negative ecological and economic consequences. As cities are hubs of anthropogenic activities, with both highly transformed and disturbed environments, these areas are often the first point of entry for alien species. We compiled a global database of cities with more than one million inhabitants that data had on alien species occurrence. We then identified the most prominent pathways of introduction and vectors of spread of alien species in these cities. Most species were intentionally introduced to cities and were released or escaped from confinement. The majority of alien species then spread within cities through natural means (primarily unaided dispersal). Pathway prominence varied across the taxonomic groups of alien species: the most prominent pathway for plants and vertebrates was the escape pathway; for invertebrates the stowaway and contaminant pathways were most likely to facilitate introductions. For some organisms, pathway prominence varied with the geographical and climatic characteristics of the city. The characteristics of the cities also influenced the prominence of vectors of spread for alien species. Preventing the natural spread of alien species within cities, and into adjacent natural environments will be, at best, difficult. To prevent invasions, both the intentional and unintentional introduction of potentially harmful alien species to cities must be prevented. The pathways of introduction and vectors of spread identified here should be prioritised for management.
KeywordsBiological invasions Pathways of introduction Prioritisation Urban invasions Vectors of spread
This research was funded by the South African National Department of Environmental Affairs through its funding of the South African National Biodiversity Institute’s Invasive Species Programme. An early version of this paper was presented at a workshop on “Non-native species in urban environments: Patterns, processes, impacts and challenges” that was hosted and co-funded by the DST-NRF Centre of Excellence for Invasion Biology in Stellenbosch in November 2016. Many participants at the workshop provided useful comments and suggestions which improved the paper. We thank The Global Invasive Species Database for the provision of data, Desika Moodley and Osadolor Ebhuoma for their technical assistance, and two anonymous reviewers for their comments and suggestions.
- Blackie RR, Sunderland TC (2015) Mapping landscape guidelines and principles to the Aichi targets. CIFOR 123:1–4Google Scholar
- Brown R (2006) Exotic pets invade United States ecosystems: legislative failure and a proposed solution. Indiana Law J 81:713–731Google Scholar
- Demographia (2014) Demographia world urban areas (built-up urban areas or world agglomerations) 10th annual edition. http://www.demographia.com/. Accessed 23 Aug 2015
- ESRI (2006) ArcGIS 9.3. Environmental Research Systems Institute, Inc, Redlands, CAGoogle Scholar
- GBIF (2016) Global Biodiversity Information Facility. http://www.gbif.org/. Accessed 01 Dec 2016
- GISD (2016) Global Invasive Species Database. Invasive Species Specialist Group (ISSG) of the IUCN Species Survival Commission. http://www.issg.org/database. Accessed 9 June 2016
- GRIIS (2016) Global Register of Introduced and Invasive Species. http://www.griis.org/. Accessed 15 Nov 2016
- Kraus F (2007) Using pathway analysis to inform prevention strategies for alien reptiles and amphibians. Manag Vertebr Invasive Species 21:94–103Google Scholar
- Mohri M, Rostamizadeh A, Talwalkar A (2012) The foundations of machine learning. The MIT Press, CambridgeGoogle Scholar
- R Core Team (2015) R: a language and environment for statistical computing. r foundation for statistical computing. Vienna, Austria. http://www.R-project.org/
- Scalera R, Genovesi P, Booy O et al. (2016) Technical report: progress towards pathways prioritization in compliance to Aichi Target 9. Information documented presented at SBSTTA 20 UNEP/CBD/SBSTTA/20/INF/5, the twentieth meeting of the CBD’s Subsidiary Body on Scientific, Technical and Technological Advice, Montreal, Canada, 25–30 April 2016Google Scholar
- Therneau T, Atkinson B, Ripley B (2015) Rpart: recursive partitioning and regression trees. R package version 4.1.10. https://CRAN.R-project.org/package=rpart
- United Nations, Department of Economic and Social Affairs, Population Division (2014) World urbanization prospects: the 2014 revision, CD-ROM edition. https://esa.un.org/unpd/wup/cd-rom/. Accessed 23 Aug 2015
- Van Wilgen NJ, Richardson DM, Baard EHW (2008) Alien reptiles and amphibians in South Africa: towards a pragmatic management strategy. S Afr J Sci 104:13–20Google Scholar