The demography of introduction pathways, propagule pressure and occurrences of non-native freshwater fish in England
Article first published online: 28 JUN 2010
© Crown copyright 2010. Reproduced with permission of Her majesty's stationery office. Published by John Wiley & Sons, Ltd.
Aquatic Conservation: Marine and Freshwater Ecosystems
Volume 20, Issue 5, pages 595–601, July/August 2010
How to Cite
Copp, G. H., Vilizzi, L. and Gozlan, R. E. (2010), The demography of introduction pathways, propagule pressure and occurrences of non-native freshwater fish in England. Aquatic Conserv: Mar. Freshw. Ecosyst., 20: 595–601. doi: 10.1002/aqc.1129
- Issue published online: 28 JUN 2010
- Article first published online: 28 JUN 2010
- Manuscript Revised: 16 MAY 2010
- Manuscript Accepted: 16 MAY 2010
- Manuscript Received: 14 JAN 2010
- PCNM analysis;
- confirmatory factor analysis (CFA);
- redundancy analysis;
- invasion pathways
- 1.Biological invasion theory predicts that the introduction and establishment of non-native species is positively correlated with propagule pressure. Releases of pet and aquarium fishes to inland waters has a long history; however, few studies have examined the demographic basis of their importation and incidence in the wild.
- 2.For the 1500 grid squares (10×10 km) that make up England, data on human demographics (population density, numbers of pet shops, garden centres and fish farms), the numbers of non-native freshwater fishes (from consented licences) imported in those grid squares (i.e. propagule pressure), and the reported incidences (in a national database) of non-native fishes in the wild were used to examine spatial relationships between the occurrence of non-native fishes and the demographic factors associated with propagule pressure, as well as to test whether the demographic factors are statistically reliable predictors of the incidence of non-native fishes, and as such surrogate estimators of propagule pressure.
- 3.Principal coordinates of neighbour matrices analyses, used to generate spatially explicit models, and confirmatory factor analysis revealed that spatial distributions of non-native species in England were significantly related to human population density, garden centre density and fish farm density. Human population density and the number of fish imports were identified as the best predictors of propagule pressure.
- 4.Human population density is an effective surrogate estimator of non-native fish propagule pressure and can be used to predict likely areas of non-native fish introductions. In conjunction with fish movements, where available, human population densities can be used to support biological invasion monitoring programmes across Europe (and perhaps globally) and to inform management decisions as regards the prioritization of areas for the control of non-native fish introductions.
© Crown copyright 2010. Reproduced with the permission of her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.