The impacts of non‐native species on UK biodiversity and the effectiveness of control

Abstract

1. The introduction of non‐native species continues to cause ecological concern globally, but there have been no published reviews of their effects in the UK. Impacts in the UK are therefore reviewed, along with current legislation and guidelines relating to the introduction and control of such species. 2. A large number of non‐native species have been introduced to the UK, both deliberately and accidentally, but only a small number of introduced non‐native species have established and caused detrimental ecological impacts. However, general declines in UK biodiversity, and the potential effects of future climate change, may increase the susceptibility of ecosystems to invasions. 3. Detrimental impacts of non‐native species on native biota have occurred through competition, predation, herbivory, habitat alteration, disease and genetic effects (i.e. hybridization). There are potential effects on genetic biodiversity as well as species biodiversity. 4. Several high profile examples highlight the technical difficulties, and financial implications, of removing an introduced species once it is established. Few UK control or eradication programmes have been successful. 5. Control might be more feasible if ‘problem’ species could be identified at an earlier stage of establishment. However, the poor success of attempts to characterize invasive species and predict which will have negative impacts highlight the individual and unpredictable nature of invasions. The difficulties of making general predictions suggest that every proposed species introduction should be subject to rigorous ecological characterization and risk assessment prior to introduction. 6. The plethora of UK legislation and guidelines developed to reduce impacts of non‐native species only go part of the way towards ameliorating impact. Many species already established in the wild might cause future problems. Illegal releases and escapes of non‐native species may augment feral populations or establish new colonies. While regulation of imports and releases is important, further enforcement of existing legislation and action against unlicensed releases is necessary.

Do species differ in their ability to coexist with the dominant alien Lupinus polyphyllus? A comparison between two distinct invaded ranges and a native range

“…Invasions of alien plant species have become widely recognized as one of the major human-induced changes, affecting the whole biosphere at the global scale (Tilman 1999, Manchester andBullock 2000). In the last decade, the attention has been focused on testing, documenting and quantifying the impacts of alien invasive species upon the resident communities (Mack et al 2000, Davis 2003, Hejda et al 2009, Vilà et al 2010.…”

Does tree seedling growth and survival require weeding of Himalayan balsam (Impatiens glandulifera)?

“…However, even for herbaceous species, contradicting results have been reported. Whereas some studies have classified Impatiens glandulifera as a strong competitor to native herbaceous species by shading them out and thus leading to a reduction of species richness (Manchester and Bullock 2000;Hulme and Bremner 2006), others observed a very little effect on community characteristics (Hejda and Pyšek 2006;Hejda et al 2009;Bartomeus et al 2010). These different assessments may be attributed to differences in the cover of Himalayan balsam (Hejda and Pyšek 2006).…”

“…The second concern is dealt with in the study presented here. As Himalayan balsam is thought to be a strong competitor (Manchester and Bullock 2000), some techniques like mechanical weed control and the use of herbicides have been discussed (Beerling and Perrins 1993). So far, biological control agents are not available (Burkhart and Nentwig 2008).…”

Impacts of Solidago Gigantea, Prunus Serotina, Heracleum Mantegazzianum and Fallopia Japonica Invasions on Ecosystems

“…They are on the IUCN 100 worst invasive species list, are the second most damaging alien plant in Germany (land holder poll) and are amongst the top 10 invasive plant species in France and UK (Bailey, 1994;Manchester and Bullock, 2000). In these countries F. japonica var japonica is one of three species recognised as having significant impacts on biodiversity (Manchester and Bullock, 2000).…”

“…They are on the IUCN 100 worst invasive species list, are the second most damaging alien plant in Germany (land holder poll) and are amongst the top 10 invasive plant species in France and UK (Bailey, 1994;Manchester and Bullock, 2000). In these countries F. japonica var japonica is one of three species recognised as having significant impacts on biodiversity (Manchester and Bullock, 2000). The species increase risk of flooding and the deep rhizomes hinder construction projects and cause physical damage to drainage structures, building foundations and road surface (Beerling, 1991).…”