Download Leopard slug Scientific name: Limax maximus

Scientific name: Limax maximus
Common name: Leopard slug
Alaska invasion/introduction history
The timing and mode of introduction of leopard slugs, also known as gaint garden slug, in Alaska is unknown. It has been reported in Wrangell, and likely occurs in other Southeast Alaska communities (Ferguson and Knight 2010). In 2010, a large slug was found in Kodiak, which may have been this species (C. Knight pers comm).
Ranking Summary
Potential Max
Score
Distribution
30
21
30
20
Biological Characteristics
30
14
Ecological Impact
10
3
Feasibility of Control
100
58
Total
Invasiveness (out of 100) = 58 Modestly invasive
Score
Distribution
Current global distribution (0‐10)
10
Leopard slugs are fairly cosmopolitan, occurring in Europe, Asia, Africa, North America, South America, Australia, and New Zealand (NatureServe 2009).
Extent of the species US range and/or occurrence 7
of formal state or provincial listings (0‐10)
Limax maximus has been reported in just under 50% of the states and in several Canadian provinces (BC, ON, NF, NS; NatureServe 2009)
Role of anthropogenic and natural disturbance in 2
establishment (0‐5)
The leopard slug primarily lives near human settlement (Forsyth 2004), but can occasionally be found in wooded areas and fields not associated with anthropogenic disturbance (Rollo and Wellington 1975).
Climatic similarity between site of origin and 2
release (0‐5)
Leopard slugs are native to Europe, North Africa, and Asia minor, which are at lower latitudes than Alaska; however, this species is able to survive in British Columbia and more northern states in the US.
Total for distribution
21 /30
Score
Biological Characteristics and Dispersal
Invasive elsewhere (0‐5)
5
Leopard slugs are invasive in North America, South America, Australia, and New Zealand (Forsyth 2004).
Dietary specialization (0‐5)
5
Leopard slugs primarily eats decaying plant material, fungi and pet feces. Green plants are not are major part of this species diet (Forsyth 2004), but can damage vegetable crops (Barker 1999).
0
Habitat specialization (0‐5)
This species primarily inhabits human modified habitats, such as in gardens, hedgerow, roadsides, and other sheltered damp places (Barker 1984, Forsyth 2004).
Average number of reproductive events per adult 5
female per year (0‐5)
Eggs are laid in clusters of a several dozen throughout the warm season (Pilsbry 1948).
Potential to be spread by human activities (0‐5)
In New Zealand, human activities have been attributed to the dispersal of the leopard slug throughout the country (Barker 1984).
5
Innate potential for long distance dispersal (0‐5) 0
The leopard slug does not have any long distance dispersal mechanism.
Total for biological characteristics 20 / 30
Ecological Impact
Score
Impact on population dynamics of other 7
species (0‐10)
Elsewhere, the leopard slug has displaced native banana slugs through competition for food resources (Busch 2007). In New Zealand, leopard slugs are aggressive towards other slugs and will attack and drive off intruding slugs through repeated biting (Barker 1984). Leopard slugs can reduce the reproductive success of non‐aggressive slugs and increase mortality (Rollo 1983).
Impact on natural community composition (0‐
0
10)
Leopard slugs are primarily associated with human activity and therefore are less likely to have serious interactions with native communities (Getz and Chichester 1971).
Scientific name: Limax maximus
Common name: Leopard slug
7
Impact on natural ecosystem processes (0‐10)
Slugs process decaying plant and fecal material, helping to recycle organic matter and nutrients back into a form that can be used by other organisms. Additionally, this process aids in the maintenance of soil fertility. The mucus from slug activity is also known to accelerate nutrient cycling (e.g. C, N and P) (Theenhaus and Scheu 1996).
Total for ecological impact
14 /30
Feasibility of control
Score
1
Number of populations in Alaska (0‐3)
Leopard slugs most likely occur scattered throughout southeast Alaska; however, surveys have not been completed for all regions of the state. This species has been found in Wrangell and possibly in Kodiak (Ferguson and Knight 2010, C. Knight pers comm).
Significance of the natural area(s) and native 0
species threatened (0‐3)
Leopard slugs are typically found in human disturbed areas and therefore are not known to impact vulnerable species or habitats.
General management difficulty (0‐4)
2
As with other slug species, absolute eradication is unlikely. The most effective management option includes a combination of prevention of spread, early detection and rapid response, and control. To prevent slugs from spreading, public education can raise awareness to reduce human mediated spread of slugs. Early detection and rapid response would most likely involve a watch program allowing biologists and the public to report sighting and control would involve physically removing slugs or possibly chemical treatments (Gotthardt 2010).
Total for feasibility of control
Range Map
3 / 10
References
Barker, G.M. 1999. Naturalised terrestrial Stylommatophora (Mollusca: Gastropoda). Fauna of New Zealand / Ko te Aitanga Pepeke o Aotearoa 38. 253 p. http://www.landcareresearch.co.nz/research/biosystematics/
invertebrates/faunaofnz/Extracts/FNZ38/documents/FNZ38Ba
rker19991150.pdf
Barker, G.M. and R.A. McGhie. 1984. The biology of introduced slugs (Pulmonatna) in New Zealand. 1. Introduction and notes on Limax maximus. New Zealand Entomologist 8: 106‐111.
Busch, D.S. 2007. Black arion (Arion ater), black garlic glass‐
snail (Oxychilus alliarius), brown gardensnail (Cornu aspersum), gray fieldslug (Deroceras reticulatum), leopard slug (Limax maximus). Pp. 144‐145 In: P.D. Boersma, S.H. Reichard, and A.N. Van Buren (eds). Invasive species in the pacific northwest. University of Washington Press, Seattle, WA
Ferguson, A. and C. Knight. 2010. Cooperative agricultural pest survey (CAPS) program in Alaska. Alaska Invasive Species Working Group 2010 Conference Proceeding. October 28, 2010, Fairbanks, Alaska.
Forsyth, R.G. 2004. Land snails of British Columbia. Royal BC Museum , Victoria, Canada
Getz, L.L. and L.F. Chichester. 1971. Introduced European slugs. The Biologist 53: 118‐127.
Gotthardt, T. 2010. European black slug risk assessment for the Copper River Delta area, Alaska. Alaska Natural Heritage Program, Prepared for USDA Forest Service. Anchorage, AK.
Scientific name: Limax maximus
NatureServe. 2009. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available at: http://www.natureserve.org/explorer. (Last accessed: 4 January 2010).
Pilsbry, H.A. 1948. Land mollusca of North America (North of Mexico). The Academy of Natural Sciences of Philadelphia Monograph No. 3, Vol. 2, Part 2.
Rollo, D.C. 1983. Consequences of competition on the reproduction and mortality of three species of terrestrial slugs. Researches on Population Ecology 25: 20‐43.
Rollo, C.D. and W.G. Wellington. 1975. Terrestrial slugs in the vicinity of Vancouver, British Columbia. The Nautilus. 89: 107‐115.
Theenhaus, A. and S. Scheu. 1996. The influence of slug (Arion rufus) mucus and cast material addition on microbial biomass, respiration, and nutrient cycling in beech leaf litter. Biology and Fertility of Soils 23: 80‐85.
Acknowledgements
Authors: K. M. Walton and T. A. Gotthardt, Alaska Natural Heritage Program, University of Alaska Anchorage. Reviewer(s): Robert Forsyth, Royal BC Museum.
Common name: Leopard slug