Estimating the financial costs of freshwater invasive species in Great Britain: A standardized approach to invasive species costing
Biological Invasions
Matthew P. J. Oreska (mpjo2@cam.ac.uk) 1 , David C. Aldridge (da113@cam.ac.uk) 1
1 Affiliation Address:
Aquatic Ecology Group
Department of Zoology
University of Cambridge
Downing Street
Cambridge
CB2 3EJ
United Kingdom
(0044) 122-333-6617

Online Resource 1. Ecological and economic effects of identified British freshwater invasive species
Name, origin
Azolla filiculoides
(Water fern)
South America 1
Crassula helmsii
(Australian swamp stonecrop)
Australia, New
Zealand 6,7
Elodea canadensis
(Canadian pondweed)
North America 6
Ecological Effects
Impacts biodiversity 1 ; symbiotic with nitrogen fixing algae; overgrowths kill macrophytes and algae 2
Smothers other plants 6,7 ; threatens
Damasonium alisma 7,8 , Ludwigia palustris , Galium debile 7,9 , and
Triturus cristatus 7,10
Reduces light/photosynthesis, temperature, dissolved oxygen, and pH - lowers biodiversity 6 ; might hybridize with E. nuttallii 11
Economic Effects
Dam blockage, increased siltation, and mat obstruction of slow moving waters 1 ; presents a drowning hazard 2
Potentially hazardous when obscuring water bodies, invades drainage ditches and ponds, diminishes natural capital 6
Grows in irrigation systems 11 ; commercial losses to power stations 12 ; found in lakes and reservoirs, blocks navigation and interferes with municipal water supply 6
Benefits
Removes fish farm nutrient waste; provides biogas, animal feed, compost, and paper fibre 3 ; biofertilizer of wheat 4 and rice 5
Sold as an oxygenating plant by garden centres 7
Reduces nitrogen 13 and phosphorous contamination in eutrophic waters 14 ; observed removing harmful pesticides from water 15
Elodea nuttallii
(Nuttall’s pondweed)
North America 6
Hydrocotyle ranunculoides
(Floating pennywort)
Cosmopolitan 6 ;
North America 17
Annual decomposition creates anoxia 16 ; reduces light/photosynthesis, temperature, dissolved oxygen, and pH - lowers biodiversity; replacing/hybridizing with E. canadensis 6,11
Reduces available dissolved oxygen, outcompetes native aquatic plants, blocks light to benthic macrophytes 17 ; rhizomatous mats threaten endemic ecosystems 18
Impacts fishing, tourism, navigation, and normal water flow; can cause flooding 16 ; blocks navigation and interferes with hydroelectricity generation and municipal water supply 6
Found in ponds, dykes, ditches, streams, and waste water; flooding; limits water body recreation, causes waterworks damage 17 ; can completely cover small channels/waterbodies 19
Reduces nitrogen levels in surrounding water 13
Sold by nurseries 17

Online Resource 1 continued
Name, origin
Lagarosiphon major
(Curly waterweed)
South Africa 20
Ecological Effects
Growth reduces biomass of Nitella sp. and filamentous algae 12 ; lowers water pH and dissolved oxygen content, which adversely affects some fish and invertebrates 21 ; replacing E. canadensis, E. nuttallii in the U. K.
22
Found to reduce biodiversity 6 Ludwigia
grandiflora
(Water primrose)
Americas 6
Myriophyllum aquaticum
(Parrot’s feather)
South America 6
Dreissena
polymorpha
(Zebra mussel)
Ponto-Caspian 28
Crangonyx pseudogracilis
(amphipod)
North America 33
Displacing Potamogeton crispus ,
Ceratophyllum demersum , and
Myriophyllum spicatum 25 ; lowers biodiversity 6 ; does not form dense associations in Brazil on account of fungal pathogens 26 settles on endemic mussels 28 , particularly genera Unio and
Anodonta 29 ; water filtration impacts planktonic community, improves water quality, and contributes to macrophyte growth 30
Transmits the parasite, Fibrillanosema crangonycis 33 ; possible local displacement of Gammarus pulex in
Scotland 34
Economic Effects commercial losses to power stations 12 ; surface-reaching forms in hydroelectric lakes threaten electric output 23 ; occurs in canals, ditches, and other slow moving water bodies 22
Benefits
Provides shelter and hosts food sources for small littoral fish 21 ; sold by garden centers as an oxygenating plant, often called "Elodea crispa" 22
Blocks slow moving water bodies and impacts fishing, navigation, hunting, irrigation, and lake drainage
Occurs in drainage canals 25 hydroelectric lakes
Aggregations block water intakes, impacting municipal water systems, industrial facilities, and power plants 28 ; decaying organic material corrodes pipes; fish ladders are also fouled in
Germany 29
(None identified)
6
; reduces drainage and fishing opportunities, hinders navigation, and mats can block industrial pumps 6 ; threatens small
23
Sold commercially
Sold as an oxygenating plant found in garden ponds and nurseries
Reduces eutrophication
24
6 ; often for water quality management in the
Netherlands 32 ; provides food for waterfowl 29
Used as feed for
31 ; considered
Salmo trutta ; potential bioindicator taxon for monitoring water quality 36
35
27

Online Resource 1 continued
Name, origin
Eriocheir sinensis
(Chinese mitten crab)
East Asia 37
Ecological Effects
Competes with native fauna 37 , i.e.
Austropotamobius pallipes 38 ; transmits lung fluke, Paragonimus westermanii 39
Hemimysis
anomala
(Bloody red mysid)
Ponto-Caspian 42
Forms dense populations 43 ; Impacts
Rotifera, Ostracoda, and Anamopoda taxa 44 ; reduces cyanobacteria levels; consumption of periphyton increases macrophyte growth 45
Pacifastacus leniusculus
(American signal crayfish)
Washington State 47
Procambarus
clarkii
(Red swamp crayfish)
North America 42
Carassius auratus
(Goldfish)
East Asia 31
Vector for Crayfish plague,
Aphanomyces astaci 47 salmonid juveniles 49
; Competes with native Austropotamobius pallipes 48 caddisfly, and mollusk communities
Vector for crayfish plague, aquatic plants and fish/amphibian eggs 53 ; increases turbidity/reduces photosynthesis 54
;
; damages leach,
50
Aphanomyces astaci , population explodes in new habitats 47 ; Consumes
Competes/hybridizes with Carassius carassius 54 ; increases turbidity, nutrient re-suspension, algal growth, competes with native fauna, decreases invertebrate communities 55
Economic Effects
Adverse aquaculture impacts (i.e. shrimp, Pacifastacus leniusculus ), steals fish bait, damages nets, causes bank erosion 38 , flood risk 40
Reduces planktivorous fish populations through plankton consumption; also contributes to bioaccumulation of PCB and mercury in fish 43
Environmental establishment rendered aquaculture efforts unprofitable, crayfish interfere with recreational fishing bait 47,50
Environmental establishment rendered aquaculture efforts unprofitable 50 ;
Burrowing disrupts irrigation networks 53 ; competes with farmed fish for food and interferes with fish sorting and harvesting 53
Loss in commercial fish yield in Lake
Trasimeno, Italy, attributed to goldfish 55
Benefits
USD$1.25b/yr aquaculture industry in
China 37 ; sold in London markets for
£5.55/pound 41
Introduced as a food item for fish 43
Stocked extensively by the Soviet
Union for fish feed 44,46
;
San Francisco Bay area aquaculture industry 37 ; Europe aquaculture introduction 47 ; Finland 51 , Sweden 52 harvest following noble crayfish,
Astacus astacus, fishery collapse
Constitutes 85% of freshwater crayfish grown globally, most produced in
Louisiana/Southern US 47
Value to recreational anglers for catch and release, intentionally stocked 54

Online Resource 1 continued
Name, origin
Cyprinus carpio
(Common carp)
China 56
Pseudorasbora
parva
(Topmouth gudgeon)
East Asia 60
Ecological Effects
Increases turbidity, foraging reduces photosynthesis 56 ; secondary reductions to amphipods, tabanids, and hirudinids follow macrophyte loss; chironomids and oligochaetes increase 57
Facultative parasite 60 ; competes with native 54 and stocked fish ( i.e.
Rutilus rutilus, Abramis brama ) for food and habitat 61 ; Vector for fish pathogen,
Sphaerothecum destruens 62
Economic Effects
Ground-baiting by anglers might reduce water quality 58 ; feeding habits potentially impact bank stability 56
Frequently found in angling lakes in the
U. K.
63,61 , Southern England Test and
Itchen catchments, NW England Lake
District 60 ; competition with angling species threatens angling sites 64
Benefits
Supports a large, U. K., carp-specific angling industry 54,58 ; food for human and bait consumption 56 ; supports both commercial and recreational fisheries 59
Live bait and aquarium trade 64
1 McConnachie et al. 2003; 2 Newman 2009a; 3 Redding et al. 1997; 4 Ripley et al. 2003; 5 Bao-lin 1988; 6 Sheppard et al. 2005; 7 EPPO 2007; 8 Watson
2001; 9 Dawson and Warman 1987; 10 Watson 1999; 11 Bowmer et al. 1995; 12 Howard-Williams et al. 1996; 13 Ozimek et al. 1993; 14 Gumbricht 1993;
15 Olette et al. 2007; 16 Di Nino et al. 2005; 17 EPPO 2006; 18 Ruiz-Avila and Klemm 1996; 19 Newman 2009b; 20 Gassman et al. 2006; 21 Bickel and
Closs 2008; 22 Newman 2009c; 23 Clayton and Champion 2006; 24 Renals, Environment Agency, pers. comm.; 25 Moreira et al. 1999; 26 Barreto et al.
2000; 27 Newman 2009d; 28 USGAO 2002; 29 Reinhardt et al. 2003; 30 Elliott 2005; 31 Gozlan 2008; 32 Reeders et al. 1993; 33 Johanna et al. 2003;
34 Maitland and Adams 2001; 35 MacNeil et al. 1999; 36 Gerhardt 2006; 37 Herborg et al. 2005; 38 Herborg et al. 2003; 39 Williams and Grosholz 2008;
40 Defra 2003; 41 Defra 2005a; 42 Minchin and Rosenthal 2002; 43 Ricciardi and Rasmussen 1998; 44 Ketelaars et al. 1999; 45 Stubbington et al. 2008;
46 Dumont 2006; 47 Holdich 1993; 48 Manchester and Bullock 2000; 49 Griffiths et al. 2004; 50 Defra 2005b; 51 Kirjavainen and Sipponen 2004;
52 Kataria 2007; 53 Morolli et al. 2006; 54 Hickley and Chare 2004; 55 Lorenzoni et al. 2007; 56 Kelly 2003; 57 Miller and Crowl 2006; 58 Niesar et al.
2004; 59 Cole 2006; 60 Britton and Brazier 2006; 61 Britton et al. 2008; 62 UKTAG 2008; 63 Britton et al. 2009; 64 Defra 2005c

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