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Roy, Helen E.; Rorke, Steph L.; Beckmann, Bjorn; Booy, Olaf; Botham, Marc S.; Brown, Peter M.J.; Harrower, Colin; Noble, David; Sewell, Jack; Walker, Kevin. 2015. The contribution of volunteer recorders to our understanding of biological invasions. Biological Journal of the Linnean Society, 115 (3). 678-689. 10.1111/bij.12518

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1 2 3 1 The role of biological records in understanding invasions 4 5 2 Helen E. Roy1 6 7 1 8 3 Steph L. Rorke 9 10 4 Björn Beckmann1 11

12 1 13 5 Marc S. Botham 14 15 6 Peter M.J. Brown2 16 17 7 David Noble3 18 19 20 8 Jack Sewell4 21 22 9 Kevin Walker5 23 24 1 25 1 Biological0 Records Centre, Centre for Ecology & Hydrology, Benson Lane, Wallingford, Oxfordshire, 26 11 OX10 8BB, UK 27 28 2 29 1 2Animal and Environment Research Group, Anglia Ruskin University, East Road, Cambridge, CB1 1PT, 30 UK 13 UK 31 32 33 1 3British4 Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU, UK 34 35 1 4Marine5 Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, Devon, 36 37 16 PL1 2PB, UK 38 39 1 5Botanical7 Society of Britain and Ireland, Natural History Museum, Cromwell Road, London SW7 5BD, 40 41 42 18 UK 43 44 19 45 46 20 Running title: Biological records and invasions 47 48 49 21 50 51 52 53 54 55 56 57 58 59 60 Page 2 of 30

1 2 3 22 Abstract 4 5 23 The process of invasion and the desire to predict the invasiveness (and associated impacts) of new 6 7 24 arrivals has been a focus of attention for ecologists over centuries. The volunteer recording 8 9 25 community has made unique and inspiring contributions to our understanding of invasion biology 10 26 within Britain. Indeed information on non-native species (NNS) compiled within the GB Non-Native 11 12 27 Species Information Portal (GB-NNSIP) would not have been possible without the involvement of 13 28 volunteer experts from across Britain. Here we review examples of ways in which biological records 14 15 29 have informed invasion biology. We specifically examine NNS information available within the GB- 16 17 30 NNSIP to describe patterns in the arrival and establishment of NNS providing an overview of habitat 18 31 associations of NNS in terrestrial, marine and freshwater environments. 19 20 21 32 Monitoring and surveillance of the subset of NNS that are considered to be adversely affecting 22 33 biodiversity, society or the economy, termed invasive non-native species (INNS), is critical for early 23 24 34 warning and rapid response. Volunteers are major contributors to monitoring and surveillance of 25 26 35 INNS and not only provide records from across Britain but also underpin the system of verification 27 36 necessary to confirm the identification of sightings. Here we describe the so-called “alert system” 28 29 37 which links volunteer experts with the wider recording community to provide early warning of INNS 30 38 occurrence. 31 32 33 39 We highlight the need to increase understanding of community and ecosystem-level effects of 34 35 40 invasions and particularly understanding of ecological resilience. Detailed field observations, through 36 41 biological recording, will provide the spatial, temporal and taxonomic breadth required for such 37 38 42 research. The role of the volunteer recording community in contributing to the understanding of 39 43 invasion biology has been invaluable and it is clear that their expertise and commitment will 40 41 44 continue to be so. 42 43 45 Keywords 44 45 46 46 Invasion biology, biological recording, citizen science, habitat, impact, early warning, surveillance 47 48 47 49 50 51 52 53 54 55 56 57 58 59 60 Page 3 of 30

1 2 3 48 4 5 49 Introduction 6 7 50 Non-native species (NNS) are being introduced into countries at unprecedented and unpredictable 8 9 51 rates and those that become invasive threaten biodiversity by decreasing the uniqueness of 10 11 52 ecosystems at genetic, functional and taxonomic levels (McKinney and Lockwood, 1999; Smart et al., 12 53 2006; Vila et al., 2011). The Millennium Ecosystem Assessment (Anonymous, 2005) ranked invasive 13 14 54 non-native species (INNS), alongside climate change, habitat destruction, pollution and 15 55 overexploitation, as one of the main drivers of biodiversity loss globally. The recent dramatic 16 17 56 increase in the rate of movement of species from their native geographic regions to new regions, in 18 19 57 which they are considered non-native, aligns with increases in globalisation and associated rises in 20 58 transportation by humans (Hulme, 2009). 21 22 23 59 The process of invasion and the desire to predict the invasiveness (and associated impacts) of new 24 60 arrivals has been a focus of attention for ecologists over centuries (Elton, 1958). Indeed Charles 25 26 61 Darwin evoked the “Naturalisation Hypothesis or Conundrum” (Darwin, 1859) predicting the 27 28 62 importance of phylogenetic relatedness in determining invasiveness such that non-native species 29 63 with close relatives in the invaded range will be less invasive than those which are only distantly 30 31 64 related to species within the recipient habitats (Daehler, 2001; Jiang et al., 2010; Thuiller et al., 32 33 65 2010). Such traits-based approaches continue to fascinate ecologists and provide opportunities for 34 66 exploring invasions. 35 36 37 67 Recent research recognises the inherent complexity of ecological systems and the influence of the 38 68 evolutionary history of the interactions between species within a population in determining invasion 39 40 69 success of new arrivals (Thuiller et al., 2010). Furthermore, the wider community context is also 41 70 likely to play an important role in the invasion process (Shea and Chesson, 2002). The recently 42 43 71 proposed unified framework for biological invasions reconciles and integrates characteristics across 44 45 72 a range of established invasion frameworks and eloquently outlines the invasion process and 46 73 specifically the stages and barriers to invasion from transport and introduction to establishment and 47 48 74 spread (Blackburn et al., 2011). The volunteer recording community have made unique and inspiring 49 50 75 contributions to our understanding of invasion biology within Britain. 51 52 76 GB Non-Native Species Information Portal: underpinning understanding 53 54 77 The GB Non-Native Species Information Portal (GB-NNSIP) is an on-line information system 55 56 78 (www.nonnativespecies.org ), involving a network of people including the volunteer recording 57 58 79 schemes and societies alongside the Biological Records Centre (BRC) and other organisations 59 60 Page 4 of 30

1 2 3 80 engaged in sharing information on NNS (Roy et al., 2014c). The GB-NNSIP covers species within 4 5 81 England, Scotland and Wales (hereafter referred to as “Britain”) and comprises a register of NNS, 6 82 together with supporting information including country of origin, arrival pathway, establishment 7 8 83 status, occurrence within habitats, date of first record, human impact and environmental impact. 9 84 The GB-NNSIP is being updated at least annually and is dynamically linked to the National 10 11 85 Biodiversity Network (NBN) Gateway (https://data.nbn.org.uk) which provides maps of the 12 13 86 distribution of the NNS within Britain. The role of volunteers, primarily through the recording 14 87 schemes and societies, in providing both information on species and occurrence data, has been 15 16 88 invaluable. Indeed compiling the information within the GB-NNSIP would not have been possible 17 18 89 without the contributions of volunteer experts from across Britain. 19 20 90 Lists of NNS are seen as an essential tool in the management of biological invasions (McGeoch et al., 21 22 91 2012). The use of such lists is diverse and far-reaching. There have been many influential research 23 92 studies based on NNS lists which have increased understanding particularly in relation to pathways 24 25 93 of arrival (Hulme, 2009) and impacts on biodiversity (Vila et al., 2011), both acknowledged as critical 26 94 elements within biodiversity strategy. Indeed implementation of policy and legislation is often 27 28 95 based on NNS lists (Lodge et al., 2006) prioritising those species considered to be adversely affecting 29 30 96 biodiversity, society or the economy which are termed invasive non-native species (INNS). Early 31 97 warning, prevention and control measures for INNS rely on information such as identity, associated 32 33 98 biology and distribution (McGeoch et al., 2012). Here we have examined NNS information available 34 35 99 within the GB-NNSIP to describe patterns in the arrival, establishment and spread of non-native 36 100 species within Britain. 37 38 39 101 Arrival 40 41 102 The arrival of a species within a new region is dependent on successful transport and introduction 42 43 103 but survival and reproduction is essential for the species to become established (Blackburn et al., 44 104 2011). The mechanism of arrival can be difficult to determine (Eversham and Arnold, 1992). Recent 45 46 105 advances have been made in harmonising the terminology used to describe pathways and 47 48 106 information within the GB-NNSIP has been instrumental to these developments (CBD, 2014). Over 49 107 the coming years it will be essential to prioritise research on pathways of arrival to inform strategies 50 51 108 for preventing future INNS incursions. It is also necessary to understand the origins of NNS. 52 109 Historically a large proportion of the NNS arriving in Britain were native within Europe indicative of 53 54 110 the close transport and trade links throughout history (Preston et al., 2004). However, there has 55 56 111 been a shift in the countries of origin of the NNS arriving within Britain which align with an increase 57 112 in trade and travel from regions beyond Europe (Figure 2). Recently there has been a particular 58 59 60 Page 5 of 30

1 2 3 113 increase in the number of species arriving from temperate Asia; globalisation has facilitated and 4 5 114 intensified the intentional and unintentional introduction of NNS (Meyerson and Mooney, 2007). 6 7 115 8 9 116 Establishment 10 11 12 117 There has been a dramatic increase in the number of species arriving and becoming established 13 14 118 (founding reproducing populations) within Britain over the last 400 years and there is no 15 119 indication of this trend slowing (Figure 2). Indeed since 1950 there have been 10.5 additional 16 17 120 NNS arriving and establishing per year in contrast to 0.9 additional NNS per year from 1600- 18 19 121 1799. The number of established NNS deemed to have a negative ecological or socio-economic 20 122 impact (INNS) is also increasing with 1.1 of the new species per year causing an impact since 21 22 123 2000. There are more than 3,000 species listed within the GB-NNSIP but only 1919 are 23 24 124 considered to be established within Britain. Plant species dominate within the GB-NNSIP; the 25 26 125 1,919 established NNS comprise 1,494 established non-native plants, 420 established non- 27 126 native animals and 5 other species. The escalation in the rate of new arrivals is not unique to 28 29 127 Britain and has been reported across Europe (Pyšek et al., 2010) and, indeed, globally 30 31 128 (Meyerson and Mooney, 2007) and is widely attributed to an increase in trade and transport in 32 129 recent decades (Hulme, 2009). 33 34 35 130 Spread 36 37 131 The invasibility of communities, habitats and ecosystems has been the focus of invasion biology 38 39 132 research for decades (Lonsdale, 1999; Richardson and Pyšek, 2006). However, it is recognised 40 41 133 that invasion of a region by a non-native species involves complex ecological processes driven 42 134 by traits of both the invader and the invaded community (Shea and Chesson, 2002). Indeed 43 44 135 biological invasions represent an exciting opportunity to contribute to the understanding of 45 46 136 community ecology (Shea and Chesson, 2002). Biological records have underpinned the study of 47 137 establishment and spread of non-native species within Britain (Botham et al., 2009; Eversham 48 49 138 and Arnold, 1992; Manchester and Bullock, 2000). Non-native species occur across the British 50 51 139 landscape (Figure 3) but a greater number of non-native species are present within England 52 140 compared to either Scotland or Wales. The high number of non-native species within the south- 53 54 141 east of England is almost certainly related to climatic factors coupled with prevalence of urban 55 56 142 habitats and high population density; there are particularly high numbers of non-native species 57 58 143 within urban localities. 59 60 Page 6 of 30

1 2 3 144 The association of non-native species with urban habitats is widely recognised (Alston and 4 5 145 Richardson, 2006; Botham et al., 2009; Pyšek, 1998). Indeed urban localities represent highly 6 146 disturbed habitats which are also typified by high fertility and so highly suitable for ruderal 7 8 147 species (Botham et al., 2009). Furthermore, the number of non-native species introduced into 9 10 148 urban settlements, particularly in gardens and parks, is high and so constitutes considerable 11 149 propagule pressure (Botham et al., 2009; Holle and Simberloff, 2005). Research using botanical 12 13 150 data collected by the Botanical Society of Britain and Ireland confirms the strong association of 14 15 151 non-native plants with urban habitats but suggests that there has been a reduction in the urban 16 17 152 association of archaeophytes in recent decades (Botham et al., 2009). The GB-NNSIP includes 18 153 information on the habitats occupied by non-native species within Britain, much of which comes 19 20 154 from the detailed observations of the volunteer recording community. A qualitative and 21 22 155 descriptive review of the habitat associations represented within the GB-NNSIP provides 23 156 intriguing insights which stimulate the development of hypotheses for empirical testing (Figures 24 25 157 4, 5 and 6). The botanical information is particularly comprehensive within the GB-NNSIP and 26 27 158 exploring the habitat associations of non-native plants in terrestrial environments against date 28 159 of first record highlights changes in patterns (Figure 4I and 4II). The strong association with 29 30 160 urban environments (EUNIS category J) is apparent and the proportion of recent arrivals within 31 32 161 urban environments is higher than for historic invasions. Interestingly there are no clear 33 162 patterns between the habitat associations of the invasive non-native plants and date of first 34 35 163 record although association with grasslands (EUNIS category E) is strong for both non-native and 36 37 164 invasive non-native species of plants. Previous research has highlighted the importance of fertile 38 39 165 grasslands as recipient habitats for non-native plants, particularly disturbed and fertile 40 166 components of these habitats (Maskell et al., 2006). 41 42 43 167 Habitat associations between non-native species, beyond the plants, and in non-terrestrial 44 168 environments have so far received limited attention. However, a few patterns emerge from 45 46 169 examining the habitat associations of non-native animals against date of first record which are 47 48 170 worthy of description (Figure 4 III and 4 IV; Figures 5 and 6). Interestingly, urban habitats do not 49 50 171 appear to be the major recipient of non-native animals and it is possible that this reflects both 51 172 the capacity of animals to disperse and spread rapidly, and the range of pathways through 52 53 173 which they arrive. There appears to be an increase in the proportion of non-native animals, 54 55 174 particularly those considered to be invasive, associated with marine habitats (EUNIS category A). 56 175 This could reflect increased intensity of recording within these habitats in recent years but it 57 58 176 would be valuable to investigate further. Inland waters (EUNIS category C) seem to be 59 60 Page 7 of 30

1 2 3 177 increasingly under pressure from new invasive arrivals. The number of freshwater invertebrates 4 5 178 arriving from the Ponto-Caspian region is a growing concern and it has been stated that Britain 6 179 might be on the brink of “Ponto-Caspian invasional meltdown” (Gallardo and Aldridge, 2014). 7 8 180 The recent arrival of the quagga mussel, Dreissena rostriformis bugensis, is the latest of a 9 10 181 number of new arrivals to freshwater habitats. Recreational use of water bodies for fishing and 11 182 boating are considered to be major pathways of introduction for NNS and highlight the 12 13 183 importance of biosecurity and raising awareness through campaigns such as “Check, Clean, Dry” 14 15 184 (Anderson et al., 2014). 16 17 185 Clearly there is considerable scope for research on habitat associations of non-native species. It 18 19 186 would be particularly interesting to explore the interactions between habitat fragmentation and 20 21 187 invasion (Hoffmeister et al., 2005). While it is apparent that urban and disturbed habitats are 22 188 particular foci for invasion, it is critical to consider habitats as a heterogeneous matrix on a 23 24 189 landscape scale. For some species habitat fragmentation might limit spread while for others the 25 26 190 disturbance created through fragmentation might facilitate spread. It would be interesting to 27 28 191 explore this through modelling approaches using biological records alongside life-history traits 29 192 and land cover data. Investigating the vulnerability of protected areas to invasion by considering 30 31 193 their connectivity to hot spots of invasion could provide useful insights for conservation 32 33 194 management (Thomas et al. THIS SI). 34 35 195 Horizon scanning and early warning 36 37 196 Horizon-scanning to prioritise the threat posed by potentially new INNS which are not yet 38 39 40 197 established within a region is seen as an essential component of INNS management (Copp et al., 41 42 198 2007; Shine et al., 2010). There have been a number of horizon-scanning exercises, based on 43 44 199 information from the literature coupled with risk assessment frameworks or modelling approaches, 45 46 200 for INNS in Britain involving discrete taxonomic groups, such as plants (Thomas, 2010) or animals 47 48 201 (Parrott et al., 2009), or distinct environments such as freshwater (Gallardo and Aldridge, 2013). 49 50 202 More recently a horizon scanning approach was developed that combined the structured 51 52 53 203 approaches of literature review and risk assessment (Branquart et al., 2009) with dynamic consensus 54 55 204 methods (Sutherland et al., 2011) to deliver a ranked list of species that are likely to arrive, become 56 57 205 established and have an impact on native biodiversity within the next ten years (Roy et al., 2014b). 58 59 60 Page 8 of 30

1 2 3 206 Breadth of information across taxonomic groups and environments is essential for horizon scanning 4 5 207 and the volunteer recording community in the UK provide an excellent example of “wisdom from the 6 7 208 crowd” (Galton, 1907; Lorenz et al., 2011; Sutherland and Woodroof, 2009) whereby the 8 9 209 complementary expertise within this community ensures the required collective knowledge (Roy et 10 11 12 210 al., 2014b). The list of non-native species on the resulting horizon scanning list included a “top ten” 13 14 211 and four of these species (D. rostriformis bugensis (Mollusca: Bivalvia), Hemigrapsus sanguineus 15 16 212 (Crustacea: Brachyura), Hemigrapsus takanoi (Crustacea: Brachyura), Procyon lotor (Mammalia: 17 18 213 Carnivora) were reported within six months following publication. The quagga mussel, Dreissena 19 20 214 rostriformis bugensis, was unanimously agreed to constitute the highest risk of all the species 21 22 215 considered (Roy et al., 2014b) and in October 2014 was reported as established in a reservoir in 23 24 25 216 Surrey, UK (http://www.nonnativespecies.org/alerts/index.cfm). The quagga mussel is an ecosystem 26 27 217 engineer and has a history of becoming the dominant benthic organism within invaded systems 28 29 218 (Sousa et al., 2009) with a wide range of direct and indirect impacts (Cross et al., 2010; MacIsaac, 30 31 219 1996; Schloesser et al., 2006; Sousa et al., 2009; Ward and Ricciardi, 2007). 32 33 220 34 35 36 221 Monitoring and surveillance 37 38 39 222 The volunteer recording community are major contributors to monitoring and surveillance of non- 40 41 223 native species. It is essential that the species prioritised through risk assessment and horizon 42 43 224 scanning are publicised to raise awareness and encourage reporting. Volunteers not only provide 44 45 46 225 records from across Britain but also underpin the system of verification necessary to confirm the 47 48 226 identification of sightings. The so-called “alert system” (Figure 7) promoted through the Non-Native 49 50 227 Species Secretariat website (www.nonnativespecies.org) links to iRecord (www.brc.ac.uk/irecord), a 51 52 228 website for managing wildlife records, and enables rapid reporting and verification of species 53 54 229 considered as a priority for action. On-line capability enables people to register for notification of 55 56 230 selected species of interest and ensures rapid data flow to support effective decision-making. 57 58 59 60 Page 9 of 30

1 2 3 231 The alert system includes species identified as high-risk through horizon scanning (Roy et al., 2014b). 4 5 232 The Asian hornet, Vespa velutina, is one such species. This species arrived in France in 2005 and 6 7 233 spread rapidly across the country and into Spain in 2010 (Perrard et al., 2009; Villemant et al., 2011). 8 9 234 It is a predator of pollinating insects and so poses a threat to native biodiversity (Perrard et al., 2009; 10 11 12 235 Villemant et al., 2011). There has been considerable publicity through the media on this species and 13 14 236 also targeted promotion to the beekeeping community. Consequently many people have sent 15 16 237 sightings of concern through iRecord (374 suspect Asian hornet records) and a designated e-mail 17 18 238 account for alert species (1,162 suspected Asian hornet records received; Figure 8). To date there 19 20 239 have been no confirmed sightings of the Asian hornet in Britain; most of the records have been 21 22 240 identified as European hornets, Vespa crabro. However, the high number of records received 23 24 25 241 through the e-mail alert (Figure 8) system is encouraging and highlights the role of volunteers, 26 27 242 expert and non-expert, in surveillance and monitoring of non-native species. The peaks in numbers 28 29 243 of records received (September 2013 and May 2014) coincide with reports in the national press and 30 31 244 demonstrate the importance of effective communication to raise awareness. 32 33 34 245 Understanding impacts 35 36 37 246 INNS are widely stated to be one of the major drivers of biodiversity loss (Millenium Ecosystem 38 39 247 Assessment, 2005), however there is a lack of empirical evidence for the impacts of many non-native 40 41 248 species which are considered to be invasive. There is a clear need to increase understanding of the 42 43 249 effects of non-native species on other wildlife to inform risk assessment and prioritisation of 44 45 46 250 management strategies. However, invasions also provide opportunities to gain unique insights to 47 48 251 advance understanding of processes within community ecology. It is essential that impacts are 49 50 252 quantified using experimental approaches alongside field observations. Biological recording could 51 52 253 play a critical role in the latter, however currently the interactions between species are rarely 53 54 254 captured within biological records. There is considerable potential to encourage recorders to include 55 56 57 58 59 60 Page 10 of 30

1 2 3 255 such additional information and many naturalists document interactions as comments alongside the 4 5 256 standard information (what, when, who and where) that constitutes a record. 6 7 8 257 Biological records collated through the UK Ladybird Survey (formerly the Coccinellidae Recording 9 10 258 Scheme) have been instrumental in providing evidence that the harlequin ladybird, Harmonia 11 12 259 axyridis, is contributing to the declines in distribution of native ladybirds (Brown et al., 2011; Roy et 13 14 15 260 al., 2012). Linking this research with life-history traits, climate and land cover data highlights the role 16 17 261 of H. axyridis coupled with urbanisation in causing local extinctions of native ladybirds (Comont et 18 19 262 al., 2013; Comont et al., 2012). It will be intriguing to explore the extent to which such changes in 20 21 263 ladybird community structure affect the ecological resilience of the network of aphidophagous 22 23 264 insects (Roy and Lawson-Handley, 2012). A high degree of biodiversity is widely considered to 24 25 265 enhance the resilience of ecosystems to invasion (Elmqvist et al., 2003) but few studies within 26 27 28 266 invasion biology have included ecosystem-scale approaches to underpin this intuitive theory. 29 30 267 Biological records have the potential to contribute to the understanding of ecological resilience and 31 32 268 specifically to the assessment of the state of ecosystems following perturbation. The development of 33 34 269 methods for constructing ecological networks from biological records is an exciting prospect and 35 36 270 worthy of prioritisation going forward. 37 38 39 271 Conclusions 40 41 42 272 The contributions made by volunteers to our understanding of invasion biology have been 43 44 273 invaluable. The GB-NNSIP (alongside the European inventory, DAISIE) is possibly one of the most 45 46 274 comprehensive regional databases of information on non-native species worldwide. The wealth of 47 48 49 275 information on British wildlife, both native and non-native, is inspiring, and the large-scale and 50 51 276 long-term datasets comprising biological records compiled and collated by the volunteer 52 53 277 recording community provide a unique resource for addressing questions of major ecological 54 55 56 278 importance (Roy et al., 2014a). The information available through publications on life-history 57 58 279 traits, such as PLANTATT (Hill et al., 2004), provide additional rich resources to inform analyses. 59 60 Page 11 of 30

1 2 3 280 The development of databases of life-history traits for other taxonomic and functional groups 4 5 281 should be prioritised. Integrating detailed traits-based information with biological records across 6 7 282 taxonomic groups and including relevant interactions will enhance understanding of biological 8 9 10 283 invasions immeasurably. 11 12 13 284 Acknowledgements 14 15 16 285 We are indebted to the many volunteers who have generously and enthusiastically contributed 17 18 286 their expertise and observations. The GB-NNSIP is co-funded through Defra in partnership with 19 20 287 JNCC and the Natural Environment Research Council. The Non-Native Species Secretariat 21 22 23 288 (NNSS) has provided invaluable support to the development of the GB-NNSIP. 24 25 26 289 27 28 29 290 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 12 of 30

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1 2 3 441 4 5 442 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 16 of 30

1 2 3 443 Figure 1. Origins of established non-native species (NNS) and the date of first record in Great Britain. 4 5 444 The place of origin is shown at continent level, some species have a native range that covers multiple 6 445 continents. The number of NNS indicates the total number of NNS within a native range including 7 8 446 that continent and a GB first record in that date range. The innermost circle denotes the date range 9 447 1500-1549 and each further concentric circle refers to a 50 year time period with the outermost 10 11 448 circle representing the most recent date range 1950-1999. The colour of the continent relates to the 12 13 449 most recent time period displayed (1950-1999). 14 450 15 16 451 Figure 2. Number of established non-native species (black line) and the number that are designated 17 18 452 as having a negative ecological impact, so called invasive non-native species (grey line), against date 19 453 of first record. 20 21 454 22 455 Figure 3. Richness of invasive non-native species (number of species per 10km square). 23 24 456 25 26 457 Figure 4. Number of non-native and invasive non-native plants (I and II respectively) and non- 27 458 native and invasive non-native animals (III and IV respectively) associated with terrestrial 28 29 459 habitats against date of first record. Habitat information is included with the GB-NNSIP as EUNIS 30 31 460 categories (www.eunis.eea.europa.eu/habitats.jsp). 32 33 461 34 462 Figure 5. Number of non-native and invasive non-native plants (I and II respectively) and non- 35 36 463 native and invasive non-native animals (III and IV respectively) associated with marine habitats 37 38 464 against date of first record. Habitat information is included with the GB-NNSIP as EUNIS 39 465 categories (www.eunis.eea.europa.eu/habitats.jsp). 40 41 466 42 43 467 Figure 6. Number of non-native and invasive non-native plants (I and II respectively) and non- 44 468 native and invasive non-native animals (III and IV respectively) associated with freshwater 45 46 469 habitats against date of first record. Habitat information is included with the GB-NNSIP as EUNIS 47 48 470 categories (www.eunis.eea.europa.eu/habitats.jsp). 49 471 50 51 472 Figure 7. Outline of the “alert system” in which a biological record is received either by e-mail or 52 53 473 within iRecord. The record is checked by an expert and either confirmed (verified) or not. The 54 474 database is updated and stakeholders are informed if the record is verified so that they can take 55 56 475 appropriate action. In some cases stakeholders are notified prior to verification if rapid response is 57 58 476 necessary. 59 60 Page 17 of 30

1 2 3 477 Figure 8. Number of reports of suspected Vespa velutina received through the designated e-mail 4 5 478 account for the “alert system”. Date range 2011 to 2014. Note that there have been no confirmed 6 479 sightings of V. velutina within Britain. 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 18 of 30

1 2 3 Supporting information: List of Invasive Non-Native Species considered to adversely 4 affect biodiversity in Britain 5 Environment Common name Scientific name 6 Marine a bryozoans Schizoporella japonica 7 8 Marine a bryozoans Tricellaria inopinata 9 Marine a bryozoans Watersipora subatra 10 Marine a coelenterate Cordylophora caspia 11 Marine a crustacean Dyspanopeus sayi 12 Marine a mollusc Ensis directus 13 14 Marine a mollusc Mytilopsis leucophaeata 15 Marine a tunicate Botrylloides diegensis 16 Marine a tunicate Botrylloides violaceus 17 Marine a tunicate Corella eumyota 18 19 Marine a tunicate Didemnum vexillum 20 Marine Algae Bonnemaisonia hamifera 21 Marine Algae Grateloupia turuturu 22 Marine Algae Heterosiphonia japonica 23 Marine Algae Neosiphonia harveyi 24 25 Marine American sting winkle Urosalpinx cinerea 26 Marine an acorn barnacle Austrominius modestus 27 Marine an amphipod Monocorophium sextonae 28 Marine an amphipod Gammarus tigrinus 29 Marine an annelid Ficopomatus enigmaticus 30 31 Marine an annelid Hydroides elegans 32 Marine an annelid Hydroides ezoensis 33 Marine Chinese Mitten Crab Eriocheir sinensis 34 Marine Compass Sea Squirt Asterocarpa humilis 35 Marine Dwarf Crab Rhithropanopeus harrisii 36 37 Marine Green sea fingers Codium fragile subsp.fragile 38 Marine Harpoon Weed (Algae) Asparagopsis armata 39 Marine Japanese kelp, wakame Undaria pinnatifida 40 Marine Japanese Skeleton Caprella mutica 41 Shrimp 42 Marine Leathery Sea Squirt Styela clava 43 Marine Pacific Oyster Crassostrea gigas 44 45 Marine slipper limpet Crepidula fornicata 46 Marine swim-bladder nematode Anguillicoloides crassus 47 Marine Wire Weed Sargassum muticum 48 Freshwater a mollusc Corbicula fluminea 49 Freshwater a polychaete Hypania invalida 50 51 Freshwater African clawed frog Xenopus laevis 52 Freshwater American bullfrog Lithobates catesbeianus 53 Freshwater Bloody-red mysid Hemimysis anomala 54 Freshwater Canadian Waterweed Elodea canadensis 55 56 Freshwater Curly Waterweed Lagarosiphon major 57 Freshwater Demon shrimp Dikerogammarus haemobaphes 58 59 60 Page 19 of 30

1 2 3 Freshwater Duck-potato Sagittaria latifolia 4 Freshwater Floating pennywort Hydrocotyle ranunculoides 5 Freshwater Goldfish Carassius auratus 6 7 Freshwater Italian Alpine Newt Icthyosaura alpestris 8 Freshwater Italian crested newt Triturus carniflex 9 Freshwater Jenkins' spire snail Potamopyrgus antipodarum 10 Freshwater Killer shrimp Dikerogammarus villosus 11 12 Freshwater Large-flowered Egeria densa Waterweed 13 Freshwater Least Duckweed Lemna minuta 14 15 Freshwater Marsh frog Pelophylax ridibundus 16 Freshwater New Zealand pigmyweed Crassula helmsii 17 Freshwater Northern River Crangonyx pseudogracilis 18 Crangonyctid 19 Freshwater Nuttall's Waterweed Elodea nuttallii 20 Freshwater Parrot's Feather Myriophyllum aquaticum 21 Freshwater Pumpkinseed Lepomis gibbosus 22 Freshwater Quagga mussel Dreissena bugensis 23 24 Freshwater Rainbow trout Oncorhynchus mykiss 25 Freshwater Red swamp crayfish Procambarus clarkii 26 Freshwater Signal crayfish Pacifastacus leniusculus 27 Freshwater Spinycheek crayfish Orconectes limosus 28 29 Freshwater Sunbleak Leucaspius delineatus 30 Freshwater Topmouth gudgeon Pseudorasbora parva 31 Freshwater Turkish crayfish Astacus leptodactylus 32 Freshwater Uruguayan Hampshire- Ludwigia grandiflora 33 purslane 34 Freshwater Virile crayfish Orconectes virilis 35 36 Freshwater Water Fern Azolla filiculoides 37 Freshwater Wels catfish Siluris glanis 38 Freshwater White river crayfish Procambarus acutus 39 Freshwater Zander Sander lucioperca 40 Freshwater Zebra mussel Dreissena polymorpha 41 42 Terrestrial a flatworm Australoplana sanguinea 43 Terrestrial a flatworm Kontikia ventrolineata 44 Terrestrial Aesculapian snake Zamensis longissimus 45 Terrestrial Alexanders Smyrnium olusatrum 46 47 Terrestrial American mink Mustela vison 48 Terrestrial American Skunk-cabbage Lysichiton americanus 49 Terrestrial an ant Lasius neglectus 50 Terrestrial Arrow Bamboo Pseudosasa japonica 51 Terrestrial Austrian Pin Pinus nigra 52 53 Terrestrial Bear's-breech Acanthus mollis 54 Terrestrial Berberis sawfly Arge berberidis 55 Terrestrial Bermuda-buttercup Oxalis pes-caprae 56 Terrestrial Biliary parasite Pseudamphistomum truncatum 57 Terrestrial Billard's Bridewort Spiraea alba x douglasii = S. x billardii 58 59 60 Page 20 of 30

1 2 3 Terrestrial Black rat Rattus rattus 4 Terrestrial Black-bindweed Fallopia convolvulus 5 Terrestrial Bladder-senna Colutea arborescens 6 7 Terrestrial Blotched Monkey Flower Mimulus luteus 8 Terrestrial Bluebell Hyacinthoides non-scripta x hispanica = H. x 9 massartiana 10 Terrestrial Brazilian Giant-rhubarb Gunnera manicata 11 Terrestrial Bridewort Spiraea salicifolia 12 Terrestrial Broad-leaved Bamboo Sasa palmata 13 Terrestrial Brown rat Rattus norvegicus 14 Terrestrial Buddleia Buddleja davidii 15 16 Terrestrial Canada Goose Branta canadensis 17 Terrestrial Canadian Goldenrod Solidago canadensis 18 Terrestrial Cherry Laurel Prunus laurocerasus 19 Terrestrial Common Michaelmas- Aster novi-belgii x lanceolatus = A. x salignus 20 daisy 21 Terrestrial Comon Wall lizard Podarcis muralis 22 Terrestrial Confused Bridewort Spiraea salicifolia x douglasii = S. x 23 pseudosalicifolia 24 Terrestrial Dump fly Hydrotaea aenescens 25 Terrestrial Dutch Rose Rosa Hollandica 26 27 Terrestrial Eagle Owl Bubo bubo 28 Terrestrial Eastern Gray Squirrel Sciurus carolinensis 29 Terrestrial Edible Dormouse Glis glis 30 Terrestrial Egyptian Goose Alopochen aegyptiacus 31 Terrestrial Entire-leaved Cotoneaster integrifolius 32 Cotoneaster 33 Terrestrial European rabbit Oryctolagus cuniculus 34 35 Terrestrial Evergreen Oak Quercus ilex 36 Terrestrial Fallow Deer Dama dama 37 Terrestrial False-acacia Robinia pseudoacacia 38 Terrestrial Feral Cat Felis catus 39 Terrestrial Feral Goat Capra hircus 40 41 Terrestrial Ferret Mustela furo 42 Terrestrial Few-flowered Garlic Allium paradoxum 43 Terrestrial Garden Lady's-mantle Alchemilla mollis 44 Terrestrial Giant Hogweed Heracleum mantegazzianum 45 Terrestrial Giant Knotweed Fallopia sachalinensis 46 47 Terrestrial Giant-rhubarb Gunnera tinctoria 48 Terrestrial Great Brome Anisantha diandra 49 Terrestrial Green Alkanet Pentaglottis sempervirens 50 Terrestrial Hairy Bamboo Sasaella ramosa 51 Terrestrial Harlequin Ladybird Harmonia axyridis 52 53 Terrestrial Heath Star Moss Campylopus introflexus 54 Terrestrial Himalayan Balsam Impatiens glandulifera 55 Terrestrial Himalayan Cotoneaster Cotoneaster simonsii 56 Terrestrial Himalayan Knotweed Persicaria wallichii 57 Terrestrial Horse chestnut scale Pulvinaria regalis 58 59 60 Page 21 of 30

1 2 3 Terrestrial Hottentot-fig Carpobrotus edulis 4 Terrestrial House mouse Mus domesticus 5 Terrestrial Japanese Knotweed Fallopia japonica 6 7 Terrestrial Japanese Rose Rosa rugosa 8 Terrestrial Juneberry Amelanchier lamarckii 9 Terrestrial Late Michaelmas-daisy Aster laevis x novi-belgii = A. x versicolor 10 Terrestrial Lesser Knotweed Persicaria campanulata 11 Terrestrial Lesser Periwinkle Vinca minor 12 13 Terrestrial Mandarin duck Aix galericulata 14 Terrestrial Maritime Pine Pinus pinaster 15 Terrestrial Monk parakeet Myiopsitta monachus 16 Terrestrial Montbretia Crocosmia aurea x pottsii (C. x crocosmiiflora) 17 Terrestrial Narrow-leaved Aster lanceolatus 18 Michaelmas-daisy 19 Terrestrial New Zealand Flatworm Arthurdendyus triangulatus 20 Terrestrial Oak Processionary Thaumetopoea processionea 21 22 Terrestrial Pheasant Phasianus colchicus 23 Terrestrial Pirri-pirri-bur Acaena novae-zelandiae 24 Terrestrial Pitcherplant Sarracenia purpurea 25 Terrestrial plant hybrid Fallopia japonica x sachalinensis = F. x bohemica 26 27 Terrestrial Portugal Laurel Prunus lusitanica 28 Terrestrial Potato aphid Macrosiphum euphorbiae 29 Terrestrial Purple Dewplant Disphyma crassifolium 30 Terrestrial Red-legged Partridge Alectoris rufa 31 Terrestrial Red-osier Dogwood Cornus sericea 32 33 Terrestrial Reeve's muntjac Muntiacus reevesi 34 Terrestrial Rhododendron Rhododendron ponticum 35 Terrestrial Rhododendron Graphocephala fennahi 36 Leafhopper 37 Terrestrial Rose-ringed parakeet Psittacula krameri 38 Terrestrial Rosy Garlic Allium roseum 39 Terrestrial Ruddy duck Oxyura jamaicensis 40 Terrestrial Rum Cherry Prunus serotina 41 42 Terrestrial Russian-vine Fallopia baldschuanica 43 Terrestrial Shallon Gaultheria shallon 44 Terrestrial Sika Cervus nippon 45 Terrestrial Snowberry Symphoricarpos albus 46 47 Terrestrial Spartina planthopper Prokelisia marginata 48 Terrestrial Spiraea Spiraea 49 Terrestrial Steeple-bush Spiraea douglasii 50 Terrestrial Thorn-apple Datura stramonium 51 Terrestrial Tree-of-heaven Ailanthus altissima 52 53 Terrestrial Turkey Oak Quercus cerris 54 Terrestrial Virginia-creeper Parthenocissus quinquefolia 55 Terrestrial Wall Cotoneaster Cotoneaster horizontalis 56 Terrestrial Water Deer Hydropotes inermis 57 Terrestrial Western green lizard Lacerta bilineata 58 59 60 Page 22 of 30

1 2 3 Terrestrial White Butterbur Petasites albus 4 Terrestrial Winter Heliotrope Petasites fragrans 5 Terrestrial Wireplant Muehlenbeckia complexa 6 7 Terrestrial Yellow archangel Lamiastrum galeobdolon subsp. argentatum 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 23 of 30

1 2 3 4 5 6 7 8 9 10 For Peer Review 11 12 13 14 15 16 17 18 19

20 Number of species 21 22 0 23 24 1 - 10 25 26 11 - 50 27

28 51 - 100 29 30 101-150 31 32 33 151 - 200 34 35 201 - 250 36 Figure37 1. Origins of established non-native species (NNS) and the date of first record in Great Britain. The place of origin is shown at continent level,38 some species have a native range that covers multiple continents. The number of NNS indicates the total number of NNS within a native 39 range40 including that continent and a GB first record inBiological that date Journal range. Theof the innermost Linnean Societycircle denotes the date range 1500-1549 and each further concentric41 circle refers to a 50 year time period with the outermost circle representing the most recent date range 1950-1999. The colour of the continent42 relates to the most recent time period displayed (1950-1999). 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 24 of 30

1 2 3 Figure 2 4 5 700 6 7 600 8 9 500 10 11 400 12 13 300 14

15 Numberof species 200 16 17 100 18 19 0 20 21 22 23 24 Date of first record 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 25 of 30

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Figure 3. Richness of invasive non-native species (number of species per 10km square). 33 254x190mm (96 x 96 DPI) 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Non-Native Species Invasive Non-Native Species Page 26 of 30 I II 1 300 35 20 2 18 3 250 16 4 5 200 14 6 12 30 7 150 10 8 8 9 Plants 100 Number of species of Number species of Number 6 10 50 For Peer Review4 11 25 2 12 0 0 13 14 15 16 20 17 Date of first record Date of first record 18 III

Terrestrial Terrestrial IV 19 20 60 6 21 22 50 15 5 23 40 4 24 25 30 3 26 10 27 20 2 Animals 28 species of Number 29 10 species of Number 1 30 31 0 0 32 5 33 34 35 36 Date of first record Date of first record 37 0 38 1500-1549 1550-1599 1600-1649 1650-1699 1700-1749 1750-1799 1800-1849 1850-1899 1900-1949 1950-1999 39 A B C D E F 40 EUNIS Category G H I J U X 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 27 of 30 Non-Native Species Invasive Non-Native Species I II 135 35 10 35 4.5 2 9 4 3 4 8 3.5 5 7 3 630 30 6 30 2.5 7 5 2 8 4 9 Plants 1.5 Number of species of Number 3 species of Number 10 2 For Peer Review1 1125 25 25 0.5 12 1 0 13 0 14 15 1620 20 20 17 Date of first record Date of first record

18 Marine 19 III IV 20 35 10 9 2115 15 30 15 22 8 23 25 7 24 20 6 25 5 26 10 10 15 10 4 27 Animals

Number of species of Number species of Number 3 28 10 29 2 5 30 1 315 5 0 5 0 32 33 34 35 360 0 Date of first record 0 Date of first record 37 1500-154915001550-1549-159915501600-1599-164916001650-1649-169916501700-1699-150017491700-15491750-1749-155017991750-15991800-1799-160018491800-16491850-1849-165018991850-16991900-1899-170019491900-17491950-1949-175019991950-1799-19991800-1849 1850-1899 1900-1949 1950-1999 38 39 A AB BC CD DE EF FG AGH BHI CJI DUJ UEX FX G H I J U X 40 EUNIS Category 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Non-Native Species Invasive Non-Native SpeciesPage 28 of 30 I II 1 12 35 8 2 35 3535 35 7 3 10 4 6 5 8 5 6 30 7 6 4 30 3030 30 8 3 9 Plants 4 Number of species of Number species of Number 10 2 2 For Peer Review 11 25 1 12 25 2525 25 0 13 0 14 15 16 20 17 20 Date of first record Date of first record 20 201820 III IV

19 Freshwater 30 12 20 21 25 15 10 22 15 1515 15 23 20 8 24 25 15 6 26 10 10 4 27 Animals Number of species of Number species of Number 10 102810 10 29 5 2 30 0 0 31 5 32 5 3355 5 34 35 Date of first record Date of first record 36 0 37 1500-1549 1550-1599 1600-1649 1650-1699 1700-1749 1750-1799 1800-1849 1850-1899 1900-1949 1950-1999 0 3800 0 150039 -154915001500--1550154915491500-159915501550-1549--1600159915991550-164916001600-1599--1650164916491600-169916501650-1649--1700169916991650-174917001700-1699--1750174917491700-179917501750-1749--1800179917991750-1849A18001800-1799--185018491849B1800-189918501850-1849C --1900189918991850-1949D19001900-1899--195019491949E1900-199919501950-1949F --199919991950G -1999H I J U X 40 EUNIS Category 41 A AAB ABBC BCCD CDDE DEEF FEFG GFGH GHHI HIJI JUJI UUJX UXX X 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 29 of 30

1 2 3 Biological record 4 5 6 7 8 9 Database 10 For Peer Review 11 12 13 14 15 16 Expert verifier 17 18 19 20 21 Yes No 22 Record verified? 23 24 25 26 27 28 29 Stakeholders 30 31 informed 32 33 34 35 36 37 Action 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 Page 30 of 30

1 2 3 Figure 8 4 5 300 6 7 8 250 9 10 200 11 2011 12 150 2012 13 14 2013 15 100

Number ofNumber e-mails 2014 16 17 50 18 19 20 0 21 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60