Risk Assessment: ………….. ACACIA SALIGNA Prepared by: Etienne Branquart (1), Vanessa Lozano (2) and Giuseppe Brundu (2) (1) [[email protected]] (2) Department of Agriculture, University of Sassari, Italy [[email protected]] Date: first draft 01 st November 2017 Subsequently Reviewed by 2 independent external Peer Reviewers: Dr Rob Tanner, chosen for his expertise in Risk Assessments, and Dr Jean-Marc Dufor-Dror chosen for his expertise on Acacia saligna . Date: first revised version 04 th January 2018, revised in light of comments from independent expert Peer Reviewers. Approved by the IAS Scientific Forum on 26/10/2018 1 2 3 4 5 6 7 1 Branquart, Lozano & Brundu PRA Acacia saligna 8 9 10 Contents 11 Summary of the Express Pest Risk Assessment for Acacia saligna 4 12 Stage 1. Initiation 6 13 1.1 - Reason for performing the Pest Risk Assessment (PRA) 6 14 1.2 - PRA area 6 15 1.3 - PRA scheme 6 16 Stage 2. Pest risk assessment 7 17 2.1 - Taxonomy and identification 7 18 2.1.1 - Taxonomy 7 19 2.1.2 - Main synonyms 8 20 2.1.3 - Common names 8 21 2.1.4 - Main related or look-alike species 8 22 2.1.5 - Terminology used in the present PRA for taxa names 9 23 2.1.6 - Identification (brief description) 9 24 2.2 - Pest overview 9 25 2.2.2 - Habitat and environmental requirements 10 26 2.2.3 Resource acquisition mechanisms 12 27 2.2.4 - Symptoms 12 28 2.2.5 - Existing PRAs 12 29 Socio-economic benefits 13 30 2.3 - Is the pest a vector? 14 31 2.4 - Is a vector needed for pest entry or spread? 15 32 2.5 - Regulatory status of the pest 15 33 2.6 - Distribution 17 34 2.7 - Habitats and where they occur in the PRA area 22 35 2.8 - Pathways for entry 24 36 2.9 - Likelihood of establishment in the natural environment in the PRA area 25 37 2.10 - Likelihood of establishment in managed environment in the PRA area 26 38 2.11 - Spread in the PRA area 26 39 2.11.1 - Natural spread 26 40 2.11.2 - Human-mediated spread 27 41 2.12 Impact in the current area of distribution 28 42 2.12.1 - Impacts on biodiversity 28 43 2.12.2 - Impact on ecosystem services 29 44 2.12.3 - Socio-economic impact 31 45 2.13. Potential and actual impact in the PRA area 32 46 2.14 Identification of the endangered area 34 47 2.15 Climate change 34 2 Branquart, Lozano & Brundu PRA Acacia saligna 48 2.15.1 - Define which climate projection is being used from 2050 to 2100 35 49 2.15.2 - Components of climate change considered most relevant for A. saligna 36 50 2.15.3 - Influence of projected climate change scenarios on A. saligna 36 51 2.16 - Overall assessment of risk 37 52 Uncertainty 38 53 Remarks 38 54 2.21 – REFERENCES 39 55 Appendix 1. Relevant illustrative pictures (for information) 51 56 Appendix 2. Biological traits and soil factors for Acacia saligna subspecies 55 57 Appendix 3. Impact of Australian acacias on ecosystem functioning and services 57 58 Appendix 4. Projection of climatic suitability for Acacia saligna establishment 59 59 4.1 - Aim 59 60 4.2 - Data for modeling 59 61 4.4 – Results: current climate 63 62 4.5 – Results: future climate projection 63 63 64 65 66 Acknowledgements 67 68 The authors are enormously grateful to Daniel Chapman who shared his experience and 69 modelling skills in order to define the area suitable for Acacia saligna establishment in Europe 70 under current and future climates. They also want to thank Brian van Wilgen and Jean-Marc 71 Dufour-Dror for the information they provided concerning the impact, the public perception and 72 the management of this exotic tree in South Africa and Israel, respectively. Useful comments 73 and suggestions were also provided on a previous version of this text by Robert Tanner and two 74 anonymous peer reviewers. 75 76 77 3 Branquart, Lozano & Brundu PRA Acacia saligna 78 Summary of the Express Pest Risk Assessment for Acacia saligna 79 80 PRA area: European Union excluding outermost territories 81 82 Main conclusions 83 The results of the PRA show that A. saligna poses a high risk to the endangered area within the European 84 Union under current climate (i.e. significant parts of the Mediterranean Biogeographical region, but also 85 countries along the Atlantic and the Black sea coasts for the ‘pruinescens ’ subspecies), with a low 86 uncertainty (figure 5 in Appendix 4). Impacts in the current introduced range are high, and although the 87 risk of further introduction in the European Union is considered as low, there is a moderate perceived risk 88 of spread from established populations, facilitated by water and movements of soils contaminated by 89 seeds or fragments of root suckers. Furthermore, the endangered area is likely to increase a lot during the 90 coming decades due to climate change (figure 6 in Appendix 4). 91 Entry and establishment 92 A. saligna is already established in the endangered area within the European Union. It is a 93 widespread IAS in the coastal areas of Cyprus, Italy, Portugal and Spain; it is also recorded from 94 Croatia, France, Greece and Malta, but on a more sporadic basis. A. saligna is still absent from 95 Bulgaria, Slovenia and Romania, although appropriate climatic conditions and habitats are 96 encountered. The risk of further entry into the region as seeds and plant for planting is considered low 97 with a low uncertainty. The potential for establishment in both the natural and managed environment is 98 high with a low uncertainty. This potential is known to be favoured by fire and soil disturbance that create 99 suitable conditions for germination (breaking seed dormancy) and establishment of seedlings of A. 100 saligna . 101 Potential impacts in the PRA area 102 Impacts on biodiversity are likely to be similar in the PRA area as to those documented in the current area 103 of distribution (high with a low uncertainty). In Cyprus, Italy, Malta and Portugal, A. saligna forms 104 extensive dense stands which can exclude most native plant species and change community composition, 105 especially in coastal sand dune and riparian ecosystems. Impacts on several Red Data Book species in the 106 EU are expected such as for Aegilops bicornis, Anchusa crispa subsp. maritima and Anthyllis hermanniae 107 subsp. brutia . 108 Impacts on ecosystem services will be similar to those seen in the current area of distribution (high with a 109 moderate uncertainty). A. saligna persistently transforms ecosystems and their disturbance regime 110 through reinforcing feedback processes. It affects provisioning (reduction of surface runoff and soil water 111 reserves), regulating and supporting (modification of nutrient cycling and soil properties) and cultural 112 services (reduction of aesthetic and recreational landscape quality). It may also increase fire intensity and 113 frequency under extreme climatic conditions. 114 Socio-economic impacts will be similar in the PRA area as to those seen in the current area of distribution 115 (high with moderate uncertainty), due e.g. to the very high costs caused by a strong hydrological impact 116 (loss of water provision) and its long-term management. 117 Climate change 118 Climate change scenario RCP8.5 is predicted to increase suitability dramatically and to cause a strong 119 expansion of the endangered area within the European Union. Major parts of the Mediterranean, Black 120 Sea, Atlantic and Continental biogeographical regions will be at risk for all the different subspecies; it is 121 also predicted that the ‘ lindleyi ’ and the ‘ pruinescens ’ subspecies will be able to establish in a wider 122 range, including a larger part of the Continental biogeographical region and most of the Pannonian 123 biogeographical region (see figure 6 in Appendix 4). Climate change is also expected to alter the 4 Branquart, Lozano & Brundu PRA Acacia saligna 124 geographic distribution of wildfire, a process that could promote further establishment of Acacia saligna 125 close to plantations and invaded sites. 126 Socio-economic benefits 127 While the plant is traded as an ornamental, as forestry species or for other uses including honey 128 production, the value it currently generates within the European Union is limited and benefits it produces 129 are unlikely to exceed the cost of negative impacts it causes. Moreover, alternative species are available. 130 Future profits generated by biomass production on marginal soils are expected to be limited due to 131 suboptimal growth conditions and accompanied by high profitability uncertainty. 132 Phytosanitary risk for the endangered area : HIGH 133 Level of uncertainty of assessment: LOW 134 Other recommendations: 135 With the exception of South Africa, very limited efforts have been conducted in the invaded range and in 136 the European Union to distinguish among the different subspecies or variants described for Acacia 137 saligna . Other Australian acacia species (e.g. A. dealbata, A. longifolia, A. mearnsii and A. melanoxylon) 138 are introduced and planted for various purposes within the European Union and some of them are 139 reported to colonise natural environments. An accurate assessment of their invasiveness should be 140 conducted before further use. 141 5 Branquart, Lozano & Brundu PRA Acacia saligna 142 Express Pest Risk Assessment 143 ACACIA SALIGNA 144 Prepared by: Etienne Branquart (1), Vanessa Lozano (2) and Giuseppe Brundu (2) 145 (1) [[email protected]] 146 (2) Department of Agriculture, University of Sassari, Italy [[email protected]] 147 Date: first draft 01 st November 2017 148 Date: first revised version 04 th January 2018 149 Stage 1.