Development of an ecological quality classification system for aquatic bioinvasions Sergej Olenin, Klaipeda University, Lithuania

European Alien Species (DAISIE) Database Marine species total # 1016 (747 established) –inland species total # 693 (313 established) 4290 introduction records (events) –A record of an alien species in a country/region Aquatic species 14% n = 1512 Terrestrial species (plants animals etc) 86% n = 9288 Data coverage: >50 countries/regions and coastal seas

The number of introduced species tells little about the real threat of bioinvasions What matters is the MAGNITUDE of the impacts! »Examples of the Mediterranean (>620 NIS known) and the Black (165 NIS recorded) Seas. »In the later, just one species (the American comb jelly Mnemiopsis leidyi) caused catastrophic, ecosystem wide impacts!

How to assess “levels (of NIS) that do not adversely alter the ecosystems”? Promising approach: Olenin et al 2007, Marine Pollution Bulletin, 55 (7-9),

XVI Congresso della Società Italiana di Ecologia - Ancona 2007 BIOPOLLUTION AND ALIEN SPECIES: AN INDEX OF ENVIRONMENTAL QUALITY FOR THE NORTHERN ADRIATIC SEA D. Savini, A. Occhipinti Ambrogi 5

Aim: We apply to the Northern Adriatic Sea, recognized as a major hotspot of xenodiversity in the Mediterranean, the method “Assessment of biopollution in aquatic ecosystem” proposed by Olenin et alii (2007) for the Baltic Sea 6

Presentation outline:  Rationale of the AS Biopollution Index (BPL)  A selected study case: the predatory gastropod Rapana venosa  Biopollution in the Northern Adriatic Sea  Final remarks 7

Biopollution index (BPL) - rationale Postulates: Abundance, distribution range and magnitude of AS impact can vary over time AS produce measurable effects only after they have attaining a particular level of abundance and when occupying a sufficiently large area Prerequisites for BPL: Data on AS abundance and distribution range Ecological, biological knowledge of AS Impact magnitude: 1.Community 2.Habitat 3.Ecosystem 8

BPL- rationale 1) Ranking abundance (low, moderate, high) and distribution range (one, several, many, all localities) CodeAn AS occurs: A in low numbers in one or several localities B in low numbers in many localities in moderate numbers in one or several localities in high numbers in one locality C in low numbers in all localities in moderate numbers in many localities in high numbers in several localities D in moderate numbers in all localities in high numbers in many localities E in high numbers in all localities 9

One locality for a Sea Several localities for a coastal zone Many localities for a lagoon within the coastal zone All localities for a zone of a coastal lagoon The study area should be defined 10

Impact on species & community level - rationale Impacts: Hybridisation Competition with native sp (food, nutrients, light, space) Grazing Predation Parasitism Toxin production Change in species ranking Displacement of native species Loss of type specific community Loss of keystone species 11

Impact on species & community level - score CodeImpactDescription C0 None No displacement of native sp in presence of AS Ranking of native sp quantitatively unchanged. Type specific community present C1 Weak Local displacement of native sp (no extintion). Quantitative change in ranking of native sp, dominant species unchanged Type specific community present C2 Moderate Large scale displacement of native sp (decline in abundance and distribution range (no extintion) Shift in community dominant species Type specific community noticeably changed C3 Strong Local population extinction Native dominant species still present but highly reduced (AS dominant) Loss of type specific community C4 Massive Local population extinction of keystone native species Local extinction of type specific community in more than one ecological group 12

Impact on habitat - rationale Impacts: Substrate alteration (physical, chemical) Sediment transport, water flow Nutrients regime, water turbidity Replacement of keystone habitat forming species Structural alteration Spatial reduction Habitat loss Key habitat loss 13

Impact on habitat - score CodeImpactDescription H0 None No alteration H1 Weak Structural alteration No reduction of spatial extent H2 Moderate Structural alteration Reduction of spatial extent H3 Strong Structural alteration of a key habitat Severe reduction of its spatial extent Loss of habitat within a locality of the assessment unit H4 Massive Loss of habitat in most or the entire assessment unit Loss of a key habitat 14

Impact on ecosystem functioning - rationale Impacts: Shift in trophic nets Alteration of energy and organic material flow Alteration of benthic- pelagic coupling Addition or loss of ecosystem functions 15

CodeImpactDescription E0 None No measurable effect E1 Weak Measurable but weak changes (no loss or addition of ecosystem function) E2 Moderate Moderate modifications of ecosystem performance Addition or reduction of existing functional group(s) in some part of the assessment unit E3 Strong Severe shift in ecosystem functioning in part of the assessment unit Reorganisation of the food web E4 Massive Loss of the role of one or more functional groups Extreme shift in the food web Impact on ecosystem functioning - score 16

Biopollution levels (0-4) based on abundance and distribution range (A-E) out of 75 possible combinations only 50 make sense e.g. if an AS occurs in low numbers in one locality (A), is highly unlikely that it causes large scale displacement of native species (C2), but is highly possible it causes local displacement of native species, weak structural alteration of the habitat and localised changes in ecosystem functioning BPL integrated matrix 17

BPL total score BPL should be assessed for a defined water body (assessment unit) and for a defined period of time (assessment period) Assessment should be performed for each AS known in the assessment unit BPL Score is determined according to the greatest impact level (conservative approach) e.g. if an AS causes: Weak impact on species- community level (C=1) Moderate impact on habitat (H= 2) Weak impact on ecosystem functioning (E= 1) The Overall BPL score (for the assessment unit/study area) is determined according to the greatest impact level for at least one species during the evaluation period e.g. in a five years assessment period, BPL score is  1 for 19 AS and = 3 for one species. Tot BPL = 2 Tot BPL = 3 18

Selected study case: the predatory gastropod Rapana venosa A SUCCESSFULL INVADER – WHY? high reproduction rates high diffusion capabilities no efficient competitors no efficient predators no commercial value (?) Tolerant to: salinity temperature water pollution low oxygen concentration Neogastropoda: Muricidae Origin: Japan and adiacent seas First report: 1973 Vectors: Ballast waters, no target species associated with bivalve cultures Max size (Italy): 14 cm SL Max weight (Italy): 470 g FTwt 19

1. Abundance and distribution range (ADR) (Cesari & Pellizzato, Savini et al ) Lagoons ADR CODE: A Low numbers in several localities: Grado, Marano, Venice, Goro Coast ADR CODE: C moderate numbers in many localities 20

2. Impact on species community Code C1 (week) local (Cesenatico) displacement of native species, dominant species unchanged, type specific community present (Predation rates on bivalve community- Savini, Occhipinti 2006) d1d1d3d3d7d7d9d9d13d15d17d21d28d31d35d37d39d44 time total n. eaten M.galloprovincialisA. inaequivalvisT. philippinarum Av. daily ingestion rate: 1.2 g day -1 (fresh body wt) the preferred prey is a non native (A. inaequivalvis) native natural mussel beds develop on artificial structures (breakwaters) 21

3. Impact on habitat Gastropod predation removes mussels (habitat structuring species) from hard bottom (mainly artificial structures) (Savini et al 2004) Code H2 (moderate) structural alteration, local reduction of spatial extent 22

4. Impact on ecosystem functioning Functional alteration: 1)Rapana is a top predator of bivalves (Harding, Mann 1998, Savini et al 2002, Savini et al 2006) 2) Strong predation can alter local benthic-pelagic coupling (Harding, Mann 1998) 3)Young gastropods and egg cases are potential prey for crab and fishes (Savini, Occhipinti 2004) 4) Live and empty shells of Rapana provide substrata for epibionts (Savini et al. 2004) Code: E2 (Moderate) Moderate modifications of ecosystem performance, addition or reduction of existing functional group(s) in some part of the assessment unit 23

R. venosa BPL score Assessment unit: lagoon (BPL = 1 weak impact) Assessment unit: coast (BPL = 2 moderate impact) 24

Biopollution in the Northern Adriatic Sea Summarising…… 25

Assessment unit: Lagoons 7 Algae 7 Bivalves 1 Gastropod 3 Crustaceans 1 Bryozoan tot: 19 established AS Impact info : 11 AS TOT BPL = 3 - Strong (R. philippinarum, M. senhousia) Assessment period: 34 years Assessment unit: Coast 1 Algae 4 Bivalves 1 Gastropod 1 Amphipod tot: 7 established AS Impact info : 6 AS TOT BPL = 2 - Moderate 26

Final remarks BPL index appears to be an easy straightforward method for quantifying AS impact and compare study sites at different geographical scales Despite the “gap of knowledge” on AS distribution, abundance and impact in the Northern Adriatic Sea, the application of BPL index discriminates between lagoons and coastal areas (assessment units) BPL index confirms that lagoons and brackish waters ecosystems are preferential sites of AS species introduction and biopollution A national cooperative effort between researchers is necessary to fill gaps of knowlege, in order to: increase confidence in results, answer to EU reccomandations, provide administrators with convincing decision support systems. 27

Confidence level applied for assessing the impacts High The impacts were documented by field and/or experimental studies for the given assessment unit Medium The impacts were documented by field and/or experimental studies for a part of the assessment unit and extrapolated to the entire system by expert judgment Low The impacts were not documented neither by field nor by experimental studies expert knowledge of the species impact based on data from studies made elsewhere was applied

The decision support scheme for assessment of Biopollution Level (BPL) Used to develop the Computerized Biopollution Assessment Tool

Biopollution assessment tool Provides a uniform approach for assessment of alien species impacts enabling comparison between different alien species and different areas. May be used for: –acquiring baseline information on alien species –monitoring of biopollution impacts –prioritizing impacting species (target species lists) –evaluation of effectiveness of bioinvasion management.

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