(SPA/RAC - ONU Environment/PAM, 2017).
Although our ability to predict whether a NIS will become invasive is still limited, several
tools, such as the Aquatic Species Invasiveness Screening Kit (AS-ISK), can produce
estimations, which can assist the decision-making processes on NIS management (Hewitt
& Hayes, 2002; Copp et al., 2016). The AS-ISK tool assess the invasiveness potential of
NIS within a certain area. It follows the EU Regulation No 1143/2014 on invasive alien
species of EU concern (EC, 2014), and is particularly designed to work with marine
autotrophs, invertebrates and fish.
A continuous update of NIS spatial distribution, temporal occurrence and abundance,
especially in high-risk areas, is recommended by the Mediterranean Action Plan
concerning Species Introduction and Invasive Species (UNEP/MAP-RAC/SPA, 2008)
and the National Monitoring Program for Biodiversity and Non-indigenous Species of
Tunisia (SPA/RAC - ONU Environnement/PAM, 2017), which is in line with the
requirements of the Integrated Monitoring and Assessment Program of the Mediterranean
Sea and Coast and Related Assessment Criteria (UNEP/MAP, 2016a, 2016b; PNUEPAM-CAR/ASP, 2017). In this context, this study aims to identify the topics and
questions, among those provided by AS-ISK, that are most relevant for the risk
assessment of the invasiveness potential of NIS in the Mediterranean Sea, with special
focus on Tunisian coasts.
Materials and methods
A risk assessment was conducted using AS-ISK (Copp et al., 2016) on 20 taxa identified
on rapid assessment surveys conducted in six marinas of Tunisia in summer 2021 (see
Chebaane et al., 2022 for more details). A total of 55 questions were answered for each
taxon during the AS-ISK screening protocol. These include 49 questions for a Basic Risk
Assessment, which outputs the baseline and most accurate risk rank (Vilizzi et al., 2022)
and verses on the biological, biogeographical, ecological and socioeconomic aspects of
the scanned taxon. Also, 6 questions for a Climate Change Assessment, which evaluates
how future predicted climate conditions are expected to affect the risks of the taxon
introduction, establishment, dispersal, and impacts. The AS-ISK questions were
answered based on bibliographic information extracted from peer-reviewed literature
whenever possible, and a confidence level, ranging from ‘very high’ to ‘low’, was given
to each answer, based on the amount and quality of the information available to answer
(Copp et al., 2016).
After conducting the AS-ISK for all species (Chebaane et al., 2022), a subset of 37
suitable AS-ISK questions was selected and their answers were transformed into ordinal
variables, ranging from 0: negative response with the highest confidence to 7: positive
response with the highest confidence. These variables were then used to calculate
Euclidean Distances resemblances among the 20 assessed taxa. We used SIMPROF to
search for statistically homogeneous groups among these taxa and BEST to relate taxa
similarity with the summed scores of each group of questions by topic, as defined for ASISK by Copp et al. (2016). Results were visually displayed using a Principal Coordinates
Ordination (PCO) and those topics with a Spearman correlation higher than 5.0 with any
PCO axis were overlayed as vectors on the PCO plot. Analyses were conducted using
Primer-e v6 +PERMANOVA.
Results
The topics grouping questions on the taxon capacity for: (1) generate undesirable effects
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
69
Although our ability to predict whether a NIS will become invasive is still limited, several
tools, such as the Aquatic Species Invasiveness Screening Kit (AS-ISK), can produce
estimations, which can assist the decision-making processes on NIS management (Hewitt
& Hayes, 2002; Copp et al., 2016). The AS-ISK tool assess the invasiveness potential of
NIS within a certain area. It follows the EU Regulation No 1143/2014 on invasive alien
species of EU concern (EC, 2014), and is particularly designed to work with marine
autotrophs, invertebrates and fish.
A continuous update of NIS spatial distribution, temporal occurrence and abundance,
especially in high-risk areas, is recommended by the Mediterranean Action Plan
concerning Species Introduction and Invasive Species (UNEP/MAP-RAC/SPA, 2008)
and the National Monitoring Program for Biodiversity and Non-indigenous Species of
Tunisia (SPA/RAC - ONU Environnement/PAM, 2017), which is in line with the
requirements of the Integrated Monitoring and Assessment Program of the Mediterranean
Sea and Coast and Related Assessment Criteria (UNEP/MAP, 2016a, 2016b; PNUEPAM-CAR/ASP, 2017). In this context, this study aims to identify the topics and
questions, among those provided by AS-ISK, that are most relevant for the risk
assessment of the invasiveness potential of NIS in the Mediterranean Sea, with special
focus on Tunisian coasts.
Materials and methods
A risk assessment was conducted using AS-ISK (Copp et al., 2016) on 20 taxa identified
on rapid assessment surveys conducted in six marinas of Tunisia in summer 2021 (see
Chebaane et al., 2022 for more details). A total of 55 questions were answered for each
taxon during the AS-ISK screening protocol. These include 49 questions for a Basic Risk
Assessment, which outputs the baseline and most accurate risk rank (Vilizzi et al., 2022)
and verses on the biological, biogeographical, ecological and socioeconomic aspects of
the scanned taxon. Also, 6 questions for a Climate Change Assessment, which evaluates
how future predicted climate conditions are expected to affect the risks of the taxon
introduction, establishment, dispersal, and impacts. The AS-ISK questions were
answered based on bibliographic information extracted from peer-reviewed literature
whenever possible, and a confidence level, ranging from ‘very high’ to ‘low’, was given
to each answer, based on the amount and quality of the information available to answer
(Copp et al., 2016).
After conducting the AS-ISK for all species (Chebaane et al., 2022), a subset of 37
suitable AS-ISK questions was selected and their answers were transformed into ordinal
variables, ranging from 0: negative response with the highest confidence to 7: positive
response with the highest confidence. These variables were then used to calculate
Euclidean Distances resemblances among the 20 assessed taxa. We used SIMPROF to
search for statistically homogeneous groups among these taxa and BEST to relate taxa
similarity with the summed scores of each group of questions by topic, as defined for ASISK by Copp et al. (2016). Results were visually displayed using a Principal Coordinates
Ordination (PCO) and those topics with a Spearman correlation higher than 5.0 with any
PCO axis were overlayed as vectors on the PCO plot. Analyses were conducted using
Primer-e v6 +PERMANOVA.
Results
The topics grouping questions on the taxon capacity for: (1) generate undesirable effects
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
69