Juan SEMPERE-VALVERDE, BOUHLEL R., BENZARTI O., CHEBAANE S.
Laboratorio de Biología Marina de la Universidad de Sevilla (LBMUS)/Estación
deBiología Marina del Estrecho (Ceuta), Departamento de Zoología, Facultad de Biología
de la Universidad de Sevilla, Av. de la Reina Mercedes, 41012 Sevilla, Spain.
E-mail: jsvalverde@us.es
INVASION ECOLOGY THROUGH RISK ASSESSMENT
QUESTIONS: A MULTIVARIATE COMPARISON AMONG NONINDIGENOUS SPECIES TRAITS IN THE MARINAS OF TUNISIA
Abstract
Marinas are highly modified habitats, hotspots of non-indigenous species (NIS) and hubs for NIS
introduction, acclimation and spread. Although most of the NIS that thrive inside marinas do not
have an invasive behavior in nearby natural coasts, they have the potential to become invasive in
these areas and generate ecological and socio-economic impacts. Therefore, it is imperative to
assess the risk of invasion for these species to inform management choices. The NIS and
cryptogenic species assessed in this study were identified during a rapid assessment survey
conducted in 6 marinas of Tunisia in August 2021. A multivariate dataset was generated from the
Aquatic Species Invasiveness Screening Kit (AS-ISK) questions answered to assess the risk of
invasion of each of these species. In this study, the answers to 37 AS-ISK questions were used as
variables to assess the Euclidean distances among NIS and cryptogenic species and identify the
traits related to their invasiveness potential. The main contributors to the risk of invasion were
the questions on the taxon capacity for (1) generate undesirable effects in the risk assessment
area, (2) exploit and sequestrate ecosystem resources and (3) reproduction and dispersal. Active
predators (decapods) scored highest in these traits, followed by sessile filter feeders and
ecosystem engineers. Overall, a subset of the questions provided a fairly accurate assessment of
the invasion risk and findings will be useful to understand the traits shared by potentially invasive
species and for the management of coastal NIS hotspots.
Key-words: Marinas, AS-ISK, Non-indigenous Species, Cryptogenic Species, Invasiveness
Introduction
The Mediterranean Sea is considered one of the main global hotspots of marine biodiversity,
as it represents less than 1% of world aquatic surfaces, but it hosts 18% of its macroscopic
marine species, from which about 30% are endemic (Bianchi & Morri, 2000). However, it is
also considered one of the most impacted marine regions of the world (Lejeusne et al., 2010).
Among the main threats that jeopardize its native biodiversity and ecosystems functioning
and services are the effect of human activities (e.g., habitats destruction, fragmentation, and
degradation), the effects of climate change and the impacts derived from marine invasions
(Bianchi & Morri, 2000; Lejeusne et al., 2010).
Marinas are hubs for non-indigenous species (NIS) introduction, acclimation and spread
(Molnar et al., 2008). These structures constitute the nodes of a network of highly
modified water bodies (HMWB) connected by recreational maritime traffic (Pineda et al.,
2011; Ros et al., 2020). Therefore, it is imperative to monitor NIS in these habitats and
assess the risk of invasion that these species pose to nearby areas (Chebaane et al., 2019;
Rondeau et al., 2022). Ultimately, a better understanding of NIS ecological risk will
improve the management strategies against biological invasions in coastal habitats
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
68
Laboratorio de Biología Marina de la Universidad de Sevilla (LBMUS)/Estación
deBiología Marina del Estrecho (Ceuta), Departamento de Zoología, Facultad de Biología
de la Universidad de Sevilla, Av. de la Reina Mercedes, 41012 Sevilla, Spain.
E-mail: jsvalverde@us.es
INVASION ECOLOGY THROUGH RISK ASSESSMENT
QUESTIONS: A MULTIVARIATE COMPARISON AMONG NONINDIGENOUS SPECIES TRAITS IN THE MARINAS OF TUNISIA
Abstract
Marinas are highly modified habitats, hotspots of non-indigenous species (NIS) and hubs for NIS
introduction, acclimation and spread. Although most of the NIS that thrive inside marinas do not
have an invasive behavior in nearby natural coasts, they have the potential to become invasive in
these areas and generate ecological and socio-economic impacts. Therefore, it is imperative to
assess the risk of invasion for these species to inform management choices. The NIS and
cryptogenic species assessed in this study were identified during a rapid assessment survey
conducted in 6 marinas of Tunisia in August 2021. A multivariate dataset was generated from the
Aquatic Species Invasiveness Screening Kit (AS-ISK) questions answered to assess the risk of
invasion of each of these species. In this study, the answers to 37 AS-ISK questions were used as
variables to assess the Euclidean distances among NIS and cryptogenic species and identify the
traits related to their invasiveness potential. The main contributors to the risk of invasion were
the questions on the taxon capacity for (1) generate undesirable effects in the risk assessment
area, (2) exploit and sequestrate ecosystem resources and (3) reproduction and dispersal. Active
predators (decapods) scored highest in these traits, followed by sessile filter feeders and
ecosystem engineers. Overall, a subset of the questions provided a fairly accurate assessment of
the invasion risk and findings will be useful to understand the traits shared by potentially invasive
species and for the management of coastal NIS hotspots.
Key-words: Marinas, AS-ISK, Non-indigenous Species, Cryptogenic Species, Invasiveness
Introduction
The Mediterranean Sea is considered one of the main global hotspots of marine biodiversity,
as it represents less than 1% of world aquatic surfaces, but it hosts 18% of its macroscopic
marine species, from which about 30% are endemic (Bianchi & Morri, 2000). However, it is
also considered one of the most impacted marine regions of the world (Lejeusne et al., 2010).
Among the main threats that jeopardize its native biodiversity and ecosystems functioning
and services are the effect of human activities (e.g., habitats destruction, fragmentation, and
degradation), the effects of climate change and the impacts derived from marine invasions
(Bianchi & Morri, 2000; Lejeusne et al., 2010).
Marinas are hubs for non-indigenous species (NIS) introduction, acclimation and spread
(Molnar et al., 2008). These structures constitute the nodes of a network of highly
modified water bodies (HMWB) connected by recreational maritime traffic (Pineda et al.,
2011; Ros et al., 2020). Therefore, it is imperative to monitor NIS in these habitats and
assess the risk of invasion that these species pose to nearby areas (Chebaane et al., 2019;
Rondeau et al., 2022). Ultimately, a better understanding of NIS ecological risk will
improve the management strategies against biological invasions in coastal habitats
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
68