and valuable tool for managing NIS is an up-to-date knowledge on their location, which
is crucial for conservation priorities (e.g. alien vs. protected species). For this reason,
inventories and mapping of alien species are increasingly important, and a major
international effort focused on collecting and summarizing data on the current status is
crucial, so as to have a robust baseline for assessing historical changes occurring in
ecosystems, Local Ecological Knowledge (LEK; Beaudreau et al., 2014) is the
information that people have about local ecosystems where they spend most of time.
This knowledge is acquired by individuals during daily activities such as fishery,
therefore, considerable efforts should be taken into account i.e. through biodiversity
inventories (which are, however, demanding in terms of sampling resolution) or
complementary sources of information such as LEK, which have been attracting
increasing interest in recent years (Azzurro et al., 2019) .
In Sardinia Island (Italy), studies on the distribution of NIS and autochthonous species
are rather rare or fragmentary, mostly attributable to temporally or spatially reduced
surveys, as is the involvement of society in scientific research (Grech et al., 2020). This
is particularly true considering that Sardinia is the main connection towards the western
Mediterranean basin: an outpost of early detection of NIS on a large island poorly
inhabited land with complex and fragmented coastline, where the participatory approach
of the population is still in its infancy, but with a great increasing potential. Indeed,
these actions, if properly supported, can also trigger important synergies, generating
awareness in society and improving the exchange of information within the general
public, something that is of paramount importance in the field of invasion biology
(Alvito & Grech, 2021).
Some pioneering approaches about this topic have recently been presented by Azzurro
& Cerri (2021) in the Lesina lagoon (Adriatic Sea), and similar social involvement
initiatives are underway in projects sharing standardized protocols for Mediterraneanscale data collection in Marine Protected Areas (Garrabou et al., 2018; 2022).
The aim of this study is to investigate occurrence, abundance and spatio-temporal
changes on the distribution of NIS in the study area of Oristano lagoons, Sardinia
(Western Mediterranean Sea).
Materials and methods
The study area is located in the West coast of Sardinia, an island with more than 1,800
km of coastline and almost 500 km
2 of wetlands (ca. 2% of the territory) representing a
biodiversity hotspot where field-based NIS inventories are demanding, due to the
extension of these ecosystems and the lack of in-depth research.
NIS occurrence and temporal dynamics were quantified by eliciting the LEK of smallscale fishers in 6 coastal lagoons (Is Benas, Mistras, Cabras, Santa Giusta,
S’EnaArrubia, Marceddì).
Local fishermen have been asked to draw the distribution of selected species on preprinted maps, indicating areas characterized by different perceived abundances. Species
were selected after targeted bibliographic research. The abundance of each species was
rated on an ordinal scale, according to LEK standard protocol (Azzurro et al., 2019;
Azzurro & Cerri, 2021) abundance values (0 = Absent, 1 = Rare, 2 = Occasional, 3 =
Common, 4 = Abundant, 5 = Dominant) and if possible, to give a temporal score of
abundance during years. Maps were then digitized applying a mesh on a GIS and
abundances were overlapped and synthesized (mean) in a unique layer per species for
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
43
is crucial for conservation priorities (e.g. alien vs. protected species). For this reason,
inventories and mapping of alien species are increasingly important, and a major
international effort focused on collecting and summarizing data on the current status is
crucial, so as to have a robust baseline for assessing historical changes occurring in
ecosystems, Local Ecological Knowledge (LEK; Beaudreau et al., 2014) is the
information that people have about local ecosystems where they spend most of time.
This knowledge is acquired by individuals during daily activities such as fishery,
therefore, considerable efforts should be taken into account i.e. through biodiversity
inventories (which are, however, demanding in terms of sampling resolution) or
complementary sources of information such as LEK, which have been attracting
increasing interest in recent years (Azzurro et al., 2019) .
In Sardinia Island (Italy), studies on the distribution of NIS and autochthonous species
are rather rare or fragmentary, mostly attributable to temporally or spatially reduced
surveys, as is the involvement of society in scientific research (Grech et al., 2020). This
is particularly true considering that Sardinia is the main connection towards the western
Mediterranean basin: an outpost of early detection of NIS on a large island poorly
inhabited land with complex and fragmented coastline, where the participatory approach
of the population is still in its infancy, but with a great increasing potential. Indeed,
these actions, if properly supported, can also trigger important synergies, generating
awareness in society and improving the exchange of information within the general
public, something that is of paramount importance in the field of invasion biology
(Alvito & Grech, 2021).
Some pioneering approaches about this topic have recently been presented by Azzurro
& Cerri (2021) in the Lesina lagoon (Adriatic Sea), and similar social involvement
initiatives are underway in projects sharing standardized protocols for Mediterraneanscale data collection in Marine Protected Areas (Garrabou et al., 2018; 2022).
The aim of this study is to investigate occurrence, abundance and spatio-temporal
changes on the distribution of NIS in the study area of Oristano lagoons, Sardinia
(Western Mediterranean Sea).
Materials and methods
The study area is located in the West coast of Sardinia, an island with more than 1,800
km of coastline and almost 500 km
2 of wetlands (ca. 2% of the territory) representing a
biodiversity hotspot where field-based NIS inventories are demanding, due to the
extension of these ecosystems and the lack of in-depth research.
NIS occurrence and temporal dynamics were quantified by eliciting the LEK of smallscale fishers in 6 coastal lagoons (Is Benas, Mistras, Cabras, Santa Giusta,
S’EnaArrubia, Marceddì).
Local fishermen have been asked to draw the distribution of selected species on preprinted maps, indicating areas characterized by different perceived abundances. Species
were selected after targeted bibliographic research. The abundance of each species was
rated on an ordinal scale, according to LEK standard protocol (Azzurro et al., 2019;
Azzurro & Cerri, 2021) abundance values (0 = Absent, 1 = Rare, 2 = Occasional, 3 =
Common, 4 = Abundant, 5 = Dominant) and if possible, to give a temporal score of
abundance during years. Maps were then digitized applying a mesh on a GIS and
abundances were overlapped and synthesized (mean) in a unique layer per species for
2nd Mediterranean Symposium on the Non-Indigenous Species (Genoa, Italy, 22-23 September 2022)
43