22/09/2022

Daniele GRECH, PILLONI Z., BURTON M., SERRA E., BRUNDU G., BAROLI M., PORPORATO E.M.D., MASSARO G., CECCHERELLI G., CERRI J., AZZURRO E.

Abstract
The Mediterranean basin is among those areas of the world most affected by the introduction of
Non-Indigenous Species (NIS). NIS are a growing driver of change for terrestrial and aquatic
ecosystems, but their management and presence evaluation within the decision-making
process,is often constrained by the lack of spatially-explicit information, such as about their
presence, abundance and spatial distribution (mapping). Therefore, considerable efforts are
devoted in collecting this information, for example through biodiversity inventories, which are
nevertheless demanding and complementary sources of information such as Local Ecological
Knowledge (LEK) raise growing interest. The aim of this study is to investigate the spatio-
temporal changes of the distribution of NIS in Oristano lagoons, Sardinia (Western
Mediterranean Sea). This island, with more than 1.800 km of coastline and almost 500 km2of
wetlands (ca. 2% of the Sardinian territory) represents 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 small-
scale fishers, in order to evaluate the perceived distribution and historical changes. Local
fishermen have been asked to draw the distribution of selected species on pre-printed maps,
indicating areas characterized by different perceived abundances. The abundance of each
species was rated on an ordinal scale, according to LEK standard protocol, from 0 (Absent) to
5 (Dominant, always in captures and abundant). Afterwards, maps were digitized on a GIS and
abundances overlapped and synthesized in a unique layer per species. These findings will
contribute to consolidate the use of participatory mapping approach in relation to the
increasing ecological and socio-economic pressures posed by marine bioinvasions, providing
new insights for spatially informed management of NIS in Sardinia coastal waters

UNEP/MAP – SPA/RAC 2022