Spatial distribution modelling of the endangered bivalve Pinna nobilis in a Marine Protected Area

Abstract

The spatial distribution of Pinna nobilis densities have been analysed through a geostatistical approach in the MPA of Cabrera National Park, Balearic Islands (Spain), Western Mediterranean Sea. Regression kriging was used to model the effect of environmental variables on the density of living individuals of P. nobilis and generate a predictive map of its distribution within the MPA. The environmental variables considered for the model were: depth; slope; habitat type and heterogeneity; wave exposure; and MPA zoning. A total of 378 transects were randomly distributed with a total of 149,000 m 2 surveyed at a depth range from 4.2 to 46 m. The recorded P. nobilis densities are among the highest in the Mediterranean Sea. With respect to the prediction model, results indicate that benthic habitats play a key role in the spatial distribution of P. nobilis, with higher densities in seagrass meadows of Posidonia oceanica. The fan mussel population density peaked at 9 m depth, decreasing with depth. Also, decreasing densities are expected with increasing exposure to waves. The predicted map shows some hotspots of density different in size and distributed along the MPA, and provides valuable information for the spatial conservation management of this species.

S.O.S. Pinna nobilis: A Mass Mortality Event in Western Mediterranean Sea

“…In our case, given that P. nobilis presents the highest population densities in the central Spanish Mediterranean Sea (Southern Catalonia, Valencia Community, Murcia and the Balearic Islands; Guallart and Templado, 2012;Prado et al, 2014) and that in many of those areas the population has suffered a drastic decline close to 100%, it is estimated that the P. nobilis population could have been reduced by more than 90% at the national level (Spanish Mediterranean). In the case of the Balearic Islands, the Valencian Community and the Murcia Region some emblematic and long-studied localities for this species were found, such as Tabarca Marine Reserve in Alicante (Garcia-March et al, 2016), the Cabrera National Park in the Balearic Islands (Vázquez-Luis et al, 2014;Deudero et al, 2015) and Isla Grosa Natural Park in Murcia Region (Ruiz et al, 2016) with no individual alive to date. Taking into account that many of the most relevant populations at national level have been impacted by the MME, the consequences in the distribution, potential recovery, and therefore in the viability of the species are unknown and alarming, since most of the populations were already fragmented (Guallart and Templado, 2012).…”

Reproductive investment of the pen shell Pinna nobilis Linnaeus, 1758 in Cabrera National Park (Spain)

“…In total, 120 individuals ranging between 0.13 and 0.69 m shell length and 0.06 to 0.28 m shell width were extracted. This number represents a very low percentage of the pen shell population in the MPA and this number should not have affected the natural population (Vázquez-Luis et al, 2014a;Deudero et al, 2015).…”

“…The MPA was established in 1991 with an area of 100.21 km 2 , of which 87.03 km 2 are maritime. A differential zonation guarantees full protection at no-take zones and pen shell populations in these zones where no anchoring damage is inflicted are more mature and more numerous compared to populations at the main island of Mallorca (Hendriks et al, 2012a;Vázquez-Luis et al, 2014a;Deudero et al, 2015). Since most confounding factors present in intensively used coastal regions are excluded in this area, the National Park has been the site of choice for studies addressing ecological responses of http://epublishing.ekt.gr | e-Publisher: EKT | Downloaded at 29/03/2019 05:49:06 | Pinna nobilis and evaluating the effect of anthropogenic impacts, with Cabrera MPA as a control zone (Hendriks et al, 2012a, b;Vazquez-Luis et al, 2014a, b;Alomar et al, 2015;Deudero et al, 2015).…”

Benthic species of the Kerguelen Plateau show contrasting distribution shifts in response to environmental changes

“…Species geographic responses to the multiple effects of climate change may include resilience, distribution range shift toward the pole, where they would find more suitable conditions, and local extinction (Doney et al., ; Walther et al., ). Species distribution models (SDM) have been currently used to address these biogeographic issues for conservation purposes (Marshall, Glegg, & Howell, ; Reiss et al., ; Ross & Howell, ; Zucchetta, Venier, Taji, Mangin, & Pastres, ), assess the direct impact of human activities on ecosystems (Vázquez‐Luis, March, Álvarez, Álvarez‐Berastegui, & Deudero, ; Vierod, Guinotte, & Davies, ), and predict species distribution range shifts in response to climate change (Guillera‐Arroita et al., ; Tingley, Vallinoto, Sequeira, & Kearney, ). SDM relate species occurrence records to abiotic environmental predictors (Elith & Leathwick, ; Elith et al., ) to identify species suitable areas (Phillips et al., ).…”