CIESM Tropicalization Program: tropicalization of the Mediterranean Sea

RATIONALE
The impact of climate change has become a matter of great concern worldwide. There is increasing scientific evidence that climatic changes significantly contribute to the alteration of marine biodiversity, leading to species loss, introduction of alien species, changes in foodwebs and modification in the abundance and distribution of species.

In the Mediterranean Sea, where changes in biodiversity are occurring at an unprecedented rate and where some 30% of the species are endemic, the importance of investigating causes and patterns for these changes is a matter of urgency. In fact, due to its unique location at the cross-road between the Atlantic and Indo-Pacific biogeographic domains, the magnification of climatic signals in its enclosed basin, the Mediterranean Sea is a remarkable case study to investigate the influence of climate change on biodiversity.

The warming of waters, along with a marked alteration of the precipitation and evaporation regimes, are accelerating the establishment of tropical species in the Mediterranean and the retreat of cold-temperate species towards northern colder areas of the Basin. This ongoing process of Mediterranean “tropicalization” remains poorly understood, based on fragmented, occasional, usually local observations.

SCIENTIFIC OBJECTIVES
The overall aim of the Tropicalization Program is to track at regional level changes in the abundance and geographic range of distribution of key selected marine species in relation to climate change. The program will:
    • Review and integrate existing information on past and current status of selected taxa;
    • Identify a set of “sentinel species” which can reliably represent indicators of climate change;
    • Track the geographic expansion of “warm-water” species (with affinity to warmer waters) and the retreat of “cold-water” species (with affinity to colder waters);
    • Record mass events (invasions, blooms, mass mortalities) in the Basin;
    • Relate changes in abundance and distribution ranges of Mediterranean species to the variability and trends of the hydro-climatic environment.
EXPECTED LONG-TERM OUTPUTS:
    • The establishment of a Mediterranean “biodiversity warning system”, based on climate-indicator species, to detect and monitor major changes in marine biodiversity across the Basin.

    • The identification of a list of species or taxa that will be mostly threatened by increasing warming of waters and climate-related events and thus in need of special protection.

    • The development of dynamic, web-interfaced, interactive distribution maps providing information on taxonomy, ecological traits and geographic trends of climate-indicator species.

    • The publication of collaborative papers in international per-reviewed journals and expert reports synthesising trends in Mediterranean marine biodiversity.
ADDED VALUE TO THE WIDER COMMUNITY
-   The multi-national character of the program will encourage exchange of scientific knowledge and expertise, seed and strengthen collaborations between researchers of all shores.
-   The program is relevant to main recommendations of the Barcelona Convention, EU Habitat and Water Framework Directives, and will help to forge conservation strategies for biodiversity.
-   The program outcomes will contribute to assess tropicalization impacts on species commercially important for fisheries, for example by providing information on geographic shifts as a consequence of warming of waters and/or competition with fast advancing species of low economic value.
PLANNED ACTIVITIES (2008-2012)
The Program, co-financed until 2012 by the Prince Albert II Foundation, will unfold as follow:
    • 2008 – 1. In depth study of CIESM archives (“Fiches faunistiques”, scientific papers) and other data sources; 2. Definition of criteria for selection of indicator species and strategic monitoring areas; 3. Expert meeting (validation of key indicator species, detailed monitoring work plan and protocols, definition of common format for meta-base);

    • 2009-2011 – 1. Field surveys of key indicator species in targeted areas; 2. Data analysis and correlation with hydro-climatic trends (links with HydroChanges, JellyWatch, MedGloss CIESM Programs; satellite data); 3. Organisation of special Panel at the 2010 CIESM Congress; 4. Annual meetings (work progress, results outputs); 5. Establishment of the “biodiversity alert system” in key strategic areas;

    • 2012 – 1. Continuation of field monitoring activities; 2. Data analysis and dissemination of project results (scientific collaborative articles, general audience publications and presentations to conferences); 3. Wrap-up meeting (program outcomes, planning for continuation of field monitoring activities, addition of new research modules, etc.).

PARTICIPATING INSTITUTES
Leading experts in marine taxonomy, biogeography and climate change from 22 Institutes based in 15 riparian countries have been invited to constitute the core of the Program.