Dear colleagues

I work on marine biodiversity and this contribution focuses on this.
Our concern about the loss of species at a global scale is probably right for terrestrial habitats, but it is difficult to name one marine species that has become extinct. Picard made the list of the hydrozoans of the Mediterranean in 1958 and listed less than 200 species. Now the list has doubled. Apparently biodiversity increased! And the mediterranean is one of the most impacted seas of the planet. If they ask us for numbers (not based on estimates but on real data) we might come up with no numbers or, paradoxically, with greater numbers today than in the past. We continue to describe new species, and so we give the impression that the more we look the more we find. Only very few marine species are so well known that they cause concern if threatened. The majority of them is inconspicuous and if they disappear ... nobody cares.

I have a species of hydrozoan that has not being recorded since 1865 and, to me, this calls for some attention on its status. It is Tricyclusa singularis (by the way, it is the only representative of a family). So, if you ask me to name one species that has disappeared from the mediterranean I say Tricyclusa singularis, but this does not impress many people. Even if I say that it is a whole family.

It is probably better to focus at the habitat level, but this is less impacting, and there are no extinct habitats as far as I know.

Jaques Cousteau, 30 years ago, said that the mediterranean sea would be dead in 20 years. Cousteau died and the Mediterranean is still there. These messages can be very dangerous. I too am concerned about the loss of biodiversity, but I am also concerned about having strong arguments (and not only estimates). The "name one" question about extinct species in the sea is crucial. And one is not enough. One should ask if this one species would have died anyway. Species die, just like people. We know it from evolutionary biology.

In my opinion we have to use the information on species stored in the taxonomic literature and then we have to monitor the last record for each one of them. If they are absent from the literature for more than 100 years, then we should look for them. If we do not find them, then we can raise a case for extinction. Numbers would immediately become greater. And we have to identify places where biodiversity (in terms of both species and habitats) is more at risk.

An example: the Northern Adriatic is the coldest part of the Mediterranean Sea. It hosts species of boreal affinity that live only there, like Fucus virsoides (and Tricyclusa singularis). If there is global warming (and there is) what is the place in the Mediterranean that will be most affected? If the temperature rises, the cold water species go north or go deeper. In the northern Adriatic they cannot go north (there is the land) or deeper (it is a shallow basin). The communities of boreal affinity of the Northern Adriatic are probably the most sensitive to global warming. Let's make a list of the species that live just there (I gave two examples, but there are many more) and then let's see if they are still there. My bet is that they are in distress. We need data, and not estimates. These things can be done by taxonomists, because they know the history of the knowledge on biodiversity. Taxonomic literature is there to tell us when and where most species have been recorded.

I am not claiming that this is the only approach to this problem, but this is one of the many ways that we might run to foster our views while having real data.

Ferdinando Boero
DiSTeBA (Dipartimento di Scienze e
Tecnologie Biologiche e Ambientali)
Universita' di Lecce
73100 Lecce
Italy