Memorias de la RSEHN (segunda época)

Se comentan brevemente algunas características de la biodiversidad marina en comparación con la terrestre. Mientras que la riqueza de especies del conjunto de metazoos y macrófitos en el medio terrestre es notablemente superior a la del marino (alrededor del 85% frente al 15%, respectivamente), la biodiversidad medida en modelos estructurales y formas de vida es muy superior en mares y océanos, donde están representados casi todos los grandes grupos de organismos pluricelulares.

Tras esta introducción, se analizan las particularidades del medio marino en España que determinan que nuestras aguas alberguen las mayores cifras de biodiversidad de todo el ámbito geográfico europeo y norteafricano. Los estudios sobre nuestra flora y fauna marinas se intensificaron de una forma muy notable durante el último cuarto del siglo pasado. Ello ha conducido a un buen nivel actual de conocimientos en los aspectos más básicos (taxonómicos, florísticos y faunísticos). En el presente trabajo se aportan los números de especies de los diferentes filos de organismos pluricelulares marinos conocidos a nivel, mundial, europeo, español y canario. Se conocen en la actualidad unas 10.300 especies de organismos pluricelulares en nuestras aguas marinas territoriales, incluyendo Canarias (unas 1.050 de macrófitos y unas 9.250 de metazoos), lo que supone alrededor del 4,6% del número de especies marinas conocidas a nivel mundial.

Finalmente, se comenta el alarmante declive de la taxonomía morfológica en los últimos años, a favor de otras disciplinas, como la sistemática molecular o la ecología, mejor valoradas por los criterios actuales de evaluación de la actividad investigadora.

Species diversity (of metazoan and macrophytes) appears to be far lower in the sea (around 220,000 known species) than on land (near 1,7 million known species), probably because marine water is a continuous environment, without apparent barriers to dispersion (most marine species have wide geographical range), and they are physically much less variable in space and time than terrestrial environment. Besides, the most diverse group of organisms, the insects (within the animal kingdom) and the angiosperms (within the vegetal kingdom) are almost exclusive of terrestrial and freshwater environments. Nevertheless, the diversity of major lineages (phyla and classes) is much greater in the sea than on land or in freshwaters. Except Onychophora and Pentastomida, all animal phyla, are represented in the marine realm, and many of them are exclusive of the marine environment (14 are exclusive, whereas 14 occur also in freshwater, where none is endemic, and only 11 have terrestrial representatives).

The geographic and oceanographic peculiarities that converge in the Spanish coasts favour a very rich marine biodiversity. Knowledge of marine biodiversity in Spain has increased enormously in the past 25 years, and many systematic inventories have been developed. Due to this effort, up to day about 10,300 species of macroscopic organisms have been recorded in the Spanish marine realm (around 1,050 species of macrophytes and near 9,250 of metazoans), about 4.6% of all known marine species globally. The numbers of known marine species of the different groups of macrophytes and metazoans are given, globally, in European coasts and seas, in Mediterranean, in Spanish marine waters (including the Canary Islands), and in the Canary Islands. The Strait of Gibraltar and some neighbouring areas of the Alboran Sea show the highest species richness of the European seas.

Finally, it is pointed out the alarming decline of morphological taxonomy in recent years in Spain in comparison with other disciplines, such as molecular systematics or ecology, which receive better reviews due to the current evaluation criteria used for research activities.