FILMED campaigns go on sampling around the Mediterranean bassin (and more)

Mediterranean maquis mostly compound by Pistacia lentiscus L. on the hills of Lixus, the cellebrated archaeological site near Larache (N Morocco) © E. Laguna 2007

During the last 2-3 months the research team of the project has harvested most than 50% of the expected samples of the 8 FILMED’s species (Arbutus unedo, Celtis australis, Myrtus communis, Nerium oleander, Pistacia lentiscus, Quercus coccifera, Rhamnus alaternus and Rosmarinus officinalis); the sampling targets for leaves (to develop the philogeographical research) are practically finished for the Western Mediterranean area, but they will continue the next months for the Eastern side and along Northern Africa. In addition some samples of relictic populations under non-strictely Mediterranean climates are made, i.e. for Nerium oleander in central and Southern Morocco (Saharo-Sindic region, under Saharian climate), or Arbutus unedo in Galicia.

Arbutus unedo L. in the relict Mediterranean forest, bordering the river Lor, near Folgoso do Caurel (Galicia, Spain). The forest dominant species are Quercus pyrenaica, Q. robur and Castanea sativa © E. Laguna 2007

In the case of A. unedo, the leaves were picked up from a population of the Caurel Mountains (provinces of Lugo and Ourense, Galician plateau), guided by Dr. Luis Guitián (University of Santiago), who kindly explained Dr. Emilio Laguna the impressive value of the relictic Mediterranean vegetation in NW Spain, living under atlantic climate. There, A. unedo mainly lives as a co-dominant species in the medium-tall tree layer, of the Quercus pyrenaica forests, sharing this plant community with other Mediterranean species like Ruscus aculeatus, Tamus communis, etc.

Dr. Luis Guitián, professor of the University of Santiago de Compostela, giving a field lesson on the importance of the Mediterranean relict vegetation in Galicia © E. Laguna 2007

Currently the difficulties are higher to sample Celtis australis, due that this tree has very few populations in wild, and most of them are submitted to frequent disturbation. For instance, one of the populations to be sampled -some dozens of specimens living as rupicoous plants on the rocky walls of the cellebrated roman bridge in Córdoba, Andalusia-, has been destroyed during 2007 as a result of the restoration works to conserve this monument.

The cellebrated Roman Bridge of Cordoba (Andalusia, Spain), which housed a rock-dwelling population of Celtis australis, foreseen to be sampled in 2007. This population has been removed as a result of the conservation works of this monument. © E. Laguna 2007

Is Celtis australis a native tree to the Mediterranean area?

Leaves of Celtis australis L., near Navajas (Castellón, Spain) © E. Laguna, 2007

Celtis australis –the European Hackberry- was choosen as one of the 8 species representative of the Mediterranean bassin eco-region, in order to develop the project FILMED. The election was made after the evidence of its distribution area, extended by all the areas with typical Mediterranean climate, mainly by the Western and Northern sides of the Mediterranean bassin.

Riverine forests of Celtis australis L. near Navajas (Castellón, Spain) © E. Laguna, 2007

However, after consultation with several expertises from other Mediterranean countries, we noticed that C. australis could be an archaeophyte introduced in Central and Western Mediterranean from the Himalayan mountains and the Irano-Turanian area in ancient times, in order to obtain their benefits (wood, fruits). C. australis is still used around the Mediteranean sea as the main provider of wood and branches to make agricultural tools. The hypothesis of a primitive introduction from Eastern territories can be tested by the FILMED protocoles, if seeds or plant material from the possible origin areas is received.

Is Celtis australis suffering graphiosis attacks?

In a recent excursion to the river Zarra (Western side of the province of Valencia), Drs. Rafael Currás and Emilio Laguna saw ill specimens of Celtis australis L., whose external aspect reminded the efects of the Graphiosis disease, caused by Ceratocystis ulmi on most species of the genus Ulmus -Elm Tree-. In the next months, the collaboration of several specialists will be requested to test the hypothesis of the Ceratocystis’ attacks, samplimg branches and leaves of the affected population.

Mixed forests of Populus sp. pl. and Celtis australis L., on the terraces bordering the river Zarra (Valencia, Spain) © E. Laguna 2007

The graphiosis have destroyed most part of the European populations of native species of Ulmus, and particularly on the best adapted species to Mediterranean conditions like Ulmus minor. Its extension to other species of Ulmaceae can signify a serious problem in terms of conservation, due that some species are threatened endemic plants (i.e. Zelkova sicula, endemic to Sicily). In the case of Celtis australis, the disease could put in peril the traditional handcrafting activity made with the branches of this species in several parts of the Mediterranean area, and its associated cultural landscapes.