Excursion guide. Outline vegetation of Tenerife Island (Canary Islands)

Résumé

This paper has been structured in four different parts which have been well illustrated with several maps and drawings. It has been arranged as a geobotanical guide of the postsymposium excursion programmed for the "36th International Symposium of IAVS". It contains: 1. Fisical environment. First, an introduction give a general view of the situation, extension, relief, hydrography, climatology, history, colonization, island enviromnent transformation, and natural areas of the island. The section of geology makes clear the volcanic character of the territory, the age of the island (Maximum about 7 x 106 years), and its litological diversity. In the section of soils, following the FAO classification, the different kinds of vegetation and soils are correlated, and a map of soils is made. In the bioclimate section, according to the new bioclimatic classification of the earth (Rivas-Martínez 1993, inéd.), the different bioclimatic belts from the island are given. They have arisen from the application of the formula: bioclimatic belt = zonobioclimate+ thermotype+ ombric type. We have recognized in the island the mesophytic mediterranean, xerophytic mediterranean, and desertic mediterranean zonobioclimates; the inframediterranean, thermomediterranean, mesomediterranean, supramediterranean, and oromediterranean thermotypes; and the arid, semiarid, dry, subhumid, and humid ombric types. All of them are quantified with their respectives bioclimatic indices. In order to have a better comprehension of this bioclimatic classification the different bioclimatic indices are defined. According to the data from 14 ombric-thermics meteorological stations of Tenerife we have made two tables correlating their bioclimatic indices with bioclimatic belt and climatophilous vegetation series. In the section " biogeographical approach", a typological scheme from Western Europe, Northwestern Africa and the Macaronesian or Atlantic Archipelagos is proposed. 2. Natural potencial vegetation: vegetation series. This second part shows the climatophilous vegetation series, edaphophilous vegetation series, and vegetation macroseries from the island. They are accompanied with a diagnostic phrase 3. Itinerary: localities and vegetation cards. The excursions program between April 18 and April 22 is showed. Each locality to visit is accompanied by vegetation cards where the region, locality, altitude, date, bioclimatic belt, climatophilous vegetation series, and communities present are showed. 38 cards have been made with their corresponding drawings. 4. Catalogue of the plant communities of Tenerife: syntaxonomy. We have include this catalogue in order to make easy looking for the name of the communities and their syntaxonomical attachment. It brings together the plant communities known from the island which are studied in detail in the next paper of this Itinera.