Bioclimatology and climatophilous vegetation of Hierro (part 2) and La Palma (Canary Islands)
Del-Arco, Marcelino; Acebes, Juan-Ramón; Pérez-de-Paz, Pedro-Luis; Marrero, María del Carmen
Some refinements of our previous paper "Bioclimatology and climatophilous vegetation of the Island of Hierro (Canary Islands)" (Del-Arco et al. 1996), have been performed. Additionally, bioclimatic belts and climatophilous vegetation series are established for La Palma. The criteria of Rivas-Martínez (1995, 1997) were followed to characterize bioclimatic belts from indices obtained from standard meteorological data. However, the presence or absence of trade-wind cloud formations was used as differential criterion. This complex factor implicitly assumes that areas under the influence of clouds receive additional water due to "horizontal precipitation" in addition to the annual rainfall, and have a lower evapotranspiration rate, facts not taken into account in the bioclimatic indices used. The following new criteria were used to delimit the areas of climatophilous series: a) Considering the change between lower-dry and upper-dry ombrotypes of the pluviseasonal Thermomediterranean belt as delimiting between juniper and pine climatophilous series. b) Extending the potential area of evergreen laurel forest, within pluviseasonal territories under the influence of clouds, from dry Inframediterranean to the beginning of upperhumid Mesomediterranean belts. Additionally, phytosociological tables are shown for the terminal communities of the climatophilous series for La Palma.