Defining phytoclimatic units in Galicia, Spain, by means of multivariate methods

Abstract

Abstract. Floristic and climate data from 150 plots in 25 sites in Galicia, Spain, were analysed to test the hypothesis that climate is the major factor governing the distribution of woody plant species. TWINSPAN classification, Detrended Correspondence Analysis and Canonical Correspondence Analysis were applied in successive stages of the data analysis to describe vegetational variation in relation to climatic gradients. Six groups of species were defined, two clearly oceanic (Maritime and Cool Maritime), one mediterranean maritime, and three mediterranean (Cold Mediterranean, Cool Mediterranean and Temperate Mediterranean). An aridity gradient was revealed as the primary factor regulating the distribution of the species considered. This main gradient reflects the transition between the Eurosiberian and Mediterranean bio‐geographic regions. The gradient can be characterized by means of the Vernet bioclimatic index. A value ≥ 4 for this index can be taken to define the mediterranean zone in our study area. The mean minimum temperature in the coldest month was the second most influential climatic variable. Partial ordination analysis revealed that the residual variation was insignificant and that the observed variation in vegetation can be fully accounted for by climatic variables.

Upland vegetation in the north-west Iberian peninsula after the last glaciation: Forest history and deforestation dynamics

“…The western slopes are directly exposed to humid oceanic winds which give rise to annual precipitation of over 1400 mm (Rivas-Martinez et al 1987;Retuerto and Carballeira 1991). However, on the eastern slopes there is less rainfall and greater potential evapotranspiration, so that the atmosphere is more xeric and soils are drier.…”

Multivariate analysis of the vegetation of the volcanoes Tláloc and Pelado, Mexico

“…2 and 3 may be a temperature gradient, changing from cool in the lower part of the diagram to mild or even warm in the upper part. Retuerto & Carballeira (1991) suggested a similar temperature gradient related to elevation. In the present study, no climatic data were available to document the existence of this temperature gradient.…”

Pedunculate oak (Quercus robur L.) silviculture in natural stands of NW Spain: Environmental conditioners

“…The variability in this parameter is due to the high thermal range, accentuated by the variation in altitude among stands (Retuerto and Carballeira, 1991). The high values of both total annual and summer precipitation are indicative of the moisture requirements of Q. robur (Timbal and Aussenac, 1996;Guchu et al, 2006).…”