Autoecology and potencial distribution of holm oak (Quercus ilex subsp. ballota (Desf.) Samp.) in North Monegros

Abstract

Rodríguez-Ochoa, R., Olarieta, J.R., Chocarro, C., Martínez, V., Bilbao, I.  2014. Autoecology and potencial distribution of holm oak (Quercus ilex subsp. ballota (Desf.) Samp.) in North Monegros. Ecosistemas 23(2): 108-115. Doi.: 10.7818/ECOS.2014.23-2.14

In order to understand the ecology and potential distribution of holm oak (Quercus ilex subsp. Ballota (Desf.) Samp.) in North Monegros we mapped the present distribution of this and associated species. We also studied 37 plots in which Q. ilex is present analyzing the relations between the characteristics of the stands and the plant species recorded and the biophysical variables. On the basis of the soil map of the area, the potential distribution of holm oak in North Monegros was defined as that occupied by soils similar to those described in plots with actual presence of this species. The areas where it may be excluded were defined as those with saline-sodic soils, with eroded soils on lutites, or river banks. Mean annual rainfall was estimated at 400 - 500 mm, mean annual temperature at 12.9 - 16.8 ºC, with an accumulated mean annual moisture deficit of 364 - 741 mm. The most frequent soil taxa described were Lithic-xeric Torriorthents (31 %) and Calcic Petrocalcids (11 %). Soils were well-drained, non-saline, had a sand concentration higher than 30 %, and a rootable depth of 8-70 cm. The Q. ilex stands had a basal area of 1.1 - 27.6 m².ha^-1, a mean diameter of 3.9 - 27.7 cm, and a dominant height of 3.0 - 10.7 m, and regeneration of this species was present in 81 % of the plots. The Q. ilex potential distribution map shows that over 60 % of the study area may be a suitable habitat for this species.