DISTRIBUCIÓN Y ASPECTOS ECOLÓGICOS DEL GÉNERO QUERCUS (FAGACEAE), EN EL ESTADO DE COAHUILA, MÉXICO

Abstract

The oak flora of the state of Coahuila is
composed by 31 taxa, from which 20 species,
including three varieties, are white oaks
(section Quercus) and 10 species are red oaks
(section Lobatae). The oak species more
widely distributed are Quercus pringlei, Q.
intricata, Q. laceyi, Q. invaginata and Q.
gravesii. The endemism concept is applied to
indigenous species with distribution limited
to the state including areas of bordering states.
The endemic species are Quercus
carmenensis, Q. coahuilensis, Q. gravesii, Q.
hintoniorum, Q. invaginata and Q.
saltillensis. The highest diversity is found in
the oak forest followed by the pine-oak forest
and lastly by the submontane shrubland. In
general terms, most of the species are
distributed in an altitudinal range of 1,500-
2,700 m.
The white oaks grow in mountain slopes, hills
of semiarid areas and borders of streams in
forest canyons. The red oaks prefer humid
areas, frequently at the bottom of canyons and
slopes of temperate-subhumid forests.
Most of the species were found in the northwest mountains and the southeastern portions
of the state, from which Sierra del Carmen is
the mountain with the richest oak flora (16
species). The state of Coahuila has species
from the Sierra Madre Oriental in the southeastern and from the U.S.A. and Sierra Madre
Occidental in the northwestern portions.
The sites with oaks were analyzed through
the similarity coefficient of Jaccard. The
mountains from the central part of the state
are more related with the northwestern mountains. The Planicie Costera del Golfo showed
the lowest levels of similarity, with limited
relation with the other groups of mountains.
The species distribution of patterns are discussed