TREES AND SHRUBS DISTRIBUTION AND ABUNDANCE IN SIERRA FRIA, AGUASCALIENTES, MEXICO

Abstract

Our objectives were to recognize the composition of forest species, characterize their
distribution and abundance, and identify
the factors that determine their presence or
absence in the area of Sierra Fria, Aguascalientes, Mexico. A sampling plan was elaborated using three criteria: altitude, relief and
forest cover. Sixty samplings were realized
in sites of 600 m2 and randomized in different solar expositions. The arboreal and
brush species, the frequency, and ecological
conditions that determine their presence or
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Núm. 34: 99-126 Agosto 2012
absence in site were identified. A Canonical
Correspondence Analysis and Montecarlo’s
test (α≤0.05) was conducted. We identified
50 species; three are new reports in the area.
Quercus potosina was found and Juniperus
deppeana is more widely distributed; the
most abundant are J. deppeana, Q. potosina,
and Pinus leiophylla. The greater ß diversity
is in convex sites (ßw= 5.80) and sites with
altitudes of 2400 and 2600 m (ßw = 7.22).
The altitude, relief, the slope and solar exposition are variables more implicated in the
distribution and abundance of the species
(Montecarlo’s test, p = 0.0020). For this
reason, the interventions of handling must
consider the relation species-environment