Abstract

MAZA-VILLALOBOS, Susana et al. Structural and composition variation of tree and shrub communities among vegetation types in the Cuitzeo Basin, Michoacán, Mexico. Bot. sci [online]. 2014, vol.92, n.2, pp.243-258. ISSN 2007-4476.

This work analyzed the structural variation of tree and shrub communities present in different vegetation types (subtropical scrub, oak forest, mixed forest, pine and fir forest) across altitudinal gradients and soil depth at the Cuitzeo Basin, Michoacán. The basin covers 4,000 km² and altitudinal range of 1,700 to 3,420 m a.s.l. In the entire basin we sampled 50 sites 1,000 m² each, recording a total of 4,941 plants with a diameter at breast height ≥ 1 cm, representing 164 species, 88 genera and 47 families. Families with more species were Asteraceae (30, 18.4% of total species) and Fagaceae (16, 9.8%). Above 2,500 m a.s.l. were found pine, fir and mixed (pine-oak) forests; below 2,300 m a.s.l. were found the oak forest and subtropical scrub. Plant density was similar among vegetation types but different indicators of community biomass increased with altitude and soil depth. The subtropical scrub and mixed forest were the most diverse in species and coniferous forest the less diverse. There was a high turnover of species within and among vegetation types (index of Bray-Curtis similarity, range: 5.4-25.4%). The vegetation composition varied significantly associated with altitude and soil depth. We offer some guidelines for the conservation of the important vegetation complex present in the Cuitzeo Basin.

Keywords : alfa and beta diversity; altitude-vegetation relationship; environmental gradients; hydrological watershed; soil-vegetation relationship.