|
Boletín de la Sociedad Geológica Mexicana
http://dx.doi.org/10.18268/BSGM2003v56n1a3 |
 |
Análisis integral de la toposecuencia y su influencia en la distribución de la vegetación y la degradación del suelo en la Subcuenca de Zapotitlán Salinas, Puebla.
Francisco López-Galindo*, Daniel Muñoz-Iniestra, Mayra Hernández-Moreno, Alfonso Soler-Aburto, María del Carmen Castillo-López, Ismael Hernández-Arzate
Laboratorio de Edafología, Unidad de Biología, Tecnología y Prototipos (UBIPRO), Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México Av. de los Barrios #1, Los Reyes Iztacala, 54090, Tlalnepantla, México.
* This email address is being protected from spambots. You need JavaScript enabled to view it.
Abstract
In the present work we evaluate the effect of parent material and of geomorphological, soil and climatic parameters on the establishment of plant communities and on soil degradation along a toposequence. The study was carried out in the Zapotitlán Salinas subbasin in order to provide basic information for the design of strategies for the conservation and restoration of deteriorated natural systems in the area. Within the 270 km2 of the subbasin, a 28 km long transect line was defined, which includes the highest heterogeneity of geoforms, lithology, soils, and vegetation. The preliminary prospection was done by aerial photographs and TM satellite images interpretation. On the field, physiographic and soil surveys were carried out, soil samples were collected in 60 sites, and vegetation types and degree of soil degradation were determined. Analysis and taxonomic classification of soils were carried out. The floristic inventories were complemented with literature reviews and the revision of the herbarium plant collection. A database was produced for a multivariate similarity analysis; and cartography of superficial lithology, land systems and soil degradation, scale 1:20,000, was edited with a Geographic Information System. The results demonstrate a toposequence with seven land systems and 13 land facets. The gradient shows temperature variations from 15 to 25 °C and annual precipitation from 370 to 610 mm. A catena was distinguished with Leptosols, Phaeozems, Regosols and Fluvisols. Their morphogenesis is determined by subsoil type, slope conditions and precipitation levels; most of these soils are not suited for agriculture. A total of ten plant associations were recognized: Palm Groves, Rosette Scrub Forest, two types of Izotal, two types of Thorn Scrub Forest (“Tetechera” and “Garambullal”), Mesquital forest, Thorn Dry Tropical Forest, Tropical Deciduous Forest, and Mediterranean type vegetation. The similarity analysis shows some vegetation types whose distribution depends on altitude, relief and slope; others depend on precipitation, soil type, and lithology. From 270 km2 surveyed, 42.8% are stable lands with minimal degradation and little degraded natural vegetation; 86.52 km2 are affected by hydric and eolic erosion at moderate to severe levels. Physical degradation is affecting 17.80 km2, chemical degradation affects 5.10 km2, and extreme degradation is found on 10.17 km2, corresponding with formation of Bad Lands. We conclude that the geomorphological, geological and pedologic heterogeneity influenced the formation of particular land facets and the establishment of specific biological forms. The integrated toposequence analysis provided basic information concerning the environmental and biotic conditions of the zone.
Keywords: toposequence, land degradation, Zapotitlan, alluvial terraces, Bad Lands, vegetation.
