Structure and diversity of the tree vegetation of a gallery forest in Puebla State

Abstract

The gallery forests occupy transversal strips along the fluvial currents, with a particular ecosystemic structure and function. An example of them is located on the banks of the Xaltatempa river, in Puebla, which was analyzed the variables of the tree vegetation and its relationship with water quality. Six sampling units of 1 000 m², separated from each other by 2 km, were established, in which all trees and shrubs with DBH≥1 cm were measured and identified; with this, their forest value index (FVI), importance value index (IVI), Shannon-Weaver heterogeneity index (H ') and Sørensen similarity index (SSI) were calculated; In addition, water samples were taken from the river to determine its main chemical characteristics. The results indicate statistical difference between sites (α≤0.05), in which the most important species by diameter, height and coverage was Platanus mexicana (FVI = 300.00), as by its dominance, density and frequency (IVI = 182.71). The species richness (H '= 0.54) was concentrated in only six species: Alnus acuminata, Ligustrum lucidum, Parathesis serrulata, Pinus patula, Platanus mexicana and Quercus rugosa; as for the SSI, the paired combination of sites 4 (1 586 masl) and 5 (1 536 masl), coincided with Alnus acuminata, Ligustrum lucidum and Platanus mexicana (SSI = 1.00). The structure (fragmented) and diversity (very low) of the tree vegetation of the gallery forest make evident an anthropic effect, without having changes in the water quality of the Xaltatempa River.